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ELJ‘QE I 3‘ 11.51 .1 .1" ‘. 1 1-. 1 . 1. 1 ‘ ‘L ‘1 ‘1‘?" "‘1. { “mm ‘3‘?” "'11: f .r ‘1 «2.1 '. 1. " ' -1 1 ..'\ 1 1 . , . 1. .. -- 1 .' .1 ., ' 1“" ”1?"? “‘11-? > 1.1-. - '1 1.111117% 1- """"1- .. ': 1 111111.111. ' 1” "1’11. ' = l.‘ 1' ~. : - . “1,1..- 1 ..-s1::3.- "-1 . . ; .1114”, :1: a; ‘1 @131?” . 1 . ' '7 ’ .i: .. " 1 ‘ ‘ ' ’ - 1 .: ._ . ", 11:. 1‘11“ 1+ LIBRARY Michigan State University This is to certify that the thesis entitled A WATER MANAGEMENT MODEL FOR PREDICTING THE EFFECTS OF A DRAINAGE AND SUBIRRIGATION SYSTEM ON CORN YIELDS presented by Philip Nathan Brink has been accepted towards fulfillment of the requirements for M. S . degree in Ag}? . Eng]: . I / 2/”. #1 we“ 0-7639 MS U is an Affirmative Action/Equal Opportunity Institution MSU LIBRARIES a RETURNING MATERIALS: Place in book drop to remove this checkout from your record. FINES will be charged if book is returned after the date stamped below. WM? 2, h 4 1MP? 6 'E: 3993 APR 2'? “7‘7? . FT; Vt A WATER MANAGEMENT MODEL FOR PREDICTING THE EFFECTS OF A DRAINAGE AND SUBIRRIGATION SYSTEM ON CORN YIELDS By Philip Nathan Brink A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Agricultural Engineering 1985 ABSTRACT A WATER MANAGEMENT MODEL FOR PREDICTING THE EFFECTS OF A DRAINAGE AND SUBIRRIGATION SYSTEM ON CORN YIELDS by Philip Nathan Brink An improved water management and crop growth model was sought by combining two existing computer models, a water management model, DRAINMOD, by Dr. Wayne Skaggs and a crop growth model, CERES, by Dr. Joe Ritchie. By having DRAINMOD evaluate the water balance and CERES calculate the crop growth, a model was obtained that capitalizes on the strengths of the component models. A procedure was developed to convert the soil water regime status calculated by DRAINMOD into soil water content by layers as required by CERES each day. CERES calculated crop growth and the crop's water use was transferred back to DRAINMOD for the next day's water balance. Operation and behavior of the synthesized model was investigated by performing a 16 year simulation for a site in Michigan. Results show that the root zone depth responds realistically to soil water conditions existing in drainage. The root growth potential function was modified to account for wet stress. Crop stress factors that affect root water uptake, photosynthesis, and cell expansion require further modification as their relationships to wet stress are more clearly defined. Approved: // 9%? P) / ' . Approved: @afifiéfl/rr/XJ/ Department Chairman A WATER MANAGEMENT MODEL FOR PREDICTING THE EFFECTS OF A DRAINAGE AND SUBIRRIGATION SYSTEM ON CORN YIELDS Thesis for the Degree of M.S. MICHIGAN STATE UNIVERSITY PHILIP NATHAN BRINK 1985 ACKNOWLEDGMENTS I am deeply indebted to Dr. George Merva who was my guidance committee chairman for the encouragement and help he gave me in the course of my studies and research. His dedication to the soil and water area and professionalism have set great examples for me. I have 'much respect for him. I am also grateful for the help and guidance offered by the others on my committee, Dr. Ted Louden, Dr. Ray Kunze, and Dr. Joe Ritchie. The Institute of Water Resource and the North Central Computer Institute (NCCI) deserve mention for the financial support they gave. The biannual meeting sponsored by NCCI for the DRAINMOD documentation was especially helpful in keeping me abreast of new DRAINMOD developments, and it was really good to meet and have the support of all those who came to the meetings. Finally, special thanks to my colleagues, especially Cindy Phelps, and my family for moral support and encouragement given over the course of my studies and work. T A B L E O F C O N T E N T S 1. Introduction............................ ......... ...............1 2. Literature Review..... ...... ............... .............. .......u a. Drainage and subirrigation modeling ..... .......... ..........A b. Crop response modeling..... ....... ...... .................. ..16 1. Crop response to excessive soil water conditions.....17 ii. Crop response to deficient soil water conditions.....20 iii. Crop response to delayed planting date...............22 iv. Overall Crop Response Model........... ........ .......23 0. Crop Growth Modeling.................... ...... . ..... ........2A 3. Procedure... ..... ..............................................32 4. Results and Discussion...................... ................ ...u1 5. Conclusions ................. ............ ......... . ....... ......52 6. Recommendations. ..................... . ......... ................54 A P P E N D I C E S A. Michigan Site Simulation......... ...... .. ...................... 56 a. Soil Survey Results for Tappan Loam .................. .......56 b. Input data for DRAINMOD.... ........... ...... ..... ...........58 c. Input data for CERES............................. .......... .59 1. Soil data .......... .. .............. ..................59 ii. Corn genetics information........... ..... ............60 d. Abbreviated List of Synthesized Model Output... .......... ...60 B. Source Code of Synthesized Model............... ...... ..........62 C. List of References Cited .................................. ....126 D. Index of Authors .................. ........ .......... . ......... 130 iii L I S T O F F I G U R E 3 Schematic of water management system ..........................6 . Schematic of the change in ET.................................11 Soil water distribution and dry zone..........................13 Soil water distribution for a water table depth ..............14 : Relationships for corn root distribution......................15 Stress day index and yield....................................21 Soil Conservation Service curve numbers.......................28 Maximum root water absorption.................................30 : Root growth potential ..... 36 . Surface soil water content and evaporation....................39 An Abbreviated Flow Chart of the Synthesized Models...........40 Soil water distribution... ..... ...............................44 Soil evaporation............................... ..... ..........A6 Root zone depth shown to be responsive to soil water..........u7 Comparison of yields..........................................A9 1. Introduction In humid regions where organic soils require drainage during wet springs and irrigation during dry summers, interest in subirrigation has greatly increased in the last few years. Because a subirrigation system can meet both drainage and irrigation needs, it has an obvious economic edge over separate irrigation and drainage systems, requiring an investment in only one system (Worm, et a1. 1982). In addition, because the water pressure needed for subirrigation is lower than those used for sprinkler irrigation systems, power requirements are less, resulting in operational energy savings. Though not appropriate everywhere, places that require drainage due to excess water often have an impermeable layer on which a water table can be perched for crop use. Follett et al. (1974) found maximum yields in plots where the water table was 0.60 to 0.90 m below the surface. Surface irrigation of the crops over the shallow water table resulted in no increase in yield. Using drainage systems for applying water to the root zone is not a new idea, it has been in limited use for some time. Doty (1979) in his review of such systems said that French scientists, Bordas and Mathieu in 1931 reported higher yields from a controlled water table than from other irrigation systems, and Morris (1949), after considering some practical aspects of controlled subsurface drainage, concluded that in the future all artificial drainage may be controlled drainage. General adoption of this technology, however, has been quite slow despite its touted advantages. One reason for slow acceptance may be the complexity of designing and managing such a system. Better information about the response of a system and crops to various external factors and practices is needed. While a shallow water table can provide water in the root zone for the crop use, a heavy rain may inundate the field long enough to harm plants and reduce yield. Successful management requires a high level of skill and knowledge of the complex interactions of plant, soil, water, and climatic conditions. Accounting for these variations and uncertainties has made it difficult to design an efficient water management system and manage it properly. Until 1940 the depth and spacing of drains in the United States were determined through empirical field observations (Ward 1972). Advances in flow theory lead to mathematical descriptions of water movement, giving rise to numerous methods to determine water table drawdown. The dynamic nature of the interaction between the moisture regime and plant system, however, involves more complicated mathematical relationships. During the last 20 years rapid progress has been made in the simulation of agricultural processes. Models are now available to simulate discrete processes such as weather, water balance and movement in the soil, nutrient cycling and movement, tillage, erosion, soil temperature, and crop growth and development. Many of these models are quite restricted in purpose, others integrate several processes such as weather, hydrology, tillage and crop growth and predict their interacting effects on crop growth and yield. The objective of this study was to use and modify existing computer models* to obtain an improved prediction of corn yields as a function of subirrigation water management system designs and practices. *NOTE: ASAE standard of units have been used as much as possible, however, description of how certain models operated entailed the use of nonstandard units at times, most notably the length dimension of the centimeter (cm). 2. Literature Review a. Drainage and subirrigation modeling Modeling a soil water regime that includes a drainage system requires characterization of ground water flow. Many drainage models are available, ranging in complexity from the simple, steady state Hooghoudt model (1940), which deals only with saturated flow, to the complex numerical solution of the two-dimensional Richard equation for the analysis of combined saturated-unsaturated flow. Skaggs and Tang (1975) compared solutions of the Richard equation for drainage and subirrigation conditions to approximate drain spacing methods. While the numerical methods are more precise, he found the approximate methods to be as acceptable when the difficulty of determining field effective values of the soil properties was considered. Input and computational requirements of numerical methods also tend to prohibit their use for a field scale model. Most models use approximate methods that are based on the Dupuit- Forchheimer (D-F) assumptions and ignore the water in the unsaturated zone (e.g. Kirkham, 1958, van Schilfgaarde 1963, Bouwer and van Schilfgaarde, 1963, Moody, 1966). The D-F assumptions state that, under the influence of gravity alone, all flow to the drain is horizontal and the velocity at each point is proportional to the slope of the water table but independent of the depth (Forchheimer, 1930, as used by Hillel, 1982). In addition, these models assume a homogeneous soil with a constant hydraulic conductivity and a constant drainage flux (a steady-state condition). Using these assumptions, Hooghoudt (1937, as used by Hillel, 1982) obtained an equation for the elliptical shape of the water table between the drains (Figure 1) L2 = (4Km/q)(2d + m) (1) where L is the distance between the drains, K is the saturated hydraulic conductivity, m is the midpoint water table height above the drain, q is the flux in cm3/cm2/hr and d is the height of the drains above the impermeable layer. This equation has been widely used to determine the spacing and depth of drains necessary to maintain the water table at a certain level for a given flux, q. Bouwer and van Schilfgaarde (1963) modified Hooghoudt's steady state equation by using a factor C to express the proportionality between the rate of fall of the water table between the drains and the flow rate into the tile line. This resulted in an equation which, when applied in finite time steps, could described transient-flow drainage. Van Schilfgaarde (1965), using their analysis, was able to developed a model to predict the water table depth as a function of precipitation. He accounted for evapotranspiration and soil moisture storage but ignored surface runoff. Skaggs (1980) used their equation in a computer model, DRAINMOD, to estimate drainage flux in the following form: 89 woimmm ammo mm><4 m>.._.u_mkmmm \uxxn‘xxk: 2.2.x\wxxmxxath:xxtxwxzxxaxzxxuxp n _ .. 11111_ \ A \ 65 muozamflu m. ”.0qu5 zofiflmamo _::::.::::::: kw mo 44.32.41 Schematic of water management system Figure 1. 8K d + 4K m2 q = --_§-E _____ E--- (2) where q, m and L are as defined before, Ke is the equivalent saturated lateral hydraulic conductivity and de is the equivalent depth from the drains to the impermeable layer. The constant C, though it can be varied depending on the water table elevation, is assumed to-be unity. The equivalent depth, de corrects error in the drainage fluxes caused by applying the D-F assumptions at the drains where convergence occurs. The equivalent saturated hydraulic conductivity corrects the assumption of a homogeneous soil. Prior to every flux calculation, DRAINMOD calculates the equivalent conductivity by using a weighted average of the values of K for the layers that are saturated. This enables simulation of layered soils where each layer has a different K value. A modified form of Equation 2 is also used to predict subirrigation flux. DRAINMOD accounts not only for drainage and subirrigation flux, but all the components of the water balance equation. It is a computer simulation model that characterizes the response of the soil water regime to various combinations of surface and subsurface water management. It predicts the response of the water table and the soil water above the water table to rainfall, evapotranspiration, given degrees of surface and subsurface drainage, and the use of watertable control or subirrigation practices. A water management system is simulated over a long period of time using climatological data to evaluate its performance allowing an optimum water management system to be designed on a probabilistic basis as van Schilfgaarde (1965) proposed. DRAINMOD has been widely accepted, used by the $08 and others for the design of subirrigation systems. It is reviewed in some detail here. The model is based on the water balance for a thin vertical slice of a soil profile from the surface to the impermeable layer midway between the drain tiles as AV:D+ET+DS-F (3) a where Ava is the change in air volume in the soil profile, D is the drainage, ET is the evapotranspiration, DS is the deep seepage and F is the infiltration, all for a time increment At. The amount of runoff and surface storage is computed from a water balance at the soil surface for each time increment which may be written as P : F + AS + R0 (4) where P is the precipitation, F is the infiltration, AS is the change in volume of water stored on the surface, and R0 is the runoff during time At. The model includes methods to independently evaluate infiltration, subsurface drainage, surface drainage, potential and actual evapotranspiration, subirrigation and the soil water distribution in terms of the water table elevation, soil water content, soil properties, site and drainage system parameters, crop type and stage of growth, and atmospheric conditions. In order to simplify the required inputs and to allow use of available data, approximate methods are used for each component. Precipitation is one of the major inputs to DRAINMOD. The accuracy of the model's prediction for infiltration, runoff and surface storage is dependent on the complete description of rainfall intensity, duration and time distribution. The shorter the time increment for the rainfall input data, the better the estimates of these components will be. A basic time increment of one hour is used in the model because of the availability of hourly rainfall data for many locations in the U.S. The infiltration component is important in predicting the rate of water flow into the soil, and whether storage of water at the surface and subsequently runoff will occur. The model uses the Green and Ampt's (1911) approximate equation to characterize infiltration as f:A/F+B (5) where f is the infiltration rate, F is the accumulative infiltration and A and B are parameters that depend on soil properties, initial water content, and surface conditions such as cover or crusting. Surface drainage is characterized by the average depth of depression storage that must be satisfied before runoff can begin. In most cases it is assumed that depression storage is evenly distributed over the field. A value for the maximum storage depth is required as input to the model. When the surface storage depth as determined by 10 Equation 4 exceeds this value, the additional excess is allotted to surface runoff. The model assumes that water available for runoff moves immediately from the surface to the outlet. The evapotranspiration component of the model accounts for water loss by evaporation from the soil surface or by transpiration from the plants. Daily potential evapotranspiration (PET) is calculated from recorded daily maximum and minimum temperature values using the empirical methods developed by Thornthwaite (1948) and Thornthwaite and Mather (1957). Adjustments for day length and number of days in the month are made in the model based on latitude and date. After PET is calculated, checks are made to determine if ET is limited by the soil water conditions. When the ET demand can not be satisfied directly from the water table by an upward flux of water to the root zone, water is extracted from the root zone down to a lower limit water content, usually the wilting point. This creates a dry zone at the surface with a maximum depth equal to the rooting depth. If enough water is available, ET is set equal to PET, otherwise ET is set equal to the limiting amount supplied from the soil system (see Figure 2). The relationship between maximum rate of upward flux and water table depth need to be estimated for a soil and entered into the model in tabular form. The relationship is approximate because it is defined for steady state conditions while the actual upward water movement process is transient. Generally, upward flux relationships must be calculated from basic soil properties, using numerical procedures. Knowledge of the soil water distribution in the soil profile is ll ET: PET _____._e£3;___ ____ - . DRY ZONE DEPTH: ROOT ZONE DEPTH )3- v- - h. 5 ‘so P ‘AUX u—" F9047~‘ u _ “17: ~“ 6 ~ TzuprR . ‘3 FLUX 1 TIME Figure 2. Schematic of the change in ET with time for a constant PET as treated in the model. When the dry zone depth reaches the bottom of the root zone ET is assumed to decline to the rate of upward flux. Source: Skaggs (1980) 12 needed to evaluate individual components such as drainage and ET which depend on the position of the water table and the soil water distribution in the unsaturated zone. The water table depth is a key variable that is determined at the end of every water balance calculation. The soil water distribution above the water table is assumed to be in equilibrium with the water table up to the surface or to the bottom of the dry zone if one exists (Figure 3), and independent of the means by which water was removed from the profile, whether by ET or drainage (Figure 4). With this assumption, the air volume is related to the water table depth through the soil water characteristic curve, and, assuming hysteresis can be neglected, the water table depth can then be determined from the volume of water that enters or is removed from the profile over an arbitrary period of time. An effective rooting depth is used in the model to define the zone from which water can be removed as necessary to supply ET demands. The rooting depth also gives the distance from the bottom of the root zone to the water table which is used to determine the upflux available from the water table. Since the simulation process is usually continuous for several years, an effective depth is defined for all periods. When the soil is fallow, the effective depth is defined as the depth of the thin layer that will dry out at the surface. A table of effective rooting depth versus the date is required as input. Generally, the depth above which 60% of the total root length exists is used as shown for corn in Figure 5. This method of treating the rooting depth is an approximation at best as the depth and distribution of plant roots are affected by many factors including l3 “MTER CONTENT G-LL ‘ 9- SAT my 2004: | -----------4 WET ZONE POTENTWAL ET DEPTH INTER TABLE ‘7 m Q Figure 3. Soil water distribution and dry zone when a dry zone is created near the surface. Source: Skaggs (1980) 14 WATER CONTENT (cm3/cm3) 0:0 _ 0.15 0.20 0.25 030 (ll CLZ C13 CL4 DEPTH (m) CLS CLG Of? CLB Figure 4. rlTIllrllllillllllrllrj EVAR'RAJEE THME (mm ldcy) (days) -—- ClC) 8t5 .A CL24I ’8.| a 2.4 5.1 o . 4.8 4.6 WAGRAM LOAMY SAND L.= SCHn b tl.8 0 8C18 meER TABLE AT (DJHn Soil water distribution for a water table depth of .7m for various drainage and evaporation rates. Source: Skaggs (1980) in 15 0.6 - PERCENTAGE OF TOTAL 0.5 r- ROOT LENGTH AWE GIVEN DEPTH E 3‘ 0.4 - 30% g 10% ’_ (lSF ‘ 6093 8 50% c 0.2 - I, O. l - I l I I ” .4.7 L. .L______L______L—_——__J—__. 20 40 DO 80 DO 120 TIME AFTER PLANTING , DAYS Figure 5. Relationships for corn root distribution with time. Source: Mengel and Barber (1974). 