AN ENERGY EUHHIIV.. - DETERMNED BY 0mm“ mum REMENT 'EY SOIL M Thom hr the Dunc. c‘ M. 5. “EH15“ STATE UNIVERSHY Robert H. Wilkinson 1960 V L [B R A R Y Michigan State University T-fi.‘ EVAPOTRANSPIRATION 0F FRUIT TREES AS DETERMINED BY AN ENERGY EQUATION AND BY SOIL MOISTURE MEASUREMENT by Robert H.‘Wilk1nson. A THESIS Submitted to the College of Agriculture of Michigan State university of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of IJIASTER OF SC IEIEECE Department of Agricultural Engineering 1960 Approved by W. /9iv3 "1 l/ ,/ . '.m '6) -d. ACKIOWLEDGHEETS The author wishes to express his sincere thanks to Professor E. H. Kidder of the Agricultural Engineering Department for his council and guidance as major pro- fessor during the course of this study. Sincere appreciation is also expressed to Dr. A. E. Erickson of the Soil Science Department for the use of laboratory equipment and for his helpful suggestions. The assistance of Dr. A. E. Mitchell and Dr. A. L. Kenworthy of the Horticultural Department is grate- fully acknowledged. Dr. Nitchell for permitting the work to be done in the orchard and Dr. Kenworthy for help in laying out the experiment. TABLE QE_CONTENTS ~ page I. INTRODUCTIONQOOOQ00000000000000000000000.0001 II. REVIEW OF LITERATURE........................3 A. Moisture Use by Trees...................3 B. Measured Transpiration of Fruit Trees...8 C. Energy Methods for Evapotranspiration..10 III. PROCEDURE............;.....................13 ‘ A. Moisture Block Installation............13 B. Meisture Block Calibration.............16 C. Processing of Data.....................17 D. Plotting of Data.......................19 E. Energy Equation........................2h IV. DISCUSSION OF RESULTS......................29 A. Calculated Water Consumption...........29 B. Measured Water Consumption.............29 C. Similarities and Differences...........32 v. CONCLUSIONS................................57 VI. SUGGESTIONS FOR FUTURE STUDIES.............58 VII. REFERENCES.................................S9 VIII. APPENDIX I. ...... ..........................6h IX. APPENDIX II................................6§ X. APPENDIX III...............................79 ‘page XI. APPmDIx IVOOOOOCOOO. ......... 00.00.00.000600081 XII. APPENDIX V82 XIII. APPENDIX V183 XIV. APPENDIX V1181+ XV. APPENDIX VII185' XVI. APPENDIX 1X87 XVII. APPENDIX X88 XVIII. APPENDIX X189 Figure Figure Figure 1. 2. ‘ Figure M., Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 11. 12. 13. 11+. 15. 16. 17. 18. 19. 20. 21. 22. LIST gr; FIGUE pa e Sketch of Horticultural Farm.............1 Typical Block Location...................15 Percent Soil Mbisture in Apple Orchard...21 Percent 30.11 Moisture in Peach Orchard...22 Percent Soil Moisture in Cherry OrChard..23 Apple Orchard Tree Spacing...............27_ Peach Orchard Tree Spacing...............28 Cherry Orchard Tree Spacing..............28 8011 Soil Soil and Rainfall.....37 Tree 1...38 Tree 2...39 Tree 3...h0 Tree 1...h1 Moisture Depletion Mbisture Depletion - Mcisture Mbisture Depletion - Mbisture.Depletion - Moisture Moisture Apple Depletion - Apple Soil Soil Apple Peach Soil Soil Soil Depletion - Peach Tree 2...h2 Depletion - Peach Tree 3...h3 Mbisture Depletion ; Cherry Tree 1..#% Soil Mcisture Cherry Tree 2..h5 Soil Calculated Average Weekly Depletion - Moisture Depletion - Cherry Tree 3..#6 water ' consumption.00.00.000.000.000000000000000H'? Average'Weekly Water Consumption for Apple Tree1on00000000000000eeeooooooooool'I'B Average Weekly'water Consumption for ’ Apple Tree 2......0000eoeeeeoec00.000.09.011'9 Average Weekly‘Water Consumption for Apple Tree 30.00.00.0000000000000.0.0.000050 Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 23. 2h. 25. 26. 27. 28. 29. 30. 31. 32. 33-- 3h. 35. 36. 37. 38. 39. no. #1. Average Weekly Water Consumption for PeaChTree1000OOOOOOOOOOOOOOOCOCO...0.0051 Average weekly Water Consumption for Pea-Ch Tree 20.0.00...0.000.000.000000000052 Average Weekly Water Consumption for PeaCh Tree 3.0.00.0000000000000.0.0.0....53 Average weekly'Water Consumption for Cherry Tree1000OOOOOOOOOOOOOOOOOOOOOO... Average Weekly water Consumption for Cherry Tree 2.000.000.000000000000000.0.0055 Average Weekly water Consumption for Cherry Tree 300‘.ooeoooeoeooeooooeoeooco.056 Curve - Soil No. 1...........66 Curve - 8011 No. 2...........67 Soil No. 3...........68 Soil No. h...........69 Soil 5...........7O Soil 6...........71 Soil 7...........72 8...........73 9...........7h 1o..........75 11..........76 12..........77 13..........78 Calibration Calibration Calibration Calibration Curve - Calibration 'No. Calibration No. Calibration‘ No. Soil ’Soil Calibration No. Calibration No. Soil Soil Soil Soil Calibration Calibration No. No. Calibration No. Calibration No. new page Table 1 Comparison of Calculated Evapotranspiration Using Pyroheliometer Radiation Values and Computed Radiation Values...............36 INTRODUCTI OI»: During recent years, the practice of using irrigation to supplement natural rain fall, has become more common among tree fruit growers. Since the investment in irrigation equipment is rather large, the grower would like to have the assurance that there will be a higher value fruit crop as a result of irrigation, to eventually pay for the investment. The value of the irrigated crop is increased not only by greater tonage, but by quality also, as large fruit is worth more than small fruit. This fact alone is not sufficient assurance that irrigation is desirable. The duration and frequency of the drought must also be great enough that the irrigated orchard will produce crops of sufficiently higher value than unirrigated orchards in order to justify the effort and expense of irrigating. Basic information on the rate of water use by the fruit trees must be known in order that the length of time required for exhaustion of the soil water supply may be predicted. When a drought exceeds the time that it takes the tree to use the available moisture, the crop will suffer. In peaches and cherries this is particularly true during the weeks just prior to harvest as this is when these fruits make their largest gain in size, but is true in apples to a lesser extent, all through the growing season. When the length of time that is required for removal of the soil moisture is known, the frequency of droughts of this length.cu-greater length may be determined from existing Michigan weather studies. 