bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation of Soil Tests for Available Phosphorus and Potassium with Crop Yield Responses to Fertilization
Authors: Long O. H. , Seatz L. F. 
Published: July 2010

AbstractSeparate yield responses to applied P and K were correlated with soil tests for these elements on 72 experiments with corn, 18 with cotton, 35 with small grains, 28 with legume hays and 11 with permanent pastures. Sodium perchlorate in N/10 perchloric acid was the extracting agent.Results are presented in graphic form showing soil‐test values for P and K plotted against crop yields obtained without P or K expressed as percent of yields where phosphate or potash was applied.Two methods of approach are used in showing the degree of correlation. One method is concerned with “prediction accuracy” at only the lower values of soil P or K. The other method is concerned with the regression curves and correlation coefficients for the experiments as a whole.Responses of corn to phosphorus fertilization on loess‐derived soils correlated least satisfactorily with the soil test where a predicted yield response was obtained in only 17% of the tests. Permanent pastures showed the best correlation; all experiments were on soils low in phosphate and responded to applications of P. The prediction accuracies obtained with other crops were as follows: corn, on limestone‐derived soils, 64%; cotton, 54%; small grains, 70%; and legume hays, 63%.Responses of cotton to potassium fertilization indicated the best correlation with the soil test, the prediction accuracy being 60%. The prediction accuracies obtained with the other crops were: corn, 44%; small grains, 47%; legume hays, 33%; and permanent pastures, 57%.The correlation coefficient (r) was not significant with respect to P on any crop; it was significant with respect to K only on corn.
Coordinated Soil‐Plant Analysis I. Nutrient Cations
Authors: DeLong W. A. , MacKay D. C. , Steppler H. A. 
Published: July 2010

AbstractAnalytical data for composite samples of soil and of corn leaf tissue collected during two years from four soil types, all soils receiving very closely similar fertility and management treatments, are presented. The area from which the samples were taken is operated as a seed production unit. The sequence of crops is cereal grain, corn, cereal grain, cereal grain, clover and timothy. Commercial fertilizer, 4‐12‐6, is used and crop residues are left on the land. Exchangeable calcium, magnesium and potassium, and exchange capacity were determined, and tests for free carbonates were made on the soil samples. Total calcium, magnesium and potassium values were determined for the leaf samples. All cation determinations were made by flame photometry. The range in exchangeable cation values for the four soils, except for the carbonate phase of one soil, was relatively small, about 30 percent, yet these soils under uniform management produced corn plants the leaf tissue of which differed significantly in content of potassium and of magnesium. The amounts of these elements in the leaf were modified strongly by the presence of free carbonate in the soil, and by seasonal and/or site influences. The exchangeable calcium: exchangeable potassium ratio in terms of milli‐equivalents per 100 grams soil proved to be a much better index of the potassium content of the leaf than did the exchangeable potassium value alone, the latter expressed either as milli‐equivalents or as percent saturation of the soil colloid. The calcium: potassium ratio showed a highly significant negative correlation with the amount of potassium in the leaf in both years. The exchangeable potassium of the soil showed a significant negative correlation with the magnesium content of the leaf in one year but not in the other. The potassium content of the leaf showed a significant negative correlation with the magnesium content of the leaf in both years. Further, this correlation was more significant than that of the potassium of the soil with the magnesium of the leaf in both years.
A Comparison of Five Methods for Expressing Aggregation Data
Authors: Schaller F. W. , Stockinger K. R. 
Published: July 2010

AbstractFive ways of expressing aggregation data have been in common use in recent years. These are: percent aggregates greater than 2 mm, 1 mm and 0.25 mm, and geometric mean and mean weight‐diameter. To determine the advantages or disadvantages of the several indices, aggregation results obtained by the Yoder method on several hundred soil samples from three locations in Iowa have been compared. Correlation coefficients were obtained between the mean weight‐diameter and the percent of aggregates > 2 mm, > 1 mm, and > 0.25 mm, and also the geometric mean. The geometric mean was also correlated with the three size separates. The results indicate that a single size fraction such as the > 2 mm or > 1 mm can be satisfactorily used to express soil aggregation. This method of expression would be as reliable (to within the 1% level of significance) as that indicated by the two indices, mean weight‐diameter and geometric mean, which utilize all size fractions. However, it was shown that more replications are necessary for equal accuracy when only a single size fraction is used. If time is to be saved in making the laboratory determinations, it is suggested that a size fraction such as the > 2 mm or > 1 mm might be determined more quickly and with greater accuracy by developing a method using one or two sieves and a larger soil sample. The final selection of an index for expressing soil aggregation must be based on the ability of the index to correlate with crop response.
Moisture Available to Various Crops in Some New Jersey Soils
Authors: Corey A. T. , Blake G. R. 
Published: July 2010