16 hardpans and fertilizer distribution, but especially soil water. While the variation of the root zone depth with time may be approximated for some crops from experimental data reported in the literature, the model presently ignores the effect of the depth and fluctuation of the water table on the effective rooting zone. The model can be used to analyze a broad range of drainage, subirrigation, and waste water application problems. DRAINMOD was developed and tested, however, for use in humid regions, and its application is presently limited to these regions. The methods were developed for field-sized units with parallel subsurface drains. Lateral seepage due to a sloping landscape was not considered, which limits application of the model to fields with slopes of less than about 5 percent. Deep seepage is site dependent and is not currently considered. Freezing conditions were not considered in the model, confining its application to periods when the soil is not frozen. The model simulation includes the whole year, so when the model is used where freezing conditions exist for part of the year, the results for that part of the year are generally ignored. b. Crop response modeling Quantifying the effect of drainage or subirrigation on crop yield is of vital importance in optimizing a system design. Steady state and non steady state equations for drainage design are numerous, yet little data on crop drainage requirements exists (Hiler et al. 1971). The water table must be maintained at a depth shallow enough for the crop roots to reach the water, yet deep enough to avoid root 17 zone aeration problems (Benz, 1983). Hedstrom et a1. (1971) states there have been four approaches to the determination of drainage requirements for design purposes: 1. Drainage coefficient, which is the depth of water to be removed in a 24-hour period. 2. Optimum water table depth, which is highly dependent on the type of crop and the type soil as well as other factors. 3. Falling water table, drain depth and spacing which would cause the water table to fall a specified distance within a certain length of time. 4. Fluctuating water table, similar to the falling water table model; used to more effectively represent drainage with rainfall or subirrigation. These four approaches deal either with the removal of a specified volume of water or with the location of the water table. Although the depth of water table has no direct influence on crop growth, it provides an indication of the prevailing soil water conditions, water supply, aeration and thermal properties of the soil (Wesseling, 1974). Shih (1983), for instance, found sweet corn had its best yields when the water table was at 0.60-0.90 m depth. ward (1972) states that one method of incorporating the plant requirements into the design is to relate plant response to the water table depth, but then adds "The results of many studies generally agree upon the ideal water table height, but very little has been established for determining the permitted deviation from the ideal." 1. Crop response to excessive soil water conditions Sieben in 1964 (Wesseling, 1974) introduced a stress factor to 18 evaluate the influence of fluctuating high water tables during the winter on cereal crops. He figured that yield reductions caused by excessive soil water conditions could be related to the integral of elevation and time that the water table remained in the root zone taken to a depth of 30 cm. It is defined as n SEWBO 2 15:1 (30 - yi) CIR-days I (6) where yi is the water table depth on day i, with i = 1 being the .first day and n being the number of days in the growing season. SEW30 is the sum of excess water above a 30 cm datum below the ground surface. For example, if the water table depth is at 28 cm depth for 1 day, then SEW would have a value of 2 cm-day (30 - 28cm x 1 day). Negative terms inside the summation are neglected. Using this technique he found a significant correlation between SEW30 values and yields (Nibler and Brooks, 1975). The SEW30 concept was included in the formulation of DRAINMOD as an objective criterion on which to quantify excessive soil water conditions during the growing season. As the water table depth may vary significantly during the day, SEW3O is calculated in DRAINMOD on an hourly interval to better define the time that the water table remains in the root zone. Although the SEW30 concept has some weaknesses, it still provides a convenient method of approximating the quality of drainage. One problem is knowing what value of SEW3O is a threshold value of an adequate drainage system. Generally it is assumed that drainage is adequate to protect crops from excess water 19 if the SEW30 value totals less than 100 cm-days. Obviously, with crops which are more susceptible to poor drainage, it may be necessary to adjust the critical SEW3O value to fit the crop to be grown. Hiler (1969) refined this idea by incorporating the fact that crops are more susceptible to damage at certain stages of development. He defined a stress day index (SDI) that is determined from a stress day factor and a crop susceptibility factor. The stress day (SD) factor is a measure of the degree of stress caused by excessive soil water conditions. The crop susceptibility (CS) factor is an experimentally determined parameter which reflects variations in susceptibility to stress according to the stage of growth. Its equation form is SDI = (SD1 x 051) (7) H. IIMZ _‘ where N represents the number of growing periods considered and SDi and C51 are the stress day and crop susceptibility factors respectively for period 1. Ravelo (1978) incorporated Hiler's method in DRAINMOD, using the SEW30 as the stress day factor, SD. He determined crop susceptibility factors for four growth stages of grain sorghum from experimental results presented in the literature. He then related the effects of excessive soil water to grain sorghum yield by assuming a linear relationship between SDI and the reduction in yield. Hardjoamidjojo and Skaggs (1982) applied the same approach to characterize the effects of excessive soil water on corn yields from Ohio. Their 20 analysis of the results showed a strong relationship between corn yield and SDI. ii. Crop response to deficient soil water conditions The stress day index method was also used to quantify the effects of deficient soil water during different crop growth stages on yields (Hiler et al., 1974; Shaw, 1978; Sudar et al., 1979). For drought conditions the stress day factor, SDd, was defined by Sudar (1979) as SDd = 1 — AT/PT (8) where AT and PT are the actual and potential transpiration, respectively. Multiplying this by a yield susceptibility factor gives the stress day index for drought stress, SDID, as N SDID = z sodJ x csaJ (9) i=1 where CSdJ is the crop susceptibility factors for growth period j, and N is the number of periods in the growing season. A correlation he found between SDID (labeled water stress index) and observed yield of corn is shown in Figure 6. This method of calculating the SDID for deficient soil water stress was incorporated into DRAINMOD by estimating the AT/PT ratio as ET/PET where ET is actual evapotranspi- ration and PET is potential evapotranspiration (Ravelo, 1978; Skaggs et al., 1982). This estimate was made because DRAINMOD does not 21 100 ~ Y=6364 ~746 X to" R. Sq.=O.77 9 Std. Dev.=59| kg/hc x 7.5 - (3 J: ‘\ .3 5.0 ‘C; 72.3 >' 2.5 C S C) O i I I i L 0 2 4 6 8 10 Water Sire 55 Index Figure 6. Correlation between stress day index for deficient water conditions (SDID, labeled Water Stress Index) and observed yields of corn for Grundy County, Missouri. Source: Sudar (1974) 22 calculate transpiration and evaporation separately. Use of this method is an extension of the dry day count DRAINMOD performs, where a dry day is counted when ET is limited by soil water conditions. iii. Crop response to delayed planting date Crop yields are significantly reduced if the planting date is delayed beyond an optimum period. Another method of quantifying the influence of the water management design and practice in DRAINMOD on crop yields has been determining whether soil conditions cause a planting delay. Inputs to DRAINMOD to calculate this yield reduction include the date to begin seedbed preparation and planting, the number of days needed to complete this task, and the date beyond which yield reduction occurs if the crop is not yet planted. The model determines whether trafficable conditions exist for each day and keeps a running total of suitable working days during the planting period. When enough working days have occurred to complete planting, the model fixes the planting date and determines the length of planting date delay beyond the optimum. The relative yield, YR is estimated from the following p 7 equations: if PDELAY < DELAYI, mp = 100 - PDRF x PDELAY (10a) if PDELAY > DELAYI, YRp : 100 - PDRF x PDELAY - PDRF2 x (PDELAY — DELAY1) (10b) 23 where DELAYI is a breakpoint past which the yields decrease at a faster rate, and PDRF and PDRF2 are the slopes before and after the breakpoint. The values of PDRF, PDRF2 and DELAY1 are inputs that need to be determined for the crop to be modeled. The last day planting can be completed without yields being reduced, JLAST, the required number of working days for seedbed preparation and planting, REQWRK, and the number of days in the growing season, IGROW, are also model inputs. These equations are the general form of a relationship determined -from the results of field tests conducted near Plymouth, N.C. which were presented in an Extension Corn Production Guide by Krenzer and Fike (1977). Similar results have been obtained for Ohio conditions (Nolte, 1976). Use of these data to estimate the effect of delay in planting on yield assumes that the observed effects are due to factors such as temperature and day length and not to deficient or excessive soil water conditions. iv. Overall Crop Response Model The yield version of DRAINMOD was programmed so that the time- varying root depth function and the computation of the stress-day indices are initiated after the required number of working days is satisfied and the planting date established. The stress-day factors are calculated for each day and stored. At the end of the year's simulation, the stress-day factors are multiplied by the appropriate crop susceptibility factors and the stress-day indices determined. 24 The relative yields as affected by excessive soil water conditions, deficient soil water conditions and delay in planting date are determined, and overall relative yields are calculated as a product of the three. A basic assumption in the use of these methods is that the three factors are independent; interactive effects are neglected. This approach was shown to be valid by Hardjoamidjojo and Skaggs (1982) for a Portsmouth sandy loam in Eastern N.C. 0. Crop Growth Modeling Crop yields depend on soil, crop management, and climatological factors and involve complex relationships. The methods discussed above show attempts to correlate crop response to various water management practices and designs by determining a relationship between crop yields and soil water conditions. Determination of this relationship requires statistical analysis of field data such as is shown in Figure 6. While using these methods helps DRAINMOD to optimize a water management system design, DRAINMOD's strength lies in characterizing the soil water regime, not crop growth and development. In contrast, crop growth models focus more on the physiology of the plant and its relationships to the environment, incorporating factors such as C02 availability and photosynthetic rate to predict yields. Such models actually simulate the plant growth. Examples of this modeling genre are the work of Childs et al. (1977) and Duncan et al. (1971). McMahon (1983) in an excellent review of a number of crop models identified two main approaches to modeling crops. The first is a 25 transpiration ratio approach that developed from the work of de Wit (1958). The second is essentially a photosynthetic approach of which the work of Ritchie (1984) is representative. Although a water balance is not the main emphasis of a crop model, simulating actual field situations of crop growth requires knowledge of the soil water regime. Sometimes the water supply is considered non-limiting (e.g. Dayan et al, 1981). Generally the water balance is based on soil water content by layers, not on the water table depth (e.g. White et a1, 1980, Saxton and Bluhm, 1982). Having a soil water content for each layer enables calculating water availability for root uptake in terms of the soil water content or pressure head (e.g. Feddes, 1976). Anderson et a1. (1976), for instance, developed a model to simulate the water balance for deep, well-drained soils where the water table is considered deep enough to prevent having any influence. The soil is divided into layers to a depth of 9 feet. Any water infiltrating into the profile fills each layer to 80% of saturation before being added to the next layer down. Any water that flows below 9 feet is accumulated as deep seepage. Singh and Young (1984) also ignored the presence of a water table in their simulation of the soil water regime. Ignoring the water table prevents the capability of modeling a water management system, which generally requires knowledge of the water table depth to solve for flow to the drains. Belmans et al. (1983) states that very few soil water, root uptake models treat the unsaturated-saturated system as an integrated zone. He developed a transient one-dimensional finite-difference soil water, root uptake model, SWARTE, that applies different types of conditions at the 26 bottom of the system. One bottom boundary condition includes the flux from the saturated zone, thus offering possibility of linking it to a watertable model. The flux can be entered or calculated from a flux- groundwater level relationship or combination of fluxes that include drainage or subirrigation and deep seepage. The pressure head is taken to be in equilibrium with the groundwater level. Water uptake by the roots is prescribed as a function of the soil water pressure head. Roots are considered concentrated to an effective depth which is required as input. One of the more recently developed crop growth model is CERES (Ritchie and Otter, 1984; Jones, 1985). This model was developed by a team of interdisciplinary scientists coordinated by Dr. J. T. Ritchie at the Grassland, Soil and Water Research laboratory of the USDA, ARS. CERES is a comprehensive model of maize growth and development which considers the independent and interacting effects of genotype, weather, hydrology and nitrogen nutrition. CERES is a daily incrementing model and several empiricisms were developed to integrate minute by minute variations in factors like solar radiation, air temperature and rainfall into daily functions. To accurately simulate maize growth, development and yield, CERES considers the following processes: --phenological development, especially as it is affected by genetics and weather; --extension growth of leaves, stems and roots; --biomass accumulation and partitioning, especially as phenological development affects the development and growth of vegetative and reproductive organs; --soil water balance and water use by the crop; 27 --soil nitrogen transformation, uptake by the crop and partitioning among the plant parts. The last item mention is an option available in the nitrogen version of CERES. The version reviewed here is the non-nitrogen version. The model requires daily weather data of rain, minimum and maximum air temperatures, solar radiation and soil information available from standard soil classification data. The model calculates the soil water balance in order to evaluate possible growth stress caused by soil and plant water deficits using the equation S:P+I-EP-ES-R-D (11) where S is the quantity of soil water resulting from the addition of precipitation (P) and irrigation (I), and the subtraction of evaporation from plants (EP) and soils (ES), runoff (R) and drainage from the profile (0). The soil water is distributed as water content in up to 10 layers of variable depth. The water content in any soil layer can change due to soil evaporation, root absorption, or flow to an adjacent layer. The field saturated water content, the field drained upper limit water content and the lower limit of plant water availability are the entered limits among which the water content can vary. CERES uses the curve number procedure of the USDA-Soil Conservation Service (SCS, 1972) to calculate runoff from daily precipitation input. The technique was modified to account for the use of layered soils with the wetness of the soil in the layers near the surface replacing the antecedent rainfall condition, shown in Runoff - cm U 20 15, 10 ’ Figure 7. 28 ’g' ’. CN ' 75 .l . 14) /' IHet I I I I, 4/ 4’ .I l’ , 1' «i I y I I I I IT .I ’ 4' I I ” /’ ’ cu 4o 1' 4’ "," " 1’ .I ./ .I'IE ./ I I ///’ DLy 1' 4' 4’ ,..a’ II” I ’J‘J I 5 10 15 25 30 Rainfall - cm Soil Conservation Service curve number relationship used to calculate runoff from rainfall. The values shown for CN refer to the curve number associated with the solid line and the dashed lines represent the alterations made for a particular curve number when the soil is wet or dry at the time of rainfall. Source: Ritchie (1984) 29 Figure 7. Any precipitation that is not estimated as runoff is considered to infiltrate into the soil. All irrigation water is automatically assumed to infiltrate. CERES calculates water movement in the soil with an empirical relation. Drainage occurs when the water content at any time, Oh, is between the field saturated water content, 00, and a drained upper limit water content, Ou. The drainage rate (D) from a given layer is: D : -Kd(Ot - QJ) Z (12) where Kd is the conductance parameter and z is the thickness of the soil layer. The value of Kd can vary between 0 for no drainage and 1 for instantaneous drainage and represents the fraction of water between 0u and at that drains in one day. The most limiting layer to water flow sets the value of Kd used for the whole profile since that layer dominates the drainage rate in the soil profile. The soil water content for all the layers is updated daily to account for any infiltration, water flow, or root uptake. CERES uses an equilibrium evaporation concept as modified by Priestly and Taylor (1972) to calculate potential evapotranspiration (ET). Then using procedures from an ET model (Ritchie, 1972), soil evaporation (ES) is separated from plant transpiration (EP) primarily using information on the leaf area index (LAI) and wetness of the soil surface. Root length density and distribution in the soil are estimated in CERES and are required for calculating root water absorption. A flow rate of 0.03 cm3/cm root per day was chosen as an approximate maximum UPTAKE RATE 3O MAXIMUM RATE 30.0~ ’/ ’I '32 xx ’1. 10.0 9' :D5 0 1’ 5.0 .g- 0 2 - .....-.._ --...._.. e 2.0 ’ o USUAL RANGE 2 L0 ,_____-__i__---_ ID .s. g 0.5 "e 0.3 (D I I l l I J l 0" 0 2 4I 6 81012 e-°/oVO|. Figure 8. Maximum root water absorption as related to 0' (the water content above the lower limit) and the root length density. Also shown is the assumed maximum possible rate and the usual range of absorption when all the soil profile is at an optimum water content. Source: Ritchie (1984) 31 plant limited flow rate (Figure 8). The calculated maximum possible root absorption rate is not allowed to exceed the plant limited flow rate or the maximum calculated transpiration rate. The absorption model was tested for a maize crop at Temple, Texas, in a study where root length density, transpiration and soil water were measured. The results show that the absorption model provides a reasonable evaluation of the water content distribution during a season. CERES calculates the water balance components using empirical relationships that have been made as general as possible to avoid using regionally fitted parameters. The model was tested with about 300 data sets from several countries to demonstrate its generality for wheat (Ritchie and Otter, 1984). For a few cases where the soil water was measured throughout the season, the model values of the soil water were in reasonable agreement with measured values. When the agreement was poor, lack of root depth and root density data prevented determination of the cause. Because the model was developed for regions where the influence of the water table could be ignored, the CERES water balance model does not account for the presence of a shallow water table or a drainage and subirrigation system. Thus, the model is not well suited for use in areas with these conditions. 