'With this information, the number of times a grower might expect to have need of irrigation equipment could be predicted, and consequently the return on his investment could be estimated. The problem resolves itself to one of knowing the amount and rate of water use by the fruit trees. Consider- able work has been done in the area of water requirement on other plants, but very little has been done in the humid areas with regard to fruit trees. Most of the values of water consumption for fruit trees at present, are based on estimates. The Penman energy budget method of predicting evapo- transpiration has been used on some orchards in the Eastern United States. Because the Penman method is very general and is not exactly designed for orchards, the results are questionable. The intent of this study was to measure the water consumption and rate of use for apples, peaches and cherries in a Michigan orchard and compare this to rates of water use as computed by an energy equation. This comparison will give an indication of the reliability of the results given by the energy method. II. REVIEW 9E LITERATURE Moisture Use. by Eggs The problem of measuring the water used by trees and plants is complex and one on which considerable work has been done. There are numerous factors which influence the amount of water used by trees and plants. The soil condi- tions that affect the water use and the rooting depth of plants are nutrition, texture, and compaction. Climatic conditions such as the amount of energy received, length of day, temperature of the air, wind, evaporation and rela- tive humidity influence water use of the plant as does competition for the water by other plants. Relating to soil moisture, Viehmeyer and Hendrickson (l3, 19, 52,53) and Veihmeyer (A8) in their work in Cali- fornia have found that in the range of readily available moisture (between field capacity and permanent wilting point) the transpiration rate is independent of the soil moisture. They report (15, 50. 51) that there is no benifit in irrigating before permanent wilting point is reached, only additional cost, and that it is not detrimental to allow the trees to reach permanent wilting poirt if this condition does not exist for more than a few days. When water is applied, recovery is swift. The effects are pro- nounced if the trees remain dry for several weeks. They also cite (5%) water use rates of from .1 inches/day for coastal region, to .# inches/day for the warm inland areas of Cali- fornia. h Magness, Degman and Furr (29) report that the growth of apples was not slowed down until the moisture content of the soil was near the permanent wilting point in the driest part of the root zone. They found that the growth rate was restored when the soil moisture was restored pro- vided the foliage was not damaged, but that the ultimate size of the fruit was reduced in proportion to the length of the drought. Magness (31) reports that in Eastern United States, mature orchards use about h inches of water per month dur- ing full leaf of the trees, May 1 to September 30 or 20 inches for the season, and that the moisture extraction is proportional to feeder root density.. Taylor and Furr(h1) found that the tree did not suddenly run out of water and wilt, but rather as permanent wilting point was reached, moisture was pulled from the fruit for transpiration. This was not detrimental to the tree or crop if not allowed to exist for a prolonged time. There was no advantage in rot having the soil reach the permanent wilt- ing point before water was applied. Kenworthy (2#) found that when 80 percent of available moisture was used, tree growth was decreased. His experiments were on a finer textured soil than Hendrickson and Viehmeyer‘s and were concerned more with growth than yield. In a survey of soil water requirements and availability, Kelley(23) cites moisture extraction patterns for various crops, all of which take 80 - 90 percent of their water from-thetop 3 feet. He reports a transpiration ratio of 500 - 1000 parts water required for every part of dry matter produced in alfalfa. This ratio depends on factors such as moisture content, soil type, soil compaction, soil fertility, and climatic factors. Kelley's summary of work done on the availability of soil moisture indicates that water above wilting percentage is not equally available in terms of plant growth. Another factor that may have a bearing on the soil water-plant growth, relationship, is the fertility of the soil. It is a well established fact as pointed out by Hanks (11) that as the fertility increased the water required for plant growth decreased. Stoltenberg (39) found that when a nutrient deficiency is limiting plant growth, differ- ences in transpiration rate due to soil moisture level may not be evident. The extent of competition by sod and other plants for the moisture in an orchard has an influence on the amount of moisture available for tree growth and fruit production. Clean cultivation in peach and sour cherry orchards has become a rather well established practice to conserve mois- ture. Kenworthy (25) found that under clean cultivation practice, the infiltration capacity of the soil decreased with age, probably due to a reduction in organic matter. Onthe other hand with orchards hasod, the water absorbing and retaining properties improved with age. Alderfer and Shaulis (1) reported that in peach orchards the infiltration capacity was decreased when heavy sods were used, until the sods had time to become well established. They concluded that trashy cultivation on a deep soil appeared to be the best method of improving in- filtration.l A Higdon (21) found that clovers, alfalfas and quack _grass depleted moisture faster than other grasses. He found that mowing the sod decreased moisture depletion at low soil moisture but increased it at high soil moisture due to rapid regrowth. He concluded that a crown mulch seemed to be the best method of retaining sod without serious competition between sod and tree for moisture. Millits and Erickson(57) report from their work on alfalfa, clover, fescue and blue grass that above permanent wilting point, moisture use ranged from a maximum of .13 inches per day down to .02 inches per day during the dormant time of mid summer. They also found that the stage of crop development had more affect on water use than did climatic conditions. Shaw (38) reported that in a Massachusetts apple orchard a heavy mulch proved very satisfactory and more fruit was produced than similarly fertilized and cultivated orchards. Toenjes, Higdon and Kenworthy (H5) report that con- serving moisture is best done in Michigan with a shallow rooted sod cover. Toenjes (MID fourd that irApeaporchards in Michigan after 12 years, the orchard in sod had larger trees, produced more and the soil was less dense than in orchards under clean cultivation. Tree root distribution and depth also have a bearing on the amount of water the tree can reach. Havis (12) found that in Ohio on Wooster Silt Loam, peach tree root distribution was related to soil profile. About 60 per- cent of the roots were in the top foot, 85 percent in the top two feet with very few roots penetrating the "C" horizon. w. S. Rogers (3 ) reports in England that apple tree roots extended beyond the branches of the tree and that most of the roots were in the top soil layer. Sandy soil produced a shallow root scaffolding and the smallest trees. Loamed soil had the deepest roots and largest trees. Viehmeyer and Hendrickson (#9) report that at a given depth on uniform soils, uniform root structure will cause the soil midway between the rows to reach permanent wilting point as soon as it will the soil close to the tree. They state (54) that it is not true that with-holding water will make roots go deep seeking water, nor is it true that light irrigation encourages shallow rooting. They attempt to show that capillary moisture does not move by capillary action but remains as it is until removed by the plant. The work of Wiersma, and Veihmeyer (56) does not lend support to the theory that plants can pick up moisture by leaves in a high humidity atmosphere and exude the moisture from their roots in dry soil areas, pick up nutrients and take up this water again for plant growth. Proebsting (3%) reports in California that temperature as well as water affect tree growth. He found 75°F. to be the best temperature for growth. Where temperatures were 85 - 95°F. he found very few roots in the top foot. Most roots were in the 2 -5 foot layer with few below the 5 foot depth. Hinrichs (22) found that the compaction of the soil had a definite effect on the rooting of peach trees. Loosening the soil by digging to a h foot depth was very beneficial in stimulating root growth and top development. Measured Transpiration of Fruit Trees ‘The use of moisture blocks and a Bouyoucos Bridge has been the most common method of measuring soil moisture and estimating evapotranspiration of plants. Anderson, and Edlefsen (2) report that block measurements are very much reproducibleixltmhavior and blocks possess a like resist- ance at similar moisture content. They found that the blocks could be calibrated at all moisture contents if they were in soils with actively transpiring trees,but that there was a tremendous lag in response by the block if plants war; not growing on the area. Edlefsen, Anderson and Marcum (7) report that moisture blocks in all the soils they tested had approximately the same resistance for permanent wilting point. They had resistance readings of MOO-600 ohms at field capacity or above and 500,000 ohms when all available moisture was gone. \o Bouyoucos and Mick (h) have made exhaustive studies on determining moisture consumption by use of moisture blocks. They report excellent dependability and reproduci— bility. Magness (30) conducted a a study intended to show the relationship of apple growth to soil moisture. He found that fruit growth is fairly uniform when the tree has available water and retarded when the wilting point of the soil is reached. He reports a very close correlation between growth and the hours that stoma were opened. Hendrickson and Veihmeyer (1%) have shown that the growth of peaches is characterized by three distinct periods. The first being rapid and ending about the first week; the second, slow lasting from early June until late July; the third, final period of rapid growth. They found that the final size was reduced if the available water was ex- hausted during the growing season. Lilleland (28) reports that the cyclic growth of the peach is characteristic of many stone fruits. First, fast for a short time period; second, slow for a long time period; third, fast until harvest. The last 5 age was the most critical as far as final size was concerned. Hendrickson and Veihmeyer (16) report that the volu- metic growth rate of pears increases during the season as contrasted to uniform apple growth and cyclic growth of peaches. lO Pieniazek (33) found that the transpiration rate of apple fruit was very high early in the season when the apple skin was permeable, then decreased to a minimum at harvest, and increasing again if the fruit became over ripe. Verner (55) made daily measurements of apple develop- ment and reports a variable rate of growth. He found that when the evaporation power of the air is low, the apple swells rapidly due to moisture available to the fruit. This lasted for a day or two and then leveled off to normal even though humidity remained relatively high. Days of high evaporation were accompanied by slow rates of growth. The rate of growth seemed to depend more on evaporating power of the air than on air temperature. Tetley (#2) found the growth rate of apples decreased during periods of rainy sunless weather, but the average rate of increase over the season was nearly constant. Energy Methods g§_Computing Evapotranspiration Gentilli (8) has pointed out that semi- emperical equations for evapotranspiration do not give the same re- sults, so obviously not more than one equation can be generally correct. Halstead and Covey (9) state as reasons why Gentilli's conclusion is true: 1. Areas and differences between surrounding country; 2. Correlation between temperature and evapotranspiration is complicated by the fact that actual evapotranspiration tends to lower both the maximum and mean temperature; ll 3. Any system which employs only one wind speed (as Pen- man) must rely on extremely crude measurements of turbulence; 1+. Any method which is based upon mean monthly and even daily figures must depend upon a correlation between instant- anious and mean values which varies with season, location and climate. Lemon, Glaser and Satterwhite (27) show that evapo- transpiration is a function of three things; soil maisture, plant, and meteorological factors, and any attempt to predict evapotranspiration without considering all pertinent factors will meet with only qualified success. They point out that evapotranspiration is controlled by soil moissure tension, physiological factors, relation of soil of irrigated areas to that of its surroundings, as well as purely meteoro- logical factors of radiation, wind air temperature and humidity. Criddle (6) presented a comparison of various energy equations pointing out advantages and limitation of each. The procedure outlined by Penman(32) has been found fairly acceptable and was the method used by T. V. Wilson (58 in his work on peaches in South Carolina. Anderson (3) from his work at Lake Hefner, Oklahoma has presented a very exhaustive study of evaporation as computed by energy-budget methods versus actual measured evaporation from a lake. The energy equation he used was the Penman formula. He reports that the classical equation 12 must be modified. Best results were obtained by measuring the solar energyixiplace of a calculation, as the reflection depends on sun altitude and surface and not on wind. Ander- son reports the energy budget gives 1 5 percent accuracy for periods of 7 days of longer. 