AbstractMoisture available to wheat, potatoes, tomatoes, and sweet corn was determined by combining moisture retaining characteristics of soils, and depths to which crops exploit the water reservoir. Soil types on which some or all of the crops were grown included Sassafras and Nixon loams, Penn silt loam, and Collington loamy sand.Available water in a unit depth varied with soil type and with horizon in a given soil type.Effective rooting depth of a crop was defined as the maximum depth to which soil continued to lose moisture after a prolonged period of rainless weather. Moisture samples determined gravimetrically were each referred to a standard of 100 cm. water tension to give relative wetness values. When depth vs. relative wetness was plotted, effective rooting depth was a clearly defined point below which insignificant quantities of water were obtained by plants.Effective rooting depth of sweet corn varied with soil type from 11 to 35 inches. It also varied on a given soil with kind and age of crop.When differences in rooting depth were combined with moisture in unit depth, tomatoes had about four times as much water at their disposal in Sassafras loam as in Nixon loam. Wheat had less than half as much as tomatoes when both were growing on Sassafras loam.
Pressure Distribution in Soil Columns Draining into the Atmosphere
Authors: Luthin James N. , Miller Robert D. 
Published: July 2010

AbstractColumns of soil 122 cms long were first wetted with water and then allowed to drain into the atmosphere. During the drainage period, measurements were made of the pressure distribution in the soil columns and of the rate at which water drained out of the columns into the atmosphere. At the conclusion of the experiment, the soil columns were sectioned and the moisture distribution measured.The experimental results emphasize the importance in drainage of the tension required to produce entry of air into the soil surface. The difficulty experienced in the drainage of tight clay soils may be due more to the high tension required to produce entry of air into the soil than to the low hydraulic conductivity of the soil.Indirect evidence indicates that in the field, movement of water in the capillary fringe above the water table may be of considerable importance. This is especially true for the case of the falling water table. The use of Laplace's equation in the study of flow in the capillary fringe is discussed briefly.
Determination of Fixed Soil Potassium
Authors: Kolterman Delbert W. , Truog Emil 
Published: July 2010

AbstractAfter making preliminary tests of methods proposed by other investigators for determining the fixed potassium of soils and also of several new approaches, the approach found most promising — heating at 500° C for two hours — was investigated in considerable detail. It was found that on heating ammonium saturated soils, illite, and bentonite in this manner, substantial release of nonexchangeable or fixed potassium could be effected without breakdown of primary potassium minerals. Not all of the fixed potassium can be released in one heating, the amount thus released representing an equilibrium point related to the amount which still remains fixed.The procedure finally adopted consists in heating ammonium saturated soil at 500° C for two hours, then extraction of the potassium made exchangeable with ammonium acetate solution, and finally determination of the potassium in the solution by means of the flame photometer. This heating, extraction, and determination are repeated once, and from the amount of fixed potassium released during the second heating, the total amount of fixed potassium present may be calculated by use of a summation formula for a geometric progression. The method is simple and is adaptable to rapid analysis of large numbers of samples. On the basis of the results obtained with soils and minerals, it is believed that the method is reasonably specific for fixed potassium, and offers the possibility of being a practicable and reliable method.
Effectiveness and Recovery of Phosphorus and Potassium Fertilizers Topdressed on Meadows
Authors: Hanway John , Stanford George , Meldrum H. R. 
Published: July 2010

AbstractA two‐year experiment was conducted in which phosphorus and potassium fertilizers were topdressed each year on an alfalfa‐timothy meadow. In 1950, rates of 0, 60, and 120 pounds per acre of P2O5 and K2O were applied alone and in all combinations. In 1951 each plot was split with a factorial of 0 and 60 pounds per acre of P2O5 and K2O. Determinations of yield, botanical composition and chemical composition of the hay were made. Soil analyses were made to determine depth distribution of available nutrients in the soil.The soil was very low in “available” phosphorus and potassium and large increases were obtained from the fertilizer applications.There was competition between the alfalfa and timothy for both phosphorus and potassium. Alfalfa was the dominant competitor for phosphorus while timothy offered the most competition for potassium.Very efficient recovery of the topdressed phosphorus was indicated.The apparent recovery of applied potassium was as high as 100% from several treatments. The chemical data indicate that even the maximum application of 180 pounds of K2O per acre in the two years was not sufficient for maximum yield on this very potassium deficient soil.Soil tests at the end of the experiment indicate a considerable increase in “available” phosphorus in the surface layer from applications of 120 or more pounds per acre of P2O5. The residual effect of potassium applications could not be detected by soil tests.
Ion Activities and Osmotic Pressures in Clay‐Water Systems
Authors: Coleman N. T. , Jakobi W. J. 
Published: July 2010

