DIAGNOSTIC SOIL AND TISSUE TESTS FOR EVALUATING THE NITROGEN NUTRITIONAL STATUS OF POTATO (SoIanum Tuberosum) Thesis for the Degrée of M. S. MICHIGAN STATE UNIVERSITY EDUARDO FERNANDEZ TUNON 1969 Tues»:- "u -— LIBRA RY Michigan . rate University II "or mm me. .'Q- BINDING .7 HO“ & SMS’ LIBR- 'Y HINDEHS :Gllfll ABSTRACT DIAGNOSTIC SOIL AND TISSUE TESTS FOR EVALUATING THE NITROGEN NUTRITIONAL STATUS OF POTATO (Solanum tuberosum) by Eduardo Fernandez Tunon The relative value of soil tests and tissue tests for diagnosing the nutritional status of potatoes, with specific. reference to nitrogen, was studied in two field experiments in l968. The Sebago variety was used on Conover loam at East Lansing; Russet Burbanks were used on McBride sandy loam on the Comden farm in Montcalm County. The nitrogen nutrition was varied at each location by varying rate and time of application of NH4N03. Soils and petioles were sampled twice during the season: (l) at tuber initiation, just before bloom in July, and (2) in August after tubers had begun to enlarge rapidly as evidenced by the presence of several B-size tubers per hill; Soil nitrate was determined in .02 N CuSOq extracts of rapidly air dried plow soil samples (O-lO inch depth). Tissue nitrate was determined in 2% acetic acid extracts of oven dried petioles. Brucine was used for estimating nitrate in both soil and tissue extracts. Eduardo Fernandez Tunon A quick test for petiole nitrate was also used in the field. llntensity and rate of devel0pment of blue color with diphenylamine were rated visually and converted to an exponen- tial numerical scale (QTN) which was found to be linearly related to the nitrate concentration in the acetic acid extracts of dried petioles sampled at the same time. Significant increases in total tuber yield and percentage A-size tubers were obtained at Montcalm for increments of total fertilizer N up to 180 pounds per acre. At East Lansing, additional increases were obtained with 2A0 pounds N per acre. Plow-down N had little influence on yields at either location. Both banded and sidedressed N influenced yields at Montcalm, but at East Lansing, major yield responses were associated with sidedressed N applications. The unusually high total N requirements and the relative ineffectiveness of plow-down N were due to extensive leaching of nitrate during rainy periods in May and June.' LeaChing I resulted in low soil tests for nitrate in July and August and low diagnostic value of the soil tests. Both the QTN indices and the quantitative determinations for petiole nitrate were useful for diagnosis. Graphical estimates of ”critical level” were QTN = 8 and petiole NO3-N = 2.0 percent. Eduardo Fernandez Tunon Interactions between nitrate and extraCtable P, K,.Ca and Mg in the August samplings of both soils and petioles were examined by simple and multiple correlation and regression analysis. Reductions of exchangeable K, Ca and Mg were consistent with the view that these bases had been subject to leaching ' along with nitrate. .Reductions of extractable soil phosphate at East Lansing and of soil pH at Montcalm suggested that acidity released by nitrification of ammonium supplied as NH4N03 may have contributed to reduced availability and uptake of P and the observed reductions in petiole P. Negative correlations between petiole P and petiole nitrate suggest that nitrate competed with phosphate in maintaining a balance between anions and cations in root uptake. Petiole K was positively correlated with petiole P, but negatively cOrrelated with petiole nitrate, Mg and Ca. The positive correlation between petiole P and K would appear to reflect the positional association of these two nutrients in the fertilizer band. The positive correlations between petiole nitrate, Mg and Ca, on the other hand, would reflect the mobility of nitrate and the fact that nitrate entering the plant would have a better chance of being accompanied by Mg and Ca from soil sources than would the phosphate in the fertilizer band. Eduardo Fernandez Tunon The overall effect of these interactions among N, P, K, Ca and Mg on Russet Burbanks appears to have.been to make P the first limiting nutrient in all treatments which received fertilizer N. DIAGNOSTIC SOIL AND TISSUE TESTS FOR EVALUATING THE NITROGEN NUTRITIONAL STATUS OF POTATO (Solanum tuberosum) - By Eduardo Fernandez Tunon A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Soil Science I969 DEDICATION My sincere gratitude to my parents, whose example has been the most powerful stimulant of my life. ACKNOWLEDGMENTS The author is greatly indebted to his major professor Dr. Henry D. Foth, for his advice and support throughout his graduate program. He wishes also, to express his sincere gratitude to Dr. Arthur R. Wolcott, for his patient guidance, constant advice and encouragement during the course of this investi- gation. Without his great interest and constant assistance, many aspects of this study would have been insurmountably more difficult. The writer is also grateful to Dr. Kirkpatrick Lawton, Director of the International Agriculture Programs, for the helpful suggestions and interest, facilitating his stay in the United States. I He wishes also to acknowledge Dr. Eugene C. Doll, Mr. Owen Pierce and Mrs. Florence Drullinger for their help in the laboratory phases of this study in the Soil Testing Laboratory. The author's stay at Michigan State University was made possible through financial assistance from the Agency for International DeveIOpment, Washington, D.C. and from Instituto Nacional de Tecnologia Agropecuaria (INTA), Argentina, who provided financial assistance which enabled him to pursue and complete the M.S. program. Use of the Michigan State University computing facilities was made possible through support, in part from the National Science Foundation. TABLE OF CONTENTS ‘ Page INTRODUCTION. . . . L . . . . . . . . . . . . . . . 1 LITERATURE REVIEW . 2 Growth Physiology In The Potato Plant. 2 Potato Quality Considerations. 7 Soil Nitrogen. .,. . . . . .,. . . . . '.* 8 Soil Tests For Diagnosing Fertilizer N Requirements . . . . . . . . . . . . . . . . l3 Diagnostic Plant Analysis. . . . . . . . . . . I5 Nitrogen Fertilizer Practices For Potatoes . . I9 MATERIALS AND METHODS . . . . . . . . . . . . . . . 25 Field Experiments. . . . . . . . . . . . . . . 25 Soil Tests . . . . . . . . . . . . . . . . . . 27 Quick Tissue Tests . . . . . . . . . . . . . . 3I Petiole Analyses . . . . . . . . . . . . . . . 32 Statistical Treatment. . . . . . . . . . . . . 33 RESULTS AND DISCUSSION. . . . . . . . .’. .I. . . . 3A Potato Yields And Specific Gravity . . . . . . 3A Soil and Petiole Nitrate . . . . . . . . . . . 38 Other Nutrients. . . . . . . . . . . . . . . . 43 Nutritional Interactions With Nitrogen . . . . A6 SUMMARY AND CONCLUSIONS . . . . . . . . . . . . . . 52 BIBLIOGRAPHY. . . . . . . . . . . . . . . . . . . . 58 Table IO ll l2 LIST OF TABLES Nitrogen treatments Basal fertilizer. Potato yields and specific gravity in relation to time and rate of N fertilizer. Linear correlation Coefficients (r) between crop parameters and inputs of fertilizer N. . . . . . . . .-. . . . ; . . Nitrate-N in soil in July and August, I968, in relation to time and rate of N fertilizer. . . . . . . . . . . . . QTN index of tissue nitrate in July and August, I968, in relation to time and rate of N fertilizer . . . . . . . . . . . Nitrate-N and soluble P content of potato petioles, in August in relation to time and rate of N fertilizer. . . . . . Potato petiole K, Ca and Mg content in relation to time and rate of N fertilizer. . . . . . . . . . Soil pH, lime requirement and phosphorus in August in relation to time and rate of N fertilizer. . . . . . . . . . . . . . Soil K, Ca, Mg in August, in relation to time and rate of N fertilizer . . . Linear correlation coefficients (r) between petiole nutrients and inputs of fertilizer nitrogen. Linear correlation coefficients (r) between soil and crop parameters, total fertilizer N (I968) and residual potassium from I967. at East Lansing. . . . . . . ,Page 6h 65 66 67 68 69 70 7T 72 73 7h 75 Table Page I3 Linear correlation coefficients (r) between soil and crop parameters and total fertilizer N applied in I968 at Montcalm. . . 77 IA ‘Soil K and petiole K and Mg at East Lansing as multiple regression functions of plow— down, banded and sidedressed fertilizer N . . 79 IS Soil K and petiole K and Mg at Montcalm as multiple regression functions of plow-down banded and sidedressed fertilizer N . . . . . 80 I6 "Soil pH, soil P and petiole P at East Lansing as multiple regression functions of plow- -down banded and sidedressed fertilizer N . . . . . 8i I7 Soil pH, soil P and petiole P at Montcalm as multiple regression functions of plow-down banded andsidedressed fertilizer N . . . . . 82 Figure LIST OF FIGURES Page Air temperatures, rainfall and irrigation at East Lansing. . . . . . . . . 28 Air temperatures, rainfall and irrigation at Montcalm. . . . . . . . . . . 29 Yields of total and Grade A tubers in relation to total fertilizer N applied. . . 35 Total-tuber yields of Sebagoes in' relation to soil and petiole nitrate at East Lansing, I968. . . . . . . . . . . . . . AI Total tuber yields of Russet Burbanks in relation to soil and petiole nitrate at Montcalm, 1968. o o o o o o o o o o o o o o LIZ Treatment means for petiole nitrate in relation to mean QTN values in August . . . AA Petiole K, Ca and Mg in relation to petiole N at Montcalm . . . . . . . . . . . 5l INTRODUCTION The search for methods to determine the quantities of nutrients in the soil and to assess their availability to crOps has been underway since the time of vonLiebig a century ago. Even though much progress has been made and many improve- ments in soil management and fertilization have contributedto' increasing rates of production, there are still no methods for evaluating nutrient status and fertilizer requirements which are apprOpriate in all conditions or for all nutrients or all crops. In the particular case of nitrogen, because of the mobility of its nitrate form, many factors tend to complicate its evaluation. The objectives of this study were (I) to compare the diagnostic usefulness of soil and tissue analyses for nitrate and (2) to examine interactions between N, P, K, Ca, and Mg in soils and tissues which might influence the responses of potatoes (Solanum tuberosum) to fertilizer nitrogen. LITERATURE REVIEW Growth Physiology In The Potato Plant In general ecological considerations of growth of the potato in the field, Milthorpe (27) recognizes three phases: (a) A period of pre-emergence, in which is considered the establishment of root and leaves, utilizing materials stOred in the mother tuber.