13 III. PROCEDURE The study was conducted on the Michigan State Univer- sity Horticulture farm in East Lansing. (See figure 1.) Three trees each of apples, peaches and cherries were selected for the measurements. Care was used to choose trees well within the orchard proper in order to eliminate border effects and also to choose healthy, typical, mature trees. It is of interest to note that the apple orchard had a sod cover while the peach and cherry orchards were clean cultivated. Moisture Blocks Installation Bouyoucos moisture blocks were used to measure soil moisture and were placed in four locations around the three apple trees. (See figure 2.) Location "A" being beneath the drip point of the branches and location "C" being midway between "A" and the trunk. Location "BF was also at the drip point, and "D" midway between "B" and the trunk, but "B" and "D" were on a line perpendicular to a lire through "A" and "C". This was done in an attempt tb minimize any affect the tree might have on intercepted solar radiation and consequently result in a difference in soil moisture. Moisture blocks were placed at depths of 1 foot, 2 feet, and 3 feet in each location around the apples. A bucket auger was used to bore the hole to place the blocks, as it was thought that the bucket auger would disturb root structure as little as possible. 1h 2¢mmm10 z. NEH—.902 ..:Om kzwomwn. m mmDGE Ir I- 3 no.» .3 .m M. Ifll nméu mo.» IN... 8 III A 5.. m3 mu.» .v w . It I I- N an. mom can .n O u Ed New Ed .~ one. new. ts J: m n f0 4:" Energy Eguation The energy equation for evapotranspiration the author chose to use was developed by Penman. This procedure has proven quite reliable within its limitations. The limit- ation being that the time period considered must be 7 days or more. The accuracy of estimate decreases as the period considered decreases, due to differences in energy storage. This energy storage averages out over a period of time, so as the period of time increases, the accuracy of estimate also increases. The length of periods under consideration for this study are 7 day increments. Values of wind speed, temperature, length of day, hours of sunshine, and humidity were recorded and averaged to give an average value of each for the weekly period. A slight deviation frOm the calculated formula for radiation was used. This was in the form of actual recorded values of total radiation from the pyroheliometer that is located at the University Exper- iment Farm. This substitution was used as it was thought it would provide a measurement that would give greater accuracy than a value calculated from an equation. The average weekly climatic values were then substituted in the Penman formula which was solved/to give a so ution in terms of inches of water per day, that would be evapotran- spired from a vegetative surface. Daily values were found for the 12 week period, and plotted against time to provide a graph of rate of water use by the trees. A comparison could then be made between measured water use and calculated water use. ’7 C; Calculation of evapotranspiration by the Penman formula involves the following equation: =AH + .212 Ea Et A + .27 SD where: Et = potential evapotranspiration in mm/day. A: = slope of saturated vapor pressure curve. (see appendix X, A.) Ht = net radiation. E = Auxiliary quantity. S3 = factor denoting influence of diffusion resistance D = factor denoting influence of length of day. Net radiation values were obtained by altering the emperical equation of: H1; = Re (1-r) (.18 + .55 §> -c‘ra l+<.56-.092vea><.i +.9§> to include the Epply Pyroheliometer values of radiation. This took the form of: Ht = (l-r) (Pyroheliometer)CfTa 1*(.56-.0927""e'd)(.l+.9§) waroheliometer values were obtained from the ARS- SWCRB—USDA Cooperative Project r = 0.20 radiation reflection coefficient for vegetation. E ‘= ratio actual to possible hours of s shine. a“ = Stefan Boltzman constant 2.01 x 10' mm/day. Ta = absolute temperature of air R. ' ed = saturation vapor pressure at mean dew point. D = hours of sunshine. values of Ea were calculated from: E .35 (ea-ed)(l+. 0098u2 ) mm/day. a = - ea = saturation vapor pressure at mean air temperature. u2 = wind speed at two meters. u2 = uh x gig: 2,6 2 Ba = mean monthly extra terrestial radiation in mm of HZO/daYo Values of S were calculated from: S =La/(La + 0. 16) where La = effective diffusion length of air which is equal'to .65 (1+ 0.0098 u2) 26 Values of D were calculated from: R/2h + l/n sin NIT/2h hours from sunrise to sunset. D N Pyroheliometer values of gm-cal/cm2 were converted to mm of water. Example - #18 cal/cm x ; c,c, x 1 gm of H20 5§0 cal/gm(H20 Vapor) x 10mm = 7.09 mm of H20 Evaporated. cm The question arose, of the actual percentage of solar energy that the trees were intercepting. If the energy that falls on the ground is not used to evaporate water from this surface, due to dry soil conditions, it is conceivable that it may be available as heat energy to remove water from the tree. Therefore it is necessary to know the percentage that the intercepted energy is of the total energy. This was investigated by measuring the tree crown diameter and row spacing, giving an indication of the ground covered by the trees. (See figures 6,77and 8.) The values of evapotranspiration as given by the Penman equation using calculated values of radiation were found for comparison purposes. Values of Ra were used as described by Griddle (6) and the equation handled in the general way. This comparison of evapotranspiration, calculated from computed radiation values is shown in table 1' W00 00 MW Jhix ._ \Kkr \CD n4' TREE DIA. W I 25'ROW l ‘ i FIGURE 7 PEACH ORCHARD TREE SPACING TREE COVER- 25% OPEN- 75"]. Is“ TREE DIA. - " ‘ 25 ‘ROW 4} mm FIGURE 8 CHERRY ORCHARD TREE SPACING TREE COVER-4I% OPEN- 59% G}r\€|\ C \>€D C9” 6‘! 29 Iv. pgSCUSSIor Q§,RESULTS Calculated Water Consumption As all the trees under study were within 1000 feet of each other, they were all subjected to the same climatic environment, so theoretically, using the Penman energy equa- tion, they would all have the same opportunity for potential evapotranspiration. Plotting the values calculated from the Penman Equation for weekly increments provided the rate of water use curve shown in figure 19. This curve was also overlaid on figures 20-28 to make an easier comparison. The rate of water use data given by the energy equation, was affected by temperature and this accounts partly for’ the trend of the curve. The curve shows a rate of approxi- mately .12 inches per day in early July decreasing fairly consistently to a rate of approximately .07 inches per day late in September. Measured Eater Congumption The graphs figure 10-18 show the amount of water in inches that was present in the soil. The rains in mid sum-- mer raised the soil water content to near field capacity, from which point'water consumption continued without inter- uption until the soil moisture content was near permanent wilting point. This provided a fairly reliable picture of water use for this period. The average slope of this water use curve was calculated for weekly increments to give the rate of water use per week. This calculation was broken down to daily rate figures. The daily rate of water consump- tion is shown plotted for each tree in figures 20-28. 