3. Procedure The objective of this study was to use and modify existing computer models to improve prediction of corn yields as a function of water management system design and practice. The water management model, DRAINMOD, by Skaggs (1980) was selected for the simulation of a water management system; the non-nitrogen version of the crop growth model, CERES, by Ritchie (Jones, 1984) was selected for the prediction of crop growth and yield. Both models have been tested and proven for the areas of application that they were developed, both in location and in type of modeling--DRAINMOD as a water management model for artificially drained soils in humid regions, CERES as a crop growth model for non artificially drained soils in subrhumid and humid regions. Though both DRAINMOD and CERES have the ability to conduct a water balance and calculate crop yields, it was decided that a merger of the two would capitalize on the strengths of each model, producing a better model with an extended range of application. Both models were modified to transfer information to and from each other, making the simulation integrated. Information on the soil water regime calculated by DRAINMOD was transferred to CERES, while information on crop growth calculated by CERES was transferred to DRAINMOD. When any processes such as infiltration or evaporation were present in both models, the method considered to be superior was 32 33 utilized. Since DRAINMOD keeps track of the water balance via a water table level, and CERES requires knowledge of the water content of the soil layers, a subroutine, HYDRO, was added to convert the soil water status into the soil water content by layers required by CERES. A basic and necessary assumption used in HYDRO is that the soil water above the watertable is in hydrostatic equilibrium with the watertable. When this is true, the pressure head and water content distribution in the wet zone can be determined from the soil water .characteristic curve. For example, the soil water content 0.1 m above the water table corresponds to a -0.1 m pressure head. This assumption is used by DRAINMOD for the rooting zone as mentioned earlier (see Figure 4), and it is generally found to hold for conditions in which the D;F assumptions are valid (Skaggs, 1980). H0wever, HYDRO is needed because DRAINMOD does not calculate the water content of the soil above the water table directly. HYDRO determines the water content for each 0.01 m increment above the water table. It then sums the water contents of the 0.01 m increments for each layer defined by CERES and divides by the thickness of the layer to obtain the layer's average weighted soil water content. With this information, CERES can determine root growth and evapotranspiration. HYDRO performs this function for each day based on the water table depth calculated for that day. If a dry zone exists (as defined by DRAINMOD, see Figure 3), it sets the water content of the dry zone to be equal to that at the wilting point plus the upflux from the water table. A soil water characteristic curve for the rooting zone relating 34 pressure head and soil water content is required input to DRAINMOD. This curve is used to calculate the depth of a dry zone created when moisture is removed from the rooting zone. Presently, the same curve is used in HYDRO to calculate the water content above the water table for the whole profile. While the hydrostatic distribution accounts for the soil water conditions as mentioned, the upflux from the water table to the roots also needs to be described. In DRAINMOD, the upflux from the water table that is available for plant use is calculated as a function of the distance between the bottom of the root zone and the water table. While the effective depth of the rooting zone as a function of time is an input to DRAINMOD, in CERES, the root growth is simulated over the season and is accounted for by root length and density, not just an effective rooting depth. To make use of the upflux information as DRAINMOD calculates it, it was necessary to transfer to DRAINMOD an effective depth of the roots from CERES daily. The root length density is summed over the whole profile to obtain a total, then the depth which contains 90% of the root's total volume is found. This depth is transferred to DRAINMOD for calculating the upflux. This upflux is then added to the soil water content of the dry zone, if one exists, in HYDRO. In this way, water available from the water table for crop use is transferred to CERES via a soil water content increase. By accounting for both a dry zone and upflux from the water table, HYDRO describes the dynamics of the water movement and the soil water regime more realistically than just using a hydrostatic distribution. CERES accounts for dry stress, but not wet stress, so its root 35 growth routine had to be modified for use in the combined model. CERES calculates a soil water deficit factor, SWDF, each day to determine if the root growth should be reduce due to deficit soil water conditions. SWDF is a function of the amount of soil water between the LL and the DUL, that is, the extractable soil water, ESW. For each layer, SWDF is 1.0 unless the volumetric soil water, SW, falls below 0.25 of the ESW. In that case, SWDF varies linearly from O at LL to 1 at ESW = 0.25. The product of SWDF and new root growth calculated for the day gives the amount the roots grew that day. When the water content is greater than the DUL, the SWDF is undefined in CERES, that is, it is left to be unity; in the synthesized model, it should reflect stress due to excess water. Figure 9a shows the root growth potential function, SWDF, before being modified to account for wet stress. Though the SWDF function needs to be defined above the DUL, its definition eludes easy delineation. Feddes (1976) states "a fixed 'anaerobiosis point' at which deficient aeration conditions exist and root growth is seriously hampered, is hard to define." He determined a suitable oxygen diffusion rate from literature for a sandy loam to be at a soil water pressure head of -0.5 m. He cautions, however, that relationships between ODR and soil water pressure heads vary for different soils. A root upper limit, RUL, of soil water content was defined to be the limit above which wet stress would limit root growth and cause senescence. Above this limit, the root growth potential, SWDF, is assumed to be linear between 1 at the RUL and O at the SAT. Presently, the RUL is arbitrarily taken to be the soil water content 36 [a] Root Growth Potential l - /— A .8 . . .6. 1 LI. C3 3 U) .4. 1 .2. . 0P « LL . DUL SAT Soil Water [bl Root Growth Potential 1~ . .8. . .6. . LI. 0 3 U) .4 » i .2. . 0. [L L L DUL RUL SAT Soil Water Figure 9. Root growth potential before [a] and after [b] being modified to account for wet stress. 37 midway between the DUL and SAT. RUL : DUL + .5(SAT - DUL) (13) This linear relationship, shown in Figure 9b, appears to be adequate at present, but is subject to change as more becomes known about the limiting conditions for root growth. The SWDF factor was also made to cause root senescence by reducing the root length volume, RLV, of a layer if the soil water content is above RUL for more than two days in succession. RLV = RLV x SWDF (1A) This equation is used for each succeeding day that the water content is above RUL. The root growth function has now been modified so that when the soil water content is above the RUL for a given layer, it reduces root growth, prevents roots growing deeper, and finally causes complete senescence. CERES calculates two other zero to unity soil water deficit factors. The less sensitive (SWDF1) is used to affect photosynthesis. The more sensitive factor (SWDF2) affects plant cell expansion. These factors account for deficient water stress during the various growth stages of corn. Like the root stress factor was before being modified, they do not account for excessive soil water conditions. These factors, or ones similarly defined, are needed to affect photosynthesis and plant cell expansion for excessive soil water 38 conditions. In the present stage of development of the merger, these factors have not been modified. The CERES model was used to determine evaporation and transpiration, as its methods were considered superior to the Thornthwaite method used by DRAINMOD, both in better estimates on a daily basis and in determining evaporation separate from transpiration. An accurate estimate of these values is important in simulating plant growth. The calculation of actual soil evaporation required a supplemental method since CERES does not account for upflux from a water table. CERES’s prediction is primarily a function of the time since the last infiltration event; the soil continually dries until the next rainfall or irrigation. But in reality, the surface soil layer, as well as those below, may stay "wetter" than predicted because of the water provided by a water table. An empirical equation based on the relationship shown in Figure 10 (Ritchie and Burnett, 1971) was added to calculate evaporation due to the water content in the surface 0.03 m layer. If the evaporation predicted using this equation is greater than that predicted by CERES, it is used. This equation was added to the model and is valid for a Houston Black clay. Adjustments may be necessary for different soil types. The infiltration calculations used in the synthesized model are those of DRAINMOD, based on the Green and Ampt methods, instead of the SCS curve numbers method of CERES. When an infiltration event occurs in DRAINMOD, the amount of infiltrated water is transferred to CERES for its calculation of the soil evaporation. Figure 11 shows a generalized flow chart of how the models were 39 linked together. After CERES is initialized, a subroutine, CDMOD, checks to see if it is the first day of the month. If so, DRAINMOD's main program reads the weather data for the month, otherwise, DRAINMOD's main subroutine, FORSUB, conducts the water balance for one day. HYDRO then determines the water content of the soil layers for use in CERES using the the soil water regime information calculated by DRAINMOD. Next, CERES calculates evaporation, root growth, and plant growth. Both the actual ET and the root depth calculated are used in DRAINMOD the next day when the cycle is repeated. The models exchange information on a daily basis. In this way, actual water use and plant growth information are kept in balance between the two models. 3" r I I I l 'n \ E E ‘3. t: < 8 22)- 9 p- 4 3 IL‘” ‘>‘ 0 Ill 3 99.3,) ice L L :3 JO JS SOIL WATER CONTENT 0' to 3-cm depth (gm/gm) Figure 10. The influence of the surface soil water content on the water evaporation rate from bare soil. Source: Ritchie and Burnett (1971) 40 I START I CERES DRAINMOD r —“-1 F ---------------- 1 I I I I : READ WEATHER DATA? 1 I I . . FDR DAY 'JDATE' / i’ - . . I l I I l I I I : I l I 1 MAIN PROGRAMI 7 I g I I READ CLIMATE } l I . DATA FOR MONTH , I 1 | I 3 5 1” i I 1 l . - . ' FORSUBI 7 ' I I : I ggg$utgig,;T' I Li, I CONDUCT VATERI I I ' I I BALANCE FOR ' I I DEPTH AND I I 1 ' DEFICIT FACTORS I I I I I ._ ---------- .- ------- J . l . I l I V l { ISUDRDUTINES I I l I l l l l I l l l I I 1 I l I I L. ____________________ .I 13 CERES DONE BUT DRAINMOD IS NOT 7 HYDRO! CALCULATE SUM. VATER CONTENTS FUR CERES Figure 11. An Abbreviated Flow Chart of the Synthesized Models 4. Results and Discussion The models DRAINMOD and CERES were linked together as explained in the preceding chapter. Operation and behavior of the synthesized model was investigated by performing a 16 year simulation for a site .in Tuscola county, Michigan. Most of the soil information was obtained from literature. Hydraulic conductivities for some layers were obtained from field measurements. Nearby weather stations provided the climate data. A complete listing of the data used can be found in Appendix A. No actual yield data or measured water table levels for the years simulated were available for comparison with the model results. Much was learned, however, about the feasibility of the two models working together, what aspects need improvement, and what additional data are required. In spite of the intrinsic difference between the two models in the way in which they handle the soil water information, HYDRO proved to be an adequate means of transferring this information between DRAINMOD and CERES. Given a water table depth, a dry zone depth, and the upflux from the water table from DRAINMOD, HYDRO calculated an average soil water content for each layer in CERES each day. The adequacy of HYDRO as a link between the two models depends upon how well the soil water curve is defined for the soil profile, since HYDRO uses that curve to calculate water content in terms of a 41 42 hydrostatic pressure head. The better the soil water curve is defined, the more accurately HYDRO will be able to predict soil water contents. Another factor that influences the accuracy of HYDRO is the thickness of the layers defined for CERES. The thicker the user has defined a layer, the greater the error in using an average soil water content for the whole layer. Each layer needs to be restricted in size if the average soil water content calculated for a layer is to approximate its actual water content from the top of the layer to the bottom of the layer. This should not be a problem if the recommenda- tions given for use of CERES are followed. CERES documentation (Jones, 1985) recommends that the first two layers be less than 15 cm each, preferably 10 cm, and that all the additional layers should be less than 30-30 cm. In the simulation, the layers from top to bottom were defined to be 15, 17, 22, 2A, 45, 47, and 22 cm. A better definition would have been to split the top two layers into 3 layers. The soil at the site was determined to be similar to a Tappan loam with an impermeable layer at a depth varying between 1 and 2 meters. Information from the Nebraska soil survey on the Tappan loam was used to determine the soil water characteristic curve for use in both DRAINMOD and HYDRO. A utility program by Ritchie (Jones, 1985), based on field measurements, was used to determine the soil water limits from the soil texture for use in CERES. The program gave the lower limit (LL), drain upper limit (DUL), and the saturation limit (SAT) as 14%, 23%, and 28% water by volume. The DUL is generally the water content that corresponds to a pressure head between 10 and 33 kPa. The survey sheet, on the other hand, gave 31% water by volume at 43 33 kPa which exceeds what the program predicted at saturation or 0.0 kPa (281). Since the soil survey uses laboratory measurements and in lieu of direct field measurements, values closer to the results of the utility program were used in the simulation with LL, DUL, and SAT being I“, 26, and 36% respectively. The utility program gave soil water limits for each defined layer but because HYDRO and DRAINMOD currently uses only one curve, the curve for the first layer and its corresponding soil water limits calculated were used for the top u layers, down to 78 cm. As the soil is quite uniform over this depth, this provided an adequate I description for this simulation. Generally, however, a soil water curve and the corresponding limits should be defined for each layer in the profile. HYDRO could be adapted to calculate the soil water contents for layered soils as shown in Figure 12. The evapotranspiration calculation in CERES requires solar radiation in addition to minimum and maximum temperature to calculate potential ET. As information on solar radiation was not available from the weather stations used, the Thornthwaite method in DRAINMOD was used to calculate the potential ET for the day. This potential ET was transferred to CERES where the actual ET was still calculated using the method in CERES as the sum of soil evaporation, Es, and plant transpiration, Ep as described before. The calculation of the soil evaporation, Es, by CERES was supplemented by a method that included the effect of a water table as described previously. Figure 13 shows the comparison between Es values calculated by CERES and those calculated by the supplemental method. The peaks show an increase in Es calculated by CERES due to 44 Aowo.v nwwmxm "cocoon .— Huom sponge: a pom cowusnwuumfiu pogo: Haom on» accomonaon Anv a“ o>uso somepn one .oanmu noun: a o» asunnfiafisom o» vocamau Any Haom vouozmH a can Amy HHom shakes: a non acaasnflnumau Loam: Huom .m. opsmfim m D UJth mwbq; D . 1 a / «4.8 I , x O 1 3 I. Do I]. H 1 IA N I_:um \ z \ N U I \ L uuuuuw\\> ‘ nuuwj>r\\ . 4.0m \ O \ x I \\w b \\ wofiEDm 4.0m AnEU\nEUv hzwhzoo cub»; a $5358 5328 52; O K ‘HldBO 45 an infiltration event. After an event, CERES's calculation of Es decreased in value and eventually became less than what the supplemental calculation predicted. In either case, the two values of Es predicted were compared, and the higher value of Es was taken to be the soil evaporation for each day. The results of several simulations showed that a better description of the effective root zone depth was achieved. Root growth is now affected by the soil water conditions. During conventional drainage, when the water table was kept drained to a 1.0 m depth, the roots extended deep into the soil. During subirrigation, when the water table was raised to 0.60 m depth, the roots remained closer to the surface. If the water table was raised up near or into some roots, so that the soil water content of the layer containing those roots was above the root upper limit, RUL, for 2 days, the roots were reduced for every succeeding day that the excess water conditions persisted, eventually killing those roots. The root zone depth fluctuating as a result of the water table movement can be seen in Figure 1“. The results were compared to simulations run with the yield version of DRAINMOD, using the crop response parameters from Ohio. Under conventional drainage, the yield version of DRAINMOD had a yield reduction due to drought conditions, while the synthesized model experienced none. Because the effective rooting depth is a fixed function in DRAINMOD, it does not respond to dry conditions or to a low water table by increasing in depth. In DRAINMOD, the maximum effective depth for the simulation was fixed at 0.30 m. The effective depth in the synthesized model which varies according to soil Evaporation (mm/day) 46 Soil Evaporation r I I I I I I I 2.75_ ..(; 1 EL 1 J l I J l O 20 4O 80 80 100 120 140 Days During Growing Season ————-CERES method .-.. Supplement method Figure 13. Comparison of the two methods of estimating soil 180 evaporation. CERES accounts for infiltration, which causes the peaks. The other method accounts for surface soil water content as calculated by HYDRO. V ‘1. 47 .nco«uaucoo Loam: Huom o» o>wncoammu on cu czozm canon ocou goom .2. ousmfim commmw acwzocm ocfitno m>mo oma Ova ONa OOH 0m 0w 0v ON 4 — 4 a d d u _ 392. .533 I1 5qu aczoom minus»; IIIIv L I7 P — b h h F Lemma ocflboom m>Apcthm Uidao (w) 48 conditions, on the other hand, extended down to 0.48 m. The plants suffered no stress from lack of water, hence, the yield predicted was maximum at 18621 kg/ha. Though this yield is high, it must be remembered that the soil fertility was considered to be adequate; the yield predicted shows response to water stress conditions only. The depth and distribution of plant roots are affected especially by soil water conditions, but other varying factors, including physical and chemical barriers, and fertilizer distribution are also important. Factors that might reduce root growth or prevent it can be accounted for in each layer by root preference factors, one of CERES' input. These factors can range from zero for no growth to one for maximum growth. When the input root preference factors where adjusted so that the roots in the synthesized model were not allowed to exceed 0.32 m, the crop experienced dry stress, resulting in yield reductions comparable to the yield version of DRAINMOD, shown in Figure 15. It must be mentioned that while the yield version of DRAINMOD gives yield as a percent, CERES and hence the synthesized model predicts the actual yield. To compare the results of the two models, the yields predicted by synthesized model were converted to percents by dividing by 18621 kg/ha, which was the maximum yield predicted. While the average yield percent predicted for both was about 80%, a quick look shows that the results are not real consistent with each other. The correlation between the two was quite low, only 0.36, suggesting that the factors responsible for the reduction are not the same for both models. Operation of the synthesized model indicates that the CERES growth component of the model lacks sensitivity to wet conditions. PERCENT YIELD 100 80 60 40 20 49 PREDICTED CORN YIELD - - I I I”“I ”I I"”"I"~I‘ T'“ Id" r—I I I l l I l l l l l i, 1958 l l l l l 1964 1966 1968 1970 1972 YEARS SIMULATED l l 1 960 1962 SYNTHESIZED MODEL IIITH RESTRICTED ROOTS YIELD VERSION OF DRAINMOD Figure 15. Comparison of yields between the synthesized model and the yield version of DRAINMOD when the roots are restricted to the same depth for both. 50 Even though the root growth function was modified to be responsive to wet conditions, yield reductions did not occur unless the roots were completely killed. For example, maximum yields were obtained when the crop was subirrigated at 0.90 m; however, when the crop was subirrigated at 0.30 m, the roots were completely killed, resulting in no yield. In comparison, the yield version of DRAINMOD predicted a relative yield due to excess water of 99.0 and 94.9% respectively, showing a better resolution to wet stress conditions. There.appears to be two reasons for this. One is that even though the roots might be reduced appreciably because of a high water table, even a few roots can usually and apparently do supply the needed water as they can increase their intake above the normal range as shown in Figure 2-8. It was thought at first that the reduction in roots would reduce yield, but since the few roots that remained supplied the needed water, the plants still produced maximum yields. Some means of reducing water uptake when the roots are under wet stress needs to be implemented to more correctly handle how the plant behaves in the field. The second is that photosynthesis and cell expansion in the model are affected by dry stress, but not wet stress, due to the nature of CERES being developed to be responsive to dry, but not wet, conditions. For dry stress, the factors that affect photosynthesis and cell expansion, SWDFI and SWDFZ respectively, are reduced in some proportion to the amount the root water uptake is less than or equal to the demand. They are then further adjusted with factors determined for different crop growth stages. Field experience indicates that when under wet stress, plants exhibit similar characteristics as when 51 they experience dry stress, such as wilting. If the root water uptake function was corrected on the wet side so that water uptake was reduced when excessive wet conditions occurred, then a similar scheme for reducing these factors in some proportion to the amount the root water uptake is less than or equal to the demand could be implemented. These factors could then be further adjusted by factors that account for different crop growth stages, same as is done for the dry stress. The proportion between the growth factors and the water uptake and crop growth stage factors will need to be determined. By correcting ,the root water uptake and the crop growth response to excess water conditions, the synthesized model could be made more sensitive to wet stress conditions. If 5. Conclusions The water management model, DRAINMOD, and the crop growth model, CERES, have been successfully linked to obtain a synthesized model that capitalizes on the strengths of each. The synthesized model conducts the water balance for a water management system and simulates crop growth and yield. A procedure was developed to convert the soil water regime status calculated by DRAINMOD into soil water content by layers required by CERES. Crop growth and water use calculated by CERES was transferred back to DRAINMOD. Operation and behavior of the synthesized model was investigated by performing a 16 year simulation for a site in Michigan. Results show that important improvements in modeling crop response to a water management system have been made. A better description of the effective root zone depth was achieved as the root zone depth responds realistically to soil water conditions existing in drainage. During subirrigation, the roots remained close to the surface; during conventional drainage, the roots extended deeper into the soil. In addition, an improved evapotranspiration routine was obtained by adding a supplementary method that accounts for the presence of a water table. Crop growth stress and resulting yield reductions caused by 52 53 deficient soil water conditions has been shown to occur when the roots were not allowed to extend below 0.32 m. The root stress factor, one of three crop stress factors CERES calculates, was modified to account for wet stress thereby affecting root growth potential and the amount of roots. This first attempt at defining wet stress seems to be in the right direction as root growth and the amount of roots were reduced. However, root water uptake, photosynthesis, and cell expansion were not modified to be affected by wet stress conditions. Thus, unless the roots were completely killed, excessive water did not reduce yield, showing the synthesized model lacks sensitivity to excessive water conditions. The investigation indicates the need for further modification before the linkage between DRAINMOD and CERES can be used as a working model. 