- Soil tempera- .ture and the size of sprout at planting time are determinating factors in this step. (b) A period in which haulm (stalk) growth is predominant. (c) Tuber growth, a stage closely interrelated with haulm growth. Among mechanisms involved in tuber initiation, probably the most important phase in the growth of the potato, Slater (2) considers two factors being important: (a) Short days seem to be more favorable for tuber initiation, than long days. This is probably due to some Specific tuber-forming hormone which is produced under short day conditions. In long days, plants have much greater haulm growth and tuber initiation is delayed. There are great differences between varieties in their response to photoperiod. (b) Temperature regime is the second factor involved in these mechanisms. At high temperatures, tuber initiation is delayed. Slater (37) mentions studies made by Borah and Milthorpe (I963). They found that "3? “A.“ .v .-.. the carbohydrate balance within the plant is involved in determining the time of initiation. 1’.“ un‘ 5‘ .0: 2‘9 At high temperatures, greater prOportions of assimilate “ u, are used in root, stem and stolon growth than at lower tempera- I ture. Tuber initiation is associated with high concentration of soluble carbohydrate at the stolon tips. In greenhouse experiments, measurement of carbohydrate concentration after a period of low temperature showed an increase in the haulm and stolon tips. Slater's conclusion (37) is that the formation of tubers is related to changes in quantity and proportion of substrate and growth substances at the stolon tips. Temperature, radiation and photoperiod play an important role in this mechanism. The conclusion of a study of these factors in the develop- ment of potatoes made by Bodlander (6) is that: Low temperature, high light intensity and short days generally accelerate the development of potatoes; stem elongation terminates early, tuber initiation starts early and the plants die early. Under these circumstances small stems and large leaves are formed and tuber growth is stimulated. High temperatures, low light intensity and long days, on the other hand, promote elongation but are unfavourable for leaf expansion and delay tuber formation; stolon growth, second growth of tubers, the formation of wild stolons emerging above the soil and sometimes branching of stems and stolons are also promoted by long days and high temperatures. Flowering needs high light intensities, long days and intermediate temperatUres. I I I The final tuber yield will be determined by the combined action of these climatological facotrs by influencing tuber initiation, the leaf area duration and the assimilation rate per unit leaf area per day. The time from emergence to tuber initiation is inversely related to the rate of haulm growth; vigorous stem and leaf growth leads to an appreciable delay in tuber formation. But as tubers develop, competitive effects appear between the growing tubers and the vegetative plant. Tuber initiation and enlargement can occur only when products of photosynthesis accumulate in the plant in excess of the requirement for growth (50). If tubers are initiated when only a small leaf area has developed, branch and leaf production cease earlier and existing leaves senesce more quickly, giving smaller final yields than when tubers are initiated on plants with larger vegetative apparatus (#9). There appears to be appreciable migration of nitrogen, phosphorus and potassium from the t0ps to the tubers during the later stages of tuber growth; nevertheleSS, uptake from the soil continues throughout most of the life of the plant. Among the nutrient effects, nitrogen is important. In the early growth period, nitrogen promotes vegetative activity. Augmenting the effect of long days or high temperatures, a moderate to high supply of nitrogen late in the season prolongs growth in tOps and tubers and delays their ripening (A9). The effect of moisture supply is similar to the nitrogen supply in its effects. Fluctuations in moisture or temperature act indirectly by regulating the basic metabolism of the plant. Therefore, a period of low moisture supply sets the stage for injurious competitive relationships within the plant when growth processes are stimulated by a subsequent period of improved moisture supply (SI). The growth of lateral branches induced by abundant nitrogen is greater at nodes near the base and tip of the shoot than in the intermediate zone, but the leaves on the main stem are largest at intermediate nodes and are increased in size by additional nitrogen more than those at higher or lower nodes (27). Watson (A9) studied the supply of mineral nutrients. that affects the rate of dry matter production chiefly by changing leaf area. Nitrogen, phosphorus and potassium effects were considered by the same author: Nitrogen increases leaf production by stimulating activity of apical or lateral meristems; it increases leaf expansion and hastens the death of older leaves. Phosphorus also increases meristematic activity and leaf expansion, but these effects begin earlier and are less persistent than for nitrogen. The effect on longevity is variable. The chief effect of potassium is in leaf expansion and delay of maturity. In the potato growth, tuber initiation is retarded when leaf area expansion is induced by large amountsof fertilizer. If the growing season is prolonged enough, large tuber yield would result from large leaf surface. A compromise solution in areas of short growing season is to obtain as long a period for tuber grthh as possible. This can be obtained by controlling the fertilizer supply so as to deveIOp quickly an adequate leaf surface and then maintain it during the period of tuber bulking (A9). This may call for limited early applications of fertilizer nitrogen followed by judicious sidedressings later. ”‘5‘. autumn-t M’ fl ‘ o - .‘ . ‘ .. Potato Quality Considerations Specific gravity of potatoes has been USed as'a measure of their suitability for specific methods of food preparation. Potatoes with low specific gravity, because they slough less, are preferred for scalloped potatoes, salads and boiling, whereas those of high specific gravity are preferred for chips, french fries, baking and dehydration (28). The effect of nitrogen, phosphorus and potaSSium fertili- zation on the specific gravity has been studied. Teich and others (A3) have shown that on soil types representative of the main potato growing areas (Canada) specific gravity was reduced by application of nitrogen and potassium. Phosphorus affected specific gravity in only one area. Ascorbic acid tended to decrease with increasing nitrogen and potassium, but was unaffected by phosphorus (A3). On the average, specific gravity of potatoes increases with increasing fertilizing rates; specific gravity was greater from rotations with red tOp than under a>ntinuous cultivation (3l). Youngen and others (53) in studies on the influence of fertilizer nitrogen on the yield, grade and specific gravity of potatoes in eastern Oregon concluded from ID to IA farms on which the specific gravity determination was made, that increased ratescf nitrogen produced statistically significant decreases in Specific gravity of potatoes sampled from early tUber set to near maturity. At all rates of nitrogen, specific gravity increased progressively with time as the potatoes approached maturity. The relationships between Specific gravity and total and non-protein nitrogen and ascorbic acid content in the Ontario variety susceptible to precooking discoloration were studied by Mondy and Rieley (28). Total and non-protein nitrogen, expressed on a dry weight basis, decreased as specific gravity increased to the mean specific gravity for the variety. Potatoes having the mean specific gravity had the lowest total and non-protein nitrogen content. Both total and non-protein nitrogen were significantly higher in the center of the tuber than in the cortex tissue. High Specific gravity was Significantly correlated with high ascorbic acid content. Tubers of low Specific gravity showed. a greater loss of ascorbic acid during storage than those of high Specific gravity. Soil Nitrogen The plant nutrient that limits crOp production in all the world more than any other is nitrogen. This nutrient is utilized by plants for production of structural proteins, enzymes and numerous nitrogen compounds involved in bio- chemical and genetic control of all plant functions. Almost all the nitrogen in the Surface of the soil is organically combined. Although plants are capable of utilizing organic forms of nitrogen such as amino-acids and amides, practically all of the organic soil nitrogen cannot be utilized directly by plants (A2). Some of it (of the order of l to 3% annually) is mineralized by microbial processes during the growing season. This provides a sub- stantial amount of plant available nitrogen in mineral forms (NHD+. N05) (52). One of the major contributions of soil organic matter to soil fertility iS that it supplies a conSiderable quantity. of nitrogen for plant growth and acts as a natural storehouse for this important nutrient. However, the amount of nitrogen made available by mineralization of soil organic matter during the growing season is rarely sufficient to meet the demand for this nutrient in current cropping practices (8). The transformations of organic nitrogen and available mineral forms have been studied extensively. The conversion from organic nitrogen to inorganic forms (NHQT, N02" and N03) by microorganisms is known as minerali- zation. The reverse process is called immobilization. Mineralization occurs in two steps: Ammonification (organic-NHz—i NHL,+) and nitrification (NHL,+—-)NOZ'_,,NO3'). “Immobilization” is usually used to indicate the trans- formation of inorganic nitrogen to organic forms. This is a microbiological process which is carried out by microorganisms, « - A _. I, _-fi—....' “ls-”Wfi “WW - —- ... IO using inorganic nitrogen and carbonaceous energy substrates to synthesize cell tissue. In addition to cellular proteins, other forms of organic nitrogen (humic acidS) appear which are relatively resistent to furthertflological breakdown (I7, A2, 20). The C/N ratio in the plant residues added to the soil is an important factor in the process of nitrogen immobilization. When plant materials with large C/N ratio are added to ' the soil, much of the nitrogen available in the Soil may be utilized by the heterotrOphic microorganisms, using it in their own growth. If the C/N ratio of plant residues is larger than 25 or 30 to l, biological immobilization is at a maximum and an external source of nitrogen will be needed to satisfy microbial requirements. When the C/N ratio is 20 or less no external source of nitrogen for maximum microbial activity is needed. Microbial competition with higher plants for available nitrogen can be considered to have been neutralized (3, 2l). Mineralization, on the other hand, is used to indicate the microbiological transformation of organic nitrogen to inorganic forms. Allison (l) lists the factors which affect rate of release of nitrogen from soil organic matter as: (l) nature ll of soil organic matter, (2) temperature, (3) moisture, (A) aeration, (5) reaction, (6) supply of inorganic nutrients and (7) nature of soil microflora.