30 .Apple Tree Evapotranspiration Curves (Figures 20,21 and 22) A comparison between the rate use curves (moisture blocks) of the apple trees, shows there is not exact agree- ment on the rates of water use. The variation in'root structure, tree size and soil texture can largly be held responsible for this difference. Superficially, soil texture may appear to have more effect on the rate of water use than it actually does. The fact that a plant growing in a coarse texture soil would remove the available water faster than it would if grown on a fine textured soil, wcukimake it appear that it was using the water at a higher rate. I . Although there is not exact agreement between trees, the general trend of all three is similar.) The water use rate is fairly low for all early in July, about .05 inches per day. This rate increased to a maximum of .16 inches per day toward the end of August and then gradually decreased again to about .05 inches per day. Peach Tree Eyapgtzanspiration Curve§ (Figures 23, 2% and 25) The behavior pattern for the tree peach trees is similar to that of the apples in that there is not exact' agreement between individual trees, but the general trend of all is in agreement.' The rate of water use was fairly low .Oh - .05 inches per day when the data recording was’ begun in July. \It remained low increasing slowly during the rainy part of the summer, until about the middle of August. At this point there was a sharp increase in rate, all three trees reaching a maximum rate of approximately .2h inches per u‘ .31. day, at harvest time, the first week in September. Follow- ing harvest, the rate of water use declined sharply to .06 inches per day throughout the remaining part of September. This trend of water use, low during the mid part of the growing season, and increasing during the final few weeks of growth until harvest, lends support to the findings of Viehmeyer and Hendrickson (15) and Lilleland (28) re- garding the growth rate of peaches. Cherry Tree Evapotransniration Curves (Figures 26,27 and 28) The graph of water use rate for cherries shows the greatest difference between trees; but, some general trends may be seen. The cherries were just entering their ripening stage as data recording was begun on July 12. This is indicated by the rugh rate of water uSe of approximately .20 inches per day during the first two weeks, decreasing to a minimum of .03 inches per day in the fourth week. This minimum rate continued during the wet part of the summer until the sixth week. At this time the weather became fairly warm and dry, and as the cherries were not harvested, the rate of water use took a sharp increase reaching a maximum of .32 inches per day during the 8th and 9th week. Pieniazek (33) reports similar increase in water use by apples when they were not harvested. From the 9th week on to the end of September, the cherries began to dry up and drop off, which was accom- panied by a decreasing rate of moisture use to the minimum of .03 inches per day. 32 Similarities and Differerces Between Measured Water and Calculated water Consumption (Figures 20-28) From a study of the graphs, it is obvious that there is considerable variation between the Penman curve for evapo- transpiration and the curve developed from moisture block data for any fruit tree considered in this experiment. The differences between the calculated evapotranspiration and measured evapotranspiration vary with the type of fruit tree being considered. The author feels that there is valid justification for these differences. Although the Penman equation pro- duces fair results for a period of time of a few weeks or longer, Halstead and Covey (9) have pointed out that some rather crude estimation of climatic conditions, greatly affect the accuracy over a short time interval. It is in- teresting to note that while weekly rates of evapotranspir— ation varied considerable, the total evapotranspiration for the complete experiment (12 weeks) for alltrees studied was within 7.7 percent of the total calculated from the Penman equation. This lends support to the fact that as the time interval considered increases, the agreement between calculated and actual evapotranspiration improves. Another reason why there is considerable variation between Penman rates and measured rates, is due to the physiological characteristics of the fruit tree. The Penman equation was first developed for a body of water, and modi- fied to include a factor to simulate the evaporation from a vegetative surface. The factor is very nondescriminating 33 with regard to the type of vegetation surface, assigning the same value to all, with no regard as to varying water requirements of plants with maturing fruit crops. Penmans original work was done using 12 cylinders, 6 feet deep and 2IU2 feet hidiameter. They were treated as uniform surfaces of open water, bare soil and turfed soil. He found that when the water table was deeper than 2% inches, the soil and turf surfaces were not kept supplied with moisture for the maximum evaporation rate, and actual values did not correspond to the calculated values. In explaining values of evapotranspiration that did not agree with calculated values, Penman states on page 1HH (32): ("Ffom the conclusions, one would expect the corresponding values of the annual evaporation from cropped land to be 3/# of Ea (water surface evaporation) if the crop transpired at maximum rates all the year; in practice the rates will be less than this because of the ripening pro- cess in annual vegetation and /or the lack of summer rain- fall." In an attempt to explain the larger amount of water indicated as used, above the amount shown possible to transpire by the energy available, the possibility of water storage in the fruit was investigated. The average yield of an apple tree is about 15 bushel. The apple weight is #5 pounds per bushel and water content is 8h.l percent. This gives a total water storage of 567.5 pounds of water or 8.78 cubic feet. This quantity of water spread out over 31+ the area from which the tree removes its water, amounts to about .03h inches of water for the season, a very negligable amount. It is obvious then, that if only a small portion of the water is actually stored in the fruit crop, the balance of the water extracted from the soil must be tran- . spired. The question then logically arises, that the Penman equation is based on heat or the energy that is available to evaporate water, and if this heat is not available, how can water be transpired. This can be explained by noting the amount of solar radiation that is intercepted by the trees. In the case of the Penman formula, the rate of evapotranspiration is calculated and it is assumed that the figure found, for example .12 inches per day, represents the quantity of water that it is possible to evaporate from 8 100 percent of the area considered. The situation of the orchard differs from the assumed set up for Penman procedure, in that the trees in the orchard only intercept about he percent or less of the solar energy. The remaining 56 