6. Recommendations 1. Growth stress factors and corresponding crop growth stage factors for wet stress need to be determined and implemented for photosynthesis and cell expansion. Some of the research currently being done on wet stress for the yield version of DRAINMOD could be used to establish these stress factors for plant growth to make the model responsive to not only dry conditions, but also to wet conditions. 2. The root water uptake function needs to be defined for excessive water conditions. 3. The root growth potential function needs to be defined more precisely as presently, the roots are reduced somewhat arbitrarily. A better method would be having a variable account for the time and severity of stress for the roots similar to the SEW concept used in DRAINMOD, possibly as REV : Z (1 - SWDF) (15) A relationship could then be determined between RED and root senescence. 4. The subroutine HYDRO needs to be adapted to calculate the soil water content for layered soils. A soil water curve for each 54 55 layer in the profile needs to be defined and entered. 5. Better methods of determining the soil water curve and the corresponding lower limit, drained upper limit, and saturation limit need to be developed. 6. Input data and variables that are duplicated for both models need to be consolidated. The number of layers that DRAINMOD could handle, for example, might be increased to 10 to be consistent with CERES so that the same variables might be used for defining the layers. ' 7. CERES has a function to calculate delay in germination due to lack of moisture, but it does not account for planting delay due to wet conditions. The routine in the yield version of DRAINMOD could be used to determine planting delay due to excessive wet conditions hindering trafficability. 8. In the synthesized model, though DRAINMOD is technically a subroutine of CERES, the structure of both models is for the most part left intact. It might be feasible to make one more of a subroutine of the other. Presently, setting up CERES to have a drainage option seems to be the more reasonable approach. Either way, however, neither model can be reduced very much without it losing its integrity. A. Michigan Site Simulation a. Soil Survey Results for Tappan Loam SOIL CLASSLPICLIIOI-Tlflc DIPLLQUOLL IIIZ-LOLII. DIX! SZIIZS - - - - - - -TLPPII D (CILCLRZOUS), IZSIC o. s. DIPLRTBIII 0! AGRICULTURE SOIL COISIIVAIIOI SERVICE, 615C ILTIOILL SOIL SUI'Z! LABOILTOI! LIICOLI, IIIILSIL 5016 60 ‘ ‘ - ‘ ' ' 57661-63-1 C0662! ’ ' ‘ 6060' 6666666 6626065- ' -16".‘.'261'2' 536612 605. 766653-766660 66976 6062206 (' ' ' ‘ ‘ ' ’ ’ ' ‘ ‘ ‘ ‘ ‘ P‘iflCLi 5126 66661515. L! 266, 321. 3613. 3316 - - - - - - - - - )63910 '16! ( ‘ ‘ ’ ' ' 5660 ‘ ' ' ‘ - ‘ )(' ' '5162- - - ‘1 16,6 61.6 606' 601 5660 5262 CLI! CLI! 'COS C065 6205 2665 7,65 C051 2652 '65! 5366 21 C66! C03‘ 15- 2- o 05- 6.2 t! 2- 7- a 5- o 25- 0 1°- 0 05 o 02 .005. 2- a 2- '10 CL‘! '6. .05 .002 .002 .0002 1 .5 .25 .10 .05 .02 .002 .002 .10 .02 CLI! 20 C6 (' ' ‘ ‘ ’ ‘ ' ‘ ’ ' ' ' ' ‘ ° ' ' ’ ‘ PCT 62 266 ‘ ' ‘ ’ ‘ ‘ ' ' ‘ ‘ ‘ - - - - - -) PC! PCT CLI! 0-26 I! 65.6 33.2 21.0 3.1 6.2 10.7 16.3 7.5 12.6 20.6 36.3 29.2 .63 26-32 L12 66.5 33.6 19.7 2.6 5.6 10.6 19.6 6.1 36.6 51.6 .51 32-37 6116 51.9 32.7 15.6 2.5 7.0 10.6 22.1 9.7 16.5 16.2 62.2 37.2 .33 37-56 6126 33.5 62.3 26.2 2.0 3.6 7.5 13.1 7.1 16.6 27.9 26.6 29.1 .36 56-76 626 37.3 60.1 22.6 .9 2.6 6.5 6.6 13.9 7.7 16.6 25.5 29.6 30.5 31 .39 76-123 C1 60.9 37.0 22.1 6.0 3.6 5.6 9.6 16.7 7.2 12.1 26.9 33.7 27.9 36 .36 123-170 C2 60.1 36.2 21.7 3.2 5.3 9.5 16.6 7.3 16.6 23.6 32.6 30.6 .36 170-192 C3 37.7 39.6 22.5 2.6 6.9 9.2 13.7 7.1 12.5 27.3 30.6 27.6 .36 66,26 (96621CL6 5126 66662515. 66. 36. 361. 362)( 6066 0665127 )(- - - ‘66266 COITIIC' ‘ ' ') C66606622 (' ‘66 - -) '01. (' ‘ - ’ ‘ ' ' 661062 ’ ' ° ’ - - -) 6616 6616 661 661C 661C 662 6C1 6616 3616 6C16 6C16 GT 6! 75-20 20-5 5'2 L! 20-2 1/3- 0766 COL! 1/10 1/3- 15- 660 L! L! 1/1 1/2 2 75 .076 6C: 666 06! 666 666 666 C6] 2 .002 620 CLCL C6 PC? PC! " ' ‘ PC! L! 75 ‘ ' - 1 6220 C/CC C/CC PC! PCT PCT CI PC! PC! 0-26 2 0 0 3 2 56 5 1.56 1.67 .017 16.6 9.0 .15 7 7.6 7.3 26-32 3 0 1 1 6 55 5_a1.56 1.66 .019 19.5 10.1 .16 6 7.6 7.2 32-37 16 0 6 6 6 63 15 1.76 1.62 .012 15.6 5.1 .16 12 7.7 7.3 37-56 3 0 1 3 2 66 5 1.72 1.76 .010 17.7 9.2 .16 27 7.9 7.5 56-76 16 0 1 16 6 52 22 71:66 1.96 .011 16.3 6.6 .15 26 7.9 7.5 76-123 9 0 2 7 5 56 12 1.9 6 1.96 .013 13.9 6.5 .09 30 7.6 7.5 123-170 6 0 2 6 6 60 6 1.91 1.96 .009 13.6 6.2 .09 30 7.6 7.5 170-192 11 0 6 6 6 60 9 1.96 1.97 .006 12.6 6.1 .06 31 7.7 7.5 0662. (OIGIIIC 662,66 1 1606 6605 (- '61266C26666 66565 5666- -) ACT! IL (C62 62C.) 66210 66210 C3 (6656 5621 6616 6616 C]. 6C26 6626 6026 6626 6026 6616 6616 5633 5666 661 603 5,1 5C3 5C1 0666 6126 31! 2026 C6 66 66 6 506 6IC6 [CL 6226 666C 666C C6 562 6126 666C C666 '6 6226 266 622 6C!! 20 20 666C 3C2! Cl PC! PC: PC! PC! (’ ’ ' ‘ ' ' ’ ‘ ' ’ -660 / 100 6' - - - - - ‘ ‘ ‘ - ) C662 66 PC! PC: PC: 0-26 1.60 .6 1.9 .2 .9 1.9 13.3 .63 28-32 2060 03 202 07 06 20‘ 110‘ 0" 32-37 .66 .3 1.9 .1 .3 .9 7.9 .51 37-56 .60 1.3 2.5 .2 .6 6.2 .36 56-7. .65 .6 2.2 02 a. 6.7 .30 16-123 .61 .7 2.5 2. .5 5.6 .26 723-170 060 o“ 20‘ 0‘ on ‘09 .23 170-192 .35 .6 2.9 .1 .6 6.6 .21 06926 (562066260 63522) 63 63 56L! 629 (- - ° ‘ ’ ‘ - - - 5620639106 22266CI 661- - - - - - - - - ) 322666666 661 6C16 6A 502 56 605 6611 6311 6616 6016 6616 6016 6213 6313 6‘16 661] 6611 6’1 612 6652 96 620‘ 659 566 TOIL 6C C3 66 63 6 C03 6C03 CL 506 603 L010 6652 066‘ 50L0 66605/ L61? 1602 C6 C6 PCT 6C! 996 PC? C6 ( ’ ‘ ' ' - - - - - 66° / LIIII ' ' - - - ‘ - ‘ ‘ ‘ ’ 1 602 0-26 26-32 32-37 37-56 56-76 22 7 76-123 123-170 3300 7.9 33.2 .71 20 7 170-192 1600 7.6 32.6 2.66 56 | r 57 Pedon classification: 'l‘ypic Haplaquoll; fine-loamy, mixed (calcareous), mesic Series classification: (Sam e) Soil: Tappan Soil Non: S76HI-63- I (31.8 Nos. 763453- 743460) Location: Huron County, Michigan; lSZ feet south and 23100 feet west of the northeast corner of Sec. 19, TISN, R1011. Climate: Average annual precipitation is about 28 inches. Mean annuals ir temperature is about 47° 17., and the stmaaer air temperature is about 68° F. Frost-free season is 150-160 days. Vegetation and land use: Navy beam. Cropland- Parent material: Loam till. Physiograpby: Till plain. Topography: Nearly level. Gradient is 1 percent. Drainage: Po oorly drained. Ground water: At ’48 inches. Erosion: Slight. Permeability: Moderate or moderately slow Described by: I. Stroesenreuther, L. Linsemier, S. Cowan, and H. Frederick. (Colors. are for moist soil unless otherwise stated.) AL 653 0 to 28 cm (0 to ll inches). Very dark grayish brown (10“ 3/2) loam, grayish brown (10m 5/2) dry; weak coarse granular structure; friable; few fine roots; 1 percent by volume of pebbles; slight effervescence; moderately alkaline; abrupt smooth boundary. All #54 28 to 32 cm (11 to 13 inches). Very dark grayish brown (10?! 3/2) loam, grayish brown (10“ 5/2) dry; weak mediu- subangular blocky atructure; friable; fev fine roots; about 2 percent by volume of pebbles; slight effervescence; moderately alkaline; abrupt wavy boundary. lllg 455 32 to 37 cm (13 to 15 inches). Light brownish gray (lOYR 6/2)(501) and gray (lOYR S/l)(501) loam; few fine prominent yellowish brown 10“ 5 6) mottles; weak medium subangular blocky structure; friable; few fine roots; about 5 percent by volume 'of pebbles and cobbles; slight effervescence; moderately alkaline; clear wavy boundary. 312g 656 37 to 5!. cm (15 to 21 inches). Grayish brown (10“ 5/2)(601) and dark yellowish brown (107R “10(501) loam; few fine distinct yellowish brown (1.0“ 5/6) mottlea; moderate fine angular blocky structure; 6 percent by volume of pebbles and cobbles; strong effervescence; moderately alkaline, clear wavy boundary. 32g 557 56 to 78 cm (21 to 31 inches). Gray (10“ 5/1) loam; comon medium prominent yellowish brown (10“ 5/6) and few fine prominent strong brown (7. YR 5/6) mottles; moderate coarse platy parting to moderate medium angular blocky structure; firm; 6 percent by volume of pebbles and cobbles; strong effervescence; moderately alkaline; gradual wavy boundary. _C_l 656 78 to 123 cm (31 to 48 inches). Yellowish brown (lOY‘B S/b) loam; coupon medium prominent gray (10“ 5/1) andc fine distinct yellowish brown (10“ 5/6) mottlea; weak coarse angular blocky structure; firm, 4 percent by volume of pebbles and cobbles; strong effervescence; moderately alkaline; gradual smooth boundary. CZ 659 123 to 170 cm (1.6 to 67 inches). Yellowish brown (10“ 5/4) loam; few fine distinct yellowish brown (10“ tum prominent light gray 1 6/1) mottles; weak coarse platy structure; firm; 1. percent by volume of pebbles and cobbles; strong effervescence; moderately alkaline; gradual smooth boundary. c3 ‘60 170 to 192 cm (67 to 76 inches). Dark brown to brown (7.5“ All.) loam, grayish brown (10“ 5/2) on faces of pods; strong coarse platy structure; firm; 4 percent by voluw-e of pebbles and cobbles; strong effervescence; moderately alkaline. 1237A 58 b. Input data for DRAINMOD *** Job Title *** Tappan Loam 4 layers (2 in CERES) For CERES and DRAINMOD simulation *** Printout Control *** 2 *** Climate *** b: flint bzl ape er 202846 204655 1958 1 1973 12 4303 40 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00 1.00 1.00 *** Drainage System Design *** 01 100.00 52.85 1006.00 2.50 3.50 1.00 11.11 0.00 1.00 0.50 0100 0100 0100 0100 0100 0100 0100 0100 0100 0100 0100 0100 *** Soils *** 192.00 32. 4.00 54. 3.00 123. 2.00 170. 0.50 192. 0.20 99 ' 1114 0.36000 0 0.30000 -25 0.26000 -50 0.22500 -75. 0.20000 -100. 0.18500 -150 0.16000 -200 0.14500 -300 0.14100 —400 0.14000 -500 0.13000 -1000. 0.0000 0.0000 0.1700 10.0000 0.1200 0.1700 20.0000 0.4800 0.1700 30.0000 1.0700 0.1000 40.0000 1.8300 0.0500 50.0000 2.7500 0.0300 60.0000 3.8200 0.0160 80.0000 6.3800 0.0060 100.0000 9.3800 0.0030 120.0000 12.6400 0.0014 150.0000 17.7500 0.0005 200.0000 27.1300 0.0001 500.0000 50.0000 0.0000 1000.0000 100.0000 0.0000 oooobboobbb 59 6 0.00 0.00 2.00 30.00 0.44 2.00 60.00 1.32 1.50 120.00 2.06 1.25 150.00 5.28 1.25 500.00 5.28 1.25 *** Trafficability *** 415 520 820 . OO 00 —b—l 00 WW 9151031 820 in» Crop Qua 0.130 6 1 9 1 30.00 6 1 9 1 10 1 1 3.0 5 1 3.0 512 4.0 522 8.0 6 1 16.0 615 22.0 7 1 30.0 915 30.0 916 3.0 1232 3.0 121 130 0.5000 8.0000 1.8000 29.0000 30 3 11.1600 -1.1700 0.0580 -0.0005 100.0000 1.5000 100.000 1.220 103.000 0.420 110 130 1 0 420.51 43 800.33 811400.02 0.000.000.500.500.501.001.001.001.001.752.002.001.301.301.301.301.301.201.000.50 0.000.000.000.000.000.000.000.000.000.00 *** Wastewater Irrigation *** 0 0 0 365 0 0 0 0 0 0 0 0 0 0 0.00000 0.00000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0. Input data for CERES 1. Soil data DEPTH (CM) LL DUL SAT ROOTING PREFERENCE 15.000 .13 .26 .36 1.0 17.000 .13 .26 .36 .9 22.000 .13 .26 .36 .5 24.000 .13 .26 .36 .01 45.000 .14 .23 .33 .00 47.000 1 .14 .23 .33 .00 22.000 .14 .23 .33 .00 soil no. of runoff albedo layers drainage coef. .11 7.00 .09 78.00 60 ii. Corn genetics information DEKALB 987 - cultivar name 190 - growing degree days with a base temperature of 8°C (GDDB) from seedling emergence to the end of the juvenile phase. .500 - photoperiod sensitivity coefficient (1/hr). 685.0 - GDD8 from silking to physiological maturity. 825.4 - potential kernel number (kernels/plant) 10.15 - potential kernel growth rate (mg/(kernel d)) d. Abbreviated List of Synthesized Model Output FOR YEAR 1958 VARIETY NUMBER 916 VARIETY NAME DEKALB 987 LAT =42.7 , SOWING DEPTH : 5.0 CM , PLANT P0? = 7.0 PLANTS/M**2 GENETIC CONSTANTS P1 =190. P2 :.50 P5:685. G2 :825. G3 :10. SOIL ALBEDO=0.11 U: 7.0 SWCON=0.09 RUNOFF CURVE N0.=78. SOIL N0.=134 DEPTH-CM LOW LIM UP LIM SAT SN EXT SN INIT SN NR 0.- 15. 0.130 0.260 - 0.360 0.130 0.260 1.000 15.- 32. 0.130 0.260 0.360 0.130 0.260 0.900 32.- 54. 0.130 0.260 0.360_ 0.130 0.260 0.500 54.- 78. 0.130 0.260 0.360 0.130 0.260 0.010 78.- 123. 0.140 0.230 0.330 0.090 0.230 0.000 123.- .170. 0.140 0.230 0.330 0.090 0.230 0.000 170.- 192. 0.140 0.230 0.330 0.090 0.230 0.000 78.0 26.1 46.5 65.7 20.4 46.5 TOTAL PROFIL JUL CUM WATER BALANCE COMPONENT DAY DAY DTT PHENOLOGICAL STAGE CUMULATIVE AFTER GERMINATION 5/ 3/84 124 0. SONING BIOMASS LAI CSD1 ET PREC PBS“ 5/ 4/84 125 3. GERMINATION 19. 0. 30.3 5/19/84 140 51. EMERGENCE 7. 0. 30.5 6/ 8/84 160 202. END JUVENILE STAGE 15. 0.33 0.00 21. 0. 0. 6/14/84 166 280. TASSEL INITIATION 45. 0.81 0.00 35. 0. 0. 7/21/84 203 766. SILKING, LNO: 19.0 1050. 4.89 0.00 204. 0. 24. 8/ 3/84 216 934. BEGIN GRAIN FILL 1401. 4.54 0.00 259. 0. 0. 9/10/84 254 1418. END FILL, GPP=650. 2795. 1.15 0.01 403. 0. 9/12/84 256 1443. PHYSIO MATURITY 2795. 1.15 E S 0300 61 PREDICTED VALUES MEASURED VALUES SILKING JD 203 0 MATURITY JD 256 0 GRAIN YIELD KG/HA (15) 18621. O. KERNEL WEIGHT 0 (DRY) 0.3460 0.0000 FINAL GPSM 4547. O. GRAINS/EAR 650. 0. MAX. LAI 4.89 O. BIOMASS G/SM 2795. 0. Table 1. Relative yield results for years 1958 to 1973* 1 Year A 3 B C D E 1958 100.00 1 100.00 80.89 94.45 81.08 1959 100.00 . 100.00 95.32 99.17 71.24 1960 100.00 100.00 80.62 99.75 77.41 1961 100.00 100.00 86.27 99.49 81.39 1962 100.00 100.00 68.19 93.42 91.87 1963 100.00 99.73 69.33 99.99 46.64 1964 100.00 100.00 80.03 98.99 88.7 1965 100.00 100.00 75.45 93.31 46.45 1966 100.00 99.72 63.98 .100. 52.47 1967 100.00 100.00 80.14 100. 93.8 1968 100.00 100.00 93.41 98.92 97.27 1969 100.00 100.00 79.93 100. . 100. 1970 100.00 100.00 76.96 98.11 5 97.29 1971 100.00 100.00 62.61 99.07 i 89.7 1972 100.00 100.00 1 00.00 99.25 1 99.25 1973 100.00 100.00 62.04 1 100. 1 82.29 *A. Synthesized model, subirrigation. B. Synthesized model, conventional drainage. C. Synthesized model, conventional drainage, roots limited to 32 cm. D. Yield version of DRAINMOD, subirrigation. E. Yield version of DRAINMOD, conventional drainage. OOOOOOOOOOOOOOOOO B. Source Code Of Synthesized Model PROGRAM MAIZE ' THIS IS THE CERES-MAIZE PROGRAM FOR IBM-PC 5.1 THIS HAS BEEN REPROGRAMMED FOR THE IBM-PC BY ED MARTIN AND FRIENDS REPROGRAMMED FOR USE WITH DRAINMOD BY PHIL BRINK AND OTHERS WEATHER TAPE IS NOW TAPE 1 SOIL TAPE IS NOW TAPE 2 IRRIGATION TAPE IS NOW TAPE 3 THIS PROGRAM HAS AUTOMATIC IRRIGATION AND SOWING. TO TURN OFF THE AUTOMATIC IRRIGATION, LET IIRRzO ALSO, THE OUTPUT SWITCH HAS BEEN TURNED OFF CORNMODL ----- DS MAIN PROGRAM CERES-MAIZE JANUARY 1985 VERSION* DEVELOPED BY RITCHIE,KINIRY,JONES,KNIEVEL,DYKE AND OTHERS REAL LAT,LL,LAI,LFWT,MAXLAI COMMON /PARAM/ISOW,PLANTS,KOUTGR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /GENET/ P1,P2,P3,P5,G2,G3 COMMON /SOILI/ SALB,SWCON,CN2,DLAYR(10),DUL(10),LL(10),SW(10), 1 SAT(10),DEPMAX,TDUL,NLAYR,SMX,WF(10),WR(10),RWU(10),SWEF COMMON /IRRIC/ NIRR,JDAY(366),AIRR(366) COMMON /TITL/ TITLE(20) COMMON /CLIMT/ TEMPMN,TEMPMX,RAIN,SOLRAD,TMFAC(8) COMMON /DATEC/ M0,ND,IYR3,JDATE,JDATEX,IDIM(12) COMMON /WATER/ SUMEs1,SUMEsz,T,TLL,PESN,TSN,CUMDEP,ESN(1O), 1 CSD1,CSD2,SI1(5),SIZ(5),ICSDUR,ES,EP,ET,E0,CES,CEP,CET, 1 RLV(10),PRECIP,CRAIN,DRAIN,IDRSW,RTDEP,SWDF1,SWDF2, 1 SWDF3,TRWU,RWUMX,SUMIR,SWUT COMMON /WRITS/ AES,AEP,AET,AEO,ASOLR,ATEMX,ATEMN,ARUNOF, 1 ADRAIN,APRECP,ASWDF1,ASWDF2,IOUTGR,IOUTWA,JHEAD,KHEAD, 2 TPRECP,RUNOFF COMMON /PHENL/ CUMDTT,TBASE,SUMDTT,S1,C1,ISTAGE,JJDATE, 1 DTT,IDUR,CUMPH,SSTT,CSTT,SIND,P9,TEMPM COMMON /GROTH/ GPSM,GPP,GRORT,LAI,BIOMAS,PLA,SENLA,PTF,TLNO, 1 LFWT,SEEDRV,REGM,LN,XPLANT,RTWT,STMWT,GRNWT,SWMIN,LWMIN, 62 Up 240 10 15 63 1 EARNT , EMAT , SUMP , IDURP ,PLAY , PLAMx ,CARBO , XN, XNTI, 1 PLAO,GROSTM,GBLA(35),SLA(35),EARS COMMON /FILE/SWATER,CIRRIG,WEATHER,CGENET,MISOIL,WATCORN,BIOCORN COMMON /CDNO/LOPC,MFLAG,LOPE,IQUIT3,JDATE3,JDAY3 COMMON/CDET/CDTWT,CROOT,CFVOL,DWET(10),SURWET,TRD60,IPET,PETD,AETC COMMON/PERCIP/RVOL,CRO CHARACTER*12 SWATER CHARACTER*12 CIRRIG CHARACTER*12 WEATHER CHARACTER*12 CGENET CHARACTER*12 MISOIL CHARACTER*12 WATCORN CHARACTER*12 BIOCORN WRITE(*,*)'ENTER 1 TO USE DRAINMOD PET, 9 TO USE CERES PET ' READ(*,240) IPET WRITE(*,*) IPET PORMAT( I2) CALL PARMFLS OPEN(22,PILE=swATER, STATUS:'OLD') 0PEN(23,FILE='CNDET') OPEN(5, FILE:CIRRIG, STATUS:'OLD') OPEN(4, FILE=WEATHER,STATUS:'OLD') OPEN(2, FILE:MISOIL, STATUS='0LD') 0PEN(12,FILE=WATCORN,STATUS='OLD') 0PEN(13,FILE:BIOCORN,STATUS:'OLD') 0PEN(17,FILE='FLOW', STATUS:'0LD') 0PEN(15,FILE:CGENET, STATUS='0LD') 0PEN(16,FILE='COUT', STATUS='0LD') DO 3 1:1,10 DWET(I):0. CONTINUE MFLAG=0 LOPC=0 IQUIT:O IQUIT3:0 CRO:0. RVOL=0. TRD60=0. ET=O. RTDEP:0. CALL PROGRI IF (ISWSWB.NE.0) CALL SOILRI REWIND 2 READ (11,30) IYR3,JDATE,SOLRAD,TEMPMX,TEMPMN,RAIN JDATE3:JDATE 00 T0 15 READ (4,30,END:20) IYR3,JDATE,SOLRAD,TEMPMX,TEMPMN,RAIN IF(JDATEX.EQ.367)CALL CALDAT PRECIP:RVOL LOPC:LOPC+1 AETC:ET*0.1 CRO0T=.60*RTDEP wRITE(17,*) 'RTDEP,TRD60',RTDEP,TRD60 CALL CDMOD C C 000 C 64 IF(IQUIT3.LT.-1) GOTO 5 IF (ISWSWB.NE.O) CALL WATBAL IF(JDATE.EQ.ISOW.OR.ISTAGE.NE.7) CALL PHENOL(*5) IF (ISTAGE.LT.6) CALL GROSUB CALL WRYTE GO TO 10 20 IQUIT=999 IQUIT3=999 AETC:0. GOTO 17 STOP 70 FORMAT(20A4) 30 FORMAT (7X,12,1X,I3,3X,F4.0,3F6.1) END *§********************** PROGRAM INITIALIZATION ***************** SUBROUTINE PROGRI REAL LAT,LL,LAI,LFWT,MAXLAI COMMON /TITL/ TITLE(20) COMMON /PARAM/ISOW,PLANTS,KOUTGR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /GENET/ P1,P2,P3,P5,02,G3 COMMON /CLIMT/ TEMPMN,TEMPMX,RAIN,SOLRAD,TMFAC(8) COMMON /DATEC/ M0,ND,IYR,JDATE,JDATEX,IDIM(12) COMMON /wATER/ SUMES1,SUMEse,T,TLL,PESW,TSN,CUMDEP,ESN(1o), 1 CSD1,CSD2,SI1(5),SI2(5),ICSDUR,ES,EP,ET,EO,CES,CEP,CET, 1 RLV(10),PRECIP,CRAIN,DRAIN,IDRSW,RTDEP,SWDF1,SWDFZ, 1 SWDF3,TRWU,RWUMX,SUMIR,SWUT COMMON /WRITS/ AES,AEP,AET,AEO,ASOLR,ATEMx,ATEMN,ARUNOP, 1 ADRAIN,APRECP,ASWDF1,ASWDF2,IOUTGR,IOUTWA,JHEAD,KHEAD, 2 TPRECP,RUNOFF COMMON /PHENL/ CUMDTT,TBASE,SUMDTT,S1,C1,ISTAGE,JJDATE, 1 DTT,IDUR,CUMPH,SSTT,CSTT,SIND,P9,TEMPM COMMON /GROTH/ GPSM,GPP,GRORT,LAI,BIOMAS,PLA,SENLA,PTF,TLNO, 1 LFWT,SEEDRV,REGM,LN,XPLANT,RTWT,STMWT,GRNWT,SWMIN,LWMIN, 1 EARWT,EMAT,SUMP,IDURP,PLAY,PLAMX,CARBO,XN,XNTI, 1 PLAG,GROSTM,CBLA(35),SLA(35),EARS COMMON /CDNO/LOPC,MFLAG,LOPE,IQUIT3,JDATE3,JDAY3 DIMENSION VARTY(5) 1o NEWSOL=1 NEWWET:1 MULTYR:0 Iswst=1 20 IF(IQUIT.EQ.999) GOTO 65 39 IF (NEwwET.EQ.0) REWIND 10 IF (NEWWET.EQ.0) NEWWET:2 XPLANTzPLANTS S1=SIN(LAT*0.01745) C1:COS(LAT*0.01745) CJCIC) (JCDCD 40 50 60 65 65 ISTAGE=7 TBASE=10 LAI:O. SNDF1=1.0 SWDF2=1.0 ICSDUR=0 JHEAD=0 KHEAD:0 IF(ISWSWB.EQ.0) KOUTWA=0 IF (KOUTWA.NE.0) CALL OUTWA IF (KOUTGR.NE.0) CALL OUTGR *****************INITIALIZING NEW PARAMETERS********************** SUMIR:O. IDATE=0 ICDTT:O *****************************************************************§ JDATEX:367 CUMDTTzo. SUMDTTzo. DTT=0. CRAIN=O. PRECIon. RENIND 15 READ (15,110,END=50) IVARTY,(VARTY(NN),NN=1,4),P1,P2,P5,02,03 IF (IVARTY.NE.KVARTY) GO TO 40 REWIND 15 GO TO 60 WRITE (16,120) KVARTY STOP CONTINUE WRITE (16,130) IVARTY,(VARTY(NN),NN=1,4) WRITE (16,90) LAT,SDEPTH,PLANTS WRITE (16,180) P1,P2,P5,GZ,G3 RETURN WRITE(16,140) IF DRAINMOD GOES ANOTHER YEAR, REINITILIZE PARAMETERS IF(IQUIT3.LT.-1) THEN REWIND 4 REWIND 2 REWIND 22 REWIND 15 IQUIT=0 IQUIT3=O GO TO 10 END IF WE NOW CLOSE THE FILES AND STOP THE PROGRAM CLOSE(1) CLOSE(2) CLOSE(3) 66 CLOSE(12) CLOSE(13) CLOSE(15) CLOSE(22) CLOSE(6) STOP 90 FORMAT (/1X,5X,'LAT =',F4.1,' , SOWING DEPTH = ',F3.1, 1 ' CM , PLANT POP = ',F4.1,' PLANTS/M**2') 110 FORMAT (1X,I4,1X,4A4,F6.2,F6.4,F6.2,F6.2,F6.3) 120 FORMAT (' CROP VARIETY INFORMATION IS MISSING FOR',I5) 130 FORMAT (6X,'VARIETY NUMBER ',I4,' VARIETY NAME ',4A4) 180 FORMAT (/1X,5X,'GENETIC CONSTANTS',2X,'P1 =',F4.0,2X, 1 'P2 :',F3.2,2X,'P5=',F4.0,2X,’02 =',F4.0,2X,'G3 :',F3.0) 140 FORMAT(' CROP MATURE FOR SINGLE YEAR RUN') END *****F**** SUBROUTINE TO READ AND INITIALIZE SOIL INFORMATION *** SUBROUTINE SOILRI REAL LAT,LL,LAI,LFWT,MAXLAI COMMON /PARAM/ISOW,PLANTS,KOUTGR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /SOILI/ SALB,SWCON,CN2,DLAYR(10),DUL(10),LL(10),SW(10), 1 SAT(10),DEPMAX,TDUL,NLAYR,SMX,WF(10),WR(10),RWU(10),SWEF COMMON /IRRIG/ NIRR,JDAY(366),AIRR(366) COMMON /wATER/ SUMES1,SUMES2,T,TLL,PESW,TSW,CUMDEP,ESW(10), 1 CSD1,CSD2,SI1(5),SI2(5),ICSDUR,ES,EP,ET,EO,CES,CEP,CET, 1 RLV(10),PRECIP,CRAIN,DRAIN,IDRSW,RTDEP,SWDF1,SWDF2, 1 SWDF3,TRWU,RWUMX,SUMIR,SWUT COMMON /PHENL/ CUMDTT,TBASE,SUMDTT,S1,c1,ISTAGE,JJDATE, 1 DTT,IDUR,CUMPH,SSTT,CSTT,SIND,P9,TEMPM COMMON /GROTH/ GPSM,GPP,GR0RT,LAI,BIOMAS,PLA,SENLA,PTF,TLN0, 1 LFWT,SEEDRV,REGM,LN,XPLANT,RTWT,STMWT,GRNWT,SWMIN,LWMIN, 1 EARWT,EMAT,SUMP,IDURP,PLAY,PLAMX,CARBO,XN,XNTI, 1 PLAG,GROSTM,GBLA(35),SLA(35),EARS IF (NEWSOL.EQ.0) GO TO 60 10 READ (2,210,END:30) NSOIL,SALB,U,SWCON,CN2 IF (NSOIL.NE.KSOIL) GO TO 10 WRITE (16,120) SALB,U,SWCON,CN2,NSOIL GO TO 30 30 DEPMAX:O. CUMDEP: 0. D0 40 NLAYR:1, READ (2,130)ODLAYR(NLAYR),LL(NLAYR),DUL(NLAYR),SAT(NLAYR), 1WR(NLAYR) 13o FORMAT (4F10. 