- ' I These two processes of immobilization and mineralization occur simultaneously in most soils where organic material is undergoing microbiological degradation (20). Even though the organic forms containing nitrogen can be taken up by the plants, as was mentioned before, practically the large bulk of nitrogen that plants absorb is as N03 and I NHAT. Practically, there is little preference between the absorption of N03' or NH4+ by plants, since nitrifying microorganisms rapidly oxidize the NHL,+ form to NO2' and then to N03” and plants have little opportunity to utilize it in the NHAT form (Al). Besides clay minerals with expanding lattices can absorb ammonia and sometimes so tightly that it is not readily available to either plants or microorganisms (2). It is true that ammonium can exist in exchangeable form in the soil, but iS quickly transformed to nitrate form (in well aerated soil). Nitrates have high solubility and do not absorb in the colloidal complex of the soil; they are readily lost by leaching (29). l2 On the other hand, in water logged conditions denitri- fication can occur and there is a loss of N2 gas from the nitrate (9). I I. I The availability of soil nitrogen to plants depends upon two categories of factors: (a) A capacitive factor (amounts and forms of nitrogen in the soil). (b) Physical—chemical factors (temperature, water level. aeration and pH, to mention the most important). These factors influence the nature and levels of micro- bial activities in the soil, as well as the effectiveness of plant roots in supplying plant requirements for water and nutrients. We can anticipate therefore that there will be a Shortage of nitrogen in soil for crop needs: (a) When there is not an adequate supply of available forms or of readily mineralizable organic nitrogen; (b) In well drained soil, when there is an excess of. ' water (heavy rainfall or irrigation) and leaching of nitrate occurs; (c) When physical conditions (permeability, aeration, water logging) or chemical (pH) are not appropriate for desired microbial activities or root function. l3 Soil Tests For Diagnosing Fertilizer N Requirements As nitrogen readily available for plants is very mobile in the soil, to maintain the correct supply for plant needs it is generally necessary for it to be supplied from outside during the crOp season. That is why in the practice of fertilization it is very important to know the correct amount and the correct time of application of this nutrient in the soil, as well as the requirement at different stages of plant assimilation and utilization. The necessity to find a method which predicts the need for nitrogen fertilizer was recognized a long time ago. Although the search for such methods has been underway for over a century, it still continues. The lack of generally useful testing methods is due to the dynamic nature of the soil system and the fact that one is dealing with a tremen- dously varied complex 0f living organisms. In earlier times, soil scientists tried to predict the need for nitrogen fertilization by analysis of the mineral nitrogen in soil. However, the amounts of these forms of nitrogen in the soil fluctuate Since they are influenced by many external factors (such as nature of the soil, pH, plant growth, weather conditions, season, fertilization, etc.) and other factors already mentioned. IA There is not yet one method which will predict the needs for nitrogen fertilization for all types of soils or under different weather conditions. Many biological and chemical methods have been proposed (8). Allison (l) classifies methods reported in the literature into four types that are in use or have been proposed for measuring probable nitrogen release from soils. These are: (a) Vegetative tests in the field or greenhouSe;, (b) Nitrification tests; (c) Release by chemical reagents; (d) Determination of total nitrogen either directly, or indirectly by measuring total organic matter. In addition, plant tissue analyses for nitrate-nitrogen are of value. Due to the fact of the dynamic nature of the soil system and that one is dealing with living organisms, useful corre- lations with any given method appear to be restricted to similar types of soil within the same climatic zone and system of farming and frequently to soil samples collected within a single season. The relationships between soil nitrogen, nitrate production and yield were largely studied. l5 MacKay and others (26) studied the relation of soil test values to fertilizer response by potatoes at l8 locations over 3 years in Canada. Bray's modified Mitscherlich equation was used to determine the relationship of potato yields (percent of maximum) to soil - N03 production and to nitrogen fertilization. The relationship was closer in fresh soil samples than in those air-dried for 6 months. The influence of various factors on absolute yields was also assessed by analysis of variance. Highly Significant effects were due to the “rates of nitrogen and soil-test values", but the interaction of these two factors was not significant. The polynomial response curves derived from regression analysis showed that maximum yields were approached at the rate of 200 pounds per acre of applied nitrogen, regardless of soil -NO3 production values. Tuber yields were also influenced by the soil series; the nitrogen fertilizer ref quirement was greater for some soils than for others. Diagnostic Plant Analysis Soil tests estimate the concentration of a soil nutrient available to the plant. The soil nutrient concentration test value requires Special interpretation in accordance with the environmental nature of the soil, kind of crop and l6 climatic conditions. The basis for interpretation must be derived from experience and field calibration experiments with each crop and soil type (or group of similar.soil types). Plant analyses are based on the premise that the amount of a given element in the plant is an indication of the availability of that particular nutrient. The availability may or may not be directly related to the quantity in the soil (AS). I The imbalanced nutrition reflected by the Shortage of an element is frequently accompanied by abnormally high accumulations of the other elements in the cell sap giving high test values, regardless of the supply. Two types of plant analysis have been used. One is the tissue test which is made on fresh tissue in the field. The other involves more specific and quantitative chemical analysis made on the whole plant or part of the plant. Plant material, dried, ground and ashed is used if we want to determine the total concentration of the element within the plant. Sometimes a soluble compound or compounds, as example nitrate, or phosphate, are determined in 2% acetic acid extracts of fresh, frozen or dried plant material. These quantitative chemical analyses measure the nutrient composition of the plant at the time of sampling and in the tissue that is sampled. l7 The basic concept in using plant analysis for guiding fertilizer practice is that an element essential for the growth of a plant must be contained within the plant at suffi- cient concentrations for optimum plant growth. Essentially all the potassium in plant tissue is present in solution as the cation. The level of soluble nitrogen or phosphorus in the plant at a given time represents an equili- brium between rate of uptake from the soil and rate of metabolic assimilation within the plant (36). Establishing a correlation between the nutrient concen- tration found in the plant at critical periods of growth with final yields or quality parameters makes it possible to establish critical nutrient levels for optimum crop performance. The nutrient concentration found in the plant directly reflects the ability of the plant, at the time of sampling, to acquire nutrients from the soil in the environment in which the plant is growing (A7). . Concurrent use of plant tests and soil tests greatly enhances the value of each as a means of determining corrective measures for unbalanced nutrient conditions present in a crOp (ll). Each crop and each nutrient is a special problem unto itself, but once the basis for evaluating the nutrient status of the cr0p has been established the same system can l8 be used and tested over a wide range of soils and climatic conditions with reasonable assurance of success. The critical concentration necessary for optimum plant growth is determined on a cell basis or, at most, on a tissue basis, using tissue samples which are comprised of cells with similar function (A7). This is practically accomplished by selecting leaves or parts of leaves, or Stems or pafts of stems for analysis. It is essential to test that part of the plant which will give the best indication of the nutritional status of the plant with regard to a Specific nutrient. AS an example, if the supply of nitrogen decreases, the upper part of the plant, in which maximum utilization of plant nutrients is in progress, will Show a low test for nitrate. In the case of phosphorus and potassium, the reverse is true, and the lower part of the plant will become deficient first (A5). Ulrich and others (A8) determined the NO3-N content in 2% acetic acetic acid extracts from petioles of recently matured leaves of sugar beet plants receiving increasing amounts of nitrogen. Plotting these values against beet weight, they obtained curves Showing that petiole nitrate was not affected by the first AO pounds of nitrogen application, although the yield increased Significantly. For 80 pounds, Yield and nitrate content increased Simultaneously. After l9 2A0 pounds, there was a Sharp petiole nitrate increase after each application of nitrogen fertilizer; but yield remained unaffected. I. I I I The same authors conclude that it is possible also to determine different zones in these calibration curves; luxury consumption, adequacy and poverty or starvation concentrations. In general, there is a Sharp transition between zones of adequacy and defiCiency_in the calibration curves, and this break identifies the “critical level” of the nutrient. Nitrogen Fertilizer Practices For Potatoes According to Cooke (l0), fertility of soil is defined as its capacity to produce plants and it depends on land use. Soil productivity integrates the biological, physical, climatic and chemical factors which influence supplies of nutrients, air and water, anchorage of roots, and absence of toxic substances. Chemical fertility is concerned with nutrient supplies. Deficiencies are not an obstacle to productivity, since they are easily corrected by fertilizer, but other chemical and physical prOperties determine whether soil is a good vehicle for the extra fertility that is added. Adding extra nutrients now allows us to control chemical soil fertility. The main problems of highly deveIOped agri- culture is the diagnosis of deficiencies, as well as to deveIOp the best methods of correcting them. 20 The potato has heavy plant nutrient requirements for high yield. A good crop of potatoes removes