per- cent of solar energy falls on the ground between rows and ‘when the ground is wet, this energy is used to evaporate moisture from this surface. This leaves the water transpired by the trees proportional to the Mk percent of the energy they receive. As the ground drys out and grass goes dormant, the energy that falls on the ground is changed to heat and is available to pick up water from the tree. This energy combined with that intercepted by the tree can conceivably I 35 double the energy available for transpiration from the tree. This is supported by the results of the graphs which show the rate of water used by the tree about double the Penman values, during the‘warm dnypart of the season. The comparison of calculated values of evapotranspiration based on phyroheliometerrediation data and values based on computed radiation are shown in table 1. This comparison shows that weekly evapotranspiration rates based on computed radiation range from a minimum of 1% error on the hth week to a maximum of #1 % on the llth.week. The values are ran- dom with some being high, others low. The average error for the 12 week period was 3% of the value given by the pyroheliometer. This emphasizes again that the accuracy of values of evapotranspiration calculated by the Penman equation increase as the length of time considered increases. 36. 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N .02 mum... >mmw10 m0“. 20....1230200 mm>43 >4¥wm>> w04mw>4 KN $.30... #100 .034 >435 0M MN 0. m N 0N m. N. m .mN NN m. m . . . ._TJ N O y N m 0 NN ... 0 N x 0 1. E44 0004430440 .|.. 1 .0 0 w R xx 544 00430402 I l N.oz mump >mmuzo _ _ i 290 (AVG 83d SBHONI) 380 HBlVM 56 57 V. CONCLUSIONS From a study and comparison of the graphs of water use rate given by Bouyoucos moisture blocks, and the potential evapotranspiration rate calculated by the Penman procedure, the following observations are noted: . l. The potential evapotranspiration as calculated for weekly intervals by the energy equation, is not a reliable indication of the actual evapotranspiration of fruit trees. This is due to the partial ground cover by trees, variations in root structure, soil conditions and physiological plant functions. 2. The solar energy falling between rows, is available to the tree when the ground is dry or the cover vegetation is dormant, and accounts for a much higher rate of water use by the tree than would normally be expected. 3. The use of moisture blocks makes possible a more re- liable procedure for determining the correct time of irriga- tion than does the energy equation. h. The rate of water use indicated by the energy equation, should be multiplied by a factor of 3 or h when using this method to determine the time of irrigation, prior to harvest, for a young orchard. 5. Irrigation water should be placed as near the tree as possible rather than in mid row in order to be available to the roots. I 6. The physiology of a maturing fruit crop causes a vari- ation in moisture use. This is particularly true in peaches and cherries, which have a low moisture use rate in mid season, increasing prior to harvest and decreasing again at harvest. 58 VI. SUGGESTIOES,§QB FUTURE sggpg To further check the reliability of the Potential Evapotranspiration as given for orchards, by the Penman method, and to possibly alter the modifying coefficients so that they would be more correct, various other studies could be made. These might be: 1. Make a more exhaustive study of the same type as done here, using many more moisture blocks on a uniform soil type. This would eliminate variables and give more weight to the data. 2. Use another method of checking water consumption, such as neutron scattering method. 3. Employ a weighing lysimeter to obtain the quantity of water used by a fruit tree during a growing season. Use this information to alter the energy -equation to include the area and plant affect, thus giving more re- liable results. 59 VII.lREFERENCES l. Alderfer, R. B., and N. J. Shaulis. (l9h3). Some affects of cover crops in peach orchards on run off and erosion. Am. Soc. Hort. Sci. Proc. Vol #2. pp. 21-29. 2. Anderson, A. B. C., and N. E. Edlefsen. (19H2). Laboratory study of the response of 2 and h electrode plaster of paris blocks as soil-moisture content indicators. Soil Sci. V01 53. No. 6. pp. h13-h28. June. 3. Anderson, E. R. (l95h). Water loss investigation. Lake Hefner Studies. U. 3. Geological Survey Tech. Report 269. pp.71-ll9. H. Bouyoucos, G. J. and A. H. Mick. (l9h0). An electrical resistance method for the continuous measurement of soil moisture under field conditions. Michigan State Agr. Exp. Sta. Tech. Bul. 172.' 38 pp. 5. Cahow, T. W. (1952). Study of drought frequencies in lower pennisula of Michigan. Thesis for De ree of M. S. Mich. State Univ. E. Lansing. (Unpublished) 6. Griddle, W. D. (1958). Methods of computing consumptive use of water. Am. Soc. C. E. Jour. Irrigation Drain. Div. V01. 8%. No. 1R1. 7. Edlefsen, N. E., A. B. C. Anderson and W. B. Marcum. (1952). Field study of response of the electrical resistance of 2 and # electrode plaster of paris blocks to variation of soil moisture. Soil Sci. Vol. 5%. No. H. pp. 2754 279. 8. Gentilli, J. (1953). Die Ermittlung der MBglichen Oberflachen und Rflanzenverdunstung, Dargelegt am Beispiel von Australian: Das Suchen nach einer Formel, Erdekurde. Bonn 7 (2): pp. 81-93. 9. Halstead, M. H., and W. Covey (1957). Some meteorological aspects of evapotranspiration. Soil Sci. Soc. of Am.Proc. V01. 21. No. 5. pp. h61-h6h. Sept. Oct. ' 10. Halkias, N. A., F. J. Veihmeyer and A. H. Hendrickson (1955). Determining water needs for crops from climatic data. Hilgardia. Vol. 2%., No. 9. pp. 207-233. December. 11. Hanks, R. J., and C. B. Tanner (1952). Water consumption by plants as influenced by soil fertility. Agronomy Jour. V01. 181*. pp. 98-100. 12. Havis L. (1938). Peach tree root distribution. Ecology. Vol. 19. No. 3 pp. h59-h62. l3. Hendrickson, A. H., and F. J. Veihmeyer (1929). Irrigation ,-- experiments with peaches in California. Calif. Agr. Expt. Sta. B111. l4'79. pp. 1-56. NOV. 1h. 15. 16. 17. 18. 19. 20. 21. 22. 23. 2h 25. 26. 60 Hendrickson, A. H. and F. J. Veihmeyer. (193%). Size of peaches as affected by soil moisture. Am. Soc. Hort. Sci. Proc. Vol. 32. pp. 284-286. Hendrickson, A. H., and F. J. Veihmeyer. (1937). Responses of fruit trees to available moisture. Am. Soc. Hort. Sci. Proc. V01. 35. pp. 289-292. Hendrickson, A. H. and F. J. Veihmeyer. (19H1). Some factors affecting the growth of pears. Am. Soc. Hort. SCI. PTOC. V01. 39. PD. 1‘70 Hendrickson, A. H., and F. J. Veihmeyer. (19h2). Irrigation experiments with pears and apples. Calif. Agr. Exp. Sta. Bul. 667. pp. 1-93. May. Hendrickson, A. H., and F. J. Veihmeyer. (1992). Readily available.soil moisture and sizes of fruit. Am. Soc. Hort. Sci. Proc. Vol. #0. pp. 13-18. Hendrickson, A. H., and F. J. Veihmeyer. (19H5). Permanent wilting percentages of soils obtained from field and labor- atory trials. Plant Physiol. Vol. 20. pp. 517-539. Hendrickson, A. H., and F. J. Veihmeyer. (1951). Irrigation experiments with grapes. Calif. Agr. Exp. Sta. Bul. 728. 