3, 10x, F10. 3) IF (SOILN. LE. 1. )GOT 037 38 IF (DLAYR(NLAYR). GT. 0. ) READ(22, 135) SW(NLAYR) 135 FORMAT (1x, F5 3) GO TO 9 37 SW(NLAYR)=LL(NLAYR)+(DUL(NLAYR)-LL(NLAYR))*SOILN I ll. 0000000000 67 CUMDEP:CUMDEP+DLAYR(NLAYR) IF(CUMDEP.LE.110.) GO TO 39 DLL=0.008*(CUMDEP-11O.)*(DUL(NLAYR)—LL(NLAYR))+LL(NLAYR) IF(SW(NLAYR).LT.DLL) SW(NLAYR):DLL 39 CONTINUE DEPMAX:DEPMAX+DLAYR(NLAYR) IF (DLAYR(NLAYR).LE.0.) GO TO 50 40 CONTINUE 00 T0 60 50 NLAYR=NLAYR-1 6o GOTO 80 60 IF (IIRR.EQ.0) GO TO 80 WRITE (16,140) J=1 NIRR=O 70 READ (IIRR,150) JDAY(J),AIRR(J) IF (JDAY(J).EQ.0) GO TO 80 WRITE (*,160) JDAY(J),AIRR(J) J=J+1 NIRR:NIRR+1 GO TO 70 80 CONTINUE SWR=(SW(1)-LL(1))/(DUL(1)-LL(1)) IF (SWR.GE..9) GO TO 90 SUME32:25.-27.8*SWR SUMES1=U T:(SUMESZ/3.5)**2 GO TO 100 90 SUME32=0. SUMES1=100.-SWR*100. T:O. 100 CONTINUE WRITE (16,190) xx=0. IDRSW:0 D0 110 L=1,NLAYR DL2=DL1+DLAYR(L) ESW(L)=DUL(L)-LL(L) WRITE (16,200) DL1,DL2,LL(L),DUL(L),SAT(L),ESW(L),SW(L), 1 WR(L) DL1:DL2 CUMDEP=CUMDEP+DLAYR(L) TSW:TSW+SW(L)*DLAYR(L) TPESW:TPESW+ESW(L)*DLAYR(L) TLL:TLL+LL(L)*DLAYR(L) TDUL:TDUL+DUL(L)*DLAYR(L) TSAT:TSAT+SAT(L)*DLAYR(L) 000000 68 WX=1.016*(1.-EXP(-u.16*CUMDEP/DEPMAX)) WF(L)=Wx-xx ' xx:wx 110 CONTINUE DEPMAX:0. DO 115 L:1,NLAYR IF(WR(L).E0.O) GO TO 116 DEPMAx=DEPMAx+DLAYR(L) 115 CONTINUE 116 RTDEP=DEPMAx WRITE (16,170) RTDEP,TLL,TDUL,TSAT,TPESW,TSW CN1=-16.91+1.348*CN2—0.01379*CN2**2+0.0001172*CN2**3 SMX:254.*(100./CN1-1.) SWEF=0.9-0.00038*(DLAYR(1)-30.)**2 CET:0. CES:O. CEP:0. CRAIN=0. RWUMX:0.03 RETURN 120 FORMAT (1X,5X,'SOIL ALBEDO:',F4.2,2X,'U=',F4.1,2X, 1 'SWCON=',F4.2,' RUNOFF CURVE N0.=',F3.0,' SOIL N0.=',I3) 130 FORMAT (6F10.3) 140 FORMAT (/6X,'JULIAN DAY IRRIGATION(MM)') 150 FORMAT (2x,I3.5x,F5.0) 160 FORMAT (8x,15,7x,F5.0) 170 FORMAT (/1X,8X,6F9.1,' TOTAL PROFILE',/) 190 FORMAT (1H0,6X,'DEPTH-CM',6X,'LOW LIM',3X,' UP LIM',3X,'SAT SW', 1 3X,'EXT SW',3X,'INIT SW',4X,'WR',/) 200 FORMAT (1H ,3X,F6.0,'-',F6.0,2X,6F9.3) 210 FORMAT (I4,34X,2F6.2,6X,2F6.2) 220 FORMAT (' SOIL DATA IS MISSING') END **§******* OUTPUT SUBROUTINE FOR WATER BALANCENNNNNNNNNNNNNNHNMNN SUBROUTINE OUTWA REAL LAT,LL,LAI,LFWT,MAXLAI COMMON /TITL/ TITLE(20) COMMON /PARAM/ISOW,PLANTS,KOUTOR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /SOILI/ SALB,SWCON,CN2,DLAYR(1O),DUL(1O),LL(10),SW(10), 1 SAT(10),DEPMAX,TDUL,NLAYR,SMX,WF(10),WR(10),RWU(10),SWEF COMMON /DATEC/ M0,ND,IYR,JDATE,JDATEX,IDIM(12) COMMON /WATER/ SUMES1,SUMEsz,T,TLL,PESW,TSW,CUMDEP,ESW(10), 1 CSD1,CSD2,SI1(5),512(5),ICSDUR,ES,EP,ET,EO,CES,CEP,CET, 1 RLV(1O),PRECIP,CRAIN,DRAIN,IDRSW,RTDEP,SWDF1,SWDF2, 1 SWDF3,TRWU,RWUMX,SUMIR,SWUT 0000 000 0 69 COMMON /WRITS/ AES,AEP,AET,AEO,ASOLR,ATEMx,ATEMN,ARUNOF, 1 ADRAIN,APRECP,ASWDF1,ASWDF2,IOUTGR,IOUTWA,JHEAD,KHEAD, 2 TPRECP,RUNOFF DIMENSION AVFARG(10) EQUIVALENCE (AVEARG(1),AEs) IF (JHEAD.EQ.1) GO TO 10 IF(KOUTWA.NE.O)WRITE(12,45)TITLE IF (KOUTWA.NE.O) WRITE (12,50) JHEAD:1 GO TO 30 1O DAWA:FLOAT(IOUTWA) DO 20 I=1,7 AVEARG(I)=AVEARG(I)/DAWA 2O CONTINUE CALL CALDAT WRITE (12,60) MO,ND,IYR,JDATE,AVEARG,SW,PESW THE FOLLOWING STATEMENT CAN BE USED TO STORE SOIL WATER CONTENTS IN LOGICAL UNIT 9 FOR USE IN PLOTTING RESULTS IF THE COMMENT CODE IS REMOVED. WRITE(9,70)JDATE,(SW(I),I:1,6) 30 DO 40 I:1,1O AVEARG(I):O. 4O CONTINUE IOUTWA:O RETURN 45 FORMAT (1H1,//,2OX,2OA4//) 50 FORMAT (1H ,9X,'JUL',2X,12('-'),' AVERAGE ',12('-'),2X, 1 '---- PERIOD ----',2X,8('-'),' SOIL WATER CONTENT ', 2 'WITH DEPTH ',9('-'),T123,'TOTAL',/,4X,'DAY',3X,'DAY',3X,'ES', 3 3X,'EP',3X,'ET',3X,'EO',2X,'SR MAX MIN RUNOFF', 4 ' DRAIN)PREC SW1 SW2 SW3 SW4 SW5 SW6 SW7 SW8 SW9 SW10 5 PESW' 6O FORMAT (1X,I2,'/',I2,'/',I2,I4,4F5.1,F5.0,2F5.1,F6.2,2F6.2,10(1X, 1 F4.2),3X,F7.1) 7O FORMAT(IB,6F6.3) END NNNNNNNNHNNNHHNNOUTPUT SUBROUTINE FOR GROWTH***************%§**** SUBROUTINE OUTGR COMMON /TITL/ TITLE(20) REAL LAT,LL,LAI,LFWT,MAXLAI COMMON /CLIMT/ TEMPMN,TEMPMx,RAIN,SOLRAD,TMFAC(8) COMMON /PARAM/ISOW,PLANTS,KOUTGR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /WATER/ SUMES1,SUMESZ,T,TLL,PESW,TSW,CUMDEP,ESW(10), 1 CSD1,CSD2,SI1(5),SIZ(5),ICSDUR,ES,EP,ET,E0,CES,CEP,CET, 1 RLV(1O),PRECIP,CRAIN,DRAIN,IDRSW,RTDEP,SWDF1,SWDF2, 1 SWDF3,TRWU,RWUMX,SUMIR,SWUT COMMON /DATEC/ M0,ND,IYR,JDATE,JDATEX,IDIM(12) COMMON /WRITS/ AES,AEP,AET,AEO,ASOLR,ATEMX,ATEMN,ARUNOF, 0000 000 0 70 1 ADRAIN,APRECP,ASWDF1,ASWDFZ,IOUTGR,IOUTWA,JHEAD,KHEAD, 2 TPRECP,RUNOFF COMMON /PHENL/ CUMDTT,TBASE,SUMDTT,S1,C1,ISTAGE,JJDATE, 1 DTT,IDUR,CUMPH,SSTT,CSTT,SIND,P9,TEMPM COMMON /GROTH/ GPSM,GPP,GRORT,LAI,BIOMAS,PLA,SENLA,PTF,TLNO, 1 LFWT,SEEDRV,REGM,LN,XPLANT,RTWT,STMWT,GRNWT,SWMIN,LWMIN, 1 EARWT,EMAT,SUMP,IDURP,PLAY,PLAMX,CARBO,XN,XNTI, 1 PLAG,GROSTM,GBLA(35).SLA(35),FARS IF (KHEAD.EQ.1) GO TO 10 IF(KOUTGR.NE.0)WRITE(13,25)TITLE IF (KOUTGR.NE.0) WRITE (13,30) KHEAD21 00 TO 20 1o DAGR=FLOAT(IOUTGR) ASWDF1=ASWDF1/DAGR ASWDF2=ASWDF2/DAGR CALL CALDAT WRITE (13,40) MO,ND,IYR,JDATE,BIOMAS,LN,LAI,SUMDTT,TRWU, 1 RTWT,STMWT,GRNWT,LFWT,SENLA,ASWDF1,ASWDF2,RTDEP,PTF, 2 RLV(1),RLV(2),RLV(3).RLV(u),RLV(5),RLV(6),RLV(7).RLV(8) THE FOLLOWING STATEMENT CAN BE USED TO STORE SOIL WATER CONTENTS IN LOGICAL UNIT 9 FOR USE IN PLOTTING RESULTS IF THE COMMENT CODE IS REMOVED. WRITE (9,50) JDATE,BIOMAS,LAI,PSW,RTWT,STMWT,GRNWT,LFWT,RTDEP 20 ASWDF1:O. ASWDF2:0. IOUTGR:O RETURN 25 FORMAT (1H1,//,20X,20A4//) 30 FORMAT (1H ,4X,'DATE JUL BIO LEAF LAI SUMDTT TRWU', 1 3X,'RO0T STEM GRAIN LEAF SEN SW SW ROOT ',5x, 2 'RO0T LENGTH VOLUME',/,11X,'DAY MASS N0.',16X,' ',2X,'WT',5X, 3 'WT',5X,'WT',5X,'WT',4x,‘ LFA DF1 DF2 DPTH PTF L1 L2', u 2X,'L3 L4 L5 L6 L7 L8',/) 40 FORMAT (1X,I2,’/',12,'/',12,I4,1X,F5.0,1X,I3,1X,P5.2,1X,F5.0, 1 F5.2,4(1X,F6.2),1X,F5.0,2(1X,F3.1),1X,F4.0,F5.2,8(1X,F3.1)) 50 FORMAT (I3,2X,F5.0,2X,F5.2,2X,F6.1,2X,F7.3,2X,3(F6.3,2X),F4.0) END ********** SUBROUTINE TO CONVERT JULIAN DAY TO CALENDAR DATE **** SUBROUTINE CALDAT COMMON /DATEC/ MO,ND,IYR,JDATE,JDATEX,IDIM(12) WRITE(*,*) 'CALDAT' IF (JDATE.GE.JDATEX) GO TO 20 DO 10 I:1,12 IDIM(I)=31 1O CONTINUE IDIM(4):3O IDIM(6)=3O IDIM(9)=3O IDIM(11)=30 IDIM(2)=28 IF (MOD(IYR,4).EQ.O) IDIM(2):29 71 IF (JDATEX. E0. 367) WRITE (12, 50) JDATE 20 M0=1 ND=31 30 IF (ND.GE.JDATE) GO TO 40 M0=MO+1 ND=ND+IDIM(MO) GO TO 30 A0 ND:JDATE-ND+IDIM(M0) JDATEX=JDATE RETURN 50 FORMAT (/12X,'THE PROGRAM STARTED ON JULIAN DATE{,2x,I3,/) END **§*§***** WATER BALANCE SUBROUTINE *NNNNNNNNNNNHNNNNMNNRNNNMNNNN 000 SUBROUTINE WATBAL REAL-LAT,LL,LAI,LFWT,MAXLAI COMMON /PARAM/ISOW,PLANTS,KOUTGR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /SOILI/ SALB,SWCON,CN2,DLAYR(10),DUL(10),LL(10),SW(10), 1 SAT(10),DEPMAX,TDUL,NLAYR,SMX,WF(10),WR(10),RWU(10),SWEF COMMON /IRRIG/ NIRR,JDAY(366),AIRR(366) COMMON /CLIMT/ TEMPMN,TEMPMX,RAIN,SOLRAD,TMFAC(8) COMMON /DATEC/ M0,ND,IYR3,JDATE,JDATEX,IDIM(12) COMMON /WATER/ SUMES1,SUME82,T,TLL,PESN,TSW,CUMDEP,ESW(10), 1 CSD1, CSD2, 811(5), 812(5), ICSDUR, ES, EP, ET, EO, CES, CEP ,CET, 1 RLV(10), PRECIP, CRAIN, DRAIN, IDRSW, RTDEP, SWDP1, SNDFZ, 1 SWDF3, TRWU, RWUMX, SUMIR, SWUT COMMON /WRITS/ AES, AEP, AET, AEO ,ASOLR,ATEMX,ATEMN,ARUNOF, 1 ADRAIN,APRECP,ASWDF1,ASWDFZ,IOUTGR,IOUTWA,JHEAD,KHEAD, 2 TPRECP,RUNOFF COMMON /PHENL/ CUMDTT,TBASE,SUMDTT,S1,C1,ISTAGE,JJDATE, 1 DTT,IDUR,CUMPH,SSTT,CSTT,SIND,P9,TEMPM COMMON /GROTH/ GPSM,GPP,GRORT,LAI,BIOMAS,PLA,SENLA,PTF,TLNO, LFWT,SEEDRV,REGM,LN,XPLANT,RTWT,STMWT,GRNWT,SWMIN,LWMIN, EARWT,EMAT,SUMP,IDURP,PLAY,PLAMX,CARBO,XN,XNTI, PLAG,GROSTM,GBLA(35),SLA(35>,EARS COMMON/CDET/CDTWT,CROOT,CFVOL,DWET(10),SURNET,TRD60,IPET,PETD,AETC DIMENSION RLDF(10) C/ to account for surface evaporation when D has precipataion WINF:CFVOL C\ ICSDUR=ICSDUR+1 C *******************POTENT I AL Ev APORAT ION ROUT I NE***************** 100 TD=O.60*TEMPMX+O.40*TEMPMN ALBEDO:SALB IF (ISTAGE.LT.5) ALBEDO:O.23-(O.23-SALB)*EXP(-O.75*LAI) EEQ:SOLRAD*(2.04E-4-1.83E-4*ALBEDO)*(TD+29.) EO=EEQ*1.1 IF(TEMPMX.GT.35.)EO=EEQ*((TEMPMX-35.)*0.05+1.1) IF(TEMPMX.LT.5.0)EO=EEQ*0.01*EXP(O.18*(TEMPMX+20.)) 72 PETD=PETD*10. c WRITE(17,*)'-PET- E0 PETD',E0,PETD IF(IPET.LT.2)E0=PETD EOS=EO*(1.-O.43*LAI) IF (LAI.GT.1.)EOS=E0/1.1*EXP(-0.4*LAI) C §§§i§§§§§fififlififlflifiiiiisoIL AND pLANT EVAPORATION ROUTINENHNNNHNHH IF (SUMES1.GE.U.AND.WINF.GE.SUME82) GO TO 110 IF (SUMES1.GE.U.AND.WINF.LT.SUMESZ) GO TO 120 IF (WINF.GE.SUMES1) GO TO 150 SUMES1=SUMES1-WINF 00 T0 160 110 IF (WINF.LT.SUME32) GO TO 120 WINF:WINF-SUMESZ SUMES1=U-WINF T=O. IF (WINF.GT.U) GO TO 150 GO TO 160 120 IF(SW(1).LT.LL(1))GO TO 180 T:T+1. ES=3.5*T**0.5-SUMESZ IF (WINF.GT.0.) GO TO 130 IF (ES.GT.EOS) ES:EOS GO TO 140 130 ESX:0.8*WINF IF (ESX.LE.ES) ESX=ES+WINF IF (ESX.GT.EOS) ESX:EOS ES:ESX 140 CONTINUE SUME82=SUMESZ+ES-WINF T=(SUMES2/3.5)**2 GO TO 191 150 SUMES1=0. 160 SUMES1=SUMES1+EOS IF (SUMES1.GT.U) GO TO 170 ES:EOS GO TO 191 170 ES:EOS-0.4*(SUMES1-U) SUMES2:0.6*(SUMES1-U) T:(SUMES2/3.5)**2 00 T0 191 180 IF(ES.GT.EOS)ES=EOS SUME82:SUME82+ES-WINF C/ C---ROUTINE TO CHECK FOR Es BY SOIL WATER CONTENT C---SURWET IS WATER IN TOP 3 CM OF WATER C---IF THE ES CALCULATED HERE IS GT ONE ABOVE THEN IT IS USED 191 IF (SURWET.LT. 0.32) THEN ESY=0.94*SURWET+.2 ELSE ESY=9.4*SURWET-2.5 END IF WRITE(17,53) ES,ESY,EOS 53 FORMAT(1X,'ES ESY EOS',3F7.3) IF (ES.LT.ESY) ES:ESY “99 192 195 C& 200 C 51 210 220 300 C/ 73 IF (ES.GT.EOS) ES:EOS GO TO 200 WRITE (17,51) (SW(I),I=1,NLAYR) SW(1):SW(1)-ES*.1/DLAYR(1) IF(SW(1).GE.LL(1)*SWEF)GO TO 192 ES=0. SW(1)=LL(1)*SWEF NIND=NLAYR-1 D0 195 L:1,NIND IF(L.GT.5) GOTO 200 M=L+1 THET1:SW(L)-LL(L) IF(THET1.LE.0.)THET1:0. THET2=SW(M)-LL(M) IF(THET2.LE.0.)THET2:O. DBAR:O.88*EXP(35.4*(THET1+THET2)*O.5) IF (DBAR.GT.100.) DBAR:100. FLOW=DBAR*(THET2-THET1)/((DLAYR(L)+DLAYR(M))*0.5) SW(L):SW(L)+FLOW/DLAYR(L) SW(M):SW(M)-FLOW/DLAYR(M) CONTINUE CONTINUE WRITE (17,51) (SW(I),I=1,NLAYR) FORMAT(1X,'SW',1OF8.3) CES:CES+ES EP=0. IF (ISTAGE.GE.6) GO TO 210 IF (LAI.LE.3.0) EP=EO*(1.-EXP(-LAI)) IF (LAI.GT.3.0) EP=EO WRITE (17,*) 'EP E0 ES',EP,E0,ES IF (EP+ES.GT.E0) EP=E0-ES GO TO 300 ET=ES CET=CET+ET TSW:O. DO 220 L:1,NLAYR _ TSW:TSW+SW(L)*DLAYR(L) CONTINUE PESWzTSW-TLL RETURN ****§**********ROOT GROW}! AND DEPTH ROUTINE‘N‘Wl-flifii'fi‘l'ifiiiiii'fi IF (GRORT.EQ.0.) GO TO 340 RLNEW:GRORT*O.80*PLANTS TRLDFzO. CUMDEP=O. DO 310 L:1,NLAYR L1=L CUMDEP:CUMDEP+DLAYR(L) SWDF:1. IF(SW(L)-LL(L).LT.0.25*ESW(L))SWDF:4.*(SW(L)-LL(L))/ESW(L) 74 C---CHECK FOR IF SHOULD REDUCE ROOTS GROWTH POTENTIAL DUE TO EXCESSIVE WATER C 56 C\ 310 320 RUL=.5*(SAT(L)-DUL(L))+DUL(L) IF ((SW(L).GT.RUL).OR.(DWET(L).GE.1.0))THEN IF (SW(L).LE.RUL) THEN DWET(L):O. ELSE DWET(L)=DWET(L)+1. IF(DWET(L).GT.2.)SWDF=1+(RUL-SW(L))/(SAT(L)-RUL) WRITE(17,56) L,DWET(L),SWDF FORMAT(1X,'DWET SWDF ',12,2F8.3) END IF END IF IF(SWDF.LT.0.)SWDF=0. RLDF(L)=SWDF*WR(L) IF (CUMDEP.LT.RTDEP) GO TO 310 RTDEP=RTDEP+DTT*O.22FAMIN1(SWDF1*2.O,SWDF) IF (RTDEP.GT.DEPMAX) RTDEP:DEPMAX RLDF(L)=RLDF(L)*(1.-(CUMDEP-RTDEP)/DLAYR(L)) TRLDF:TRLDF+RLDF(L) GO TO 320 TRLDF:TRLDF+RLDF(L) IF(TRLDF.LT.RLNEW*0.00001)GO TO 3uo RNLFzRLNEW/TRLDF TRV:O. CUMDEP:0. D0 330 L:1,L1 RLV(L):RLV(L)+RLDF(L)*RNLF/DLAYR(L) C/---REDUCE 0R KILL ROOTS IF BEEN WET MORE THAN 3 DAYS C 57 C\ 330 335 R2R=RLV(L) IF(DWET(L).GT.2.)RLV(L)=RLV(L)*SWDF WRITE(17.57) L,R2R,RLV(L) FORMAT(1X,'L RLV(L) ',I2,1X,2F10.4) IF(RLV(L).LT.0) RLV(L):O. IF(RLV(L).GT.5.0)RLV(L)=5.0 TRV:TRV+RLV(L) IF(RLV(L).GT.0.000001)CUMDEP:CUMDEP+DLAYR(L) CONTINUE IF(RTDEP.GT.CUMDEP+1.)RTDEP:CUMDEP+1. TR60=0. TRD60=0. I=0 I:I+1 XTR60:TR60+RLV(I) IF(XTR60.LT.TRV) THEN TR60:XTR60 TRD60=TRD60+DLAYR(I) GOTO 335 ELSE TR060=TRD60+((TRV-TR60)/RLV(I))*DLAYR(I) END IF 75 340 CONTINUE IF(TRD60.LT.2.)TRD60=2. C ********** CALCULATE WATER UPTAKE AND SOIL DEFICIT FACTORS ****** C WRITE (17,*) 'EP:',EP IF(EP.EQ.O.)GO T0 370 EP1=EP*0.1 TRWU=O. D0 350 L:1,NLAYR IF (RLV(L).EQ.0.0) GO TO 355 AEEJ:62.*(SW(L)-LL(L)) RWU(L)=2.67E-3FEXP(62.*(sw(L)-LL(L)))/(6.68-AL00(RLV(L))) IF(RWU(L).GT.RWUMX) RWU(L)=RWUMx C(sic)IF(SW(L).LT.LL(L)) RWU(L)=RWUMx RWU(L)=RWU(L)*DLAYR(L)*RLV(L) TRWU=TRWU+RWU(L) 350 CONTINUE 355 WUF:1. IF (EP1.LE.TRWU) WUF:EP1/TRWU TSW=O. DO 360 L:1,NLAYR RWU(L)=RWU(L)*WUF SW(L)=SW(L)-RWU(L)/DLAYR(L) TSW=TSW+SW(L)*DLAYR(L) 360 CONTINUE ' PESW=TSW-TLL C& WRITE (17,*) 'PESW IN 2595 = 1 , PESW SWDF2:1. IF (TRWU/EP1.LT.1.5) SWDF2=O.67*TRWU/EP1 IF (ISTAGE.GE.2) GO TO 362 SWDF3=O.3+35.*(SW(1)-LL(1)) IF (SWDF3.LT.O.) SWDF3:0. 362 SWDF1=1. IF (EP1.LT.TRWU) GO TO 370 SWDF1:TRWU/EP1 365 EP=TRWU*10. 370 ET=ES+EP CEP:CEP+EP CET:CET+ET CSD1=CSD1+1.0-SWDF1 CSD2:CSD2+1.0-SWDF2 RETURN END ********** SUBROUTINE T0 CALCULATE PHENOLOGICAL STAGE *********** 000 SUBROUTINE PHENOL (*) REAL LAT,LL,LAI,LFWT,MAXLAI COMMON /PARAM/ISOW,PLANTS,KOUTGR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /GENET/ P1,P2,P3,P5,02,G3 COMMON /SOILI/ SALB,SWCON,CN2,DLAYR(1O),DUL(1O),LL(1O),SW(10), 1 SAT(1O),DEPMAx,TDUL,NLAYR,SMY,WF(1O),WR(10),RWU(1O),SWEF 31 15 20 30 40 100 76 COMMON /DATEC/ MO,ND,IYR,JDATE,JDATEx,IDIM(12) COMMON /CLIMT/ TEMPMN,TEMPMX,RAIN,SOLRAD,TMFAC(8) COMMON /WATER/ SUMES1,SUMES2,T,TLL,PESW,TSW,CUMDEP,ESW(10), CSD1,CSD2,SI1(5),SI2(5),ICSDUR,ES,EP,ET,EO,CES,CEP,CET, RLV(1O) ,PRECIP,CRAIN,DRAIN, IDRSW,RTDEP,SWDF1,SWDF2, SWDF3,TRWU,RWUMx,SUMIR,SWUT COMMON /WRITS/ AES,AEP,AET,AEO,ASOLR,ATEMx,ATEMN,ARUNOF, ADRAIN,APRECP,ASWDF1,ASWDF2,IOUTGR,IOUTWA,JHEAD,KHEAD, 2 TPRECP,RUNOFF COMMON /PHENL/ CUMDTT,TBASE,SUMDTT,S1,C1,ISTAGE,JJDATE, DTT,IDUR,CUMPH,SSTT,CSTT,SIND,P9,TEMPM COMMON /GROTH/ GPSM,GPP,GRORT,LAI,BIOMAS,PLA,SENLA,PTF,TLNO, LFWT,SEEDRV,REGM,LN,XPLANT,RTWT,STMWT,GRNWT,SWMIN,LWMIN, EARWT,EMAT,SUMP,IDURP,PLAY,PLAMX,CARBO,XN,XNTI, PLAG,GROSTM,GBLA(35),SLA(35),EARS TEMPM: ( TEMPMX+TEMPMN ) /2 . DTT=TEMPM-TBASE IF (TEMPMx.GT.TBASE) GO TO 31 DTT=O. GO TO 20 IF (TEMPMN.GE.TBASE) GO TO 15 TCOR:(TEMPMX-TBASE)/(TEMPMX-TEMPMN) DTT:(TEMPMX-TBASE)/2.*TCOR IF (TEMPMX.LE.34.) GO T0 20 TCOR=(TEMPMX-34.)/(TEMPMX-TEMPMN) DTT=(26.-1.3*(TEMPMx-3u.))*TCOR+(0.5*TEMPMN+17.-TBASE)*(1.-TCOR) SUMDTT:SUMDTT+DTT CUMDTT:CUMDTT+DTT GO TO (1,2,3,4,5,6,7,8,9), ISTAGE ***§§***************§DETERMINE SOWING DATEiifii*************§***** CALL CALDAT WRITE (16,220) WRITE (16,130) MO,ND,IYR,JDATE,CUMDTT NDAS:O. CALL PHASEI IF (ISWSWB.EQ.0) RETURN CUMDEP:0. D0 30 L:1,4 CUMDEP:CUMDEP+DLAYR(L) IF (SDEPTH.LT.CUMDEP) GO TO no CONTINUE L0=L RETURN ' **.************DETERMINE GERMINATION DATE*********************** IF (ISWSWB.E0.0) GO TO 50 IF (SW(LO).GT.LL(LO)) GO TO 50 SWSD=(SW(LO)-LL(L0))*0.65+(SW(L0+1)-LL(LO+1))*O.35 NDAS=NDAS+1 IF(NDAS.LT.40) GO TO us ISTAGE:5 PLANTS=0.01 WRITE (6,100) FORMAT (1X,'CROP FAILURE BECAUSE OF LACK OF GERMINATION', 77 1 ' WITHIN 40 DAYS OF SOWING') GPP=1. GRNWT:O. RETURN 45 IF(SWSD.LT.0.02) RETURN 50 CALL CALDAT WRITE (16,140) MO,ND,IYR,JDATE,CUMDTT,CET,CRAIN,PESW CALL PHASEI RETURN *****************DETERMINE SEEDLING EMERGENCE DATE************** 9 RTDEP:RTDEP+O.15*DTT IF (SUMDTT.LT.P9) RETURN CALL CALDAT WRITE (16,150) MO,ND,IYR,JDATE,CUMDTT,CET,CRAIN,PESW CALL PHASEI RE **EB§§*********DETERMINE END OF JUVENILE STAGE****************** 1 IF (SUMDTT.LT.P1) RETURN CALL CALDAT IF(ISWSWB.NE.0) CSC1=CSD1/ICSDUR IF(ISWSWB.NE.O) CSDZ:CSD2/ICSDUR WRITE(16,160) MO,ND,IYR,JDATE,CUMDTT,BIOMAS,LAI,CSD1,CET,CRAIN,PESW IF(ISWSWB.NE.O)WRITE(8,280) IYR,JDATE,BIOMAS,LAI,CSD1,CSD2, CALL PHASEI RETURN **************DETERMINE DATE OF TASSEL INITIATION************** 2 DEC=O.4093*SIN(0.0172*(JDATE-82.2)) DLV:(-S1*SIN(DEC)-O.1047)/(C1*COS(DEC)) IF(DLV.LT.-.87) DLV:—.87 HRLT=7.639*ACOS(DLV) IF (HRLT.LT.12.5) HRLT:12.5 RATEIN=1./(4.+P2*(HRLT-12.5)) SIND=SIND+RATEIN IF (SIND.LT.1.0) RETURN CALL CALDAT IF (ISWSWB.NE.O) CSD1=CSD1/ICSDUR IF (ISWSWB.NE.O) CSD2=CSD2/ICSDUR WRITE(16,360) MO,ND,IYR,JDATE,CUMDTT,BIOMAS,LAI,CSD1,CET,CRAIN,PESW IF(ISWSWB.NE.0)WRITE(8,280) IYR,JDATE,BIOMAS,LAI,CSD1,CSD2, CALL PHASEI RETURN ***********DETERMINE END OF LEAF GROWTH (AND SILKING)********** 3 IF (SUMDTT.LT.P3) RETURN CALL CALDAT MAXLAI=LAI ISDATE=JDATE IF (ISWSWB.NE.O) CSD1:CSD1/ICSDUR IF (ISWSWB.NE.0) CSD2=CSD2/ICSDUR WRITE(16,380) MO,ND,IYR,JDATE,CUMDTT,TLNO,BIOMAS,LAI,CSD1,CET,CRAIN +,PESW IF(ISWSWB.NE.0)WRITE(8,280) IYR,JDATE,BIOMAS,LAI,CSD1,CSD2, CALL PHASEI RETURN *****DETERMINE BEGINNING OF EFFECTIVE GRAIN FILLING PERIOD******* 78 4 IF (SUMDTT.LT.17O.) RETURN CALL CALDAT PSKER=SUMP*1000/IDURP*3.4/5.0 GPP=02*(PSKER-195.0)/(1213.2+PSKER-195.0) IF (GPP.LT.0.0)GPP=0.0 EARS:PLANTS C******DETERMINE BARRENESS**** IF (GPP.LT.G2*0.55)EARS=PLANTS*((OPP-50.)/(02-50))**0.33 IF(EARS.LT.0.0)EARS = 0.0 GPSM:GPP*EARS IF (ISWSWB.NE.0) CSD1=CSD1/ICSDUR IF (ISWSWB.NE.0) CSD2=CSD2/ICSDUR WRITE(16,400) MO,ND,IYR,JDATE,CUMDTT,BIOMAS,LAI,CSD1,CET,CRAIN,PESW C IF(ISWSWB.NE.0)WRITE(8,280) IYR,JDATE,BIOMAS,LAI,CSD1,CSD2, CALL PHASEI RETURN c ***********************DETERMINE END OF EFFECTIVE FILLING PERIOD* 5 IF (SUMDTT.LT.0.95*P5) RETURN CALL CALDAT IF (ISWSWB.NE.O) CSD1:CSD1/ICSDUR IF (ISWSWB.NE.0) CSD2=CSD2/ICSDUR WRITE(16,440) MO,ND,IYR,JDATE,CUMDTT,GPP,BIOMAS,LAI,CSD1,CET,CRAIN, +PESW ' C IF(ISWSWB.NE.0)WRITE(8,280) IYR,JDATE,BIOMAS,LAI,CSD1,CSD2, CALL PHASEI RETURN C WNNNMNNNNNNWMNNNWNNNNNNDETERM1N3 PHYSIOLOGICAL MATURITyiifiiiiiiii 6 IF (DTT.EQ.0.0)SUMDTT:P5 IF (SUMDTT.LT.P5)RETURN MDATEzJDATE CALL CALDAT WRITE(16,480) MO,ND,IYR,JDATE,CUMDTT,BIOMAS,LAI YIELD=GRNWT*10.*EARS YIELD:YIELD/0.845 SKERWTzGRNWT/GPP GPSM:GPP*EARS YIELDB:YIELD/62.8 IF (ISLKJD.EQ.0)PLSEMS:0.0 IF (ISLKJD.NE.0) PLSEMS:ISLKJD-ISOW IF(PLSEMS.LT.0)PLSEMS = 365.-ISOW + ISDATE PLSEPR=ISDATE-ISOW IF(PLSEPR.LT.0)PLSEPR:365.-ISOW + ISLKJD IF (MATJD.EQ.0 .OR. ISLKJD .80. 0) SEMTMS=0.0 IF (MATJD.NE.0.AND.ISLKJD.NE.0)SEMTMS=MATJD-ISLKJD IF(SEMTMS.LT.0)SEMTMS:365. - ISDATE + MDATE SEMTPRzMDATE-ISDATE IF(SEMTPR.LT.0)SEMTPR:365. - ISLKJD + MATJD c WRITE(09,311) KVARTY,YIELD,XYIELD,GPP,XGPE,PLSEPR,PLSEMS, C 25EMTPR,SEMTMS c311 FORMAT(I3,2X,2F7.0,2F5.0,4F5.0) WRITE(16,305) 306 FORMAT(/1X,' YIELD = ',F6.0,' BUSHELS/ACRE') WRITE(16,310) ISDATE,ISLKJD,MDATE,MATJD,YIELD,XYIELD,SKERWT,XGRWT, 1GPSM,XGPSM,GPP,XGPE,MAXLAI,XLAI,BIOMAS,XBIOM 000 79 CALL PHASEI RETURN 135 FORMAT(/1X,1X,I2,'/',12,'/',I2,1X,I3,5X,' SOWING') 130 FORMAT (1H ,1X,12,'/',12,'/',I2,1X,I3,1X,F5.0,2X,'SOWING',13X,'BIO +MASS',3X,'LAI',4X,'CSD1',2X,'ET',2X,'PREC',1X,'PESW') 140 FORMAT (1H ,1X,12,'/',12,'/',12,1X,I3,1X,F5.0,2X,'GERMINATION',30X +,F4.0,1X,F4.0,1X,F4.1) 150 FORMAT (1H ,1X,I2,'/',I2,'/',12,1X,I3,1X,F5.0,2X,'EMERGENCE',32X,F +4.0,1X,F4.0,1X,F4.1) 160 FORMAT (1H ,1X,12,'/',12,'/',12,1X,I3,1X,F5.0,2X,'END JUVENILE STA +GE',1X,F5.0,3X,F4.2,5X,F4.2,1X,F4.0,1X,F4.0,1X,F5.1) 220 F0RMAT(1H ,1OX,'JUL',3X,'CUM',34X,'WATER BALANCE COMPONENTS',/,4X, 1'DAY',4X,'DAY',3X,'DTT',3X,'PHENOLOGICAL STAGE',2X,'CUMULATIVE 2 AFTER GERMINATION',/) 280 FORMAT (3X,12,2X,I3,2X,F5.0,2X,3(F5.2,2X),5(F6.1,2X)) 360 FORMAT (1H ,1X,I2,'/',I2,'/',12,1X,I3,1X,F5.0,2X,'TASSEL INITIATIO +N',2X,F5.0,3X,F4.2,5X,F4.2,1X,F4.0,1X,F4.0,1X,F5.1) 380 FORMAT (1H ,1X,I2,'/',12,'/',I2,1X,I3,1X,F5.0,2x,'SILKING, LNO: 1, +F4.1,1X,F5.0,3X,F4.2,5X,F4.2,1X,F4.0,1X,F4.0,1X,F5.1) u00 FORMAT (1H ,1X,12,'/',12,'/',12,1X,I3,1X,F5.0,2X,'BEGIN GRAIN FILL +',3X,F5.0,3X,F4.2,5X,F4.2,1X,F4.0,1X,F4.0,1X,F5.1) uuo FORMAT (1H ,1X,I2,'/',12,'/',12,1X,I3,1X,F5.0,2X,'END FILL, GPP=', +F4.0,1X,F5.0,3X,F4.2,5X,F4.2,1X,F4.0,1X,F4.0,1X,F5.1) 480 FORMAT(1H ,1X,12,'/’,12,'/',I2,1X,I3,1X,F5.0,2X,'PHYSIO MATURITY', +4X,F5.0,3X,F4.2) 305 FORMAT (1X,/,26X,'PREDICTED VALUES',5X,'MEASURED VALUES',/) 310 FORMAT (1X,'SILKING JD',20X,I3,15X,I3,/,1X,'MATURITY JD',21X,I3, *15X,I3,/,1X,'GRAIN YIELD KG/HA (15)',5X,F7.0,11X,F7.0,/,1X, *‘KERNEL WEIGHT 0 (DRY)',6X,F7.4,11X,F7.4,/,1X,'FINAL GPSM', *19X,F7.0,11X,F *7.0,/,1X,'GRAINS/EAR',20X,F6.0,12X,F6.0,/,1X,'MAX. LAI',21X,F6.2, *12X,F6.2,/,1X,'BIOMASS G/SM',16X,F7.0,11X,F7.0,/) END NWNWNHNNNWNNNWNNNWNWNNHMWNNNNN GROWTH SUBROUTINE §***§§§***§§§**§ SUBROUTINE GROSUB REAL LAT,LL,LAI,LFWT,MAXLAI COMMON /CLIMT/ TEMPMN,TEMPMx,RAIN,SOLRAD,TMFAC(8) COMMON /DATEC/ MO,ND,IYR,JDATE,JDATEx,IDIM(12) COMMON /PARAM/ISOW,PLANTS,KOUTGR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /GENET/ P1,P2,P3,P5,G2,G3 COMMON /PHENL/ CUMDTT,TBASE,SUMDTT,S1,C1,ISTAGE,JJDATE, 1 DTT,IDUR,CUMPH,SSTT,CSTT,SIND,P9,TEMPM COMMON /CR0TH/ GPSM,GPP,GR0RT,LAI,BIOMAS,PLA,SENLA,PTF,TLNO, 1 LFWT,SEEDRV,REGM,LN,XPLANT,RTWT,STMWT,GRNWT,SWMIN,LWMIN, 1 EARWT,EMAT,SUMP,IDURP,PLAY,PLAMX,CARBO,XN,XNTI, 1 PLAG,GROSTM,GBLA(35),SLA(35),EARS COMMON /WATER/ SUMES1,SUMES2,T,TLL,PESW,TSW,CUMDEP,ESW(10), 20 25 21 80 1 CSD1,CSD2,SI1(5),SIz(5),ICSDUR,ES,EP,ET,E0,CES,CEP,CET, 1 RLV(1O),PRECIP,CRAIN,DRAIN,IDRSW,RTDEP,SWDF1,SWDF2, SWDF3,TRWU,RWUMX,SUMIR,SWUT CLG=4.5 PAR:0.02*SOLRAD PCARB=5.0*PAR/PLANTS*(1.-EXP(-0.65*LAI)) PRFT=1.-0.0025*((0.25*TEMPMN+0.75*TEMPMX)-26.)**2 IF (PRFT.LT.0.) PRFT:0. CARBO=PCARB*AMIN1(PRFT,SWDF1) IF(ISTAGE.GT.3) GO TO 12 PC=1. IF(CUMPH.LT.5) PC:.66+0.068*CUMPH TI:DTT/(38.9 *PC) CUMPH:CUMPH + DTT/(38.9*PC) XN:CUMPH + 1. LN:XN GO TO (1,2,3,4,5,6),ISTAGE PLAG=CLG*XN*XN*TI*SWDF2 IF(XN.LT.4.) PLAG:3.*XN*TI*SWDF2 PLA:PLA+PLAG XLFWT:(PLA/267.)**1.25 GROLF:XLFWT-LFWT GRORT=CARBO-GROLF IF (GRORT.GT.0.25*CARBO) 00 T0 20 GRORT:CARBO*O.25 SEEDRV=SEEDRV+CARBO—GROLF-GRORT IF (SEEDRV.GT.O.) GO TO 20 SEEDRV:O. GROLF:CARBO*0.75 FLA:(LFWT+GROLF)**0.8*267. LFWT=LFWT+GROLF SLAN=SUMDTT*PLA/10000. GO TO n0 PLAG=CLG*XN*XN*TI*SWDF2 PLA:PLA+PLAG XLFWT=(PLA/267.)