an estimated: l20-l60 lb. of N, 7-9 lb. of P, ZOO-250 lb. of K, A3 lb. of Ca, l8 lb. of Mg and lO-l2 lb. of S per acre. When any one of those more important nutrients is lacking, increasing it Should influence plant deveIOpment and final yield. The best response will occur only when levels of all necessary nutrients meet at least minimum plant requirements (A). One of the important nutritional problems in potato production concerns the use of nitrogen, especially in relation to other farming practices. The problem of appro- priate seasonal availability is more critical where potatoes do not follow a grass-legume crop or where no manure is applied. The intensity of the nitrogen nutrition varies with the physiological state of the plants. The maximum requirement is in the rapidly growing state. If, at this time, transitional periods of shortage of nitrogen occur, this inconvenience will be reflected in the crop yield. In the practice of nitrogen fertilization we must keep in mind that readily available nitrogen in soil is related to: type of soil, organic matter content (and C/N ratio), physical and chemical additions to the soil, microorganizms, as well 2l as climatic zone and season, and farming system. These many factors greatly influence observed response to fertilizer nitrogen in field experiments, as well as in the experience of growers. This is why discussions in the literature regarding type of carrier and method and time of application of nitrogen fertilizers are frequently lengthy and often contradictory. Until the mid I9SO'S the standard practice seems to have been to apply all or most of the fertilizer for potato in side-bands at planting time. Sawyer and Dallyn in I958 (3A) give the following conclusions on placement of nitrogen for potatoes: The experimental results on time, method of application and place- ment of nitrogen for potatoes indicate no increases in yields from methods other than applying all the nitrogen in the row in the standard side-placement method at planting time. However, with high rates of fertilizer, all applied in the row side bands, greater care must be exercised to obtain precise placement to avoid fertilizer injury to seed and sprouts, particularly under dry soil conditions (l6). Growers on the other hand, are cautioned against using too much nitrogen. Excessive use will delay maturity and may result in tubers lower in dry matter and mOre susceptible 22 to bruising. Also lower yields may result if weather, insect and disease control are not favorable (IS). ' Through all the literature, the best practice of potato fertilization at less cost seems to be Side dressing part of the nitnbgen as ammonium nitrate or urea shortly after emergence, but before they are over approximately 8 inches high. By Side-dressing part of the nitrogen, less nitrogen is subject to-leaching, particularly on sandy soils, and the hazard of seed-piece burning and injury to the young plants is reduced as compared with applying all the nitrogen in bands at planting time (l5). Smith and Kelly (38) using complete fertilizer found that applying one-half the fertilizer broadcast, then plowed, plus one-half in equal depth bands at planting time resulted in yields of 356 bushels/acre as compared with 323 bushels when 2,AOO lb. of S-lO-lO/acre was applied all in bands. Nobrega and Freire (30) reported in field experiments in Sao Paulo: application of nitrogen fertilizer to potatoes in furrows at planting time gave good results only in wet weather. Applying all the nitrogen as top-dressing provided insufficient nitrogen to the plants during their most active vegetative growth. Part of the nitrogen should be applied 23 near the seed at planting time and the rest top-dressed at Sprouting. . Bessey (5) reported for winter potatoes in Arizona on experiments using as much as I60 lb/acre of N. Tests were devised to compare a no N check with I60 lb. of N applied (I) all in planting, (2) half at planting plus half at midseason and (3) all at midseason. By symptom diagnosis and N03” petiole analysis, nitrogen deficiency was determined to be serious by midseason for potatoes receiving no nitrogen at planting. Available nitrogen had been depleted in plots re- ceiving all nitrogen at planting. Both midseason nitrogen treatments kept this off-season crOp growing well enough to produce acceptable yields. In California, studies by Timm and others (AA), showed high total yield was obtained with each increase of nitrogen up to 2A0 pounds per acre. However, yield of U.S. No. l tubers increased by the addition of nitrogen up to l20 pound per acre. The increased yields obtained with nitrogen above l20 pound per acre were associated with high yield of off grade tubers. Plants with less than 8000 ppm of N03—N (dry weight basis) showed nitrogen deficiency symptoms and produced lower yields. High levels of nitrogen prolonged active vegetative growth and delayed accumulation of dry matter in tubers. 2A Without exception, increasing the levels of nitrogen resulted in lower specific gravity of tubers (AA). Increasing rates of nitrogen fertilizer increased the NO3-N and Ca content and decreased the P content of the stem and/or leaf tissues. Increasing rates of phosphorus reduced the N03-N and Ca and increased the P and Mg content of the stem and/or leaf tissues. Excessive nitrogen can cause the plant to become vegetative at the expense of tuberization (39). However, as was mentioned before, the placement and the time and rate of application of the nitrogen fertilizer are important factors in the correct nitrogen utilization. Although the search has been underway for over a century, there are still no reliable methods for answering the question, ”How much, in what form, where, and at what time should a nutrient be added to give a large yield of a given cr0p of a desired quality?ll Calibration of nutrient diagnostic techniques, including soil and plant tissue testing, with known field responses, holds great promise for a more effective fertilization. MATERIALS AND METHODS Field Experiments Two field experiments were established in I968 at the following locations: (a) M.S.U. Soil Experimental Farm, located near East Lansing on the SW I/A of NE l/A of SE I/A, section I9, TAN, RIW, Meridan Township, Ingham County. (b) Montcalm Experimental Farm, located on the SW l/A of SW l/A of section 8, TIIN, R7W, Douglass Township, Montcalm County. The experiment at East Lansing was located on somewhat poorly drained Conover loam (Mollic ochraqualf). The soil at the Montcalm Experimental Farm was a well-drained McBride fine sandy locam (Alfio Frageorthod). Detailed descriptions of these two soils are given in Appendix A and Appendix B. The nitrogen treatments outlined in Table l were imposed, using a randomized block design with four replications at each location. Nitrogen was supplied as NH4N03. Plowdown applications were broadcast by hand before plowing. Banded nitrogen was metered from a belt-feed hopper and placed simultaneously with banded basal fertilizer (Table 2) in 25 26 bands of I-l/2 inches below and 2 inches to the Side of the seed. Sidedressed applications were applied by hand just before bloom. '- I At the time of sidedressing, the Sebago variety at East Lansing had initiated stolons, but tuber enlargement had not commenced and no visible flower buds had formed. In the case of Russet Burbanks at Montcalm, flower buds had formed and tubers up to l/2 inch in-diameter were found under the hills. I Potatoes at both locations had been ridged just before sidedressing. The Burbanks were uniformly IO to l2 inches high, but the foliage had not closed over the row. The Sebagoes at East Lansing were less advanced and extremely variable (A to l0 inches). This East Lansing plot area had been used in I967 for an experiment involving rates of potassium ranging from zero to A00 pounds K per acre. Potatoes (Sebago variety) had been the crop grown. 'Carryovers of fertilizer and tillage effects and of disease from I967 likely contributed to the variable development of Sebagoes at East Lansing in I968. The I968 nitrogen treatments were placed at right angles to the plots which received varying K treatments in I967. Plot sizes were such that each N treatment overlapped two I967 K treatments. This made it possible to examine the I968 data for possible residual effects of varying K applications 27 the previous year. Data will be presented which Show that residual K effects were negligible in relation to effects of the I968 N treatments. The Burbanks at Montcalm were in the first year of a three-year rotation experiment. This area was clean- fallowed in I967. The additions of P and K in basal fertilizer at East Lansing (Table.2) were greater than at Montcalm because of an error in machine calibration for the banded application. Certified B-size seed was used for both varieties. The Burbanks were Spaced IA inches apart in 32-inch rows. Sebagoes were Spaced 9 inches in 32-inch rows. A IO—day spray program was followed for control of insects and blight. Supplemental irrigation (.75 to l.5 inches per application) was given twice at East Lansing and 7 times at Montcalm (see Figures l and 2). The two center rows of A-row plots were harvested for yield and specific gravity determinations. ‘Forty linear feet of row was harvested at East Lansing and 50 feet at Montcalm on October IA and September 27, respectively. Soil Tests At each location, soil samples were taken twice, during the season: (I) just before the Sidedressed application of nitrogen, and (2) again in August when rapid tuber enlargement .mCPWCeo ummm be cowpemwgee new FFeeceeL .mmtsueemaEmp Lw< .P mesmwd Emsmfiewm _ 5:22 _ .52. _ mza, _. 22 _ Izmaq om cm on ON 9 cm ON 9 om om o_ om ON. 9 on 8 o. o .m: M...“ Al— a Rams TM . . _. . ma: 9 m 0.6. . M . . . . . - N . :zocaoEE flow - _ 4.2622... . 7 w §\§\\\<§\ \thQ .% 83 I» . 0‘ momma S .4 Om. XSXQXSQ \QENQ 00. e (SauOuI) ||0IUIDH ON C) N) UJH+UJUULUUJ_ C) Q" \Jo} C) U) ON. Om 0m 00. v I I mmmzmeamm.._ Om .E_60pcoz pm cowpmmegee wee FFeecwoL .mmesumemgsmp ev< .m oesmwm emaos< _ suns _ mzaa _. 8 0. on ON 0. Om 0.6. 9 on >42 ON 0. 