AbstractOsmotic pressures of H‐, Na‐, and K‐bentonite suspensions were measured with an Adair osmometer. Measurable osmotic pressures were observed, but the values were quite small, ranging from 0.6 cm H2O for 1% Na‐bentonite to 4.2 cm H2O for 4% H‐bentonite. The ion activity difference across the osmometer membrane, calculated from the membrane potential and the ion concentration on the solution side, was large. The ionic osmotic pressure difference across the membrane, from the van't Hoff approximation, was much larger for all systems than was the observed osmotic pressure, leading to the conclusion that the membrane potential cannot be regarded as a measure of an electrostatic potential difference between a clay suspension and its equilibrium dialysate.Electrolyte mean activities of KCl solutions were consistently slightly smaller than in 2% K‐bentonite suspensions of the same normality of KCl. Mean activities of KCl in the clay suspensions were much smaller than K+ activities measured with a membrane electrode‐saturated calomel electrode cell.The osmotic pressure data and potentiometric data are interpreted as indicative of a spurious potential at a clay‐salt bridge junction.
Reaction of Phosphate with Kaolinite in Dilute Solution
Authors: Russell Glenn C. , Low Philip F. 
Published: July 2010

AbstractA typical adsorption curve obeying the Freundlich equation was produced by the adsorption of phosphate on kaolinite. By saturating the exchange complex of the clay with aluminum ions, phosphate adsorption was markedly increased indicating that exchangeable aluminum will react with the added phosphate. Reflectance‐wave length curves of aluminon‐treated kaolinite revealed the presence of aluminum ions or hydrous aluminum oxide films on the surface of natural kaolinite. This reactive aluminum was reduced by extraction of the clay with aluminum‐complexing reagents. The adsorption of phosphate was also reduced by the same treatment. Phosphate adsorption was further reduced by the presence of an aluminum complexing reagent in the phosphate solution reacting with the extracted clay. It was concluded that adsorbed aluminum precipitates the phosphate as an aluminum phosphate on the kaolinite surface.
Effect of Tillage Practices Upon Intake Rates, Runoff and Soil Losses of Dry‐Farm Land Soils
Authors: Diebold C. H. 
Published: July 2010

AbstractDuring the growing season, serious losses of water and soil occur on extensive areas of dry‐farm land in New Mexico, Colorado, and Utah due to poor surface soil condition and to the presence of tillage pans, usually at depths of from 3 to 8 inches. Studies were made of runoff and soil losses from plots containing 30½ square feet. Simulated 10‐year storms were applied to these plots to evaluate tillage practices.The following conclusions were made during these studies. Chiseling through the tillage pan every 12 inches reduced both soil and water loss more than cultivation with either sweeps or one way disks on deep, medium textured soils. Excessive runoff and erosion occurred where the chisel spacing was 5 feet, or where chiseling, sweeps, and oneway did not penetrate through the tillage pan.Runoff from snow on frozen ground causes serious losses of soil and water in northern Utah. A frozen watershed that had been chiseled lost 0.61 inch less runoff than a similar watershed that had been cultivated with a oneway disk. Medium textured soils high in silt, when frozen at high moisture contents, had slow intake rates, irrespective of tillage practices.
Correlation of Soil Moisture and Cotton Yields
Authors: Burnett Earl , Fisher C. E. 
Published: July 2010

AbstractIn a 22‐year experiment, the correlation between the yield of lint cotton and available soil moisture at three sampling dates and six sampling depths was determined. The most significant correlation was found to exist for the available moisture in the soil on May 20, the optimum date for planting cotton. The correlation between yield and soil moisture was slightly lower for determinations made on June 20, and much lower for those made on April 20. Eliminating the moisture content of the first foot of soil, which fluctuates greatly because of weed growth and evaporation, improved the relationships on all dates. The relationships were not improved by including the moisture in the fourth and fifth feet of soil — an indication that in most years the cotton plant obtains most of the water necessary for growth from the second and third feet of soil. The importance of deep moisture storage in cotton production under sub‐humid and semi‐arid conditions is discussed.
Influence of Factorially Combined Levels of Cations and Nitrate Ions Adsorbed on Ion‐Exchange Resins on the Nutrient Absorption by Plants
Authors: Welch H. V. , Wallace A. , Mueller R. T. 
Published: July 2010