**1.25 GROLF=XLFWT-LFWT IF (GROLF.LT.CARBO*0.75) GO TO 25 GROLF=CARBO*0.75 PLA:(LFWT+GROLF)**0.8*267. GRORT:CARBO-GROLF LFWT:LFWT+GROLF SLAN:SUMDTT*PLA/10000. GO TO n0 IF (XN.GE.12.) GO TO 21 PLAG = CLG * XN * XN * TI * SWDF2 GROLF = 0.00116 * PLAG * PLA ** 0.25 GROSTM = GROLF F 0.0182*(XN-XNTI)**2 GO TO 2n . IF (XN.GE.TLNO-3.) GO TO 22 PLAG = CLG * 170. * TI * SWDF2 GROLF = 0.00116 * PLAG * PLA ** 0.25 GROSTM = GROLF*0.0182*(XN-XNTI)**2 GO TO 2n 300 301 22 24 30 10 33 34 81 PLAG = 170. F CLG / ((XN + 5. - TLN0)FF0.5)FTIFSWDF2 GROLF = 0.00116 F PLAG F PLA FF0.25 GROSTM = 3.100 F CLG F TI F SWDF2 GRORT = CARBO - GROLF - GROSTM IF (GRORT.GT.0.10FCARBO) GO TO 30 GRF=CARBOF0.90/(GROSTM+GR0LF) GROLF=GR0LFFGRF GROSTM=GROSTMFGRF GRORT=CARBOF0.1O PLA:(LFWT+GR0LF)FF0.8F267. LFWT=LFWT+GR0LF SLAN:PLA/1000. STMWT:STMWT+GROSTM GO TO n0 GROEAR=0.22FDTTFSWDF2 GROSTM=GR0EARF0.n0 GRORT:CARBO-GROEAR-GROSTM IF(GRORT.GE.0.08FCARBO) GO TO 10 GRF=CARBOF0.92/(GR0EAR+GROSTM) GRORT=CARBOF0.08 GROEAR=GR0EARFGRF GROSTM=GROSTMFGRF SLAN=PLAF(0.05+SUMDTT/170.F0.05) EARWTzEARWT+CROEAR STMWT:STMWT+GROSTM SUMP:SUMP+CARBO IDURP=IDURP+1 GO TO n0 IF (PLANTS.EQ.0.01) RETURN SLAN:PLAF(0.1+0.80F(SUMDTT/P5)F*3) RGFILL:0.0 RGFILL=1.0-0.0025F(TEMPM-26)FF2 IF(RGFILL.LT.0.) RGFILL:0. GROGRN:RGFILL*GPP*G3*0.001 IF (RGFILL .GT. 0.1)00 TO 300 EMAT:EMAT+1 . IF(EMAT .E0. 1.) GO TO 301 SUMDTT = P5 EMATzO. CONTINUE GRORT:0. GROSTM=CARBO-GROGRN IF(GROSTM.LT.0.) GO TO 33 STMWT=STMWT+GROSTMF0.5 GRORT=GROSTMF0.5 IF(SUMDTT/P5.LT.0.08) GPP=GPPF(1.+0.00nFGR0RT) GO TO 35 STMWT=STMWT+CARBO-GROGRN IF(STMWT.GT.SWMINF1.07) GO TO 35 IF(LFWT.LE.LWMIN) GO TO 3n STMWT=STMWT+LFWTF0.0050 LFWT:LFWT*0.9950 IF(STMWT.GE.SWMIN) GO TO 35 STMWT:SWMIN 0000 82 GROGRN=CARBO GRNWT=GRNWT+GROGRN EARWT=EARWT+GROGRN SLFW=O.95+0.05*SWDF1 SLFC=1.0 IF(LAI.GT.4.)SLFC:1.-0.008*(LAI-4.) SLFT=1. IF(TEMPMN.GT.O.)GO TO 50 SLFT=1.-0.0015*(TEMPMN+TEMPM+20.)**2 IF(SLFT.LT.O.)SLFT=O. PLAS=(PLA-SENLA)*(1.0-AMIN1(SLFW,SLFC,SLFT)) SENLA=SENLA+PLAS IF(SENLA.LT.SLAN)SENLA=SLAN IF(SENLA.GE.PLA)SENLAzPLA LAI=(PLA-SENLA)*PLANTS*0.0001 RTWT:RTWT+O.5*GRORT-0.005*RTWT BIOMAS:(LFWT+STMWT+EARWT)*PLANTS PTF:(LFWT+STMWT+EARWT)/(RTWT+LFWT+STMWT+EARWT) RETURN END ****************************** WRITE SUBROUTINE §§*********ii**** SUBROUTINE WRYTE COMMON /PARAM/ISOW,PLANTS,KOUTGR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /CLIMT/ TEMPMN,TEMPMx,RAIN,SOLRAD,TMFAC(8) COMMON /WRITS/ AES,AEP,AET,AE0,ASOLR,ATEMx,ATEMN,ARUN0F, 1 ADRAIN,APRECP,ASWDF1,ASWDF2,IOUTGR,IOUTWA,JHEAD,KHEAD, 2 TPRECP,RUNOFF COMMON /WATER/ SUMES1,SUMEsz,T,TLL,PESW,TSW,CUMDEP,ESW(10), 1 CSD1,CSD2,SI1(5),SI2(5),ICSDUR,ES,EP,ET,EO,CES,CEP,CET, 1 RLV(10),PRECIP,CRAIN,DRAIN,IDRSW,RTDEP,SWDF1,SWDF2, 1 SWDF3,TRWU,RWUMX,SUMIR,SWUT COMMON /PHENL/ CUMDTT,TBASE,SUMDTT,S1,C1,ISTAGE,JJDATE, 1 DTT,IDUR,CUMPH,SSTT,CSTT,SIND,P9,TEMPM COMMON /GROTH/ GPSM,GPP,GRORT,LAI,BIOMAS,PLA,SENLA,PTF,TLNO, 1 LFWT,SEEDRV,REGM,LN,xPLANT,RTWT,STMWT,GRNWT,SWMIN,LWMIN, 1 EARWT,EMAT,SUMP,IDURP,PLAY,PLAMX,CARBO,XN,XNTI, 1 PLAG,GROSTM,GBLA(35),SLA(35),EARS CRAIN:CRAIN+PRECIP IF (KOUTWA.EQ.0) GO TO 10 IOUTWA:IOUTWA+1 AES:AES+ES AEP=AEP+EP AET=AET+ET AEO:AEO+E0 ASOLRzASOLR+SOLRAD ATEMX=ATEMX+TEMPMX ATEMN=ATEMN+TEMPMN IF (IOUTWA.EQ.KOUTWA) CALL OUTWA 000 83 10 IF (KOUTGR.EQ.O) RETURN IF (ISTAGE.GT.6) RETURN IOUTGR:IOUTGR+1 ASWDF1=ASWDF1+SWDF1 ASWDF2:ASWDF2+SWDF2 IF (IOUTGR.EQ.KOUTGR) CALL OUTGR RETURN END *i*§*§**** pHASE INITIALIZATION SUBROUTINE WNNNNMMNNNNWMNNWNNMNMW SUBROUTINE PHASEI REAL LAT,LL,LAI,LFWT,MAXLAI COMMON /PARAM/ISOW,PLANTS,KOUTGR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /SOILI/ SALB,SWCON,CN2,DLAYR(10),DUL(10),LL(10),SW(10), 1 SAT(10),DEPMAX,TDUL,NLAYR,SMX,WF(10),WR(10),RWU(10),SWEF COMMON /WATER/ SUMES1,SUMESZ,T,TLL,PESW,TSW,CUMDEP,ESW(10), 1 CSD1, CSD2 ,SI1(5), 512(5), ICSDUR, ES, EP, ET, E0, CES, CEP ,CET, 1 RLV(10), PRECIP, CRAIN, DRAIN, IDRSW, RTDEP, SWDF1, SWDF2, 1 SWDF3, TRWU, RWUMX, SUMIR, SWUT COMMON /PHENL/ CUMDTT, TBASE ,SUMDTT,S1,C1,ISTAGE,JJDATE, 1 DTT,IDUR,CUMPH,SSTT,CSTT,SIND,P9,TEMPM COMMON /GROTH/ GPSM,GPP,GRORT,LAI,BIOMAS,PLA,SENLA,PTF,TLNO, 1 LFWT,SEEDRV,REGM,LN,XPLANT,RTWT,STMWT,GRNWT,SWMIN,LWMIN, 1 EARWT,EMAT,SUMP,IDURP,PLAY,PLAMX,CARBO,XN,XNTI, 1 PLAG,GROSTM,GBLA(35),SLA(35),EARS COMMON /GENET/ P1,P2,P3,P5,G2,G3 IF (ISTAGE.GT.5) GO TO 32 SI1(ISTAGE)=CSD1 SI2(ISTAGE)=CSD2 CSD1=O. CSDZ=O. ICSDUR=O GO TO (1,2,3,4,5,6,7,8,9), ISTAGE ISTAGE:2 SIND:O. RETURN ISTAGE:3 TLNO=IFIX(CUMDTT/21.+6.0) P3=(TLNO - 2.)*38.9+96.-SUMDTT XNTI:XN SUMDTT=O. RETURN ISTAGE:4 EARWT=O.167*STMWT STMWT:STMWT-EARWT SWMIN=STMWT*.8 PTF:1.0 SUMP:O IDURP=O SUMDTT:SUMDTT-P3 90 84 PLAMX:PLA RETURN ISTAGE=5 LWMIN=LFWT*0.85 EMAT=0 RETURN ISTAGE=6 RETURN ISTAGE:7 CUMDTT:O. CRAIN=O. CES=O. CEP:O. CET:O. DTT:O. RETURN ISTAGE:8 RTDEP:SDEPTH SUMDTT:O. RETURN ISTAGE=9 CET:O. P9=15.+6.*SDEPTH CES:0. CEP:O. CUMDTT:O. CRAIN:O. SUMDTTzO. TBASE=10. RETURN ISTAGE=1 P3=400. SUMDTT:SUMDTT-P9 CUMDTT:CUMDTT-P9 PLA:1.0 PLAY=1.0 PLAG:0.0 LAI=PLANTS*PLA*0.0001 LFWT:O.20 SEEDRV:O.2O D0 90 I 21935 SLA(I)=0.0 GBLA(I)=0.0 CONTINUE STMWT=O. GROSTMzo. GRNWT:O. EARWT:O. SENLA=O. GRORT:O. RTWTzLFWT BIOMAS:O. REGM=1. IDUR:0 00000 100 110 120 121 130 85 CUMPH:.514 TLNO=30. CSD1=0.0 CSD2=0.0 TBASE=8.0 CUMDEP=O. LN=1 IF (ISWSWB.EQ.0) RETURN DO 100 L:1,NLAYR CUMDEP:CUMDEP+DLAYR(L) RLV(L)=0.20’PLANTS/DLAYR(L) IF (CUMDEP.GT.RTDEP) GO TO 110 CONTINUE RLV(L):RLV(L)*(1.-(CUMDEP-RTDEP)/DLAYR(L)) L1=L+1 IF (L1.GE.NLAYR) GO TO 121 D0 120 L=L1,NLAYR DO 130 L:1,NLAYR RWU(L)=O. RETURN END *******************Ngw SUBROUTINE FOR SENINAR********§***********§ SUBROUTINE PARMFLS REAL LAI COMMON /PARAM/ISOW,PLANTS,KOUTGR,KOUTWA,SDEPTH,IIRR, 1 LAT,KVARTY,KSOIL,IQUIT,NEWSOL,NEWWET,MULTYR,ISWSWB,U, 2 SOILN,ISLKJD,MATJD,XYIELD,XGRWT,XGPSM,XGPE,XLAI,XBIOM, 3 IDATE,ICDTT COMMON /FILE/SWATER,CIRRIG,WEATHER,CGENET,MISOIL,WATCORN,BIOCORN CHARACTER ASW CHARACTERF12 BIOCORN CHARACTERF12 CIRRIG CHARACTERF12 SWATER CHARACTERF12 CGENET CHARACTERF12 WATCORN CHARACTERF12 MISOIL CHARACTERF12 WEATHER REAL LAT 0PEN(100,FILE='PARM',ACCESS:'SEQUENTIAL',STATUS='OLD') READ(100,510) WEATHER,CGENET,MISOIL,ASW,CIRRIG,SWATER,KVARTY, 1 KSOIL,ISOW,SDEPTH,LAT,PLANTS,KOUT,ISLKJD,MATJD,XYIELD,XGRWT READ( 100,520) XGPSM,XGPE,XLAI ,XBIOM,SOILN,BIOCORN,WATCORN 90 CONTINUE WRITE(*,100) 100 FORMAT(1H1,' PLEASE CHOSE THE PARAMETER YOU WISH TO CHANGE.') WRITE(*,110) 110 FORMAT(/1X,’ ENTER ZERO (0) IF NONE.') WRITE(*,120) WEATHER,KOUT 86 120 FORMAT(//1X,' 1. WEATHER FILE = ',A12,7X,' 13. FREQUENCY OF OUTPU 1T = ' 12) WRITE(F,130) CGENET,ISLKJD 130 FORMAT(1X,‘ 2. GENETICS FILE = ',A12,6X,' 1n. DATE OF SILKING = 1',13) WRITE(F,1n0) MISOIL,MATJD 1n0 FORMAT(1X,‘ 3. SOILS FILE = ',A12,9x,' 15. DATE OF MATURITY = v, 113) WRITE(F,150) ASW,XYIELD 150 FORMAT(1X,‘ n. IRRIGATION DATA (Y/N) = ', A1,9X,' 16. GRAIN YIELD 1 (KG/HA) = ',F6.0) WRITE(*.160) CIRRIG,XGPSM 160 F0RMAT(1x,I 5. IRRIGATION FILE = ',A12,4X,' 17. NUMBER OF GRAINS/ 1M**2 : ’,F6.0) WRITE(F, 170) SWATER,XGPE 170 FORMAT(1X,‘ 6. INITIAL SW FILE = ',A12,4X,' 18. NUMBER OF GRAINS/ 1EAR = ',F4.0) WRITE(*,180) KVARTY,XLAI 180 FORMAT(1X,’ 7. THE CROP VARIETY NUMBER = 1,13,5x,' 19. MAXIMUM LA 11 = ',F4.1) WRITE(F,190) KSOIL,XBIOM 190 FORMAT(1X,’ 8. THE SOIL NUMBER = ',I3,13X,' 20. BIOMASS (GRAMS/MF 1F2) : ',F5.0) WRITE(F,200) ISOW,SOILN 200 FORMAT(1X,‘ 9. THE SOWING DATE = ',I3,13X,' 21. SOILN = ',F3.1) WRITE(F,210) SDEPTH,BIOCORN 210 FORMAT(1X,‘ 10. THE SOWING DEPTH = ',F3.1,11X,' 22. BIOMASS OUTPU 1T FILE = ',A12) WRITE(F,220) LAT,WATCORN 220 FORMAT(1§,' 11. THE LATITUDE = ‘,F4.1,14X,' 23. WATER 0UPUT FILE 1: ',A12 WRITE(F,230) PLANTS,XGRWT 230 FORMAT(1X,’ 12. PLANTS/MFF2 = ',F4.1,15X,' 2n. GRAIN WEIGHT (DRY) 1 = ',F4.2) WRITE(F,232) 232 FORMAT(1X,' ') WRITE(F,233) 233 FORMAT(1X,’ ') WRITE(F,23n) 23n FORMAT(////1x, ' ') READ(F,2nO) ICHOSE 2n0 FORMAT( 12) IF(ICHOSE.LT.0.0R.ICHOSE.GT.2n) GOTO n90 IF(ICHOSE.LT.1) GOTO 500 IF(ICHOSE.LT.2) GOTO 250 IF(ICHOSE.LT.3) GOTO 260 IF(ICHOSE.LT.n) GOTO 270 IF(ICHOSE.LT.5) GOTO 280 IF(ICHOSE.LT.6) GOTO 290 IF(ICHOSE.LT.7) GOTO 300 IF(ICHOSE.LT.8) GOTO 310 IF(ICHOSE.LT.9) GOTO 320 IF(ICHOSE.LT.10) GOTO 330 IF(ICHOSE.LT.11) GOTO 3n0 250 251 260 261 270 271 28 O 281 290 291 300 301 310 311 31 320 321 32 330 331 N N IF(ICHOSE.LT.12) IF(ICHOSE.LT.13) IF(ICHOSE.LT.1n) IF(ICHOSE.LT.15) IF(ICHOSE.LT.16) IF(ICHOSE.LT.17) IF(ICHOSE.LT.18) IF(ICHOSE.LT.19) IF(ICHOSE.LT.20) IF(ICHOSE.LT.21) IF(ICHOSE.LT.22) IF(ICHOSE.LT.23) IF(ICHOSE.LT.24) IF(ICHOSE.LT.25) WRITE(F,251) GOTO 350 GOTO 360 GOTO 370 GOTO 380 GOTO 390 GOTO 400 GOTO 410 GOTO 420 GOTO 430 GOTO 440 GOTO 450 GOTO 460 GOTO 470 GOTO 480 87 FORMAT(/1X,' PLEASE ENTER CORRECT WEATHER FILE NAME.') READ(F,'(A)') WEATHER GOTO 90 WRITE(F,261) FORMAT(/1X,' PLEASE ENTER CORRECT GENETICS FILE NAME.') READ(F,'(A)') CGENET GOTO 90 WRITE(*,271) FORMAT(/1X,' PLEASE ENTER CORRECT SOIL FILE NAME.') READ(F,'(A)') MISOIL GOTO 90 IF(ASW.EQ.'N') GOTO 281 ASW='N' GOTO 90 ASW='Y' GOTO 90 WRITE(F,291) FORMAT(/1X,' PLEASE ENTER CORRECT IRRIGATION FILE NAME.') READ(*,'(A)') CIRRIG GOTO 90 WRITE(*,301) FORMAT(/1X,‘ PLEASE ENTER CORRECT INITIAL SOIL WATER FILE NAME.') READ(*,'(A)') SWATER GOTO 90 WRITE(F,311) FORMAT(/1X,’ PLEASE ENTER CORRECT CROP VARIETY NUMBER (000).') READ(*,312) KVARTY FORMAT( I3) GOTO 90 WRITE(*,321) FORMAT(/1X,’ PLEASE ENTER CORRECT SOIL NUMBER (000).') READ(*,322) KSOIL FORMAT( I3) GOTO 90 WRITE(*,331) FORMAT(/1X,’ PLEASE ENTER CORRECT SOWING DATE (000).') READ(*,332) ISOW FORMAT( I3) GOTO 90 340 341 342 350 351 352 360 361 362 370 371 372 380 381 382 390 391 392 400 401 402 410 411 n12 n20 n21 422 430 431 432 440 441 WRITE(*,341) 88 FORMAT(/1X,‘ PLEASE ENTER CORRECT SOWING DEPTH (0.0) CM.') READ(F,3n2) SDEPTH FORMAT( F3.1) GOTO 90 WRITE(F,351) FORMAT(/1X,’ PLEASE ENTER CORRECT LATITUDE (00.0).') READ(F,352) LAT FORMAT( Fn.1) GOTO 90 WRITE(F,361) FORMAT(/1X,’ PLEASE ENTER THE 1).') READ(*,362) PLANTS FORMAT( F4.1) GOTO 90 WRITE(*,371) FORMAT(/1X,‘ PLEASE ENTER 1 (00).') READ(F,372) KOUT FORMAT( 12) GOTO 90 WRITE(F,381) FORMAT(/1X,' PLEASE ENTER READ(F,382) ISLKJD FORMAT( 13) GOTO 90 WRITE(*.391) FORMAT(/1X,' PLEASE ENTER READ(*,392) MATJD FORMAT( I3) GOTO 90 WRITE(F,n01) FORMAT(/1X,' PLEASE ENTER READ(F,n02) XYIELD FORMAT( F6.0) GOTO 90 WRITE(F,n11) FORMAT(/1X,’ PLEASE ENTER READ(F,n12) XGPSM FORMAT( F6.0) GOTO 90 WRITE(F,n21) FORMAT(/1X,' PLEASE ENTER READ(F,n22) XGPE FORMAT( Fn.0) GOTO 90 WRITE(F,n31) FORMAT(/1X,' PLEASE ENTER READ(F,n32) XLAI FORMAT( Fn.1) GOTO 90 WRITE(F,nn1) FORMAT(/1X,‘ PLEASE ENTER THE CORRECT CORRECT CORRECT CORRECT CORRECT CORRECT CORRECT CORRECT CORRECT NUMBER OF PLANTS/M**2 (00.0 FREQUENCY OF DAYS FOR OUTPUT DATE OF SILKING (000).') DATE OF MATURITY (000).') YIELD (00000.).') GRAINS/MFF2 (00000.).') GRAINS/EAR (000.).') MAXIMUM LAI (00.0).’) BIOMASS (GRAMS/M**2 - 0000.) 000 000 89 1.1) READ(F,nnz) XBIOM nn2 FORMAT( F5.0) GOTO 90 n50 WRITE(F,n51) n51 FORMAT(/1X,' PLEASE ENTER THE CORRECT VALUE FOR SOILN (0.0).') READ(F,n52) SOILN n52 FORMAT( F3.1) GOTO 90 460 WRITE(*,461) 461 FORMAT(/1X,’ PLEASE ENTER THE CORRECT BIOMASS OUTPUT FILE NAME.') READ(*,'(A)') BIOCORN GOTO 90 470 WRITE(*,471) 471 FORMAT(/1X,' PLEASE ENTER THE CORRECT WATER BALANCE OUTPUT FILE NA 1ME.') READ(*,'(A)') WATCORN GOTO 90 480 WRITE(*,481) 481 FORMAT(/1X,' PLEASE ENTER THE CORRECT GRAIN WEIGHT (GRAMS - 0.00). 1') READ(F,n82) XGRWT n82 FORMAT( Fn.2) GOTO 90 n90 WRITE(F, n95) n95 FORMAT(1x, ' PLEASE CHOOSE A NUMBER BETWEEN 0 AND 23. ') GOTO 90 500 CLOSE(100) 0PEN(100,FILE:'PARM',ACCESS:'SEQUENTIAL',STATUS:'OLD') WRITE(100,510) WEATHER,CGENET,MISOIL,ASW,CIRRIG,SWATER,KVARTY, 1 KSOIL,ISOW,SDEPTH,LAT,PLANTS,KOUT,ISLKJD,MATJD,XYIELD,XGRWT WRITE(100,520) XGPSM,XGPE,XLAI,XBIOM,SOILN,BIOCORN,WATCORN 510 F0RMAT(A12,A12,A12,A1,A12,A12,313,F3.1,2Fn.1,12,213,F6.0,Fn.2) 520 F0RMAT(F6.0,Fn.0,Fn.1,F5.0,F3.1,A12,A12) CLOSE(100) KOUTWA=K0UT KOUTGR:KOUT IF(ASW.EQ.’Y') IIRR:5 IF(ASW.EQ.'N') IIRR:0 RETURN END SUBROUTINE CDMOD SUBROUTINE TO CONTROL SWITCHING BETWEEN DRAINMOD AND CERES COMMON/CDNO/LOPC,MFLAG,LOPE,IQUIT3,JDATE3,JDAY3 COMMON/DATEC/MO,ND,IYR3,JDATE,JDATEX,IDIM(12) DIMENSION HOURLY(744),ET(31),FACTOR(12) 10 IF (MFLAG .NE. 0) GO TO 20 CALL DRAINOD(IYR3,M03,ET,HOURLY,LOOP,IYED,FACTOR,NOPORT) 90 20 CALL FORSUB(IYR3,MO3,ET,HOURLY,LOOP,IYED,FACTOR,NOPORT) 0000 _A 13 0 000 LOPC:LOPC+1 IF (JDAY3.LT.JDATE3) GOTO 10 IF((IQUIT3.GT.1).AND.(LOPE.LT.1)) GO TO 10 IF((LOPE.GT.1).AND.(MFLAG .NE. 0))GO T0 20 IF(IQUIT3.GT.1) CALL PROGRI IF(IQUIT3.LT.-1) RETURN CALL WET RETURN END SUBROUTINE WET SUBROUTINE TO INTEGRATE BETWEEN DRAINMOD'S WATER TABLE AND CERES SOIL WATER CONTENT BY LAYERS COMMON/WHX/WATER(1000),W(101),H(101),X(101),NN,UPVOL,WETZ,WP COMMON/SOILI/ SALB,SWCON,CN2,DLAYR(10),DUL(10),LL(10),SW(10), 1 SAT( 10) ,DEPMAX,TDUL,NLAYR,SMX,WF( 10) ,WR( 10) ,RWU( 10) ,SWEF COMMON/CDET/CDTWT,CROOT,CFVOL,DWET(10),SURWET,TRD60,IPET,PETD,AETC COMMON/DATEC/MO,ND,IYR3,JDATE,JDATEX,IDIM(12) COMMON/EVAPO/PET,DDZ,ROOTD DIMENSION LK(10) WRITE(17,131) UPVOL,WETZ,DDZ,CDTWT FORMAT(1X, 'UPVOL WETZ DDZ CDTWT',4F10.3) IF(NN.GT.10) THEN NN=1 FIND DEPTH TO BOTTOM OF EACH LAYER DEFINED BY CERES LK(1)=DLAYR(1)+1 DO 7 I:2,NLAYR LK(I)=LK(I-1)+DLAYR(I) CONTINUE IDEEP:LK(NLAYR) END IF FIND WATER CONTENT IN SOIL PROFILE FOR EACH LAYER DEFINED BY CERES IDDZ=DDZ+1 CAN MAKE UP :UPVOL/DDZ UP=UPVOL/DDZ SURWET:O. IWETZ=WETZ+1 IWT:CDTWT+1 J=1 SMSW=O. IF(IDDZ.LT.3) GO TO 12 DRY ZONE DO 11 I:2,IDDZ IF(I.LE.LK(J)) THEN SMSW=SMSW+WP+UP IF(I.LT.5)SURWET:SURWET+WP ELSE C C C C C C 000 000 00 91 SW(J)=SMSW/DLAYR(J) SMSW=WP+UP J:J+1 IF(J.GT.NLAYR) GO TO 17 END IF 11 CONTINUE 12 CONTINUE WET ZONE D0 13 I:IDDZ+1,IWT K:IWT-I+1 IF(I. LE. LK(J)) THEN SMSW= SMSW+(WATER(K)+WATER(K+1))/2. IF(I. LT. 5)SURWET= SURWET+(WATER(K)+WATER(K+1))/2. ELSE SW(J)=SMSW/DLAYR(J) - SMSW=WATER(K) J:J+1 IF(J.GT.NLAYR) GO TO 17 END 1F 13 CONTINUE SAT ZONE DO 15 I:IWT+1,IDEEP IF(I.LE.LK(J)) THEN SMSW=SMSW+WATER(1) IF(I.LT.5)SURWET=SURWET+WATER(1) SE SW(J)=SMSW/DLAYR(J) SMSW=WATER(1) J:J+1 IF(J.GT.NLAYR) GO TO 17 END IF 15 CONTINUE 17 SW(J)=SMSW/DLAYR(J) D0 19 I=1,NLAYR IF(SW(I).GT.SAT(I)) SW(I):SAT(I) 19 CONTINUE SURWET Is FOR CALCULATING ES BY SOIL WATER CONTENT IN TOP 3 CM SURWET:SURWET/ 3 .0 FOLLOWING FOR GRAPHING WRITE(11,70)JDATE,CDTWT,(SW(I),I=1,NLAYR) 7O FORMAT(I3,1X,1OF7.3) RETURN END CC 92 SUBROUTINE DRAINOD(KYR,KMO,ET,HOURLY,LOOP,IIYED,FACTOR,NOPORT) CC VERSION: NORTHCAROLINA 2A C C MODIFIED FOR PC FORTRAN AND MODIFIED WEATHER DATA FILES BY PHIL BRINK AND OTHERS CC LANGUAGE: FORTRAN (COMPILERS -66,-G,-H, OR -77) odnnn 00 0000000 THI 100 S MODEL REQUIRES FIVE READ/WRITE FILES: LUN R/W DESCRIPTION 1 R FIELD DATA (DESCRIBED IN USER'S MANUAL) 9 R HOURLY RAINFALL (IN.) 7 R DAILY MIN/MAX TEMPERATURES (FAHREN.) 3 W DAILY/MONTHLY/YEARLY OUTPUTS 10 W A PRINTOUT OF FIELD DATA FILE #1 C C ********************************************************i****** THIS MAIN PROGRAM READS HOURLY PRECIP AND DAILY MAX AND MIN TEMPTURES FROM EITHERCARDS OR DISK (I/O UNIT 9), DETERMINES PET USING THORNTHWAITE METHOD, AND TRANSFERS HOURLY PRECIP AND DAILY PET VALUES BY MONTH TO THE SUBROUTINE FORSUB. COMMON/NAMES/ TITLE1(2O),TITLE2(2O) COMMON/CDNO/LOPC,MFLAG,LOPE,IQUIT3,JDATE3,JDAY3 DIMENSION E(241),TMAX(31),TMIN(31) DIMENSION FACTOR(12) DIMENSION HOURLY(7nn),ET(31),SET(12),IDAYBG(12),REL(366) INTEGER TMAX,TMIN,TITLE1,TITLE2 DIMENSION IDAAY(10),IHOUR(10),AMT(10) DATA SET/.O3,.05,.08,.11,.1n,.17,.16,.1n,.11,.08,.0n,.02/ DATA IDAYBG/0,31,60,91,121,152,182,213,244,274,305,335/ IIYED:0 WRITE (*,*) 'DRAINMOD' IF(LOPC.GT.1) GO TO 5 LOOP=0 LOPE=0 WRITE (F,F) 'ENTER NAME OF RUN FILE? ' READ (F,1oo) FDN WRITE(F,F)'FDN=',FDN OPEN (1,FILE:'TST4',ACCESS:'SEQUENTIAL',STATUS:'OLD') READ (1,100) FIELD,RAIN,TEMP,OUTDAT,ECHODAT CLOSE (1) OPEN (1,FILE:'FDNDAT',STATUS:'OLD') OPEN (9,FILE:'RAIN',STATUS='OLD') OPEN (7,FILE='TEMP',STATUS:'0LD') OPEN (3,FILE='OUTDAT',STATUS='OLD') OPEN (10,FILE='ECHODAT',STATUS:'OLD') OPEN (11,FILE='DAILYW',STATUS:'0LD') FORMAT(A) REWIND 1 REWIND 9 HP 93 REWIND 7 READ(1,610) TITLE1,T1TLE2 WRITE(10,610) T1TLE1,T1TLE2 WRITE(3.619) WRITE(3,620) TITLE1,T1TLE2 READ(1,611) NOPORT WRITE(10,611) NOPORT IF((NOPORT.LT.1).OR.(NOPORT.GT.3)) NOPORT:3 READ(1,6OO) IRID,ITID,IYST,IMST,IIYED,IMED,LAT,HIDx WRITE(1O,600) IRID,ITID,IYST,1MST,IIYED,IMED,LAT,H1Dx READ(1,630) (FACTOR(K),K=1,12) WRITE(1O,63O) (FACTOR(K),K=1,12) I = LAT/100 J = LAT-1F1OO WRITE(3,6nO) IRID,IT1D,IYST,IMST,IIYED,IMED,I,J,H1Dx WRITE(3.6n5) (FACTOR(K),K:1,12) XLAT1 = FLOAT(I) XLAT2 = FLOAT(J) 0000 C C C START OF THORNTHWAITE INITIALCALCULATION REL(1-366) ACCOUNTS FOR EVERYDAY IN A YEAR RLAT=0.0174533*XLAT1+0.0002909*XLAT2 SINLAT=SIN(RLAT) COSLAT=COS(RLAT) DO 50 ND=1,366 XND=ND XM=O.O17226nF(-6.E-1+XND) XLAM:4.874239+XM+0.0334762*SIN(XM)+0.0003502*SIN(XM+XM) YD=O.3979OOFSIN(XLAM) XD=SORT(1.—YDFYD) D:ATAN2(YD,XD) XD=(-O.O1n5nn-(SINLATFSIN(D)))/(COSLATFCOS(D)) YD=sORT(1.-XDFXD) REL(ND)= 0.0111111FATAN2(YD,XD)F57.29578 50 CONTINUE 6 7 E(1-241) ACCOUNTS FOR DAILY TEMPERATURE VARIATION O O 1 Y = ALOG(HIDx) F = n9239.E-5 + H1DXF(1792.E-5 + HIDx*(—771.E-7 + HIDx F 675.E-9)) D0 60 NT =1,12n XNT = NT x = -3863357.E-6 + F F (1021651.E-6 + ALOG(XNT) - Y) ETEMP = EXP(X) E(NT+65) : 24.E-2 IF (ETEMP.LT.2n.E-2) E(NT+65) = ETEMP CONTINUE DO 70 I = 1,65 E(I)=0.0 CONTINUE DO 80 1 = 190,2n1 E(I):24.E-2 94 80 CONTINUE END OF THORNTHWAITE INITIAL CALCULATION POSITION WEATHER FILES 00000 --RAIN FILE 3 READ (9,*,END=3OO) IYEAR,MONTH1 00 00 R. l WRITE(F,F) 'RAIN',IYEAR,MONTH1 IF (IYEAR .GT. IYST) IYST:IYEAR IF (IYEAR .E0. IYST) GO TO n GOTO 3 c C---TEMP FILE n READ (7,*,END=31O) IYEAR,MONTH2 c WRITE(F,F) 'TEMP', IYEAR,MONTH2 1F (IYEAR .GT. IYST) THEN IYST=IYEAR REWIND 7 GOTO 3 END IF IF (IYEAR .LT. IYST) GO TO n IF (MONTH2 .NE. MONTH1) GO TO n C KYR:IYEAR IYRST:IYEAR KMO=MONTH1 GO TO 10 C C C+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ C LOOP BEGINS HERE, READ IN WEATHER DATA ONE MONTH AT A TIME C 5 READ( 9, F, END: 20 ) KYR, KMO 1O CONTINUE DO 11 I = 1, 744 HOURLY(I) : 0.0 11 CONTINUE 12 READ( 9, 520 ) (IDAAY(I),IHOUR(I),AMT(I), 1:1, 7 ) C& C WRITE(F,52O) (IDAAY(I),IHOUR(I),AMT(I),I=1,7) D0 13 IX = 1, 7 IF( IDAAY( 1x ) .E0. 0 ) GO TO 2 IM = ( IDAAY( IK ) — 1 ) F 2n + 1H0UR( IK ) H0URLY( IM ) = AMT( IK ) 13 CONTINUE C C---TEMP DATA C 00000 000000000 20 35 300 310 400 95 SET DAYS OF THE MONTH, MDN IF (KMO.EQ.12) THEN MDN:31 ELSE MDN=IDAYBG(KMO+1)-IDAYBG(KMO) END IF IF (KMO .E0. 2) THEN MDN:28 LPYR1:KYR/4 LPYR2=LPYR1Fn 1F (LPYR2.EQ.KYR) MDN=29 END IF IF (L00P.EO.0) GOTO 25 READ (7,F,END=n1O) IYEAR,MONTH WRITE(F,F)'TEMP DATE',IYEAR,MONTH 1F ((IYEAR.NE.KYR).0R.(MONTH.NE.KMO)) GOTO n00 CONTINUE READ (7,F,END=n1O) (TMAX(I),TMIN(I), I:1,MDN) WRITE (F,F)(TMAX(I),TMIN(I),I=1,MDN) EVAPOTRANSPIRATION DO 35 K:1,MDN NT:TMAX(K) +TMIN(K) +1 ET(K)=SET(KMO) IF(NT.GT.1) ET(x)=E(NT)FREL(IDAYBG(KMO)+K) CONTINUE WRITE(*,*) 'KYR,KMO',KYR,KMO LOOP = LOOP + 1 IF((KYR.EQ.IIYED).AND.(KMO.EQ.IMED))LOPE=999 IF((KYR.NE.IYRST).AND.(LOPE.LT.1)) THEN IQUIT3z-9 IYRST:KYR ENDIF RETURN CALL FORSUB(KYR,KMO,ET,HOURLY,LO0P,IIYED,FACTOR,NOPORT) IF (KYR.GT.IIYED) GO TO 800 IF ((KYR.EQ.IIYED).AND.(KMO.GT.IMED)) GO TO 800 GOTO 5 WRITE(3,*) 'YEAR TO START IN RAIN FILE NOT FOUND',IYST,IYEAR GO TO 999 WRITE(3,*) 'YEAR TO START 1N TEMP FILE NOT FOUND',IYST,IYEAR GO TO 999 WRITE(3,F) 'WEATHER DATA MISALIGNED’ 410 800 C C 999 C C 52 53 600 630 610 619 611 96 GO T09 WRITE(3, 9"") 'END OF TEMP DATA' GO TO 999 WRITE(3,830) ITDA,KYR,KMO GO TO 999 STOP 0 FORMAT(8 (12,1x,12,1x,F3.2,1x) ) O FORMAT(12F5.2 ) FORMAT(2(16,1x),2(1n,1x,12,1x),1n,1x,F3.O) FORMAT(12F5.2) FORMAT(/20An,/,20An) FORMAT(//47X,19('*')/47X,'* D R A 1 N M O D F'/n7x,19('F') 1//51x,'T1TLE OF RUN'/51x,12('F')) FORMAT(/12/) 645 FORMAT(' ET MULTIPLICATION FACTOR FOR EACH MONTH',/ 620 640 C 830 840 i * * CDC) C)C)CI(7 C2 ()6) (1‘5 F2L 12F6.2 2) FORMAT(/l, 27x, 20A4/27X, 20An////50x, 'CLIMATE INPUTS'/50X, *1******* ****** F 6L 'DESCRIPTION', 8nL '(VARIABLE) VALUE UNIT'/ F 1x,132(1H-)) FORMAT(' RAINFALL STATION NUMBER',78(1H.),'(RAINID)',5X,I6/ F ' TEMPERATURE STATION NUMBER',75(1H.),'(TEMPID)',5X,I6/ F ' STARTING YEAR OF SIMULATION',70(1H.),‘(START YEAR)',7X,I4, F 3X,'YEAR'/ F ' STARTING MONTH OF SIMULATION',68(1H.),'(START MONTH)',9X,I2, F 3X,'MONTH'/ F ' ENDING YEAR OF SIMULATION',74(1H.),'(END YEAR)',7X,I4, F 3L 'YEAR'/ F ' ENDING MONTH OF SIMULATION' ,72(1H. ),'(END MONTH)',9x, 12, F 3L 'MONTH'/ F ' TEMPERATURE STATION LATITUDE',71(1H.),'(TEMP LAT)',6X,I2, F '.',I2,3X,'DEG.MIN'/ F 1 HEAT INDEX',94(1H.),'(HID)',5X,F6.2///) FORMAT(//1X,'SIMULATION TERMINATED NORMALLY. ',I6,1X,I4,1X,12) FORMAT(//1x,'SIMULATION TERMINATED NORMALLY. ',I6,1X,I4,1X,I2) END SUBROUTINE F0RSUB(1R,MO,ET,HOURLY,LOOP,IEDYR,FACTOR,NOPORT) * THIS SUBROUTINE IS THE MAIN BODY OF THE MODEL, DRAINMOD. IT CONDUCTS THE BASIC WATER BALANCE CALCULATIONS ON INTERVALS 0F 1 F HR., 2HR., OR 1DAY. INFILTRATION, SURFACE STORAGE, AND WATER MANAGEMENT PARAMETERS SUCH AS SEW-30 ARE CALCULATED WITHIN THIS SUBROUTINE. ID 97 * OTHER COMPONENTS SUCH AS DRAINAGE FLUX AND ET ARE CALLED FROM ADD- * ITIONAL SUBROUTINES. SECTION 1 * THIS SECTION RECEIVES DAILY PET AND HOURLY RAINFALL VALUES FOR ONE * MONTH FROM THE MAIN PROGRAM AND CHANGES THE VALUE FROM INCHES TO CM C C C C C a C C C C C/ C\ COMMON /IWK/SWKHR1,EWKHR1,SWKHR2,EWKHR2 COMMON /WRK/AMIN1,ROUTA1,ROUTT1,AMIN2,ROUTA2,ROUTT2 COMMON/ICNT/ISICNT,ISKIP,IPOST,IK,IPCNT COMMON/JCNT/JSICNM,JSKIPM,JPOSTM COMMON/IDAY/FDAYSI,NDAYSI,1NTDAY,NOIRR1,NOIRR2,NOIRR3,NOIRRn COMMON/IHR/IHRSTA,IHREND,INSIRR COMMON/PAR/TAV,REODAR,AMTRN,AMTSI,DAMTSI COMMON/WHX/WATER(1OOO).W(101),H(1O1),x(101),NN,UPVOL,WETz,WP COMMON/ABDT/EDTWT,AA(1000),BB(1OOO),A,B COMMON/EVAPO/PET, DDZ, ROOTD COMMON/DRABLK/HDRAIN, DEPTH, CONK(5), DZ(5) COMMON/DLK/SDRAIN, DDRAIN, DC, ADEPTH COMMON/POND/STOR, GEE, STORRO COMMON/DBLK/DRNSTO COMMON/PLT/YODTWT(31),YCDTWT(31),XDATE(31) COMMON/RAIN/R(2n) C0MMON/ORDR/TOSIRR(50),TOTDD(50),TOTWD(50),SEW(5O),IRY(5O) COMMON/NAMES/ T1TLE1(20),TITLE2(2O) COMMON/CDNO/LOPC,MFLAG,L0PE,IOUIT3,JDATE3,JDAY3 COMMON/CDET/CDTWT,CROOT,CFVOL,DWET(1O),SURWET,TRD6O,IPET,PETD,AETC COMMON/SOILI/ SALB,SWCON,CN2,DLAYR(1O),DUL(1O),LL(1O),SW(1O), 1 SAT(1O),DEPMAx,TDUL,NLAYR,SMx,WF(1O),WR(1O),RWU(1O),SWEF COMMON/PERCIP/RVOL,CRO DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION DIMENSION ET(31),HOURLY(7nn),DAYM(12),FACTOR(12) DROOT(37O) RVOLM(12),FVOLM(12),ROM(12),DVOLM(12),PUMPVM(12) DWIER(12),DACHNG(12),TWLOSS(12) DRYDAY(12),WETDAY(12),WRKDAY(12),WATDAY(12) ISICNM(12),ISKIPM(12),IPOSTM(12),SIRRMO(12) F(2n),FRATE(2n),HET(2n),ACCR(2n) WTD(1OOO),VOL(1OO1) SWIER(12) SEWM(12) UPFLUX(1000),HPET1(24) SUMAET(12) AMTSIM(12) KALDAY( 12) M01N(50),IDAYIN(50) DIMENSION RAIN(366),DEPTHW(366),WLLL(366) INTEGER DAYM,DAY INTEGER BWKDY1,BWKDY2,SWKHR1,SWKHR2,EWKHR1,EWKHR2,EWKDY1,EWKDY2 INTEGER FDAYSI,HOUR,TITLE1,TITLE2 DATA DAYM/31,28,31,30,31,30,31,31,30,31,30,31/ (JCICICJCICJCJCICICDCJCICICDCJCICJCIC)C) CJCIC) ! ! ! I 1 1 98 DATA KALOAI/o,31,59,9O,120,151,181,212,2u3,273,3ou,33u/ IF(MFLAG.EQ.1) GO TO 30 IF(MO.NE.2) GO TO 5 IR1=IR/u IR2=IR1*u DAYM(2):28 IF(IR .EQ.IRZ)DAYM(2)=29 D0 10 I=1,7uu HOURLY(I)=HOURLY(I)*2.5u CONTINUE DO 15 1:1, ET(I)= ET(I)*2. 