2% .. .. .I q. 3.le a a 222ng _ jEzam §\\§\\>\§\ \thQ 2 \~\\§\\>\w§\ \QEQ . _ DEAR om ON 0. C) (89W!) IIDIUIDU CU 30 was evidenced by the presence of several B-size tubers per hill (August l3 at East Lansing and August I at Montcalm). Twenty cores through the plow soil (0 to l0 inches) were composited for each plot and screened in the field to remove pebbles and trash (A mesh screen). Subsamples were Spread out in thin layers to dry quickly at 30 to A0 C. They were then ground to pass an I8 mesh Sieve before analysis. Nitrate nitrogen was determined in the samples taken on both dates. Samples were extracted (I:A) with .02N CuS04 by the method of Jackson (l9). Nitrate was determined by a modification of the brucine method described by Greweling and Peech (IA). Colorimeter readings at A20 mu were compared with a standard curve covering a range from .3 to 3.0 ppm N03-N. Additional soil tests were run only on the August sampling. Soil pH was determined by glass electrode in l:l water sus- pensions. Lime requirement was estimated uSing the p-nitrophenol, triethanoI—amine buffer of Shoemaker and others (35). Available P was estimated colorimetrically in the Bray P] extractant (l9). Exchangeable bases were estimated in Morgan's sodium acetate-acetic acid extracting solution (IA). A Coleman 3i flame emission SpectrOphotometer was used for exchangeable K, with comparisons at 383 mu to a curve with a top standard of 50 ppm. Percent absorbance at 2I2 mu and 285 mu in-a Perkin-Elmer Model 290 atomic absorption unit were compared to standard curves with top standards of A0 ppm Ca and A ppm Mg. Results are reported in ppm on the basis of air-dry soil. Quick Tissue TestS' At the same times that soil samples were taken, quick tests for nitrate in potato petioles were made in the field during the middle of the day (IO:00 a.m. to 3:00 p.m.). There was no cloud cover. For this test, the newest fully developed leaf on the stalk was selected from eight randomly selected plants in the two central rows of each plot. The petiole was cut diagonally with a sharp knife. A drop of 0.2% diphenylamine in concentrated sulfuric acid (22, l2) was placed on the exposed petiole cross section. The intensity of thetflue color and the rate of its deveIOpment were used to rate each petiole on a six-point visual scale. Visual ratings of ”zero”, ”very low”, “low”, I'medium", ”high”, and ”very high” were converted to an exponential numerical scale: 32 0, l, 2, A, 8, and I6. These numerical values for eight petioles were averaged to arrive at a numerical index (QTN) of quick test tissue nitrate for each plot. 7(The exponential scale was used to approximate Beer's law of light tranSmission by colored solutions). Petiole Analyses A sample comprised of 60 petioles was compoSited from each plot on July 30 at the Montcalm location and on August l0 at East Lansing. Six petioles representing the fourth or fifth newly deveIOped leaf on a stalk were taken from l0 randomly selected hills in the two central rows of each plot. The samples were dried in a forced draft drier at 70 C. They were then ground in a Wiley mill to pass a AO-mesh screen. The dried and ground samples were extracted (l:l00) with 2% acetic acid. Activated charcoal (l/2 teaspoon per l00 ml) was added to remove interfering pigments. Nitrate-N, P, K, Ca and Mg were determined in this extract by the same procedures described above for soil samples. Results are reported as percent, dry weight basis. The petiole samples were collected during the middle of the day (I0:00 a.m. to 3:00 p.m.). There was no cloud cove I‘ . 33 Statistical Treatment Analysis of variance in accordance with a randomized block design was employed to examine the relationship of nitrogen fertilizer treatments to the different soil and plant parameters. Multiple correlation and regression analyses were used to differentiate relationships to rate of N within times of application. Linear and multiple correlation analyses were used to examine interactions among the various nutrients in soils and in petioles (A0). The Michigan State University computing facilities were used for these analyses. Analysis of variance and least squares programs described by Ruble and associates (32) were employed. RESULTS AND DISCUSSION Potato Yields And Specific Gravity_ At both locations, response to fertilizer nitrogen was shown by Significant increases in yield of total tubers and in the percentage of A-Size tubers (Table 3). The percentage A-Size increased with total yield, the linear correlations between them being highly Significant (at EaSt.Lansing r = .8A2, at Montcalm r = .795). There were no significant effects of treatment on Specific gravity, although at both locations the highest specific gravities were associated with total N applications of I80 pounds in treatments 7 or 8. In Figure 3, mean yields for all treatments at each increment of total fertilizer N are plotted graphically. The total yields of Russet Burbanks at the Montcalm location were Similar to those for Sebagoes at East Lansing., However, the lower grading percentagefbr Burbanks resulted in yields_of A-size tubers at Montcalanhich were lower by 60 percent or more. The difference in grading percentage was probably influenced by the fact that the Burbanks were harvested about two weeks earlier (September 27 vs. October IA). However, the long shape of the Burbanks normally gives this result. 3A 35 .pm__oom z LON___uLom _mb0u op co_um_mL c_ means“ < mpmeo pcm _muou mo mp_m_> .m me:m_m «\mTz $5.55... DEE. .OVN Om. ON. CO 0 O .. G , 5343202 _ _ _ 0 62524.. 53 lid I 445.0... \ \ I Q IIIII 2Fo.cmmE cu co_um_mL c_ Oumeu_c m_owuoa Low mcmmenpcoEummep .m OL:m_m .. emsoaq zea . N_ o_. m m a. N o 1 . _ n a _ _ \— . o o o <\o I _ 0 AV 4 4 I N 4 4 . 5343202 0 62524.. 53 I m 2.. u m 27:. new. "a. I... u z... ZHO Nmm. + mm. I isnsnv %.N-€ON 310I13d A5 of petiole P in Sebagoes at East Lansing was double that in Russet Burbanks at Montcalm. This was probably due, in part, to the much higher basal application of fertilizer phoSphorus at East Lansing (cf. Table 2), Since soil phosphorus was higher at Montcalm and very high at both locations (Table 9). All of the values in Table 7 for soluble petiole phosphate in Burbanks at Montcalm are 0.1% P or less. Tyler gt a1. (A6). The heavy basal application of potash at East Lansing must have contributed to the somewhat higher levels of K in the petioles here than at Montcalm (Table 8), Since soil K levels were up to 50% lower at East Lansing (Table l0). Petiole K was significantly reduced by applications of fertilizer N at East Lansing, and there was a Similar tendency at Montcalm. None of the values at either location was less than 7.0% which California studies would indicate to be a critical level (25). Petiole Ca was higher at East Lansing, petiole Mg was much lower, than at Montcalm (Table 8). The lower Mg in petioles at East Lansing was associated also with lower soil tests for Mg (Table l0). It must be recognized that varietal differences may have contributed also to the above differences between locations in levels of soluble petiole nutrients. A6 Nutritional Interactions With Nitrogen Treatment means in Tables 6, 7, and 8 give evidence that potato response to nitrogen fertilizer treatments may have involved rather complicated interactions among the various nutrients. Some of these interactions in their relation to time of fertilizer N application can be seen in Table II. Nitrate in the petioles in August reflected mainly the nitrogen supplied in the sidedressed applications at both locations. The banded application was reflected to a lesser extent and the plowdown not at all. There was a marked tendency for soluble P and K in the petioles to decrease as the applications of fertilizer N increased. However, this effect was not so clearly related to time of application as it was in the case of petiole nitrate. Thus, there did not appear to be a simple reciprocal relationship among sap concentrations of these three nutrients. Increases in petiole Ca, on the other hand, were related to times of application at both locations in a manner similar to petiole nitrate. A Similar relation to time of application was expressed for Mg at Montcalm but not at East Lansing, where the principal increases in Mg content were associated with the plowdown application. A7 Interactions, within the plant, among K, Ca and Mg were uniquely different at the two locations. This can be seen in the linear correlations presented in Tables I2 and I3. The last two columns in the §£ond half of Table I2 Show that residual K from the I967 potash experiment at East Lansing had negligible effects on soil and plant para- meters relative to the effects of fertilizer N applied in I968. Petiole K decreased as soluble Mg increased at both locations. A Similar negative correlation between PK and PCa was expressed only at Montcalm. At both locations, increasing rates of fertilizer N were associated with reductions in petiole K and P and reductions in soil K, Ca and Mg. The statistical significance of these changes were generally low but the probabilities for several were greatly improved when time of N application was taken into consideration. * Multiple correlation analyses of East Lansing data are presented in Table IA to Show how soil K and petiole K and Mg were related to quantities of N in each of the three applications. The probabilities (PR) for significance of the overall functions were at a l percent or lower level of chance. The signs of the regression coefficients and their probabilities (Pb) indicate that both soil and petiole K were reduced by plowdown and banded applications of N, but that the Sidedressed applications promoted increases in both.= A8 The corresponding functions for Montcalm data (Table IS) differed in that decreases in soil and petiole K were associated with all three applications. I The statistical probabilities are less impressive for the Montcalm data. It is suggested, nevertheless, that declines in soil and petiole K accumulated over the three applications may have contributed to the highly significant increases in petiole Mg associated with the Sidedressed application at Montcalm. It is further suggested that the increases in soil and petiole K associated with the sidedressing at East Lansing would have tended to oppose differential accumulation of petiole Mg at this time, so that the principle increases in Mg were associated with the plowdown application at East Lansing. In support of these suggestions, it is to be noted that soil tests for nitrate indicate that much of the applied nitrogen at both locations had leached out of the plow soil by August. The nitrate would have been accompanied by bases. In plowdown and banded applications, it is likely that nitrate would have been accompanied preferentially by fertilizer K. Thus, the effect of percolating nitrate would have been to reduce the availability of K relative to Ca and Mg where NH4N03 was placed in the vicinity of plowdown KCl at A9 East Lansing and, at both locations, where NHQN03 was banded with the K in 0-20-20. Soluble phosphate in the petioles decreased with increas-' ing fertilizer N (Tables I2 and I3). At East Lansing (Table I6) this reduction was rather closely associated with the banded application (Pb = 9%) and with a reduction in soil P extractable with the Bray P] extractant. At Montcalm (Table I7), reductions in soluble petiole P were associated with both plowdown and banded N and with decreases in soil pH.. I ' The data in Tables I6 and I7 suggest that phosphate equilibria in the soil were influenced by NH4N03 and that acidity produced in the vicinity of nitrifying ammonium may have been involved. The interactions within the plant between anionic nutrient's (nitrate and phosphate) and cationic nutrients (K, Ca and Mg), which can be inferred from their intercorrelations in Tables l2 and I3, suggest that nitrate competed with phosphate in maintaining a balance between Cations and anions in nutrient uptake. A major source of P would have been the fertilizer band. The dominant cation in the fertilizer band would have been the K banded with the P. Thus, it is not surprising that petiole P and K were rather highly inter- correlated. The soil was the major source of Ca and the only source of Mg. Because of its mobility, nitrate would have been the 50 principal anion to accompany these two cations into the plant. The uptake of these two cations apparently increased as the quantity of nitrate added or formed in the soil increased. It is apparent from data plotted in Figure 7 that nutritional interactions between plant and soil and among nutrients in the plant may be very complex. The effect of a fertilizer is more than to increase the supply of the added nutrient. It also alters the relation of the plant to other nutrients. The form of the nutrient, its placement and the time of application are further complicating factors, as are rainfall patterns or irrigation practices which give rise to mass movements of soluble nitrate salts. SI v V0. um mm"; 593. Zn. mm0.