AbstractThe interaction of different levels of cations and nitrate nitrogen adsorbed on synthetic exchange resins upon nutrient absorption by plants was studied in a pot experiment. A factorial design of three levels of cations and three of N was used. Ca, Mg, and K were supplied at the same ratio at all three levels and P and S were unvaried. Three successive plantings were made. These were lemon cuttings, oats, and oats and radishes together. These two species were seeded together because their roots have different cation‐exchange capacities. The adsorbed ions proved to be an excellent source of nutrients for the plants. A balance sheet was prepared for all nutrients removed by the crops. Yields were limited in the second and third crops by both N and cation levels. K proved to be the limiting cation. Ca and Mg absorption was depressed as the cation level increased because of increased K uptake. The m.e. of cations per 100 grams dry plant weight increased with increasing cation levels for two oat crops, but was more constant for a lemon and a radish crop. Increasing N levels resulted in increased N and in an increased total anion uptake, but resulted in depressed P and S uptake. The level of adsorbed N did not appear to influence the total cation content in lemon and radish, but there was a slight effect on oats, particularly in the first crop. The level of cations did not appear to influence the N or the m.e. sum of anions in the plants beyond the differences caused by yield variations. The cation‐anion ratios in the plants were much narrower than those in the nutrient medium. Increases in N tended to result in increased K and Mg contents in the lemon cuttings and in oats when the supply of cations was high. When the cation level was low for oats, and at all levels for radishes, increases in N tended to result in decreased K. The latter effect was partly related to K depletion at the low cation levels combined with yield increases due to N.
Chemical Characteristics of Certain Profiles of Alluvial Soils in the Lower Mississippi Flood Plain
Authors: Driskell B. N. 
Published: July 2010

AbstractThe soils of the lower Mississippi Flood Plain are derived from the Mississippi or Red River depositions. In certain areas these have been mixed. The soil constituents have been modified or changed entirely by time and environment.Profiles from the Iberia, Buxin, and Baldwin soil series were studied. The comparative results indicate that the Iberia was highest in exchangeable calcium and base saturation. Exchangeable magnesium and potassium were highest in the Buxin. Baldwin was lowest in total cation exchange.The Buxin series contained larger quantities of the oxides of iron, aluminum, magnesium, potassium and sodium as shown by analysis of the clay fraction than Iberia or Baldwin. Iberia was highest in calcium oxide and Baldwin highest in silica. The content of silica increased with depth for all profiles.The ratios of SiO2/R2O3, SiO2/Al2O3, SiO2/Fe2O3, SiO2/total bases, and carbon‐nitrogen varied with the soil series, depending upon the source of materials.X‐ray patterns indicate that montmorillonite and illite were the predominating clay minerals and varied with the particular series. The Iberia clay contained more montmorillonite than the Baldwin or Buxin, especially in the A and B horizons.The characteristic study of these series has been of value in establishing fundamental facts that can be used in soil classification. It is evident that these series generally differ in chemical and mineralogical properties; yet, certain similarities exist between certain profiles of different series.
Effect of Various Exchangeable Cation Ratios on Kinds of Fungi Developing during Decomposition of Organic Residues in Soil
Authors: Martin J. P. , Aldrich D. G. 
Published: July 2010

AbstractSoils varying widely in exchangeable Ca, Mg, K, Na and H ratios were prepared from Yolo loam and Hanford sandy loam soils. The effect of these ratios on the kinds of soil fungi developing during the decomposition of organic residues in the soil was followed at various intervals over a 200‐day incubation period.In general, the nature of the organic material added to the soils exerted a greater effect on the kinds of fungi developing than did the exchangeable cation ratios. In the absence of organic residues, the fungus population remained essentially the same in all soils over the entire incubation period. Upon the addition of organic residues, Penicillium nigricans, which was present in high concentrations in the check series (no organic residues), became increasingly dominant in the most‐acid soils. With few exceptions, other species became dominant in all other soils. The kinds of fungi becoming dominant depended on the nature of the organic residue added. The dominant species included Chaetomium sp., Cunninghamella bertholletiae, Fusarium spp., Monotospora brevis, Mucor spp., Sepedonium chrysospermum, Sporotrichum sp., Stachybotrys atra, and Stysanus stemonites. Some species developed quickly in large numbers and remained dominant for the remainder of the incubation period. Others developed in high concentration, then rapidly diminished in numbers or disappeared.
Simple Diffusion Well for Measuring Soil Specific Diffusion Impedance and Soil Air Composition
Authors: van Bavel C. H. M. 
Published: July 2010

AbstractStraight, cylindrical tubes, open at the lower end and inserted into the soil can serve a dual purpose. Measurement of the re‐entrance of oxygen into the tubes after they have been flushed with nitrogen permits a calculation of the specific diffusion impedance of the soil. Charts for computing purposes are given. Measurement of the composition of the gas in the well, after a suitably long equilibration time, is a convenient means for measuring the composition of the soil air at the depth of insertion of the well.The physical and mathematical aspects of the method are briefly presented and experimental proof is offered for the formulas that are derived.