54*FACTOR1MO) CONTINUE DAY:O IF(LOOP.GT.1)GO TO 30 END OF SECTION 1 LOOP:0, I.E. FIRST TIME THROUGH THIS SECTION, GO TO SECTION 2 TO F READ INITIAL DATA; OTHERWISE GO TO SECTION u. **§****************************************************************** * * * * i i * * SECTION 2 ALL INPUT DATA FROM FILE #1 IS READ IN THIS SECTION. THE INPUT DATA IS REWRITTEN INTO FILE #10 FOR QUICK CHECKING OF ERRORS AND IS ALSO REFORMATTED AND PRINTED INTO THE OUTPUT FILE #3. STORAGE BLOCKS ARE ALLOCATED AND ARRAYS ARE DIMENSIONED. SOILS, SYSTEM PARAMETER AND PLANT ROOT DATA ARE READ IN AND LISTED ON THE OUTPUT IN THIS SECTION. ********************************************************************** IRFST:IR CRITD=500. AMINC:100. READ(1,720) INWIER WRITE(10,720) INWIER IF(INWIER.LT. 1) INWIER:1 READ(1,620)DDRAIN,HDRAIN,SDRAIN,STMAX,DC,STORRO,GEE,DTWT WRITE(10,620)DDRAIN,HDRAIN,SDRAIN,STMAX,DC,STORRO,GEE,DTWT DEPTH:DDRAIN+HDRAIN READ(1,650)DITCHB,DITCHS WRITE(10,650)DITCHB,DITCHS READ(1,705) ADEPTH WRITE(10,705) ADEPTH READ(1,625)(DZ(I),CONK(I), I: 1,55) WRITE(10,625)(DZ(I),CONK(I ),I = 1,5) PRINT OUT FIGURE IID 759 99 ICOD:INWIER IF(ICOD.EQ.1) WRITE(3,756) TITLE1,T1TLE2 IF(ICOD.EQ.2) WRITE(3,757) TITLE1,T1TLE2 IF(ICOD.EQ.3) WRITE(3,?58) TITLE1,T1TLE2 WRITE(3, 759)STMAx FORMAT(5(/), 1x,25x, 10x, 'STMAX =' ,FS. 2, ' CM',19X, 'SOIL ', 1'SURFACE'/'+ ' ,25x, _/)', 60('_ '), '/ /)_ ') WRITE(3, A12) ADEPTH, DDRAIN WRITE(3, 413) SDRAIN WRITE(3,u1u) HDRAIN WRITE(3,822) CST1=0.0 DO 8214 I:1,5 CST2:DZ(I) IF(CONK(I).GT..1E—5) WRITE(3,828)CST1,CST2,CONK(I) 8211 CST1:CST2 675 764 WRITE(3,800) DDRAIN,HDRAIN,SDRAIN,STMAX,DEPTH wRITE(3,8O1) DC,ADEPTH WRITE(3,802) STORRO,CEE WRITE(3,820) DITCHB,DITCHS WRITE(3,79H) DTWT READ(1,675)INDET,XCRITD WRITE(10,675)INDET,XCRITD IF(XCRITD. GT. 0) WRITE(3 764) XCRITD FORMAT(I2, 8x, F10. 2) FORMAT(/1X,'INDET= 0 AND CRITD: ' ,F6. 2, ' CM') IF(XCRITD. GT. 0) CRITD: XCRITD CALL PROP(WTD,VOL,WATER,AA,BB,UPFLUX) READ(1,709) WRITE(10,709) READ(1,71O) MOBw1,IDABw1,MOEw1,IDAEw1,szHR1,EwKHR1, 1 AMIN1,ROUTA1,ROUTT1 WRITE(10,710) MOBW1,IDABW1,MOEW1,IDAEW1,SWKHR1,EWKHR1, 1 AMIN1,ROUTA1,ROUTT1 READ(1,710) MOBW2,IDABw2,MOEW2,IDAEW2,SWKHR2,EWKHR2, 1 AMIN2,ROUTA2,ROUTT2 WRITE(10,710) MOBW2,IDABW2,MOEW2,IDAEW2,SWKHR2,EWKHR2, 1 AMIN2,ROUTA2,ROUTT2 BWKDY1:KALDAY(MOBW1)+IDABW1 EWKDY1:KALDAY(MOEW1)+IDAEW1 BWKDY2:KALDAY(MOBW2)+IDABW2 EWKDY2=KALDAY(MOEw2)+IDAEW2 READ(1,715) wp WRITE(10,610) WP READ(1,67O)ISEst,ISEst,ISENME,ISENDE,Swa WRITE(10,670)ISEWMS,ISEWDS,ISEWME,ISEWDE,SEWX READ(1,670)IDRYMS,IDRYDS,IDRYME,IDRYDE WRITE(10,670)IDRYMS,IDRYDS,IDRYME,IDRYDE CALL ROOT(DROOT,MOIN,IDAYIN,NNOO) READ(1,6u0)(DACHNC(I),DWIER(I),I=1,12) WRITE(10,6uo)(DACHNC(I),DwIER(I),I=1,12) READ(1,600)INSIRR,MOFDA,IDAFDA,INTDAY,IHRSTA,IHREND WRITE(10,600)INSIRR,MOFDA,IDAFDA,INTDAY,IHRSTA,IHREND READ(1,725) M0NO1,IDANO1,MON02,IDAN02,MONO3,IDANO3, f." CJCJC3C3CICJCICJCIC)AJCJCJC) 100 1 MONOu , IDANou WRITE(1O , 725) MONO1 , IDANO1 ,MON02, IDAN02 ,MONO3 , IDAN03, 1 MONOII,IDANOI1 FDAYSI=KALDAY(MOFDA)+IDAFDA NOIRR1=KALDAY(MONO1)+IDAN01 NOIRR2:KALDAY(MON02)+IDAN02 NOIRR3=KALDAY(MONO3)+IDANO3 NOIRRu=RALDAY(MONOu)+IDANOII READ(1,610)REQDAR,AMTRN,(AMTSIM(I),I:1,12) WRITE(10,610)REQDAR,AMTRN,(AMTSIM(I),I=1,12) WRITE(3,7u7) WRITE(3,810)AMIN1,AMIN2,ROUTA1,ROUTA2,ROUTT1,ROUTT2 WRITE(3,815)MOBW1,IDABW1,MOBW2,IDABW2,MOEW1,IDAEW1,MOEW2, 1 IDAEW2,SWKHR1,SWKHR2,EWKHR1,EWKHR2 WRITE(3.7u8) wRITE(3,761) WP WRITE(3.762) ISEWMS,ISEWDS,ISEWME,ISEWDE,SEWX WRITE(3,?63) IDRYMS,IDRYDS,IDRYME,IDRYDE wRITE(3.755) D0 76 I=1,NN00 JJJ=KALDAY(MOIN(I))+IDAYIN(I) wRITE(3,786) MOIN(I),IDAYIN(I),DROOT(JJJ) WRITE(3,749) WRITE(3,830) (DACHNC(I),I=1,12) wRITE(3,8uO) (DWIER(I),I:1,12) IF(INSIRR.EQ.O) wRITE(3.787) IF(INSIRR.EQ.O) GO TO 2 WRITE(3,?88) WRITE(3,850) FDAYSI,INTDAY,IHRSTA,IHREND,NOIRR1,NOIRRZ, 1 NOIRR3,NOIRR4 WRITE(3,860) REQDAR,AMTRN,(AMTSIM(I),I=1,12) JDAY=0 ! ..................................................................... 1 END OF SECTION 2 1 ..................................................................... *‘§**§*§§*§**§§*********************§********************************§ * ‘SECTION 3 * INITIALIZATION 0F VARIABLES PRIOR TO BEGINNING OF SIMULATION ******§§§*************************************i*********************** DC=DC/2u. TOFSIRzIHREND-IHRSTA IPCNT:0 EDTWTzDTWT LRAIN = O DDAY:O. ISKIP:0 Mr C& 101 IPOST=O CRO=O. IK=O ISICNT=O IRRDAY:0 DEBT:0.0 DDZ=0.0 DRNSTO:0.0 STOR=0.0 TOTR:0. TOTF=O. TOTD=0. TOTRO=O. TOTNT:0. TOTFD=O. TOTWF=O. TPUMPV=0.0 YTAV:0.0 YSUMET:0.0 WETZ:DTWT ID=DTWT+1.0 YDEBT:0.0 CRITD1:CRITD+1. ICRIT:CRITD1 CRITAV=VOL(ICRIT) AVOL:VOL(ID) TAV:AVOL UPQ=UPFLUX(ID) UPVOL=UPQ*24. UPVOL2=UPQ XNI=100. DELX=DEPMAX/XNI NI:XNI NN:NI+1 NR1:NOIRR1 NR2:NOIRR2 NDAYSI:FDAYSI D0 20 1:1,12 ISICNM(I)=O ISKIPM(I)=0 IPOSTM(I):O SIRRMO(I)=0. TWLOSS(I) SUMAET(I) ) ) WETDAY(I) WATDAY(I) nooodnooooo 2 C) 8 25 102 SWIER(I)=DWIER(I) SEWM(I):0.0 CONTINUE DO 23 I=1,50 IRY(I):0 SEW(I)= O. 0 TOTDD(I):0.0 TOTWD(I):0.0 TOSIRR(I)=0.0 X(1):0.0 DO 25 I:2,NN X(I)=X(I-1)+DELX CONTINUE END OF SECTION 3 ************************************************************i********* * SECTION u * INCREMENT DAY, DETERMINE HOURLY RAINFALL, WIER DEPTH, AND ROOT DEPTH * FOR NEW DAY. INITIALIZE VARIABLES FOR A NEW DAY ***§****************************************************§************§ 3O _. 3 32 DAY:DAY+1 IRRDAY=IRRDAY+1 JDAY:JDAY+1 IF (TRD60.GT.1) THEN ROOTD:TRD6O ELSE ROOTD=DROOT(JDAY) ENDIF AMTSI=AMTSIM(MO) IF(AMTSI .LT. 0.0)AMTSI=(TAV+AMTSI)/TOFSIR IF(AMTSI .LT. 0.0) AMTSI:0.0 DWIER(MO):SWIER(MO) PDEBT:ROOTD*(WATER(1)-WP) IF(DAY.LT.DACHNG(MO).AND.MO.EQ.1)GO TO 31 IF (DAY.LT.DACHNG(MO))DWIER(MO)=DWIER(MO-1) GO TO 32 DWIER(MO):DWIER(12) DAMTSI:0.0 DEEPETzDEPTH-DDZ JPOSTM=O JSKIPM:0 JSICNMzo WLOSS:0.0 RO:0.0 RVOL=0.0 DVOL:0.0 PUMPV:0.0 103 DELTWK=0.0 AMRAIN=0.0 STOR1=STOR STOR2=STOR AVOL1:AVOL HSEW:0.0 C C FIND HOURLY RAINFALL VALUES FOR NEW DAY C L:(DAT-1)*2u D0 35 1:1,24 K=L+I R(I):HOURLY(K) AMRAIN=AMRAIN+R(I) ACCR(I)=AMRAIN 35 CONTINUE C CHECK IF-SURFACE IRRIGATION IS PREPLANNED ON THAT DAY IF(IRRDAY.EQ.FDAYSI.OR.IRRDAY.EQ.NDAYSI)CALL SURIRR C C FIND WATER CONTENT AND HEAD DISTRIBUTION C& CALL WET(WETZ) C C/ PET:ET(DAY) PETD:PET WRITE(17,*) 'PET, AETC',M0,DAY,PET,AETC USE AET OF CERES IF(AETC.GT.O.) PET=AETC WRITE(17,*) 'PET,AETC',PET,AETC HOURLY VALUES C C C\ C GET POTENTIAL DAILY EVAPOTRANSPIRATION FOR NEW DAY - DISTRIBUTES PET C C CALL EVAP(AET,HET,HPET1,TPET) C DO HO 1:1,24 IF(R(I).GT.0.0)GO TO “5 40 CONTINUE IRATN:2H IF(STOR.GT.0.001)GO TO 50 GO TO 130 IF IT RAINS OR IF PREVIOUS SURFACE STORAGE, FIND HOURLY INFILTRATION BY USING THREE MINUTE TIME INCREMENT 1 1 END OF SECTION 4 1 ********************************************************************** * SECTION 5 * DETERMINES INFILTRATION AND CONDUCTS WATER BALANCE CALCULATIONS ON A * HOURLY BASIS. ACCUMULATE TOTALS SO AT END OF SECTION 5 HAVE ESTIMAT OOOOOOOOOOOO 104 C * ALL PARAMETERS FOR THE DAY. C **§***&*5***§*iiN*Ni;***§**i***§***********************§********§***§* C * SECTION 5A - INFILTRATION CALCULATION C *****§******************§************************************§**§***** A5 50 55 IRAIN:I DT:1.0 DDT:0.05 DTMDT:DT-0.01*DDT RDT=23-LRAIN+IRAIN F(1):0.001 IF(RDT.LT.2.5)F(1):F(LRAIN) IF(STOR.GT.0.01)F(1):F(24) IF(DTWT.LT.0.001) F(1)=0.0 IF(F(1).LT.0.001)F(1)=0.001 YESF:F(1) LRAIN:1 DO 55 1:1,2u RVOL:RVOL+R(I) IF(R(I).GT.0.0001)LRAIN=I CONTINUE J=1 IF(F(J).LT.0.01)CALL SOAK C DETERMINES INFILTRATION CONSTANTS FOR SMALL INITIAL INFILTRATION C 60 65 70 75 80 CALL DRAINS(DTWT,DFLUX) IF(AVOL1.LE.0.01)A=0.0 IF((A.LT.0.00001).AND.(DTWT.GT.0.10)) CALL SOAK IF(A.EQ.0.0)B:HET(J)+DFLUX ' IF((A.LE.0.000001).AND.(B.LT.0.0))B=0.0 FRATE(J)=A/F(J)+B IF(STOR.GT.0.0)GO TO 65 IF(FRATE(J).GT.R(J))GO T0 90 RAT1:FRATE(J) SUM:0.0 F1:F(J) DF:RAT1*DDT F2=F1+DF RAT2:A/F2+B IF(STOR.GT.0.0)GO TO 80 IF(RAT2.GT.R(J))RAT2=R(J) DF:O.5*(RAT1+RAT2)*DDT SPR:STOR+R(J)*DDT IF(DF.GT.SPR)DF:SPR F1=F1+DF SUM=SUM+DDT RAT1:A/F1+B IF(STOR.GT.0.0)GO TO 85 IF(RAT1.GT.R(J))RAT1:R(J) C)C)C)C)C)C) 105 8 STOR:STOR+R(J)*DDT-DF IF(STOR.GT.STMAX)STOR:STMAX IF(SUM.GE.DTMDT)GO TO 100 GO TO 75 UI F1=F(J)+R(J)*DT RAT1:A/F1+B IF(RAT1.GT.R(J))GO TO 95 RAT1:R(J) GO TO 70 C) 9 95 RAT1=R(J) 1OO F(J)=F1 DVOL1=DFLUX*DT DVOL:DVOL+DVOL1 IF(DVOL1.LT.0.0)PUMPV:PUMPV+DVOL1 IF(J.EQ.1)GO TO 105 FVOL:F(J)—F(J-1) GO TO 110 ************************************i********************************* * SECTION SB - WATER BALANCE CALCULATION FOR ONE HOUR INTERVAL ********************************************************************** REEVALUATION OF WETZ,DDZ ETC 105 FVOL:F(1)-YESF 11o WETZ:DTWT-DDZ IF(INDET.GT.O) GO TO 117 IF(WETZ.GT.CRITD)GO T0 115 IF(DEBT.GT.0.01)GO TO 115 TVOL:FVOL-HET(J)—DVOL1 AVOL1:AVOL1—TVOL GO TO 120 AVOL1:AVOL1+DVOL1 DEBT:DEBT+HET(J)-FVOL IF(DEBT.GT.0.0)GO T0 120 AVOL1:AVOL1+DEBT DEBT:0.0 GO TO 120 117 CONTINUE CALL ETFLUX(AVOL1,DEBT,FVOL,DVOL1,UPVOL2,HPET1(J),HET(J),PDEBT) DDZ:DEBT/(WATER(1)-WP) IF(AVOL1.GT.0.001)GO TO 125 STOR:STOR-AVOL1 IF(STOR.GT.STMAX)STOR:STMAX F(J):F(J)+AVOL1 FVOL=FVOL+AVOL1 AVOL1=0.0 IAVOL=10.*AVOL1+1.0 AV:10.*AVOL1+1.0 XV:IAVOL WETZ=WTD(IAVOL)+(AV-XV)*(WTD(IAVOL+1)-WTD(IAVOL)) INET:NET2+1. UPQ:UPFLUX(IWET) 11 U1 12 C) 12 U1 00000000000000 00 106 IF(WETZ.GT.DEEPET)UPQ:0.0 UPVOL2=UPQ*DT DTWT=WETZ+DDZ TAV1=AVOL1+DEBT DSTOR=STOR-STOR2 STOR2=STOR RO=R(J)-FVOL-DSTOR CALL YDITCH(DWIER(MO),DVOL1,YD,RO,WLO,DITCHB,DITCHS) IF(INWIER.GT. 2)YD:DDRAIN—DWIER(MO) HDRAIN:DEPTH-DDRAIN+YD WLOSS:WLOSS+WLO IF(DTWT.LT.SEWX)HSEW=HSEW+SEWX-DTWT THE FOLLOWING STATEMENTS DETERMINE IF THIS HOUR IS COUNTED AS AN HOUR IN WHICH FIELD WORK CAN BE DONE DWRKDY=0.0 IF((JDAY .GE. BWKDY1) .AND. (JDAY .LE. EWKDY1)) * CALL WORK(1,J,TAV1,DWRKDY,ACCR(J),DDAY,YTAV) IF((JDAY .GE. BWKDY2) .AND. (JDAY .LE. EWKDY2)) 1 * CALL WORK(7,J,TAV1,DWRKDY,ACCR(J),DDAY,YTAV) 1 IF(R(J) .LT. 0.01) DDAY=DDAY+1./2u. DELTWKzDELTWK+DWRKDY J=J+1 IF(J.GT.24)G0 TO 155 F(J)=F(J-1) IF(F(J).LT.0.001)F(J):0.001 GO TO 60 WHEN CALCULATIONS HAVE BEEN MADE FOR HOUR, J=2u, GO TO SECTION 7 ! ! END OF SECTION 5 ! ********************************************************************** * SECTION 6 * WATER BALANCE CALCULATION WHEN HAVE NO RAIN OR SURFACE IRRIGATION * DURING THE DAY OR SURFACE STORAGE AT THE BEGINING OF THE DAY. * THE WATER BALANCE CALCULATION IS BASED ON A 1 DAY TIME INTERVAL IF * DRAINAGE FLUX AT BEGINING OF DAY IS LESS THAN .02 CM./DAY AND ON A * 2 HR. INTERVAL IF DFLUX IS GREATER THAN THAT VALUE. ****N"!************‘N‘N'*‘N‘**************************‘N'********************* 130 HOUR=O YESF=0.0 FVOL=0.0 DO 135 1:1,2u F(I):0.0 FRATE(I)=0.0 135 CONTINUE CALL DRAINS(DTWT,DFLUX) DVOL1:24.*DFLUX IFINDET>O USE SUBROUTINE ETFLUX TO ESTIMATE AET THEN CAN GET GOOD ESTIMATE OF DVOL UPVOL=UPQ*24.0 IF(INDET.LE.O) GO TO 137 107 CALL ETFLUX (AVOL1,DEBT,FVOL,DVOL1,UPVOL,TPET,AET,PDEBT) AVOL1:AVOL DDZ=DEBT*ROOTD/PDEBT 137 CONTINUE C CHECK FOR DRAINAGE VOLUME. FOR SMALL VOLUME, TAKE 24 HOUR INCREMENT C AND FOR LARGE VOLUME TAKE 2 HOURLY INCREMENT 111 O 14 U1 147 14 m 150 IF(ABS(DVOL1).LE.0.02)GO TO 145 AVOL1:AVOL DEBT:YDEBT AET=AET/12. H2PET=TPET/12. HOUR=HOUR+2 UPVOL1=UPQ*2.0 DVOL1=2.0*DFLUX CONTINUE IF(INDET.LE.O) GO TO 147 IF(HOUR.EQ.0) GO TO 147 CALL ETFLUX(AVOL1,DEBT,FVOL,DVOL1,UPVOL1,H2PET,AET,PDEBT) IF(AVOL1.LT.0.0) AVOL1=0.0 GO TO 148 TVOL=FVOL-AET-DVOL1 AVOL1:AVOL1-TVOL IF(AVOL1.LT.0.0)AVOL1:0.0 IF(WETZ.GT.CRITD)AVOL1:AVOL1+DVOL1 IAVOL=10.*AVOL1+1.0 AV:10.*AVOL1+1.0 XV:IAVOL WETZ:WTD(IAVOL)+(AV-XV)*(WTD(IAVOL+1)-WTD(IAVOL)) IWET:WETZ+1. UPQ:UPFLUX(IWET) DDZ:DEBT*ROOTD/PDEBT DTWT=WETZ+DDZ IF(WETZ.GT.DEEPET)UPQ:0.0 CALL YDITCH(DWIER(MO),DVOL1,YD,RO,WLO,DITCHB,DITCHS) IF(INWIER.GT. 2 )YD:DDRAIN-DWIER(MO) HDRAIN:DEPTH—DDRAIN+YD WLOSS:WLOSS+WLO IF(DVOL1.LT.0.0) PUMPV=PUMPV+DVOL1 DVOL:DVOL+DVOL1 CALL DRAINS(DTWT,DFLUX) IF(DTWT.LT.SEWX)HSEW=HSEW+2.0*(SEWX-DTWT) IF(HOUR.GE.24)AET:AET*12.0 IF(HOUR.GE.24)GO TO 155 IF(HOUR.EQ.0)GO TO 150 GO TO 140 DVOL2=24.*DFLUX HSEW:12.0*HSEW DVOL:O.5*(DVOL1+DVOL2) IF(DVOL.LT.0.0) PUMPV=DVOL CALL YDITCH(DWIER(MO),DVOL,YD,RO,WLO,DITCHB,DITCHS) IF(INWIER.GT. 2 )YD:DDRAIN-DWIER(MO) HDRAIN:DEPTH-DDRAIN+YD IIP C)C)C)C)CJC)C)C1CIC)C) (JCICICJCIC) 108 END OF SECTION 6 **************§************************N********************i********* * SECTION 7 * REEVALUATION OF WATER TABLE DEPTH, DRY ZONE DEPTH, WET ZONE DEPTH, A * VOLUMES, AND RUNOFF AT END OF DAY. ALSO UPDATE SOME VARIABLES TO BE * USED DURING NEXT DAY SUCH AS UPQ ******i*************************************************************** 155 FVOL:F(24)-YESF DEBT=YDEBT UPVOL=0.5*(24.0*UPQ+UPVOL) IF(INDET.LE.O)GO TO 157 CALL ETELUX(AVOL,DEBT,FVOL,DVOL,UPVOL,TPET ,AET,PDEBT) GO TO 1 5 ********;**************************************§********************** * THE FOLLOWING SECTION (TO STATEMENT No.165) USES THE CRITICAL DEPTH *(CRITD) CONCEPT TO ESTIMATE WHEN UPWARD MOVEMENT OF WATER FROM WATER * TABLE IS LIMITED. *********************************************************************i 157 CONTINUE WETZ=DTWT-DDZ IF(WETZ.GE.CRITD)GO TO 160 IF(DEBT.GT.0.01)GO TO 160 TVOL:FVOL-AET-DVOL AVOL:AVOL-TVOL GO TO 165 16 CI AVOL:AVOL+DVOL DEBT:DEBT+AET-FVOL IF(DEBT.GT.0.0)GO TO 161 AVOL:AVOL+DEBT DEBT=0.0 GO TO 165 TAV:AVOL+DEBT IF(WETZ.GT.CRITD1)GO TO 165 AVOL:CRITAV DEBT:TAV-AVOL THE NEXT ARE NEEDED WHEN HOURLY WETZO IF(DEBT.GE.O.)GO TO 165 AVOL:AVOL+DEBT DEBT:O. 16 —A 165 DDZ:DEBT/(WATER(1)-WP) 166 DSTOR:STOR-STOR1 RO:RVOL-DSTOR-FVOL IF(AVOL.LT.0.0)AVOL:0.0 AV=10.*AVOL+1 IAVOL=AV XV:IAVOL WETZ:WTD(IAVOL)+((AV-XV)*(WTD(IAVOL+1)-WTD(IAVOL))) N9 IWET:WETZ+1. UPQ=UPFLUX(IWET) DTWT=WETZ+DDz IF(WETZ.GT.DEEPET)UPQ:0.0 TAV:AVOL+DEBT TAV1:TAV Tv=10*TAV+1 ITAV=TV XV:ITAV EDTWT=WTD(ITAV)+(Tv-XV)*(WTD(ITAV+1)—WTD(ITAV)) YDEBT:DEBT SEWD:0.0 ! ! END OF SECTION 7 ! ********************************************************************** * SECTION 8 * DETERMINATION OF PLANT GROWTH AND TRAFFICABILITY PARAMETERS, OUTPUT * 0F DAILY SUMMARIES IF DESIRED, AND MONTHLY SUMMARY CACULATIONS. **************************************1"!****************************** IF((MO.LT.ISEWMS).OR.(MO.GT.ISEWME))GO TO 169 IF((MO.EQ.ISEWMS).AND.(DAY.LT.ISEWDS))GO TO 169 IF((MO.EQ.ISEWME).AND.(DAY.GT.ISEWDE))GO TO 169 IF(DTWT.GT.SEWX)GO TO 168 SEWD=SEWX-DTWT CONTINUE IF(HSEW.GT.0.01)SEWD=HSEW/24.0 169 CONTINUE 0000000000 M (D IF(NOPORT.GT.1)GO TO 175 IF(DAY.NE.1)GO TO 170 00 0 0000 DAILY SUMMERIES WRITE(3.9OO) WRITE(3,91O)IR,MO WRITE(3,920) 17o WRITE(3,930)DAY,RVOL,FVOL,AET,DVOL,AVOL,TAV,DDZ,WETZ,DTWT, $STOR,RO,WLOSS,YD,DRNSTO,SEWD,DAMTSI C C MONTHLY CALCULATIONS 175 RVOLM(MO)=RVOLM(MO)+RVOL RAIN(JDAY):RVOL DEPTHW(JDAY):DTWT WLLL(JDAY)=WLOSS C/ C\ WRITE(17,*) 'PET,AET',PET,AET C FVOLM(MO)=FVOLM(MO)+FVOL 110 ROM(MO)=ROM(MO)+RO DVOLM(MO):DVOLM(MO)+DVOL PUMPVM(M0):PUMPVM(MO)+PUMPV TWLOSS(MO) =TWLOSS(M0)+WLOSS SUMAET(MO):SUMAET(MO)+AET SIRRMO(M0):SIRRMO(MO)+DAMTSI ISICNM(MO):ISICNM(MO)+JSICNM ISKIPM(MO):ISKIPM(MO)+JSKIPM IPOSTM(MO):IPOSTM(MO)+JPOSTM SEWM(M0)= SEWM(M0)+SEWD JDAY3=JDAY C& UP 00000000000000 IF(DDZ.GE.(ROOTD-1.0)) GO TO 172 IF(RVOL .GT. 0.005) GO TO 176 GO TO 17 IF((MO.LT.IDRYMS).OR.(MO.GT.IDRYME)) GO TO 173 IF((MO.EQ.IDRYMS).AND.(DAY.LT.IDRYDS)) GO TO 173 IF((MO.EQ.IDRYME).AND.(DAY.GT.IDRYDE)) GO TO 173 DRYDAY(MO)=DRYDAY(MO)+1.0 CONTINUE DELTWK:0.0 IF((JDAY .GE. BWKDY1) .AND. (JDAY .LE. EWKDY1)) * CALL WORK(1,-1,TAV,DELTWK,0.0,DDAY,YTAV) IF((JDAY .GE. BWKDYZ) .AND. (JDAY .LE. EWKDY2)) * CALL WORK(7,-1, TAv, DELTWK, o. O,DDAY,YTAV) DDAY: DDAY +1 176 WRKDAY(MO)= WRKDAY(MO)+DELTWK AMINC: 0. 0 IF(TAV.LT.AMINC)WATDAY(MO)=WATDAY(M0)+1. CFVOL:FVOL N 17 17 LA) IF(DAY.GE.DAYM(MO))GO TO 180 YTAV:TAV CDTWT:DTWT MFLAG:1 RETURN IF PREVIOUS DAY WAS LAST DAY OF MONTH GO TO SECTION 9; OTHERWISE RETURN TO CERES FOR NEXT DAY ! ! END OF SECTION 8 ! *§*§****************************************************************** * SECTION 9 * IF MONTH JUST COMPLETED WAS LESS THAN 12, RETURNS TO MAIN PROGRAM F0 * NEW SET OF RAINFALL AND ET DATA. IF MONTH:12, THIS SECTION PRINTS O * MONTHLY SUMMARIES, COMPUTES YEARLY SUMMARIES, PRINTS, AND DETERMINES * AVERAGES OVER PREVIOUS YEARS OF SIMULATION. ********************************************************************** 180 MFLAG:O DAYMT:DAYM(MO) WETDAY(MO):DAYMT-WRKDAY(MO) IF(MO.LT.12)RETURN lll IF(NOPORT.GT.2) GO TO 181 C C MONTHLY SUMMARIES C 181 C 1132 1133 187 185 1134 WRITE(3,940)IR WRITE(31950) WRITE(3,960)(II,RVOLM(II),FVOLM(II),ROM(II),DVOLM(II),SUMAET(II), 2DRYDAY(II),WRKDAY(II), TWLOSS(II),SEWM(II),SIRRMO(II), $ISICNM(II),PUMPVM(II),IPOSTM(II),II:1,12) CONTINUE YEARS: IR-IRFST+1 IYEAR=YEARS IRY(IYEAR):IR WRITE(11,1132) IR FORMAT(1X,I4) WRITE(11,1133)(RAIN(I),DEPTHW(I),WLLL(I),I=1,JDAY) FORMAT(1X,3F10.3) FORMAT(I4,2X,F4.0,2X,F10.3) DO 185 I:1,12 TOTR=TOTR+RVOLM(I) YSUMET:YSUMET+SUMAET(I) TOTF=TOTF+FVOLM(I) TOTRO:TOTRO+ROM(I) TOTD:TOTD+DVOLM(I) TPUMPV:TPUMPV+PUMPVM(I) TOTDD(IYEAR):TOTDD(IYEAR)+DRYDAY(I) TOSIRR(IYEAR):TOSIRR(IYEAR)+SIRRMO(I) TOTNT=TOTNT+WETDAY(I) TOTWD(IYEAR):TOTWD(IYEAR)+WRKDAY(I) TOTFD:TOTFD+WATDAY(I) TOTWF=TOTWF+TWLOSS(I) SEW(IYEAR)=SEW(IYEAR)+SEWM(I) WETDAY(I):0.0 WRKDAY(I):0.0 DRYDAY(I )=o.0 PUMPVM(I)=0.0 RVOLM(I)=0.0 FVOLM(I)=0.0 ROM(I):0.0 WATDAY(I ISICNM(I ISKIPM(I) SEWM(I):0. IPOSTM(I): CONTINUE WRITE(11,1134) SEW(IYEAR),ISEWMS,ISEWDS,ISEWME,ISEWDE,SEWX,TOTR,TOTWF FORMAT(1X,F7.0,1X,4I6,3F10.1) C YEARLY SUMMARIES 191 C 112 IF(NOPORT.EQ.3) GO TO 191 WRITE(3,990)TOTR,TOTF,TOTRO,TOTD,YSUMET,TOTDD(IYEAR),TOTWD(IYEAR), TOTWF,SEW(IYEAR),TOSIRR(IYEAR),TPUMPV GO TO 194 IF(ICOUNT.EQ.O) WRITE(3,?90) TITLE1,T1TLE2 ICOUNT=ICOUNT+1 IF(ICOUNT.EQ.30) ICOUNT:0 WRITE(3,791)IRY(IYEAR),TOTR,TOTF,TOTRO,TOTD,YSUMET, 1 TOTDD(IYEAR),TOTWD(IYEAR),TOTWF,SEW(IYEAR),TOSIRR(IYEAR), 2 TPUMPV C REINITIALIZATION 194 C 412 413 414 TOTR:0. TOTF:O. TOTRO:0. YSUMET=0.0 TOTD:O. TPUMPV=0.0 TOTNT=O. 1 TOTFD:0. TOTWF=0. ISKIP=0 IPOST=O JDAY=O IK=0 ISICNT:0 IRRDAY:O NDAYSIzFDAYSI NOIRR1:NR1 NOIRR2:NR2 IF(IR.EQ.IEDYR) CALL ORDER(IYEAR) FORMAT(1X,25X,6X,':',51X,':'/ 11x,25x,6x,':',51x,':'/ 21x,25x,6x,':',5x,19x,' ',2x,2x,' ',21x,':'/ 31x,25x,6x,':',5x,13x,' ',8x,8x,' ',15x,':'/ u1x,25x,6x,':',5x,8x,' ',13x,13x,' ',10x,':'/ 51X,25X,1X,'ADEPTH :',F4.0,' CM',35X,'DDRAIN :',F4.0,' CM'/ 61x,25x,6x,':',5x,3x,' ',18x,18x,' ',5x,':'/ 71x,25x,6x,':',51x,':') FORMAT(1X,25X,6X,;:',5X,'O ------------- SDRAIN :',F6.0,' CM 1, 11 ___________ O _1 FORMAT(1X,25X,6X,':',51X,':'/ 11x,25x,6x,':',51x,':'/ 21X,25X,6X,':',44X,'HDRAIN :',F4.0,' CM'/ 31x,25x,6x,':',51x,':'/ W1x,25x,6x,':',51x,':'/ 51x,25x,3u('- ')/ 61x,25x,6x,':'/ 71x,25x,6x,':'/ 81x,25x,6x,':'/ 91X,25X,6X,':',36X,'IMPERMEABLE LAYER’/'+',25X,67('_')/ 71X,25X,67('/')) 113 600 FORMAT(12,3X,212,1X,212,1X,12,1X,12) 610 FORMAT(2F10.5,12F5.2) 620 P0RMAT(8E10.2) 625 FORMAT(5(F5.0,F5.2)) 630 FORMAT(F10.2,215) 6A0 PORMAT(/12(F2.0,P3.0)) 645 FORMAT(213,212,3F10.2) 650 FORMAT(6E10.2) 660 FORMAT(20F4.1) 670 FORMAT(412,2X,F10.2) 705 FORMAT(/,F10.0) 709 FORMAT(1X) 710 FORMAT(612,8X,3E10.1) 715 FORMAT(/F10.0) 720 FORMAT(/12) 725 FORMAT(4(12,12,6X)) 747 FORMAT(1H1,52X,'TRAFFICABILITY'l53x,14('*')/) 748 FORMAT(///56X,'CROP'/56X,'****'//) 749 FORMAT(///,34X,'WIER CONDITIONS AND WASTEWATER IRRIGATION'/34X, 1 41('*')/) 755 FORMAT(//3OX,'MO DAY ROOTING DEPTHW(CM)') 756 FORMAT(1H1,2(/),49X,'DRAINAGE SYSTEM DESIGN'/49X,22('*')//, 1 1x,25x,21x,'*** 1, 2'CONVENTIONAL DRAINAGE',‘ ***'//,1X,25X,'JOB TITLE:'/, 3/35X,20A4/35X,20A4) 757 FORMAT(1H1,2(/),49X,'DRAINAGE SYSTEM DESIGN'/49X,22('*')//, 1 1x,25x,21x,'*** ', 2'CONTROLLED DRAINAGE 1,1 ***'//,1X,25X,'JOB TITLEz'l, 3/35X,20A4/35X,20A4) 758 PORMAT(1H1,2(/),49X,'DRAINAGE SYSTEM DESIGN'/49X,22('*')//, 1 1x,25x,21x,'*** ', 2'SUBIRRIGATION-DRAINAGE SYSTEM',’ ***'//,1X,25X,'JOB TITLE:'/, 3/35X,20A4/35X,20A4) 761 FORMAT(1X,'SOIL MOISTURE AT CROP WILTING POINT=',SX,F5.2) 762 FORMAT( - $/1x,'HIGH WATER STRESS: ','BEGIN STRESS PERIOD ON',2X,IZ,'/', $12/21X,'END STRESS PERIOD ON',4X,12,'/',12/21X,'CROP IS IN 1, $‘STRESS WHEN WATERTABLE IS ABOVE ',F5.1,' CM.') 763 FORMAT(/1X, - $‘DROUGHT STRESS: ’,'BEGIN STRESS PERIOD ON',2X,12,'/',12/ $21X,'END STRESS PERIOD ON',4X,12,'/',12) 786 FORMAT(30x,12,3x,12,7x,P5.1) 787 FORMAT(/5X,'NO WASTEWATER IRRIGATION SCHEDULEDz') 788 FORMAT(/5X,'WASTEWATER IRRIGATION IS SCHEDULED:') 789 FORMAT(12(12,F3.0)) 790 FORMAT(1H1,’ JOB TITLE: ',20A4/1SX,20A4// 3 2X,'YEAR ',1X,'RAINFALL',1X,'INFILTRATION',1X,'RUNOFF',1X, $‘DRAINAGE',1X,' ET 1, 'DRY DAYS 1, 'WRK DAYS', $ 1x ,'WATER LOSS',4X,'SEW',3X,'IRRIG VOL PUMPED VOL') 791 FORMAT(1X,I4,2X,7F9.2,4X,4F9.2) 79H FORMAT(/1X,'INITIAL WATERTABLE DEPTH: ',F5.1,' CM') C 800 FORMAT(/1X,'DEPTH TO DRAINzt,F5.1,'CM'/1X,'EFFECTIVE DEPTH FROM ', $‘DRAIN TO IMPERMEABLE LAYER :',F5.1,'CM'/1X,'DISTANCE BETWEEN ', 114 $‘DRAINS =',F7.1,'CM', $/1X,'MAXIMUM DEPTH OF SURFACE PONDING =',F5.2,'CM'/1X,'EFFECTIVE 1, $'DEPTH TO IMPERMEABLE LAYER=',F6.1,'CM') 801 FORMAT(1X,'DRAINAGE COEFFICIENT(AS LIMITED BY SUBSURFACE OUTLET 1, $'):',F5.2,'CM/DAY'/1X,'ACTUAL DEPTH FROM SURFACE T0 IMPERMEABLE 1, $'LAYER=',F5.1,'CM') 802 FORMAT(1X,'SURFACE STORAGE THAT MUST BE FILLED BEFORE WATER CAN 1, $'MOVE TO DRAIN (FIG.2-12) =',F5.2,'CM'/1X,'FACTOR -G- IN KIRKHAM 1, $‘EQ. 2-17 =',F10.2) 810 FORMAT(86X,'FIRST PERIOD SECOND PERIOD'l $1X,1OX,'REQUIREMENTS ','-MINIMUM AIR VOLUME IN SOIL(CM): 1, $23X,5X,F5.2,1OX,F5.2/25X,'-MAXIMUM ALLOWABLE DAILY RAINFALL(CM):', $18X,5X,F5.2,1OX,F5.2/25X,'-MINIMUM TIME AFTER RAIN BEFORE', s' TILLING CAN CONTINUE:',3X,5X,F5.2,10X,F5.2) 815 FORMAT(/1X,1OX,'WORKING TIMES ','-DATE TO BEGIN COUNTING WORK', $1 DAYS: 1,21x,5x,12,'/',12,10x,12,'/',12/25x, $'-DATE TO STOP COUNTING WORK DAYS:',23X,5X,12,'/',12,1OX,12,'/', $I2/25X,’-FIRST WORK HOUR OF THE DAY:',3OX,6X,12,13X,12/25X, $'-LAST WORK HOUR OF THE DAY:',31X,6X,12,13X,12) _820 FORMAT(/,1X,'WIDTH OF DITCH BOTTOM: ',F5.1,' CM'/1X, 1'SIDE SLOPE 0F DITCH (HORIZ:VERT)= ',F5.2,' : 1.00') 822 FORMAT(/g/BBX,'DEPTH',;X,;SATURATED HYDRAULIC CONDUCTIVITY'/ 1 39x,' CM 1,20x,' CM/HR '/ 828 FORMAT(33X,F7.1,' - ',F7.1,7X,F11.3) 830 FORMAT(1X/5X,'DEPTH 0F WIER FROM THE SURFACE'//1X,'DATE',9X,'1/' $,F3.0,3X,'2/',F3.0,3X,'3/',F3.0,3X,'4/',F3.0,3X,'5/',F3.0,3X,'6/' ::Fgéoé3§§'?:;;f3ég,g§,18/',F3.0,3X,'9/',F3.0,3X,'10/',F3.0,2X,'11/ 9 0 I 9 1 2 840 FORMAT(1X,'WIER DEPTH',12F8.1) 850 FORMAT(1X,'FIRST DAY OF SURFACE IRRIGATIONz' I3/1x, $'INTERVAL BETWEEN SURFACE IRRIGATION DAYS:',I3/1X, $‘STARTING HOUR OF SURFACE IRRIGATION:',I3/1X, $'ENDING HOUR OF SURFACE IRRIGATION:',I3/1X, $‘NO SURFACE IRRIGATION INTERVAL 1:',I4,2X,I4/1X, $‘NO SURFACE IRRIGATION INTERVAL 2:1 I4,2X,I4) 860 FORMAT(1X,'MINIMUM AIR REQUIRED TO HAVE SURFACE IRRIGATION:', $F6.2,'CM'/1X,'AMOUNT OF RAIN TO POSTPONE SURFACE IRRIGATION:', $F6.2,'CM'/1X,'SURFACE IRRIGATION FOR ONE HOUR:',12F6.2,'CM') 870 FORMAT(1X,'INDET:',I2,'WHEN INDET.GT. 0 USE READ IN VALUES TO DETE 2RMINE ET WHEN LIMITED BY SOIL CONDITIONS') 900 FORMAT 1H1 910 FORMAT(2I10) 920 FORMAT(//2X,'DAY',3X,'RAIN',3X,'INFIL',6X,‘ET',4X,'DRAIN',2X, $'AIR VOL',3X,'TVOL',4X,'DDZ',4X,'WETZ',3X,'DTWT',4X,'STOR', $1X,'RUNOFF',2X,’WLOSS',3X,’YD',3X,'DRNSTO',2X,'SEW',2X,'DMTSI') 930 PORMAT(2X,I3,8F8.2 ,8F7.2) 9A0 FORMAT(1HO,15X,'MONTHLY VOLUMES IN CENTIMETERS FOR YEAR',16) 950 FORMAT( 2X,'MONTH',1X,'RAINFALL',1X,'INFILTRATION',1X,'RUNOFF',1X, $‘DRAINAGE',1X,' ET 1, 'DRY DAYS 1, 'WRK DAYS', g.) 1x ,'WATER LOSS',4X,'SEW',3X,'MIR',4X,'MCN',1X,'PUMP',2X,’MPT 960 FORMAT(1x,I3,F10.2,F11.2,F1O.2,F8.2,F10.2,2F8.2, F11.2,F1O.2, 23X,F5.2,I4,F7.3,I4) 990 FORMAT(1HO/1X,'TOTALS',7F9.2,4X,4F9.2) 000000000 0000 00 IQK~H~K * * 115 END OF SECTION 9 END OF FORSUB RETURN TO MAIN FOR NEW SET OF DATA TO START SIMULATION FOR FIRST MON OF THE NEXT YEAR. RETURN END SUBROUTINE DRAINS(DTWT,DFLUX) THIS SUBROUTINE FINDS THE EFFECTIVE LATERAL HYDRAULIC CONDUCTIVITY A* COMPUTES DRAINAGE OR SUBIRRIGATION FLUX. DU! 2 U1 U1 3 4O 45 COMMON/DRABLK/HDRAIN,DEPTH,CONK(5),DZ(5) COMMON/DLK/SDRAIN,DDRAIN,DC,ADEPTH COMMON/POND/STOR,GEE,STORRO DIMENSION W(20) Y:DTWT IF(Y .GT. ADEPTH) Y=ADEPTH ABOVE:0.0 DO 10 I=1,5 N=I L=DZ(I) IF(L.EQ.0) 00 TO 15 IF(Y.GT.Dz(I))GO TO 5 W(I):DZ(I)-Y X:DZ(I)-ABOVE IF(W(I).GT.x)W(I)=x GO TO 10 W(I):0.0 ABOVE:DZ(I) N=6 N=N-1 SUM:0.0 SUM=SUM+W( I )*CONK( I ) DEEP:DEEP+W(I) IF((DEEP.LE. .0001).0R.