+.~um0. noon. w..." m mm"; ugJN. 2a m. 1+8. "as; nus..." m mMuhv sum—KNb Zn. mmN.I.N_.mn xm z MAO—Pun. o\o m N _ 00.. ON.— 0¢.. 6w 31ouad % Z MIST—mm o\o m N 2 MAC. m hum o\o N 00.0 00.0 9. . o‘ 0:) 3310!le °/. l0 c5 _ 86 ad 0.» % d 3 me. u 0 .I 3 o.m x 0.0 ontcalm. 4 l Petiole K, Ca and Mg in relation to petiole N at i Figure 7. SUMMARY AND CONCLUSIONS The relative diagnostic usefulness of soil and petiole tests for nitrate was studied in two field experiments in which time and rate of nitrogen fertilization were varied. Two varieties of potatoes (Solanum tuberosum) were used. The Sebago variety was grown on Conover loam at East Lansing, and Russet Burbanks were grown on McBride sandy loam at Montcalm. Soils and petioles were sampled twice for nitrate determinations: (I) at about the time of tuber initiation just before flowering in July, and (2) after rapid tuber enlargement was evidenced by the presence of several B-size tubers (l-l/2 to 2 inches diameter) per hill in August. A rapid visual field test for petiole nitrate was converted to an arbitrary exponential scale (QTN) for numerical analysis and comparison with quantitative deter- minations of nitrate in extracts of petioles and of soils. Nutritional interactions between nitrate and extractable P, K, Ca, and Mg were also examined in the August samplings of soils and petioles. Analysis of variance and simple and multiple correlation and regression analyses were used in evaluating relationships that existed. 52 53 The results of these analyses may be summarized as follows: I. Response to fertilizer nitrogen was significant in yield of total tubers and in percentage of A-size tubers. No significant effects on specific gravity were observed. Plowdown nitrogen was relatively ineffective in influencing yields at both locations. 'Both banded and sidedressed nitrogen influenced yields of Burbanks at Montcalm, but at East Lansing the major yield responses with Sebagoes were associated with the sidedressed applications. At Montcalm, a total of l80 pounds fertilizer N per acre was adequate for maximum yields, but at East Lansing additional yield increases occurred at 2A0 pounds. These unusually high N requirements and the relative inefficiency of plowdown N were due to eXtensive leaching of nitrate during cool, humid periods of frequent rains in late May and late June. Because of extensive leaching, nitrate levels in the plow soil (O-IO inches) in July and August were unusually low (0.5 to 6 ppm). For this reason the soil tests for nitrate were of low diagnostic 54 value in both of these experiments. It is likely that their value would have been much greater if samples had been taken to greater depth. . Both the QTN indices and the quantitative determina- tions for petiole nitrate gave very useful correlations with tuber yields of Burbanks at Montcalm. The graphical estimates of ”critical level” were QTN = 8 and petiole NO3-N = 2.0 percent. These values are based on petioles sampled when rapid tuber enlargement was evidenced by the presence of several B-size tubers per hill. Because of greater soil variability at East Lansing and greater scatter of experimental poils, estimates of ”critical levels” for Sebagoes were less precise but consistent with those for Burbanks at Montcalm. There was a very strong linear relationship between quantitative values for nitrate in petioles and the exponential QTN index. “This indicates that thé quick field test can be calibrated in terms of petiole nitrate content. Soluble P and K in petioles were reduced by N fertilizer application at both locations and soluble petiole Ca and Mg were increased. Effects on petiole K and Mg were associated principally with plowdown applications at East Lansing, whereas I0. ll. l2. l3. 55 effects on petiole Mg at Montcalm were associated primarily with the sidedressing. Increases in petiole Ca at both locations were associated with the sidedressing. Soluble P, K, and Ca in petioles were higher in Sebagoes at East Lansing than in Burbanks at Montcalm. This may have been due to varietal differences, or it may have reflected the higher basal application of 0-20-20 at East Lansing. Petiole P and K were positively correlated with each other. Both were negatively correlated with petiole nitrate, Ca, and Mg. Exchangeable K, Ca and Mg in August soil samples were lower in plots receiving N fertilizer than in control plots. Reductions associated with plowdown or banded applications were significant or approaching significance at East Lansing. Reductions at Montcalm were atla l0wer order of significance but were associated also with sidedressed N appli- cations. These reductions probably reflect leaching ofthese bases in association with nitrate. Extractable P was lower in soils receiving plowdown or banded N at East Lansing-' Soil pH was lower at Montcalm in soils receiving plowdown or sidedressed IA. 56 applications. At both locations, acidity released by nitrification of ammonium from NH4N03 may have contributed to reduced availability and uptake of I P and the lowered levels of phosphate P in the petioles. At both locations, petiole phosphate tended to be negatively correlated with total fertilizer N and with petiole nitrate. This suggests that nitrate competed with phosphate in maintaining a balance between anions and cations in root uptake. Banded 0-20-20 would have been an important source of phosphate. The dominant cation to accompany P into the root from the fertilizer band would have been K (and to a lesser extent, Ca). The positive correlations between petiole P and K would reflect this positional association of these two nutrients in the fertilizer band. The strongly positive correlations between petiole nitrate, ca and Mg, on the other hand, would reflect the positional mobility of nitrate in the soil and the fact thatnitrate would have a better chance of being accompanied into the root by Mg and Ca from soil sources than would the phosphate in the fertilizer band. I5. 57 The overall effect of interactions in uptake of nitrate, phosphate, K, Ca, and Mg was such that petiole phosphate concentration was reduced as the rate of plowdown and/or banded fertilizer N increased. In the case of Russet Burbanks at Montcalm, these interactions may have made P the first limiting nutrient in all treatments which received fertilizer N. BIBLIOGRAPHY Allison, F. E. I956. Estimating the abilit of soils to supply nitrogen. Agr. Chem. ll(h):h6- 8. Allison, F. E. I966. The fate of nitrogen applied to soil. Adv. Agr. 18:2l9-258. Allison, F. E., and C. J. Klein I962. Rates of immobilization and release of nitrogen following additions of carbonaceous materials and nitrogen to soils. Soil Sci. 93:383-386. Benepal, P. S. I967. Interactions among plant nutrients, application levels of yield of potatoes. Amer. Potato J. 44:l87-l94. Bessey, P. M. I967. Nitrogen fertilizer timing for winter potatoes. Amer. Potato J. AA:2lA-ZI7. Bodlander, K. B. A. I963. Influence of temperature, radiation and photoperiod on development and yield. p. I99-2l0. in J. D. lvins and F. L. Milthorpe (eds). The growth of the potato. Univ. of Nottingham. Bray, R. H. I96l. You can predict fertilizer needs with soil tests. Better Crops with Plant Food. A5(3)l8-l9, 25-27. Bremner, J. M. I965. Nitrogen availability indexes. p. l32A-l345. lg C. A. Black (ed). Methods of soil analysis. ll. Chemical and microbiological properties. Am. Soc. Agron. Monograph No. 9. Madison, Wisconsin. Broadbent, F. E., and F. Clark. I965. Denitrification. p. 344-359. jg W. V. Bartholomew and F. E. Clark (eds.) Soil Nitrogen. Am. Soc. Agron. Monograph No. l0. Madison, Wisconsin. . Cooke, W. G. I962. Chemical aspects of soil fertility. Soil and Part. 25:4l7-420. . Danielson, L. L. I953. Rapid chemical plant tissue test for diagnosing fertilizer deficiencies in growing vegetable crOps. Va. Truck Exp. Sta., Bul. ll2. 58 l2. l3. IA. ‘5. l6. l7. l8. I9. 20. 2l. 22. 59 Doll, E. C., D. R. Christenson, and A. R. Wolcott. Potato yield as related to nitrate levels in petioles and soils. (Unpublished Manuscript). Gascho, G. J. I968. Soil nitrogen availability indexes and effects of potassium carriers and levels of potassium and nitrogen fertilization on the yield and quality of sugar beets. Ph.D. Thesis, Michigan State University. Grewelin , T., and M. Peech. I960. Chemical soil tests. Bul. 9 0. Cornell University. Agr. Expt. Sta. New York State College of Agric., Ithaca, N.Y. Hawkins, A. I956. Response of potatoes to fertilizer nitrogen in the northeast. Amer. Potato J. 33:226-233. Hawkins, A. I965. New ways of fertilizing potatoes. Amer. Potato J. A2:76-77. Hiltbold, A. E., W. V. Bartholomew, and C. H. Werkman. l95l. The use of tracer techniques in the simultaneous measurement of mineralization and immobilization of nitrogen in soil. Soil Sci. Soc. Am. Proc. l5:l66-l73. Hutchinson, H. B., and E. H. Richards. I92l. Artificial faryard manure. Ministry of Agr. 28:398-4ll. Jackson, M. L. I958. Soil chemical analysis. Prentice- Hall, Inc., Englewood Cliffs, New Jersey. Jansson, S. L. I958. Tracer studies on nitrogen trans- formations in soil with special attention to mineralization-immobilization relationships. Ann. Royal Agr. Coll. Sweden (Uppsala). 24:l0l-36l. Jansson, S. L., M. J. Hallam, and W. V. Bartholomew I955. Preferential utilization of ammonium over nitrate by micro-organisms in the decomposition of oat straw. Plant and soil. 6:382-390. Krantz, B. A., W. L. Nelson, and L. Burkhart. Plant tissue tests as a tool in agronomy research. Chap. V. jfl_Diagnostics tech. for soil and crOps. Pub. by Amer. Potash Inst., Inc., Washington, D.C. 23. 24. 25. 26. 27. 28. 29. 30.. 3I. 32. 33. 60 Lorenz, 0. A. I963. Effect of mineral nutrition on quality of ve etables. Proc. A. Meet. Coun. Fertil. Applic. 