31 pp. Higdon, R. J. (1953).' Soil moisture depletion by various grasses and legumes used as orchard sods. Thesis for degree of Ph. D. Michigan State Univ., East Lansing. Hinrichs H., and F. Gross. (19h3). Relationship of compact subsoil to root distribution of peach trees. Am. Soc. Hort. Sci. Proc. Vol. #2. pp. 33-38. Kelley, 0. H. (195%). Requirements and availability of soil water. Advances in Agronomy. V01. 6 pp. 67-91. Kenworthy, A. L. (19M9). Soil moisture and growth of apple trees. Am. Soc. Hort. Sci. Proc. V01. 5%. pp.29-39. Kenworthy, A. L. (1953). Moisture in orchards as influenced by age of sod and clean cultivation. Michigan State Exp. ' Sta. Quart. Bul. May 1953. pp. ASA-#59. King, K. M., C. B. Tanner and V. E. Suomi. (1956). A floating lysimeter and its evaporation recorder.‘ Tran. Am. Geophy. Union. V01. 37, No. 6. pp. 738-792. December. 27. 28. 29. 30- 31. 32. 33- 3#. 35. 36. 37. 38. 39. 61 .Lemon, A. B., A. H. Glaser., and L. E. Satterwhite. (1957). Some aspects of the relationship of soil, plant and mete- orological factors to evapotranspiration. Soil Sci. Soc. of Am. Proc. V01. 21, No. 5. pp. #6#-#68. Sept.‘ Oct. Lilleland, 0. (1932). Growth study of peach fruit. Am. Soc. Hort. Sci. Proc. Vol. 29. pp. 8-12. Magness, J. B., E. S. Degman.and J. R. Furr. (1935). Soil moisture and irrigation ivestigation in eastern apple orchards. U. 8. Dept. Agr. Tech. Bul. #91. 3pp. Magness, J. R. (1952). Soil moisture in relation to fruit tree functioning. Report of the Thirteenth International Hort. Congress. Vol. 1. pp. 230-239. Magness, J.-R. (195#). Orchard irrigation in humid areas. Am. Fruit Grower. June. pp. 9. Penman. H. L. (l9#8). Natural evaporation from open water, bare soil and grass. Proc. of Royal Society of London. Series A. Vol. 193. pp. 120-l#5. Pieniazek, S. A. (19#3). Maturity of apple fruits in relation to the rate of transpiration. Am. Soc. Hort. Sci. Proc. V01. #2. pp. 231-237. Proebsting, E. L. (19#3). Root distribution of some deciduous fruit trees in California orchards. Am. Soc. Hort. 5010 Proc. V010 1+3. Pp. l-l'l'. Richards, L. A. (19#7). Pressure membrane apparatus - construction and use. Agr. Eng. Vol. 28. pp..#51-#5#. Oct. Rogers, w. S. (1935). Some observations of roots of fruit trees. East Malling Reasearch Station Annual Report. pp. 210-212. Ryall, A. L. and w. w. Aldrich. (1937). The effects of water supply to the tree upon water content, pressure test, and quality of Bartlett pears. Amer. Soc. Hort. Sci. Proc. Vol. 35. pp. 283-288. Shaw, J. K. (l9#3). Hay mulches in apple orchards. Am. Soc. Hort. Sci. Proc. Vol. #2. pp. 30-32. Stoltenberg, N. L. (1955). Discussion of "Transpiration and soil moisture. ' Am. Geophy. Union Trans. Vol. 36. No. 3. pp. #25—##8. June. no. #1. M2. M3. #5. M6. #7. #8. #9. 50. 51. 52. 62 Suomi, V. E., and D. B. Tanner. (1958). Evapotranspir- ation estimates from heat-budget measurements over a field crop. Trans. Am. Geophysical Union. vol. 39, No. 2 pp. 298-30h. ~April. Taylor, C. A., and J. R. Furr. (1937). Soil moisture and fruit growth. U. S. D. A. Cir. #26. 23 pp. Tetley U. (1931) Morphology and cytology of the apple fruit. Jour. Pom. and Hort. Sci. Vol. 9. pp. 278- 2970 1 " Toenjes. W. (l9hl). The first twenty years results in a Michigan apple orchard. Michigan Exp. Sta. Spec. Bul. 313. 18 pp. Toenjes.‘w. (1955). The response of Bartlett pear trees under sod mulch and clean cultivation systems of soil management. Mich. Agr. Exp. Sta. Quart. Bul. v01. 37. PP. 363'37h'o Toenjes H., R. J. Higdon, and A. L. Kenworthy. (1956) Soil moisture used by orchard sods. Mflchigan Exp. Sta. Quart. Bul. V01. 39, No. 2. pp. 1-20. United States Department of Agriculture. Michigan Hydrologic Research Station.' Average weekly solar radiation of East Lansing, Michigan. July-Sept. 1956. United States Department of Commerce. Climatological Data. July-Sept. 1956. veihmeyer.F. J. (1927). Some factors affecting the irrigation requirements of deciduous orchards. Hil- gardia vol. 2. pp. 125-286. Jan. veihmeyer, F. J., and A. H. Hendrickson. (1938). Soil moisture as an indication of root distribution in dgciduous orchards. Plant Physiology. Vol. 13. pp. 1 9-1770 1 Veihmeyer, F. J. and A. H. Hendrickson. (1950). Responses of fruit trees and vines to soil moisture. Am. Soc. Hort. Sci. Proc. vol. 55. pp. 11-15. Véihmeyer F. J., and A. H. Hendrickson. (1952). The effects of soil moisture on deciduous fruit trees. Report of the 13th International Hort. Cong. Vbl. 1. pp. 306-3190 Veihmeyer F. J., and A. H. Hendrickson. (1955). Does transpire ion decrease as the soil moisture decreases. Am. Geophysical Union Trans. Vol. 36, No. 3. pp. ”25-,4J4'8 . J1me o 53. 55. 56. 57. 58. 63 Veihmeyer, F. J., and A. H. Hendrickson. (1955). Rates of evaporation from wet and dry soils and their significance. Soil Sci. V61. 80, No. 1. pp. 61-67. July. Veihmeyer, F. J., and A. H. Hendrickson. (1955). Irrigating orchards in dry regions. U. S. D. A. Year- Verner, L. (1937). A study of growth rates in Stayman ‘Winesa Apples. Am. Soc. Hort. Sci. Proc. vol. 35. pp. 12 -l3l. ‘Wiersma, D. and F. J. veihmeyer. (195M). Absence of ‘water exudation from roots of plants grown in an at- mosphere of high humidity. Soil Sci. V61. 78, No. 1. pp. 33-36. July. Willits, N. A. and A. E. Erickson. (1956). Moisture utilization by several forage crops. Soil Sci.’Soc. of Am. Proc. V61. 20, No. 1. pp. 126-218. Jan. Wilson, T. V. (1958). Written Communication. . n «An «Jam 13 Ta 744%?qu (M.,-HQ mo «3&1 Aumigflqulmaflojlmfidml flow 5 ind)?” «1m warm Tuna mmaum («4%ij speed was «its m- MAT... Te MT... Mafia. 1%.st 8383 sooam A 5328 39030 N >933 H Ego “sowed N sowed H nomad oonHII ma ma 2 3 m m a 395 Sam . dun mid mum mJnm, $411le To «Jawq 4mm” N46 To M46 Sow ) MANATm m.m.a..m1T|||mfllm mmelJ_ 5 :38 ea... mus. mine dd méé UNJA. 8383 .308 0.543. m «algae u wanna. a 3.22 H 3&4! .31 e a .1 m N A 34 mmbomo .HHom EamHmH E oazH 950.5 EmHoz ho wZHmDomw H Nanmmmd 65 APPENDIX II FIELD CAPACITY - WILTING POIET, BULK DENSITY AND CALIBRATION CURVES OF SOILS "Soii Permanent Field Bulk Density ‘ No. Soil Texture gigging gagfgétgre Gm/3 inch core 1% Moisture; 1 Sandy L.;m. 2.6% 12.56 55h.2 2 Sandy Loam n.68 '15.33 599.9 3 Sandy Clay Loam 6.63 17.71 571.0 M Loamy Sand 2.51 9.30 578.9 5 Fine Sand 1.91 8.45 578.8 6 Fine Sand 1.52 10.57 555.7 7 Loam 7.71 16.85 611.5 8 Loamy Sand 2.83 12.2% 571.8 9 Loamy Fine Sand 2.87 12.90 589.6 10 Sandy Loam 3.57 10.2% 507.7 11 Sandy Loam 3.72 13.15 600.1 12 Loamy Sand 2.73 11.58 5H1.3 13 Loamy Fine Sand 2.0% 8.8% 529.0 66 APPENDIX II COI‘ITIICUED _.oz sow mo“. mine 20:45:40 mm 38.... $2113 mozfimamm 50.6 . 80.8. 80.8 80.0. coon 08. 08 |_! n _ A e! 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ZO_._.440 >Ozm30 20_i_.240.— .v .02 4.0m & 22' pl 0| 8| .LNBOHBd BHOASIOW “HOS 70, n .02 ...0m .10.. 