(SUM.LE. .0001)) GO TO 35 CONE:SUM/DEEP GO TO 45 CONTINUE SUM=CONK(1)*DZ(1) DEEP=DZ(1) D0 40 I:2,5 SUM:SUM+CONK(I)*DZ(I) DEEP:DEEP+DZ(I) CONE:SUM/DEEP CONTINUE 0000000 5 42 O 116 HDMINzDEPTH-DDRAIN IF(HDRAIN.LT.HDMIN) HDRAIN:HDMIN IF((STOR.GT. STORRO).AND.(DTWT .LT. 0.5)) GO TO 50 EM=DEPTH-Y-HDRAIN IF(EM .LT. -O.1) GO TO 42 DFLUX:4.0*CONE*EM*(2.0*HDRAIN+EM) /SDRAIN**2 IF(DFLUX .GT. DC) DFLUX:DC IF(DFLUX .LT. .0)DFLUX=0.0 IF(EM.LT.0) DFLUX:0.0 DDRANP:DDRAIN-O.1O DOT:HDRAIN+ADEPTH-DEPTH DFLUX:4.0*CONE*EM*HDRAIN*(2.0+EM/DOT)/SDRAIN**2 IF((DEPTH-HDRAIN).GE.DDRANP)DFLUX:O. RETURN DFLUX:12.5663*CONE*(DEPTH-HDRAIN+STOR)/(GEE*SDRAIN) IF(DFLUX.GT.DC) DFLUX:DC RETURN END SUBROUTINE ETFLUX (AVOL,DEBT,FVOL,DVOL,UPVOL,POTET,ACTET,PDEBT) * THIS SUBROUTINE DETERMINES ACTUAL HOURLY OR DAILY ET BASED ON PET AN* * UPWARD FLUX FROM THE WATER TABLE. * * IF UPWARD FLUX IS INSUFFICIENT TO SUPPLY ET DEMAND, WATER IS REMOVED: FROM ROOT ZONE TO MAKE UP THE DIFFERENCE. IF ROOT ZONE WATER IS NOT AVAILABLE, ET IS LIMITED. 2 * i 2 UI 28 O 3 31 IF(DEBT.GT.0.0) GO TO 50 IF(UPVOL.LT.POTET) GO TO 25 ACTET:POTET DEBT:0.0 AVOL:AVOL+DVOL+ACTET—FVOL RETURN DEBTzDEBT-FVOL XXD:DEBT+POTET-UPVOL IF(DEBT.GE.0.0)GO TO 28 ACTET:POTET AVOL:AVOL+DVOL+DEBT+ACTET DEBT:0.0 RETURN IF(XXD.GT.PDEBT)GO T0 30 ACTET:POTET DEBT:DEBT+POTET-UPVOL AVOL:AVOL+DVOL+UPVOL RETURN ACTET:PDEBT-DEBT+UPVOL IF(ACTET.GE.0.0) GO TO 31 ACTET:0.0 DEBT:DEBT—UPVOL AVOL:AVOL+DVOL+UPVOL RETURN CONTINUE 0000000 00 00000 O 5 60 70 117 DEBT:PDEBT AVOL:AVOL+DVOL+UPVOL TURN RE IF(POTET.GT.UPVOL) GO TO 25 EXCESS=UPVOL ~POTET ACTET:POTET DEBT:DEBT-FVOL YDEB:DEBT DEBT:DEBT—EXCESS IF(DEBT.LT.0.0)GO TO 60 AVOL:AVOL+DVOL+UPVOL GO TO 70 AVOL:AVOL+DVOL+ACTET+YDEB IF(DEBT.LT.0.0)DEBT=0.0 RETURN END 1 SUBROUTINE EVAP(ET,HET,HPET1,TPET) L * THIS SUBROUTINE DISTRIBUTES DAILY PET OVER 12 HRS. FROM 0600 TO 1800* * WHEN RAINFALL .GT. 0 PET FOR THAT HOUR IS SET: 0. * THEN HOURLY PET SUMMED TO GET DAILY PET. * FIND DAILY EVAPOTRANSPIRATION U'l As COMMON/EVAPO/PET,DDZ,ROOTD COMMON/RAIN/R(24) DIMENSION HET(24),HPET1(24) FIGURE ET BASED ON 12 HRS TPET:0.0 HPET:PET/12.0 DO 5 I:1,6 HET(I)=0.0 HPET1(I):0.0 CONTINUE D0 10 I=7,18 HET(I):HPET HPET1(I)=HPET using aet of ceres for pet of drainmod, need make drainmod use all of pet which is what plants actually used in ceres. 10 15 IF(DDZ.GT.ROOTD)HET(I)=0.0 IF(R(I).GT.0.0)HET(I)=0.0 IF(R(I).GT.0.0)HPET1(I)=0.0 CONTINUE DO 15 1:19.24 HET( I ):0 .0 HPET1(I):0.0 CONTINUE ET:0.0 DO 20 1:1,24 ET:ET+HET(I) TPET:TPET+HPET1(I) IP 118 20 CONTINUE C RETURN END SUBROUTINE ORDER(IYEAR) * THIS SUBROUTINE DETERMINES THE RANK 0F TOTDD, TOTWD, SEW, AND TOSIRR: * AND THEIR AVERAGES DURING THE SIMULATED YEARS. 0000 COMMON/ORDR/TOSIRR(50) ,TOTDD(5O) ,TOTWD(50) ,SEW(50) , IRY(50) DIMENSION NRANK1(50),NRANK2(50),NRANK3(50),NRANK4(50) DATA SUMWKY,SUMSEW,SUMDDY,SUMIRR/4*0.0/ CALL RANK(TOTWD,NRANK1,IYEAR,IRY) CALL RANK(SEW,NRANK2,IYEAR,IRY) CALL RANK(TOTDD,NRANK3,IYEAR,IRY) CALL RANK(TOSIRR,NRANK4,IYEAR,IRY) WRITE(3,10) DO 20 I:1,IYEAR WRITE(3,30)I,TOTWD(I),NRANK1(I),SEW(I),NRANK2(I),TOTDD(I), 1 NRANK3(I),TOSIRR(I),NRANK4(I) SUMWKY=SUMWKY+TOTWD(I) SUMSEW:SUMSEW+SEW(I) SUMDDY=SUMDDY+TOTDD(I) 20 SUMIRR:SUMIRR+TOSIRR(I) C CALCULATE AVERAGES AVGWKY:SUMWKY/IYEAR AVGSEW:SUMSEW/IYEAR AVGDDY:SUMDDY/IYEAR AVGIRR=SUMIRR/IYEAR WRITE(3,40) AVGWKY,AVGSEW,AVGDDY,AVGIRR 10 FORMAT('1',14X,'RANK',3X,'WORK DAYS',2X,'YEAR',1OX,'SEW',6X,'YEAR' 1,8X,'DRY DAYS',3X,'YEAR',7X,'IRRIGATION',2X,’YEAR'/) 30 FORMAT(15X,I4,4(F11.2,I7,5X)) 40 FORMAT('O',1OX,'AVERAGE',4(F12.2,11X)) RETURN END SUBROUTINE PROP(WTD,VOL,WATER,AA,BB,UPFLUX) THIS SUBROUTINE READS IN SOIL WATER CHARACTERISTIC, INTERPOLATES VALUES, AND CALCULATES RELATIONSHIP BETWEEN WATER TABLE DEPTH AND DRAINAGE VOLUME. AS AN ALTERNATIVE CAN READ IN DRAINED VOLUME - WATER TABLE DEPTH RELATIONSHIP WHICH MAY ALSO INCLUDE UPWARD FLUX VALUES. A TABLE OF CONSTANTS FOR THE GREEN - AMPT INFILTRATION EQUATION FOR VARIOUS WATER TABLE DEPTHS IS READ IN AND INTERPOLATED. ALL SOIL PROPERTIES ARE STORED IN ARRAYS SO THAT THEY CAN BE EASILY RECALLED KNOWING THE WATER TABLE DEPTH. ********* *****¥*** READ SOIL PROPERTIES AND STORE THE INFORMATION INTO PROPER ARRAYS BY INTERPOLATION DIMENSION THETA(50),HEAD(50),WATER(1000),VOL(1000),WTD(1000) DIMENSION D(10),E(10),F(10),AA(1000),BB(1000) 0000000000000 ! 1 ! 1 000000 00 000000000 701 2 O 7 119 DIMENSION AIA(1000),BIB(1000) DIMENSION xv0L(100),x(100) DIMENSION UPFLUX(1000),FLUX(100) THE FOLLOWING SECTION READS IN SOIL WATER CHARACTERISTIC, AND CAL- CULATES RELATIONSHIP BETWEEN DRAINED VOLUME AND WATER TABLE DEPTH. READ(1,900) NUM,IVREAD WRITE(10,900) NUM,IVREAD READ(1,905)(THETA(I),HEAD(I),I:1,NUM) WRITE(10,905)(THETA(I),HEAD(I),I:1,NUM) DATA READ IN ORDER OF DECREASING WATER CONTENT DO 5 I = 1,NUM HEAD(I) : -HEAD(I)+1.0 I=1 WATER(1)=THETA(1) P:WATER(1) L VOL(1)=O DO 10 J = 2,1000 U1 AJ 2 J IF(AJ.GT.HEAD(I+1))I=I+1 AI = I AIM:I-1 WATER(J) = THETA(I)+(AJ-HEAD(I))/(HEAD(I+1)-HEAD(I))* C(THETA(I+1)—THETA(I)) AVG = (WATER(J)+WATER(J—1))/2 VOL(J) : VOL(J-1) + P-AVG 1O CONTINUE THE FOLLOWING READS TABULAR VALUES FOR W.T. DEPTH VS. DRAINAGE VOLUM AND UPWARD FLUX. THE NUMBER OF VALUES READ IS IVREAD. IF IVREAD .LE. 0, USE ABOVE W.T.D.-VOL. RELATIONSHIP AND CRITICAL DEPTH CONCEPT FOR UPWARD FLUX. IF(IVREAD.LE.O) GO TO 14 IF WATER VOL VS. WATER TAB DEPTH IS READ IN GO TO NEXT STEPS IF WATER VOL VS. WATER TAB DEPTH IS READ IN GO TO NEXT STEPS READ(1,930)(X(I),XVOL(I),FLUX(I),I=1,IVREAD) WRITE(10,930)(X(I),XVOL(I),FLUX(I),I:1,IVREAD) IF(X(IVREAD).GE.1000.) GO TO 150 IVREAD:IVREAD+1 WRITE(3,7O1) X(IVREAD) FORMAT(///1X,'PROGRAM TERMINATING... THE LAST ENTERED DEPTH ', $'VALUE WAS ',F12.2,' CM. THIS WILL CAUSE A RUN—TIME ERROR.') WRITE(3,7O2) FORMAT(//1X,'TO CORRECT THE INPUT, ADD A FINAL LINE TO THE SOIL', 8' PROPERTIES...'//,11X,'X(IVREAD) XVOL(IVREAD) FLUX(IVREAD)', s /11x,' 1000. 100. 0.0',// $ 1X,'BE SURE THAT THE SECOND TO THE LAST ENTRY EXTENDS DOWN TO ', Ilr 120 s 'A DEPTH THAT IS '/1X,'AT LEAST EQUAL TO THE DEPTH TO THE 1, $ 'IMPERMEABLE LAYER PLUS THE MAXIMUM ROOTING DEPTH') STOP 150 DO 12 I=1,IVREAD 12 x(I)=x(I)+1.0 UPFLUX(1)=FLUX(1) VOL(1):XVOL(1) I=1 DO 11 L:2,1000 XL=L IF(XL.GT.X(I+1))I:I+1 XI=I XIM=XI-1. UPFLUX(L)=FLUX(I)+((XL-X(I))/(X(I+1)-X(I)))*(FLUX(I+1)—FLUX(I)) 11 V0L(L)=XVOL(I)+((XL-X(I))/(X(I+1)-X(I)))*(XVOL(I+1)-XVOL(I)) 1 ..................................................................... 1 CONVERT TO ARRAY SO CAN DIRECTLY DETERMINE WATER TABLE DEPTH (OR WET 1 ZONE DEPTH) IF KNOW AIR VOLUME. L 1 ..................................................................... 000000 14 CONTINUE DO 15 K = 1,1000 15 VOL(K) = VOL(K)*10.0+1.0 I = 2 AI : I WTD(1) = 0 DO 25 L = 2,1000 AL = L ALM : AL-1.0 IF(VOL(L).LT.AI) GO TO 25 20 WTD(I) = ALM + (AI-VOL(L-1))/(VOL(L)-VOL(L-1))-1.0 I = I + 1 AI = I IF(VOL(L).GT.AI) GO TO 20 25 CONTINUE WRITE(31915) D0 30 I:1,1000 VOL(I) = 0.1*(VOL(I)-1.0) XI - I AI 0.1*(XI-1.0) BI - I-1 AIA(I)=AI BIB(I)=BI 3O CONTINUE D0 50 I=1,301,10 50 WRITE(3,910)AIA(I),WTD(I),BIB(I),WATER(I),VOL(I),UPFLUX(I) DO 51 I=351,501,5O 51 WRITE(3,910)AIA(I),WTD(I),BIB(I),WATER(I),VOL(I),UPFLUX(I) DO 52 I=601,1000,100 52 WRITE(3,910)AIA(I),WTD(I),BIB(I),WATER(I),VOL(I),UPFLUX(I) IP‘ 121 READ(1,900)NUMA WRITE(10,9OO)NUMA READ(1,920)(D(I),E(I),F(I),I=1,NUMA) WRITE(10,920)(D(I),E(I),F(I),I=1,NUMA) IF(D(NUMA).GE.1000.) GO TO 160 NUMA:NUMA+1 D(NUMA)=1000. E(NUMA)=E(NUMA-1) F(NUMA):F(NUMA-1) 160 WRITE(3,940) C C C WRITE(3,945) (0(1),E(I),F(I),I=1:NUMA) AA(1):O. BB(1):O. I=1 J=2 XJ:J-1 35 IP=I+1 RATIO=(XJ -D(I))/(D(IP)-D(I)) AA(J):E(I)+RATIO*(E(IP)-E(I)) BB(J)=F(I)+RATIO*(F(IP)-F(I)) J:J+1 XJ:J-1 IF (XJ.GT.D(IP))I:I+1 IF(I.GE.NUMA)GO TO 45 GO TO 35 45 CONTINUE 900 FORMAT(212) 905 FORMAT(F10.7,F10.1) 910 FORMAT(18X,F6.1,10X,F7.1,10x,':',11X,F7.1,9X,F6.4,9X,F6.2,8X,F7.4) 915 FORMAT(1H1,54X,'SOIL INPUTS'lSSX,'***********'//26X,'TABLE 1', 118X,':',33X,'TABLE 2'/51X,':'/22X,’DRAINAGE TABLE',15X,':',1OX, 2'SOIL WATER CHARACTERISTIC VS VOID VOLUME VS UPFLUX'/51X,':'/ 316X,'VOID VOLUME',3X,'WATER TABLE DEPTH',4X,':',14x,'HEAD',6X, 4'WATER CONTENT',3X,'VOID VOLUME',SX,'UPFLUX'/20X,'(CM)',13X, 5'(CM)',1OX,':',14X,'(CM)',8X,'(CM/CM)',11X,'(CM)',8X,'(CM/HR)') 920 FORMAT(3E10.2) 940 FORMAT(///1OX,'GREEN AMPT INFILTRATION PARAMETERS'/12X,'W.T.D.', $ 9X,'A',9x,'B'/13X,'(CM)',7X,'(CM)',7X,'(CM)') 945 FORMAT(GX,3F11.3) 930 FORMAT(3F10.4) RETURN END SUBROUTINE RANK(BAF,NK,IYEAR,IR) *§§*§***************************§*******§*§*********************§***§*§ * THIS SUBROUTINE DETERMINES THE RANK FOR AN ARRAY. * C *****************************§****§******%***************************** DIMENSION NK(50),BAF(50),IR(50) DO 10 I=1,IYEAR NK(I):IR(I) IF(I.EQ.1) GO TO 10 K=I-1 C REARRANGE ARRAY BAF FROM MAX T0 MIN 20 10 00000 00 10 610 600 C 0 0000 122 DO 20 J=1,K M=K-J+1 IF(BAF(M+1).LE.BAF(M)) GO TO 10 NN=NK(M+1) NK(M+1)=NK(M) NK(M)=NN AF=BAF(M+1) BAF(M+1):BAF(M) BAF(M)=AF CONTINUE CONTINUE RETURN END SUBROUTINE ROOT(DROOT,MOIN,IDAYIN,NNOO) * SUBROUTINE TO READ IN TABULAR VALUES OF EFFECTIVE ROOT DEPTH VERSUS * * TIME AND INTERPOLATE BETWEEN VALUES SO THAT ROOT DEPTH FOR ANY DAY C: * BE CALLED DIRECTLY AS A FUNCTION OF THE DAY. DIMENSION DROOT(370), INDAY(50),ROOTIN(50) DIMENSION MOIN(5O),IDAYIN(50) DIMENSION KALDAY(12) DATA KALDAY/O,31,59,90,120,151,181,212,243,273:304,334/ READ(1,600) N0 WRITE(10,600) N0 NNOO:N0 READ(1,610)(MOIN(I),IDAYIN(I),ROOTIN(I), 1:1 , NO) WRITE(10,610)(MOIN(I),IDAYIN(I),ROOTIN(I ),I=1,NO) D0 5 I=1,NO JJ=MOIN(I) INDAY(I)=KALDAY(JJ)+IDAYIN(I) J=2 DROOT(1):ROOTIN(1) DO 10 I:2,366 AI:I IF(I.GT.INDAY(J))J=J+1 DROOT(I):ROOTIN(J-1)+((AI-INDAY(J-1))/(INDAY(J)-INDAY(J-1)))* 2(RO0TIN(J)-ROOTIN(J—1)) CONTINUE FORMAT(8(212,F6.2)) FORMAT(Iz) RETURN END SUBROUTINE SOAK * SUBROUTINE TO FIND PARAMETERS IN GREEN-AMPT INFILTRATION EQUATION * * BASED ON EFFECTIVE WATER TABLE DEPTH AT BEGINNING OF RAINFALL EVENT.* COMMON/ABDT/EDTWT,AA(1000),BB(1000),A,B 000000 123 I=EDTWT+1 A:AA(I) B:BB(I) RETURN END SUBROUTINE SURIRR * THIS SUBROUTINE DETERMINES IF CONDITIONS ARE SUITABLE FOR SURFACE * IRRIGATION FOR WASTE WATER DISPOSAL. * IT ALSO COUNTS THE NUMBER OF IRRIGATION DAYS, SKIPS, AND * POSTPONEMENTS. U! U} 2 O 25 O 3 35 COMMON/ICNT/ISICNT,ISKIP,IPOST,IK,IPCNT COMMON/JCNT/JSICNM,JSKIPM,JPOSTM COMMON/IDAY/FDAYSI,NDAYSI,INTDAY,NOIRR1,NOIRR2,NOIRR3,NOIRR4 COMMON/IHR/IHRSTA,IHREND,INSIRR COMMON/PAR/TAV,REQDAR,AMTRN,AMTSI,DAMTSI COMMON/RAIN/R(24) INTEGER FDAYSI IF(NDAYSI.GE.NOIRR1.AND.NDAYSI.LE.NOIRR2)GO TO 30 IF(TAV .LT. REQDAR .AND. INSIRR .GT.0) GO TO 20 IF(TAV .LT. REQDAR) GO TO 10 IF(R(IHRSTA).GT.AMTRN) GO TO 20 IHRP1:IHRSTA+1 DO 5 I:IHRP1,IHREND R(I):R(I)+AMTSI CONTINUE DAMTSI:AMTSI*(IHREND-IHRSTA) JSICNM=JSICNM+1 ISICNT:ISICNT+1 GO TO 15 ISKIP:ISKIP+1 JSKIPMzJSKIPM+1 NDAYSI:FDAYSI+INTDAY*(ISICNT+ISKIP+IK) IPCNT:0 GO TO 25 NDAYSI:NDAYSI+1 IPOST=IPOST+1 JPOSTM:JPOSTM+1 IPCNT:IPCNT+1 IF(IPCNT .GE. 2) GO TO 10 IF(NDAYSI.GE.NOIRR1.AND.NDAYSI.LE.NOIRR2) GO TO 30 RETURN MDAYSI:NDAYSI DO 35 I=MDAYSI,NOIRR2,INTDAY IK:IK+1 NDAYSI:I+INTDAY CONTINUE NOIRR1:NOIRR3 **** 0000 124 NOIRR2:NOIRR4 RETURN END SUBROUTINE WORK(IND,J,TAV,DWRK,ACC,DDAY,YTAV) * THIS SUBROUTINE DETERMINES IF ALL OR ANY PART OF THIS DAY MAY BE * * CONSIDERED A WORK DAY. * COMMON /RAIN/ R(24) COMMON /IWK/ SWKHR1,EWKHR1,SWKHR2,EWKHR2 COMMON /WRK/ AMIN1,ROUTA1,ROUTT1,AMIN2,ROUTA2,ROUTT2 INTEGER SWKHR1,SWKHR2,EWKHR1,EWKHR2 IF(J.LT.O) GO TO 50 IF(IND.GT. 1) GO TO 25 IF((ACC.GT.ROUTA1).AND. (R(J) .GT. 0.005)) DDAY:0.0 IF((J .LE. SWKHR1) .OR. (J .GT. EWKHR1)) GO TO 60 IF(TAV.LT. AMIN1) GO TO 60 IF(DDAY .LT. ROUTT1) GO TO 60 DWRK:1.0/(EWKHR1-SWKHR1) RETURN 25 IF((ACC .GT. ROUTA2) .AND. (R(J) .GT. 0.005)) DDAY:0.0 IF((J .LE. SWKHR2) .OR. (J .GT. EWKHR2)) GO TO 60 IF(TAV .LT. AMIN2) GO TO 60 IF(DDAY .LT. ROUTT2) GO TO 60 DWRK:1.0/(EWKHR2-SWKHR2) RETURN 60 DWRK=0.0 RETURN 50 IF(IND .GT. 1) GO TO 55 IF(TAV.LT. AMIN1) GO TO 60 IF(DDAY .LT. ROUTT1) GO TO 60 DWRK:1.0 IF(YTAV .LT. AMIN1) DWRK:(TAV-AMIN1)/(TAV-YTAV) RETURN 55 IF(TAV .LT. AMIN2) GO TO 60 IF(DDAY .LT. ROUTT2) GO TO 60 DW =1.0 IF(YTAV .LT. AMIN2) DWRK:(TAV-AMIN2)/(TAV-YTAV) RETURN END SUBROUTINE YDITCH(DWIEP,DVOL,YD,R0,WLOSS,B,S) * SUBROUTINE TO DETERMINE WATER LEVEL IN OUTLET DITCH BASED ON WIER SE: * ING, DRAINAGE OR SUBIRRIGATION, AND RUNOFF. * THE AMOUNT OF WATER LOST FROM THE SYSTEM AND THAT REMAINING IN THE * * DITCH IS CALCULATED. FIND WATER LOSS AND WATER DEPTH IN DRAIN C COMMON/DLK/SDRAIN,DDRAIN,DC,ADEPTH COMMON/DBLK/DRNSTO 125 V:DRNSTO+RO+DVOL IF(V.LT.0.)V:O. CV=V*SDRAIN YD=((B/S)**2+4.*CV/S)**0.5/2.—0.5*B/S IF(YD.GT.(DDRAIN-DWIEP))GO TO 10 DDSTO=V-DRNSTO DRNSTO=V WLOSS=0. RETURN 10 YD:DDRAIN-DWIEP CV=YD*(B+ S*YD) V=CV/SDRAIN DDSTO:V-DRNSTO DRNSTO=V WLOSS=RO + DVOL-DDSTO C END OF DRAINMOD SOURCE CODE LISTING RETURN END C. List of References Cited *Anderson D.E., H.P. Johnson and W.L. Powers. 1976. A water balance model for deep loess soils. ASAE Paper 76-2004. Belmans, C., J.G. Wesseling and R.A. Feddes. 1983. Simulation model of the water balance of a cropped soil: SWATRE. Journal of Hydrology, 63:271—286. Benz, L.C., G.A. Reichman and E.J. Doering. 1983. Drainage requirements for alfalfa grown on sandy soil. Transaction of the ASAE 26(1):161-166. Bordas, J. and G. Mathieu, 1931. Resultats de Deux Annees, d'irrigation souterraine. Annales Agronomiques. n.s. 1(2):186- 194. Bouwer, H. and J. van Schilfgaarde, 1963. Simplified method for predicting fall of water table in drained land. Transaction of the ASAE 6:288-291. Childs, S.W., J.R. Gilley and W.E. Splinter. 1977. A simplified model of corn growth under moisture stress. Transaction of the ASAE 20(5):858-965. Dayan, E., H. van Keulen and A. Dovrat. 1981. Experimental evaluation of a crop growth simulation model. A case study with Rhodes grass. Agro-Ecosystems, Vol. 7(2):113-126. de Wit, C.T. 1958. Transpiration and crop yields. Institute of Biological and Chemical Research on Field Crops and Herbage, Wageningen, the Netherlands, Verse-Landbouwk. 0nderz., No. 64:1- 0 *Doty, C.W., and G.D. Christenbury. Controlled and reversible drainage past, present, and future. ASAE paper 79-2545. Duncan, W.G., A.L. Hatfield and J.C. Ragland. 1971. The growth and yield of corn. II. daily growth of corn kernels. Agronomy Journal 63:221-222. * denotes an unrefereed reference 126 127 Feddes, R.A., P. Kowalik, K. Kolinska-Malinka and H. Zarady. 1976. Simulation of field water uptake by plants using a soil water dependent root extraction function. Journal of Hydrology, 31:13- 26. Forchheimer, P. 1930. "Hydraulik," 3rd ed. Teubner, Leipzig and Berlin. Follett, R.F., E.J. Doering, G.A. Reichman, and L.C. Benz. 1974. Effect of irrigation and water-table depth on crop yields. Agron. J. 66:304-308. Green, W.H. and G. Ampt. 1911. Studies of soil physics, part I - the flow of air and water through soils. Journal Of Agricultural Science, 4:1-24. Hardjoamidjojo, S. and R.W. Skaggs. 1982. Predicting the effects of drainage systems on corn yields. Agricultural Water Management, 5:127—144. *Hedstrom, W.E., A.T. Corey and H.R. Duke. 1971. Models for subsurface drainage. Hydrology paper NO. 48, Colorado State University, Fort Collins. Hiler, E.A. 1969. Quantitative evaluation of crop-drainage requirements. Transaction of the ASAE 12(4):499-505. Hiler, E.A., R.W. Clark and L.J. Glass. 1971. Effects of water table height on soil aeration and crop responSe. Transaction of the ASAE 14(5):879-882. *Hller, R.A. and T.A. Howell. 197A. Optimization of water use efficiency through trickle irrigation and the stress day index. Texas A and M University, College Station. Water Resources Inst. Tech. Report No. 62. Hillel, D. 1982. Introduction to Soil Physics. New York: Academic Press. Hooghoudt, 5.3. 1937. Bijdregen tot de kennis van eenige natuurkundige grootheden van de grond, 6. Versl. Landbouwk. 0nderz. 43:461-676. Hooghoudt, 5.8. 1940. Bijdragen tot de kennis van enige natuurkundige grootheden van de grond, 7. Versl. Landbouwk. Jones, G.A. (editor). 1985. CERES-Maize: A simulation model of maize growth and development. In press. Kirkham, D. 1958. Seepage of steady rainfall through soil into drains. Trans. Am Geoph. Union 39(5):892-907. 128 *Krenzer, E.G., Jr. and W.T. Fike. 1977. Corn production guide - planting and plant population. North Carolina Agricultural Extension Service, N.C. State University, Raleigh. *McMahon, T.A. (Ed.). 1983. A general wheat crop model for Australia. Agr. Engr. Report No. 67/83, University of Melbourne. Moody, W.T. 1966. Nonlinear differential equation of drain spacing. Journal of the Irrigation and Drainage Division, ASCE, 92(IR2):1- 9. Morris, R.E. 1949. Practical aspects of controlled drainage. Agr. Engr. 30(6):280-284. Nibler, J.C. and R.H. Brooks. 1975. Drainage: Numerically evaluated for humid regions. Proc. of the ASCE. Irr. and Drain. Div., Specialty Conf., Logan, UT. *Nolte, B.H. et al. 1976. Timely field operations for corn and soybeans in Ohio. Bulletin 605, Cooperative Extension Service, The Ohio State Univesity, Columbus. Priestley, C.H.B. and R.J. Taylor. 1972. On the assessment of surface heat and evaporation using large—scale parameters. Monthly Weather Review. 100(2):81-92. Ravelo, C.J. 1978. A rational approach for incorporating crop needs into drainage system design. Ph.D. Dissertation, Texas A & M Univ., College Station. Ritchie, J.T. and E.Burnett. 1971. Dryland evaporative flux in a subhumid climate, II. 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Sieben, W.E. 1964. Het verban tussen ontwatering en opbnrengst bij de jonge zavelgronden in de Noordoostpolder. Van Zee tot Land. 40, Tjeenk Willind V, Zwolle, The Netherlands. (as cited by Wesseling, 1974). *Singh, P. and J.H. Young. 1984. Simulation of soil - water - regime during bare soil evaporation. ASAE Paper No. 84-2015. Skaggs, R.W. 1980. A water management model for artificially drained soils. Tech. Bulletin No. 276. North Carolina Agricultural Research Service, N. C. State University, Raleigh. *Skaggs, R.W. and Y.K. Tang. 1975. Water movement during drainage and subirrigation. ASAE Paper 75-2014. Skaggs, R.W. el al. 1982. Simulation of crop response to surface and subsurface drainage systems. Transactions of the ASAE 25(6):1673-1678. *Suder, R.A., K.E. Saxton and R.G. Spomer. 1979. A predictive model of water stress in corn and soybeans. ASAE Paper 79-2004. Thornthwaite, C.W. 1948. An approach toward a rational classification of climate. Geog. Rev., 38:55—94. 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Of the Specialty Conference on Environmentally Sound Water and Soil Management. ASCE, Orlando, FL. D. Index of Authors A Anderson et al., 1976, 25 B Belmans et al., 1983, 25 Benz, 1983, 17 Bordas and Mathieu, 1931, 1 Bouwer and van Schilfgaarde, 1963, 4, 5 C Childs et al., 1977, 24 D Dayan et al., 1981, 25 De Wit, 1958, 25 DOCY: 19799 1 Duncan et al., 1971, 24 F Feddes, 1976, 25 Follett et al., 1974, 1 Forchheimer, 1930, 5 0 Green and Ampt, 1911, 9 H HardJoamidjoJO and Skaggs, 1982, 19, 24 Hedstrom et al., 1971, 17 Hiler, 1969, 19 Hiler et al., 1971, 16 Hiler et al., 1974, 20 Hillel, 1982, 5 Hooghoudt, 1937, 5 HOoghoudt, 1940, 4 J Jones, 1985, 26, 32, 42 130 131 K Kirkham, 1958, 4 Krenzer and Pike, 1977, 23 M McMahon, 1983, 24 Moody, 1966, 4 Morris, 1949, 1 N Nibler and Brooks, 1975. 18 Nolte, 1976, 23 P Priestly and Taylor, 1972, 29 R Ravelo, 1978, 19, 20 Ritchie, 1984, 25 Ritchie and Burnett, 1971, 38, 39 Ritchie and Otter, 1984, 26, 31 Ritchie, 1972, 29 8 Saxton and Bluhm, 1982, 25 SCS, 1972, 27 Shaw, 1978, 20 Shih, 1983, 17 Sieben, 1964, 17 Singh and Young, 1984, 25 Skaggs et al., 1982, 20 Skaggs, 1980, 5, 32 Skaggs and Tang, 1975, 4 Skaggs, 1980, 33 Sudar, 1979. 20 Sudar et al., 1979, 20 T Thornthwaite and Mather, 1957, 10 Thornthwaite, 1948, 10 V Van Schilfgaarde, 1963, 4 Van Schilfgaarde, 1965, 5, 8 W Ward, 1972, 2 Ward, 1972, 17 Wesseling, 1974, 17 White et al., 1980, 25 Worm, et al., 1982, 1 "11111111111111