39:3 ~50. - Lucas, R. E. I969. Cultural trials on irrigated corn. Agr. Exp. Sta. and Crop Ext. Service, Michigan State University. Lynd, J. 0., L. M. Turk, and R. L. Cook. I949. Application of soil tests, tissue tests and foliar analysis to field experiments. Soil Sci. Soc. Amer. Proc. l4z236-24l. MacKay, D. C., C. R. MacEachern, and R. F. Bishop. I963. The relation of soil test value to fertilizer responSe by the potato. II. Nitrate production and nitrogenous fertilizer requirements. Canada J. Soil Sci. 3:242-249. Milthorpe, F. L. I963. Some aspects of plant rowth. p. 3-l6. in J. D. lvins and F. L. Milthorpe geds.). The growth of the potato. University of Nottingham. Mondy, N. l., and P. B. Rieley. I964. Relationship of specific gravity to the nitrogen and ascorbic acid content of potatoes. Am. Potato J. 4I:4l7-422. Mortland, M. M., and A. R. WoIcott. I965. Sorption of inorganic nitrogen compounds by soil materials. . l50- I97. lfl_W. V. Bartholomew and F. E. Clark (eds.). Soil Nitrogen Am. Soc. Agron. Monograph No. l0. Madison, Wisconsin. Nobrega, S. A. and E. S. Freire. I964. Method and time of application of nitrogen to potatoes. Part III. Bragantia. 23:351-364. 0dland, T. E., and J. E. Sheehan. l96l. Response of potatoes to different amounts of nitrogen, phosphoric acid and potash when grown in continuous culture and in rotation with red top. Amer. Potato J. 38:33-42. Ruble, W. L., D. F. Kiel, and M. E. Rafter. I966. Michigan Experiment Station Stat. Series Descriptions No. 7 and l . ‘ - Ryan, P. F. I960. Some aSpects of the nutrition of potato. J. Dept. Agr. Dubl. 57:68-98. 34. 35. 36. 37. 38. 39. 40. 4I. 42. 43. LILI. 45. 6I Sawyer, R. L., and S. L. Dallyn. I958. Nitrogen fertilization of potatoes. Amer. Potato J. 35:645-650. Shoemaker, H. E., E. 0. McLean, and P. F. Pratt. l96l. Buffer methods for determining lime requirement of soil with appreciable amounts of extractable aluminum. Soil Sci. Soc. Am. Proc. 25:274-277. Singh, H. M. I96I. Correlation studies with corn using seasonal soil and tissue tests. Ph.D. Thesis, Michigan State University. Slater, J. W. I963. Mechanisms of tuber initiation. p. ll4-l20. jfl_J. D. lvins and F. L. Milthorpe (eds. ). The growth of the potato. Univ. of Nottingham. Smith, 0., and W. C. Kelly. I946. Fertilizer studies with potatoes. Amer. Potato J. 23:I07-l35. Sommerfeldt, T. G., and K. W. Kuntson. I965. Effects of nitrogen and phosphorus on the growth and development of Russet Burbank potatoes grown in southeastern Idaho. Amer. Potato J. 42:35l-360. Snedecor, G. W., and W. G. Cochran. I967. Statistical Methods. The Iowa State University Press. Ames, Iowa. Stevenson, F. J. I964. Soil nitrogen. p. l8-39. 13_ V. Sauchelli (ed.). Fertilizer nitrogen: Its chemistry and technology. Am. Chem. Soc. Monograph No. l6l. Reinhold Publ. Corp., New York. Stevenson, F. J. I965. Origen and distribution of nitrogen in soil. p. I-36. lg W. V. Bartholomew and F. Clark (eds.) Soil nitrogen. Am. Soc. Agron. Monograph No. l0. Madison, Wisconsin. Teich, A. H., and J. A. Meinzies. I964. The effect of nitrogen, phosphorus and potassium on the specific gravity, ascorbic acid content and chipping quality of potato tubers. Amer. Potato J. 4l: I69- I73. Timm, H.,J. C. BishOp, and V. H. Schweers. I963. Growth, yield and quality of White rose potatoes as affected by plant populatio and levels of nitrogen. Amer. Potato J. 40: l82-I92. - Tisdale, J. L., and W. L. Nelson. I966. Soil fertility and fertilizer. p. 455-47l. The MacMillan Co., New York. 46. 47. 48. 49. 50. SI. 52. 53. 62 Tyler, K. B., 0. A. Lorenz, and F. S. Fullmer. I96l. I. Plant and soil analysis as guides in potato nutrition. Calif. Agr. Expt. Sta. Bul. 78l. Ulrich, A. I956. Plant analysis as guide to fertiliza- tion.of crOps. Better CrOps with Plant Food. 40(6): 6-I0; 35-38. Ulrich, A.,D. Ririe, F. J. Hills, A. G. George, and M. D. Morse. I959. I. Plant analysis: A guide for sugar beet fertilization. Univ. Calif. Agr. Exp. Sta. Bul. No. 66. Watson, 0. J. I963. Some features of crop nutrition. p. 233-247. jfl_J.D. lvins and F. L._Milthorpe (eds.). The growth of the potato. Univ. of Nottingham. . Wolcott, A. R. I956. Varietal response to climate and culture as releated to the deveIOpment of internal browning in potato tubers. Ph.D. Thesis. Purdue University, Purdue, Indiana. Wolcott, A. R., and N. K. Ellis. I959. Internal Browning of potato tubers: varietal susceptibility as related to weather and cultural practices. Amer. Potato J. 36:394-403. Woodruff, C. M. I950. Estimating the nitrogen delivery of soil from the organic matter determination as reflected by Sanborn Field. Soil Sci. Soc. Am. Proc. I4z208-2l2. Yungen, J. A., A. 5. Hunter, and T. H. Bond. I958. The influence of fertilizer treatment on the yield, grade, and specific gravity of potatoes in eastern Oregon. Amer. Potato J. 35:386~395. L I ST OF TABLES 64 Table l. Nitrogen treatments Pounds N per acre Treatment in NH4N03 N No. Total Plowdown Banded Side- dressed3 l 0 0 0 O 2 0 60 0 6O 3 60- 60 O .l20 h 0 6O 60 l20 5 I20 0 0 I20 6I o l20 o 120 7 I20 60 0 I80 8 0 60 I20 180 9' 60 60 60 180 ID l80 60 0 240 II2 120 60 60 240 IMontcalm location only. 2East Lansing only. 3Sidedressings applied by hand July 3 at East Lansing, July 5 at Montcalm. am mummi- st _ .7; a m. 65 Table 2. Basal fertilizer Location Pounds per acre N-P-K Plowed down Banded Total East Lansing 0-0-138 . 041053200 04054-338I Montcalm 0-0-0 0-44-I66 O-44-l662 I0-240-405 expressed as N-PZOS-KZO 20-l00-200 expressed as N-P205-K20 W. ‘F‘w. . . -A ‘n-‘“ .MM' xmam_ u CmEummL u sate aceteee_e.>_demd_e_em_ms mxcmncnm uommsmm >uo_tm> ommbom_ .m.z _.m_ .N.am .m.z ~.o_ m.:e Imooma I I I mmn0.p «N.mm «0.de OJN 00 00 ON_ __ mmko._ sm.mm.so.w_m - . - - oaN o. as om_ o— 0_m0._ «w.d: *m.Nom I . I I om_ 00 00 00 m on0._ «m.mm #o.mmm Ommo._ %:._w «w.mmm om_ ON. 00 o m . wmwo._ km.mm «o._mm wmmo.r .¢.Nm ¥©.NmN ow_ 0 00 0N_ m ono._ em.om sm.mmm - - - ON. 0 ON. 0 a . mfiwo._ m.:m m.¢mN mmmo._ :.mm N.mmN ON. 0 0 ON. m m_wo._ am.wm «m.mom mmmo._ a.mm km.mom ow_ oo oo o : o_mo._ m.om a.mmm mmno._ 3.:0 :.ow~ oN_ o co om m memo._ o.MN o mmN mmko._ N.No m.oo~ as o as .o N o_wo._ m.0N m.m_N m_mo.p m.d© 0.:_N o o 0 o _ N 83o & “3o . .Lw .am opmco U_m_> .Lo .mw opmco o_m_> _mu0H .Lompwm pmpcmm c300 I30_m .oz NE_moucoz .mc_mcm4 ummm z LoN___ucmu ucmEumoLp LmN___ume 2 mo mum; Ucm oE_u cu co_um_mL c_ >u_>mtm o_m_ooam pcm mv_m_> CumuOm .m m_nmh 66 67 Table 4. Linear correlation coefficients (r) between crop parameters and inputs of fertilizer N II Plow- Side- ‘ ' Total down Banded dressed, fertilizer East Lansing1 Total tubers .266 .329 .59l** ,692** Grade A % .240 .l76 .508** .565** Specific gravity .02l .l09 .339 . .262 Montcalm2 Total tubers .ll2 .545** .353* ,598** Grade A % .l6I .4l9** ,370* .593** Specific gravity -.089 .050 .078 -.Ol0 Idf = 30 2df = 38 *significant at P05 **significant at P01 a now" “I- a-amum . -.-.~- . ..- 68 Table 5. Nitrate-N in soil in July and August, I968, in-relation to time and rate of N fertilizer Treat- Fertilizer-N ngglng Montcalm ment Plow- . SN03 SN03 SN03 SN03 __ No. down Banded SIdedr. Total July Aug. July Aug; : PPm PPm PPm PPm I O 0 0 0 l.0 .5 l.l .7 E 2 O 60 ‘ 0 ~ 60 ' l.0 ‘l.2 ‘ I.I 7 i 3 6O 60 0 120 I.8 l.2 l.4 1.0 I 4 0 60 60 l20 .7 I.3 4.9* l.8 5 l20 O 0 I20 l.2 l.2 2.l .9 6 0 l20 0 l20 - - 4.4* l 3 7 l20 60 0 I80 I.3 l.2 I.5 I.7 8 0 60 l20 l80 l.4 I.3 6.0* 5.7* 9 60 6O 60 l80 - - 5.0% I.6 l0 l80 6O 0 240 - - 3.4 I.6 II l20 6O 60 240 3.9* I.6 - - LSDOS l.l6 N.S. 2.68 l.52 *Significantly different from treatment I at 5%. 69 Table 6. QTN index of tissue nitrate in July and August, I968, in relation to time and rate of N fertilizer " - - Tsn-nnma “humnr 1_4. . U " ' ' Treat- Fertilizer N Lagzlfiql Montcalm2 ment Plow- QTN QTN QTN QTN No. down Banded Sidedr. Total July Aug. July Aug. l 0 0 0 0 6 3 8 4 2 o 60 . o _ 6.0 ' 7 _ 3 ' .Izv': LI 3 60 60 0 120 I 9 6* 12* 8*. 4 0 60 60 I20 8 l0* l5* l0* 5 I20 0 0 l20 7 5 9 5 6 0 l20 0 l20 - - l4* 9* 7 I20 60 0 I80 II 6* l2* 9* 8 0 60 l20 I80 7 l3* l5* l3* 9 60 6O 60 I80 - - l4* 9* l0 I80 60 0 240 - - I4* 9* ll l20 60 60 240 ll I0* - - LSD05 N.S. 2.8 3.0 3.0 ISebago Variety 2Russet Burbanks *Significantly different from treatment No. I at 5% 70 _. 3' Fl! 1. “1.1.1“..3 21%.... ll. -. .Vf hi! Rm um _ .oz ucoEumocu Eotm ucotomm_o >_ucmo_mmcm_m« mxcmntsm ummmsmm >uo_cm> ommnmm_ .m.z ko.— ...m.z No.0 momma I I o~.0.. «m—.m oqw om 00 ON. .— m0.o kmo.m I I OJN 0 00 ow_ o— wo.o emN.m - - om_ as as as m wo.o «om.: w_.o «mm.m ow_ om_ om o w No.0 «m:.m m_.o n_._ om_ o om om. m mo.o m_.N I I oN_ o om_ o m mo.o mm._ _~.o Nm.o om_ o .o om_ m mo.o a_:.m m_.o «:m.N om_ om om o : mo.o mm._ w_.o No.0 oN_ o om 00 m mo.o mm.o N~.o w:.o om o oo o N o_.o mm._ mN.o mo.o o o o o _ m. 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Jm.m m:. 0N. kmw.m 00 0 00 0 N mm. 00. _m.m Nm. _N. _w.m 0 0 o o _ x x x x x N a: me x . a: .. n ._ .g, ; :_md0e_ .tede_m eddcmm aged .02 m_o_umnlopo_uom o_o_uod,Wko_uom m_o_umm o_o_uoa Izo_m ucmE NE_moucoz .mc_mcm4 ummw z LoN___uLom Iummch IIII IIIl' I III LmN___ume 2 mo mumc pcm oE_u cu :o_um_mc c_ ucoucou m: Ucm mo .x m_o_uma cumuOm .w m_nmh 72 m» ”I”! . Ila-II}. N Gil! .NII- I ‘r xm um . .oz ucmEumoLu Eotm ucotomm.v s..u:..mu.d..cm.m.,.n .m.z m_. .m.z .m.z .m.z momma I I m.00 mN.. ON.0 OJN O0 O0 ON. .. m.Nm. O0.0 I .II I OJN O O0 ow. O. J.mO. mm.0 I I I 00. O0 O0 O0 m m.0.. ¥m0.0 0.mw Rm.. m0.0 ow. ON. O0 O 0 m..N. O0.0 m.J0 m... mN.0 00. O O0 ON. A N.m.. 00.0 I I I ON. O ON. O 0 J.m.. m0.0 m..0 mN.O mm.0 ON. O O ON. m N.m.. O0.0 m.Jm Om.. 00.0 ON. O0 O0 O J m.mm mm.0 N..0 m... . mm.0 ON. O O0 O0 m J.mm. om.0 Jxm0 mN.. mm.0 O0 O O0 O N m.0O. om.0 a.mu mm.. 00.0 O O O O . Eon Eda uaa a Id a a de_d Id .maoe .tede_m eeecnm .oz ..0m ._om ..0m IL.0m F.0m Izo.¢ ucmE Iummck E.m0ucoz mc.mcm4 ummm z Low...ucou Low.._ucom 2 mo mumc 0cm oE.u op co.um.mL c. umamn< c. mucosamOLQ 0cm ucoEoL.:UmL 05.. .Ia ..0m .m p.0m. 73 mo .m.z .m.z .m.z .m.z .m.z 0.0. O04 I I I 0.0m m:NNJ J.ON OJN O0 O0 ON. .. 0.00 m.J0m m.0m I I I OJN O O0 O0. O. J.m0 0.00J m.N.. I I I O0. O0 O0 O0 0 m.m0 O.m0m J.0O. 0.NJ m.mmm m.m0 O0. ON. O0 O 0 0..N m.0OJ 0.0.. 