02.50 20:45:40 mm manor. amZIOV wozflrmamm x0040 000. noon 000.00. 000.0n 000.0. 000m A 'b! fl 1?! llllfillllmvl’ D m m m m m m pA 024m uz... n .02 4.0m 3| 9| 1N3083d BBOISIOW "HOS 71 w .02 ..:0m 10.... m>m30 20_._.m30 ZO_._.m30 zo_hm20 20:.4mm340 $210. $245.32 0.00.5 000.0n 000.0. 000m hm mmDOE 000. 00m In F . _ 1% 2| 024m wZE >240... m .02 30m 9| OZ 1N3083d 38n18|OW 'IIOS 75 APPENDIX II CONTINUED 0. .02 4.06 do“. misc 206429.40 mm wane... . 62:0. “6246.6”... 209m 000.00. 0008 000.0. 000m 000. . 00m 4|"10| _ A, _ 9 m H ale 2404 20246 0. .02 4.06 w #2 2 AN 308 3d BHDASIOW "HOS 76 1‘) APPENDIX II COHTILUE» Z .02 4.0m mom m>m30 20....4mmj40 mm meoE 6220. “8246.82 6.00.5 000.00. 000.8 000.0. 0006 000. 000 . .JIA .240.— >OZ4m : .02 4.00 r—GJ— 74W 0| bl 8| 2? 1N3383d BEHISIOW "HOS 77 COLTIKUED APPELDIX II N. .02 ..:0m m0“. w>m30 Ami-.0. moz4hm_mmm x0015 000.00. 000.8 000.0. 29.-4.10340 0000 0 .v 5.50.... 000. 000 1| ? L 1‘0, 9| oz4m >240.— N. .02 4.0m OZ 1N3083d BEHASIOW "IIOS 78 COI’TTII‘UED A PPEI‘TDIX I I J 3| 9| 6. .02 4.06 20.. m>m00 20:46:40 2. $50.... 62:0. 60246.6”... .003 000.00. 000.0... 000.0. 0006 000. 006 0| if _ _ 4 4 _ . . . 0246 m2... 240.. m. .0: ...0m OZ .1. N30 83d SBOASIOW 'IIOS 79 000.00 : 2.6 0000 60 0006 0.6 000.22 60 6 0.06 0066 60 0026 6.6 0060 60 0000 6 06-6 6.0 0606 60 0006 0.0 0606 60 0006 6 0.6 0000 60 0000 6.6 000.06 00 000.62 6 0.06 0606 60 0066 0.0 0666 _00 0006 6 06-6 0.0 0066 60 0066 2.06 0006 00 0006 6 0.6 0060 60 0060 0.6 006.66 60 000.06 6 0.66 0066 60 0066 2.06 0006 60 0006 6 66-6 0.0 0066 60 0006 0.66 0626 60 0006 6 6.0 0062 60 0062 0.2 000.06 60 000.26 6 0.66 000 20 000 6.66 0066 60 0006 6 06-6 6.66 0626 20 0206 2.66 0006 60 0066 6 2 0 FAWN : 6666 666666 2 6 amwwmm 0266 666666 66660 6620 m N mama .- mgmqmmflw 4.6.40 quHm .mo zen—“Ema HH H NHBfimmm... 8O 0.6 000.20 60 000.00 . 2.6 000.06 60 000.00 6 6.66 0000 60 0000 6.0 000.26 60 000.02 6 06-6 6.66 006 20 020 6.06 0006 60 0006 6 0.6 000.60 00 000.60 2.6 000.60 00 000.00 6 6.0 0606 00 0062 6.0 006.06 00 000.66 6 06-6 2.66 0006 60 0066 0.06 0606 00 0066 6 0.6 000.00 00 .000.00 2.6 000.60 00 000.00 6 0.06 0006 60 0066 0.0 006.06 60 000.66 6 66-6 6.66 0606 60 0066 6.06 0606 60. 0006 6 0.6 000.00 60 000.60 2.6 00.66 60 000.60 6 0.06 0006 60 0066 6.6 .000.06 60 006.66 6 06-6 6.26 026 60 060 6.66 0606 60 0066 6 2 . amwmmm 0260 6666 20 66wmn- 0260 066606 . 66060 6640 0 HQHDZHHZOO HHH NHszmmd 81 APPEIDII IV W CORRECTION FOB WISHES moors (From Ref. k) |.OOO O O O O O O o 0.. o. 0 o n n - SWHO NI BONVASISBEI )IOO'IB 500 TEMPERATURE (F') 82 APPENDIX V SAMPLE CALCULATION - IECHES OF WATER PER FOOT OF SOIL Percent water Weight of Water I 100 weight of Soil ' Weight of Water Percent Water x Weight of Soi lOO Percent'Water x Wei ht of Soil rams 100 Volume of Soil (cu. in.) x cg, cm x c 1 x 12 in, gram 16.5 cu. cm ft. h x l rams x lg,c, x CE. in, 21.2 cu. in. ) gram 1 c. c. 12 in. X.TE:__L__ 12.2 x 571.6 x .0395 2.2% in./ft. Inches of water/foot Inches of Water/foot The depth of water for each foot of soil was calculated, using the percent moisture at that position. The depth of water for each.foot was then added giving a total of the threefoot depth. This was done for each of the four block locations, A, B, C and D, around the tree. The amount of water for the four locations, was then averaged to give a representative depth of water for the tree. This data was then plotted to give the moisture use curves. Figure 10-18. 83 6 60. J. 60. 4| mmml m H601 6 _ In! r 02.6 _ 66 6 r 00 6 _ L 066$ 6 0-0 60:: 06.6L 6016 00.6 700.6 0.66 - 6.2.. 86 6M? 60H6. _fl .mm.6 6M6 -- J 60. m . a, . . 6 06 J— o .6 M .0 [um-1.6 2 r-m01l0 6 _ 60.6 06-6 6 L60 6 . 20.6 6. $16 6 -- 6| 2 00. . 60. 00.6 _ 20. 6 . 606 . 26.6.1 006-1 6 60-6 6 06-6 .60 0 60 6 2-6 2 66.6 . 66.6 6:6. 06.6 6 60M| 60- 0N4 00. . 6 J 60.6 a 066.6 m0.6 06.6 6 06-6 00 2 2.06 .06 2 00.6 60.6 06 6 6016 M06 6 60” - . 60.6 _ m0. 616- . .00-6 . 6 6 a 06.6 0 00.6 6266-6 66 0 6.66 66L: 6 6 00.0 M06 00:6. 36 6 U. 60. 60. 00.6 |06q m . 096 0.9.6 mummj 66.6 ml- 066 mm 2 06 6 .00-2 62.6 00.0 6 6 . .000 266-6 6 W706. 00...... 0.7.06. 6.7.6.6. 0.70% 0706.. wenmw 0.0.6.6. 0000... COO 0001- 000 900+ 000 901. 000 G G I. 0. 1. U. I. .e 1. U. I. B n- U. I. 0. 1. U. a B I I /e I I /e I I /a I I /e d 1 ou S by 3 by S by S n... a Q. O. Q. 0.. U. I O I O I 0 I O 9 T? b J 9 IL! I. a I. 0 0 01 1| 4 mesmefl N Emma I mamfidgd 53.43 ozgomm 4940 m0 mZOHHmom Hb NHQZEA4 81+ APPENDlX VII TOTAL WATER ADDED AND USED Average Rainfall Total H20 Used date Inches Inches H20 since H20/3 ft. Available Previous Reading , 8-20 5.h2 .h7 5.89 .85 8-23 5.12 .09 5.21 ‘ .77 8‘27 #088 035 5023 033 8-30 #097 1+0 97 . .26 85 APPENDIX'VIII EvapotranSDiration for 9th week (September 3-8) East Lansing Temperature = J‘Ta1+ W ’2: -123 [:1 p. H II N H H Wind = 57.4 m. Solar energy Ht EU 0 H H SJ 0’ H H U "Q!" N 1:: U) N 66° F. 16.71 (66° F. Appendix x1) 16.8 (Appendix X,B) Percent RH (ea) = 52(16.8) = 8.7% 77.0 percent 12.95 hr. sunrise to sunset .2 for vegetation p.d. @ 25' x {Log 656'! log 2 #62.0 gm—cal./cm2 / day 33.6 m.p.d. at 6.6' Rc - Rb (1-2) Ipyroheliometer) cora” (.56 -.092 ed)(.l 9‘n) K 1h.71 (.56 - .092 x 2.96)(.1 + .9 x .77) 1h.71 (.288)(.793) 3.36 .8 x #62 = 370 ‘ 370 cal/cm2 x l x l =.627 cm ‘390 cal./gm of H20 gm/cc .627 cm x lOmm/cm = 6.27 mm of H20 evap. 6027 ‘ 3036 2.91 .3; Ei g .?098 X 33.6) . . 29 86% E La L + .16 8%h 1.025 .8H2 Et P.E. \ 86 APPENDIX VIII CONTINUED + 1 Sin N TT/2h 1r 12.85 + .318 sin 12 (TT) 2 2 . + .318 sin 83 .5h + .318 (.99) .55 + .3195 .9 2.635 mm/day .1036 in./day Act. Et = .75 x .1036 = .0778 Act. is rounded off to .078 as the data does not justify .OOOO accuracy. APPENDIX IX 87 Climatic Data: Week E213 é g: E' II t R.H. un g i; 'd l at: MPD 4" £351 c§5301 ‘ $13 1 7.9 522.8 16.3 71.6 15.10 69 66 97.3 .116 7-16 2 688.6 16.0 61.7 16.92 66 57 67.6 .098 3 572.5 25.6 86.6 16.70 70 50 66.0 .119 6 607.6 15.2 57.1 16.65 67 62 52.6 .083 5 631.9 16.8 65.8 16.17 70 63 55.9 .101 6 672.8 16.2 70.6 13.98 72 55 60.0 .103 7 622.0 13.7 66.3 13.60 60 50 56.8 .081 8 621.0 .12.8’ 70.6 13.28 72 62 58.6 .082 9 662.0 12.2 77.0 12.95 66 52 57.6 .078 10 360.7 11.6 56.6 12.63 62 61 52.6 .059 11 352.7 10.8 8. 12.28 52 56 78.7 .066 12 9-26 659.5 10.0 93.7 11.95 56 66 53.0 .055 9-30 TEMPERATURE (OF) (°F) TEMPERATURE 88 APPEI‘TDIX X .2 .4 . 6 . 8 LC 1.2 L4 LS (min Hq/GF) A. TEMPERATURE VS. SLOPE OF SATURATED VAPOR PRESSURE CURVE. ( FROM REFERENCE 6. ) l22 |O4 86 68 g r J IO 20 3O 4O 50 60 7O 80 ea (mm Hq) B. TEMPERATURE VS. SATURATION VAPOR PRESSURE. (FROM REFERENCE 6.) 89 APPENDIX XI "Te'mperature PF 643;“ mm HZO/day* 35 11.H8 #0 11.96 #5 12.H5 50 12.9% 55 l3.%5 60 l .96 65 1 .62 70 15.09 75 15.65 80 16.25 85 16.85 90 l7.h6 95 18.10 100 ‘ - 18.80 * Heat of vaporization was assumed to be constant at 590 cal/gm of H20 (reference 6) A .1. en a r a“. . ._. ’e 3...! 1 R3 U 53 ESE {H “d. “A, __ . Thoaia,M.S. 1960 Robert H. Wilkinson T116818 ,1308 O 1960 Robert H. Wilkinson ”'TITI'ITnfll’itjflHjiflTu fliflinfy'fljtfljl 1:1me