0.0m m.0OJ m.mm O0. O O0 ON. N m.00 0.00J 0.0.. I I I ON. O ON. O 0 0.00 m.NNJ m.0J. m.NJ m..mJ N.JN ON. O O ON. m ..N0 m.m0m J.0O. 0.0m m.0OJ m.00 ON. O0 O0 O J 0.m0 m.0OJ J.mo. O.mJ 0.0JJ 0.0m ON. O O0 O0 m m.O0 m.0OJ J.JO. J.0m 0.00J m.00 O0 O O0 O N J.m. m.0OJ O.mN. 0.NJ m.N.m 0.00 O O O . Eda Eda Ema End End End a: no _ x a: no x .mao. .tdee_m addenm case .02 ..Om .rmm ._Om 4.00 ..Om ._Om Izo.a ucmE Iumoch E.mu~coz 0:.mcm4 ummm z Low...ucom Low...utmm 2 mo mum; 0cm oE.u Ou co.um.ot c. .um:m:< c. a: .mu .x ..Om .O. m.nmh 74 Table II. Linear correlation coefficients (r) between petiole nutrients and inputs of fertilizer .nitrogen Location Petiole Plow- Side- Total Nutrient down Banded dressed fertilizer (August) N N N N East Lansing N03-N -.075 .442* 906** .653** P -.064 -.369* -.200. .309 K -.388*' -.233 - 230 .214 Ca -.028 .367* .794** .595** Mg .573** .I3I .042 .53I** Montcalm N03-N .030 .27] .702** .596** P -.28I -.226 -.037 .408** K -.I63 -.03l -.ll4 .244 Ca .l3l .266 .588** .62l** Mg .075 .195 .470** .469** "A *3. L11." no u dun-naus- ‘ . . y "a. - . g. A I IDe rees of freedom: 30 at East Lansing; 38 at Montcalm 9 *Significant at P05 **Significant at POI 75 Table l2. Linear correlation coefficients (r) between soil and crop parameters, total fertilizer N (I968) and residual potassium from I967 at East Lansing SNO3 SNO3 QTN QTN PN PP PK July Aug. July Aug. SNO3 July l.000 -.073 .62** .302 .28l ..093 .l94 5N03 ' ' ' V " Aug. l.000 -.O6l .ll5 .2l4 -.263 -.0l7 QTN July l.000 .I2I .l50 .27l .l25 QTN Aug, 1.000 .857** -.446* .094 PN .000 -.264 .254 PP 1.000 .397* PK I.000 Table l2, cont. 76 - Total - PCa PMg Yield % A Fert. RESK cwt Grav. N- $N03 July .358* .232 .637** .208 .521** .uuz* .048 SNO3 Aug. .072 .003 -.076 .ll8 .I23 .329 -.065 QT . , July .357* .224_ .548** .24I .522**__.328 .lll T ‘ ' U9. .8]]%* .265 .726** .54“** .68]** .657** .225 PN .858** .l54 .685** .357* .6l6** .653** .063 PP .241 -.l38 .026 .350* .070 .309 -.Ill PK .l54 -.539* .l53 .232 .200 .2l4 .3I0 PCa l.000 .3I7 .767** .299 .692** .595** .20l PMg l.000 .426* .342 .448* .53l** -.2I9 Yield .000 .26l .842** .692** .I7l cwt Sp. .000 .339 .262 .050 Grav. . . . % A l.000 .565** .246 Total N I.000 -.059 *Significant at 5% **Significant at I% I2, "I. .1 _..._. .._._____._._._.. . ~ . . . --IA _, .m 77 Table I3. Linear correlation coefficients (r) between soil and crop parameters and total fertilizer N applied in I968 at Montcalm SN03 SN03 QTN QTN PN PP PK July Aug. July Aug. SNO July I.OOO .554** .475** .5l9** .626** -.040 .093 SN03 Aug. l.000 .348* ..544** .624**- .055 -.0I0 July 1.000 .65 ** .677** -.429**-.393* QTN Aug. l.000 .803** -.273 -.376* PN I.000 -.255 -.370* PP l.000 .407** PK l.000 .‘ L.-_' _&'_'. iii 78 Table I3, cont. . ._ , Total PCa PMG Yield Sp. % A Fert. cwt Grav. N SNO3 JuIY .436** .302 .498** .112 .545** .398* SN03 Aug. .543** .339* .374* .042 .365* .360* QTN JUIy .675** .6]6** .720** .-.O]6 ’ '743**'; .528** QTN Aug. .766** .653** .733** .l76 .600** .538** PN .794** .668** .7l9** .084 .666** .596** PP -.420** .452** .372* .07I -.232 -.408** PK -.6I4** .665** .269 -.l47 -.l64 -.244 PC8 I 000 .814** .693** .179 .597** .621** ng 1.000 .582** .38]* 537** .u59** Yield cwt .000 .267 795** .598** Sp Grav. I.000 é.052 - 0I0 % A 1.000 593** Total N I.000 *Significant at 5% **Significant at I% 79 . I _ a I .\ .. . . hijabw:‘ uhfI. 1 5.11.4.0 .i z emanatede_m z nmncmm z czovIzo.m ucmumcoo moo. I ma , .o. I as moo. I ma J0m. N Na mm. 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APPENDIX APPENDIX A DRAFT ESTABLISHED SERIES SUBJECT TO REVIEW CONOVER SERIES Conover series consists of somewhat poorly drained soils developed in loam or silt loam calcareous till in southern Michigan. Conover soils are the somewhat poorly drained member of the drainage sequence which includes the well-drained Miami, the moderately well drained Celina, the poorly drained Brook- ston soils and very poorly drained Kokomo soils. Blount soils have finer-textured BZt horizons than Conover soils and are developed on clay loam or silty clay loam calcareous till. Locke soils are developed on sandy loam till materials and are generally coarser-textured throughout the soil profile than the Conover soils. Crosby soils are also developed on loam or silt loam calcareous till but have much lighter surface colors than Con- over soils. Kibbie soils deveIOped in stratified, lacustrine silts and very fine sands. Mantamora soils deveIOped in 20 to 40 inches of loamy fine sand to sandy loam over loam, silty clay loam, clay loam, or silt loam till materials. Capac soils are the northern analogue of the Conover soils. Soil Profile: Conover loam Ap 0-8” LOAM: very dark grayish brown (IOYR 3/2); moderate, fine, granular structure; friable; moderate to high in organic matter content; slightly acid; abrupt smooth boundary. 7 to II inches thick. A2 8-I2” LOAM: grayiSh brown (IOYR 5/2) or'brown (IOYR 5/3) mottled with yellowish brown (IOYR 5/6-5/8) and light brownish gray (IOYR 6/2); mottles are common, medium, and distinct; moderate, medium granular to weak, thin, platy structure; friable; medium to slightly acid; clear wavy boundary. 2 to 5 inches thick. 84 85 BI l2-l6II LOAM: yellowish brown (IOYR 5/4) or light brown (7.5YR 6/4) mottled with dark yellowish brown (IOYR 4/4) and light brownish gray (IOYR 6/2), mottles-are common, medium, sub~ angular blocky structure; friable; slightly to medium acid; clear wavy boundary. 2 to 6 inches thick. BZIt l6-24ll CLAY LOAM: dark yellowish brown (IOYR 4/4) or yellowish brown (IOYR 5/4) mottled with brownish ellow (IOYR 6/8) and grayish brown (IOYR 5/2 mottles are common, medium, distinct, f‘I i I I I moderate, medium to coarse subangular blocky structure; firm; slightly to medium acid; . clear.to wavy boundary. 6to l2 inches thick. 822t 24-30" CLAY'LOAM: pale brown (IOYR 6/3) or light brownish gray (IOYR 6/2) mottled with yellowish brown (IOYR 5/6-5/8) and dark yellowish brown (IOYR 4/4) mottles are common, medium, and distinct; moderate, coarse sub- angular structure; firm; slightly acid to mildly alkaline; abrupt irregular boundary. 4 to l4 inches thick. CI 30”+ LOAM: brown (IOYR 5/3) to dark grayish brown (IOYR 4/2) mottled with yellowish brown (IOYR 5/4-5/6) and light brownish gray (IOYR 6/2) mottles are common, medium, distinct; massive or weak, coarse, subangular blocky structure; friable; calcareous. Range in Characteristics: Fine sandy loam, loam and silt loam t peshave been mapped. Depth to mottling-ranges from.8 to - l8 inches. The color of the Ap horizon is very dark gray (IOYR 3/l) or very dark brown (IOYR 2/2) in some places. The depth to calcareous till C horizon varies from 20 to 42 inches. The textures of BZt horizons are clay loam, silty clay loam, or sandy clay loam. Topography: Nearly level to gently sloping till plains and moraines. Slopes range from 0 to 6 percent with the dominant range between 0 and 4 percent. Drainage and Permeability: Somewhat poorly drained. Surface runoff is slow. Permeability is moderate to moderately slow. 86 Natural Vegetation: Deciduous forest consisting of sugar maple, beech, elm, ash, and hickory. Use: Largely under cultivation where drainage is adequate to corn, wheat, oats, soybeans, and forage crops. A relatively small prOportion is in permanent pasture and farm woodlots. Soil Management Group: 2.5b Type Location: Ionia County, Michigan Distribution: Southern Michigan and Northern Indiana Series Established: Miami County,0hio l9l6. Source of Name: 'Village in Miami County, Ohio National Cooperative Soil Survey - U.S.A. Reviewed for temporary use in series file. Not an official series description. Classification is tentative. ORDER: Alfisol SUBORDER: Aqualf GREAT GROUPL Ochraqualf SUBGROUP: Mollic ochraqualf FAMILY: Fine-loamy, mixed, mesic . ,r_.i._f “393' APPENDIX B DRAFT ESTABLISHED SERIES SUBJECT TO REVIEW ~ . _ . - MC BRIDE SERIES The McBride series includes well to moderately well drained soils with a Podzol upper sequum and a Gray Wooded lower sequum, with a fragipan horizon, developed in neutral to weakly calcareous sandy loam till. McBride soils arethe well to moderately well drained member of the catena that includes the imperfectly drained Coral and the poorly to very poorly drained Ensley soils. ‘The depth to the calcare0us till ranges from 42 to 66 inches. The fragipan'occurs in the lower part of the A2 horizon of the Gray Wooded sequum. Montcalm soils have coarser textured sola than McBride, lack a fragipan horizon, and have loamy sand C horizons. Isabella soils have finer textured sola than McBride, and are deveIOped in sandy clay loam to sandy clay C horizons. The Freesoil series have thinner and less acid sola than McBride, a thicker fragipan that replaces a part of the Bt horizon, and thus is finer textured in the fragipan than the McBride, and the depth to the C horizon ranges from 24 to 42 inches. Soil Profile: McBride fine sandy loam Ap 0-7” Dark grayish brown (IOYR 4/2) to very dark grayish brown (IOYR 3/2); fine sandy loam; weak to moderate, fine, granular structure; very friable; slightly to medium acid; abrupt smooth boundary. 6 to 9 inches thick. Bhir 7-I2” Yellowish brown (IOYR 5/4-5i9 to dark-yellowish brown (IOYR 4/4); fine sandy loam; moderate, medium, granular to weak, fine, subangular Bocky structure; very friable; slightly to strongly acid; clear wavy boundary. 3 to 6 inches thick. A2 I2-l5'| Pale brown (IOYR 6/3) to very pale brown (IOYR 7/4); sandy loam to loamy sand; weak, fine, platy structure; slightly firm; medium to strongly acid; abrupt wavy boundary. 2 to 6 inches thick. ' 87 .? 1 u———.—. _ , ‘M‘. ._ .0 ' .1. o I . ’_ D'. “an. 88 A2m l5-22” Gra ish brown (IOYR 5/2) to light gray (IOYR 7/2 ; loamy sand to sandy loam; massive to very weak, medium platy structure; brittle and firm; medium to strongly acid; abrupt wavy boundary. 4 to l2 inches thick. Bt 22-48” Dark brown (7.5YR 4/4) to strong brown (7.5YR 5/6), sandy clay loam; light gray coatings occur on the cleavage faces in the upper part of the horizon; thin, dark brown clay films occur on some peds; moderate to strong, medium, subangular blocky structure; firm; medium acid; clear wavy boundary. l6 to 36 inches thick. C 48”+ Brown.(7.5YR 5/4 4.l0YR 5/3); sandy loam; weak, coarse, subangular blocky structure; friable; slightly acid to calcareous. Range in Characteristics: Undisturbed areas have a very dark brown (IOYR 2/2) Al horizon, l to 3 inches thick, and a light brownish gray (IOYR 6/2) or pinkish gray (7.5YR 6/2) A2 horizon 2 to 6 inches thick. The Bhir horizon is dark brown (7.5YR 4/4) in some areas. The entire A2 horizon of the Gray Wooded sequum is a fragipan horizon in some places. The degree of develo ment of the fragipan ran es from weak to strong. The Bt fiorizon is reddish brown €5YR 5/4) in some areas, and the texture ranges from fine loam to fine sandy clay loam. Lenses, pockets, and layers of loamy sand occur in the C horizon in numerous areas. Sandy loam, fine sandy loam, and loam types have been mapped. Colors refer to moist conditions. Topography: Nearly level to steep areas on moraines and till plains. . . Drainage and Permeability: Well to moderately well drained. Runoff is medium on the milder sl0pes and rapid on the steeper slopes. Permeability is moderate. Natural Vegetation: Sugar maple, beech, and oaks, with lesser quantities of hickory, basswood, and white pine. Use: The greater prOportion is used for general and dairy fafming. Corn, oats, wheat, beans, and hay are the principal field crOps. A considerable acreage is used for potatoes. The steeper sl0pes are in pasture or second growth forest. .I.. .-gw'zi'r' -. . . ' .~ , c ‘ a V. I I I 89 Distribution: Central and northern Michigan. Type Location: NWl/A or SWl/h, Sec. l7, T8N, R8W, Ionia County,‘Michigan. . . . . Series Established: Montcalm County, Michigan, l956. Source of Name: Village in Montcalm County, Michigan National Cooperative Soil Survey - U.S.A. ORDER: Spodosol SUBORDER: Orthod GREAT GROUP: Frageorthod SUBGROUP: Alfio frageorthod FAMILY: Coarse-loamy, mixed, frigid flu“! ngfinl“:§.-sz ‘ ~ "I: I J!) F‘. . a. A . |