bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen, Phosphorus, and Potassium Content of the Corn Leaf and Grain as Related to Nitrogen Fertilization and Yield
Authors: Bennett William F. , Stanford George , Dumenil Lloyd 
Published: July 2010

AbstractOn a series of eight nitrogen side‐dressing experiments in 1950, a study was conducted to determine the effectiveness of side‐dressed nitrogen on corn as shown by yield response and by the chemical composition of the corn leaf and grain. A wide range in response to nitrogen occurred. The application of nitrogen significantly increased the percent of nitrogen in the leaf on all experiments, whereas, the nitrogen content of the grain was significantly increased on only five of the eight experiments. Phosphorus percentage in the leaf was significantly increased due to nitrogen application on certain experiments; and these increases were associated with yield responses which proved to be independent of the nitrogen effect. That a definite relationship between yield and the nitrogen and phosphorus content of the leaf existed in these experiments was shown by determining the regression of yield on the content of these nutrients. Both of the regression coefficients were significant and the multiple correlation coefficient was highly significant. When the nitrogen percentage in the leaf reached the level of approximately 2.8 or above, further increases did not appear to affect corn yields. A very striking linear relationship was found to exist between increases in yield resulting from nitrogen fertilization and associated increases in the nitrogen content of the leaf, the correlation coefficient being 0.96. The results of plant analysis suggest that phosphorus deficiency was a factor limiting yields on four of the experiments. Chemical soil tests for available phosphorus did not distinguish between five of the experiments which, however, appeared to differ in phosphorus status on the basis of phosphorus content of the leaf. In these experiments, leaf analysis provided a clearer indication of the nutrient status of the plants than did grain analysis for all three nutrients.
Nine Essential Amino Acids in the Protein of Wheat and Barley Grown on Sulfur‐Deficient Soil
Authors: Renner Ruth , Bentley C. F. , McElroy L. W. 
Published: July 2010

AbstractThe investigation was undertaken to study the possible effects of fertilizers and cropping systems on the quality of grain protein as measured by total content and proportions of nine essential amino acids. Amino acid determinations were made on acid hydrolysates of ground grain using a microbiological assay method.All grains were grown on sulfur‐deficient gray wooded soil. Most of the samples were from plots originally laid out in 1930 for long term tests to compare the effects on crop yields of various fertilizers applied in a wheat‐fallow cropping system and in a rotation in which mixed legume hay was grown in two years out of five.The protein content of wheat grown in the rotation was higher than that of wheat from the wheat‐fallow plots and the barley grown the first year after legumes contained more protein than that grown the third year after legumes. Increases in percentage of protein (N × 6.25) in the grains were associated with some decrease in quality as measured by the percentage that nine essential amino acids contributed to the protein. This decrease in quality was less marked in grains from rotation plots to which fertilizers containing sulfur were applied than in those from plots treated with fertilizers that did not supply sulfur.
The Behavior of Applied Phosphorus and Potassium in Organic Soil as Indicated by Soil Tests and the Relationship between Soil Tests, Green‐Tissue Tests and Crop Yields
Authors: Bigger T. C. , Davis J. F. , Lawton Kirk 
Published: July 2010

AbstractPhosphorus and potassium were extracted from organic soils by rapid test methods using 0.1 N HCl — 0.03N NH4F, 0.135 N HCl, and 0.018 N CH3COOH for phosphorus and 23% NaNOa, 0.135 N HCl, and 0.018 N CH3COOH for potassium. The extractable phosphorus was determined by a colorimetric method and the extractable potassium was determined with a flame photometer, except for the sodium nitrate extracts in which case a cobaltinitrite procedure was employed.A highly significant correlation exists between the amount of phosphorus and potash applied and the amount of phosphorus and potassium extracted from the soil. Applied phosphorus remained in the surface soil while potassium was found in the 12 to 18‐inch depth.Periodic green‐tissue tests of sugar beets and peppermint revealed a seasonal variation in the composition of water extractable phosphorus and potassium in these plants. Sugar beets contained 1,800 ppm and peppermint 1,000 ppm of potassium when the plants showed foliar symptoms of potassium deficiency.In correlating rapid soil tests, green‐tissue tests, and crop yields, it was impossible to establish optimum levels of phosphorus and potassium for maximum yields of sugar beets and peppermint because of the following factors: the physiological nature of the plants, the seasonal variations in plant composition, the differential response of the crops to the fertilizer ratios, and the limitation of the fertilizer analyses and rates of application in this experiment.
Recording Soil Moisture Automatically
Authors: Korty B. L. , Kohnke H. 
Published: July 2010

AbstractA method utilizing nylon blocks and an automatic recording potentiometer equipped to record resistence by means of a special ohmmeter circuit was used to follow continuously the moisture content of the soil. The information obtained was used in correlation with rainfall data to estimate the time required for water to reach various depths in the soil.The results show that water moved downward more rapidly on a watershed where conservation practices were used than on a prevailing farm practice watershed.An automatic instrument of the type used in this work that follows soil moisture conditions would be of great value in many research problems.
A Method for Determining the Stability of Soil Structure Based Upon Air and Water Permeability Measurements
Authors: Reeve R. C. 
Published: July 2010

AbstractA method is described for determining the stability of soil structure based upon intrinsic permeability, the measurement being made first with air, and then with water. The change in permeability is attributable to the instability of the soil to the wetting and slaking action of the water.Procedures and equipment for making tests with fragmented samples are described. Experimental data which show that the permeability ratio, air to water, is correlated with treatments known to produce differences in structural stability, are presented for both fragmented samples and soil cores. The air‐water permeability ratio is shown to be correlated with both the exchangeable‐sodium‐percentage and clay content of soils. The effect of a polymeric soil conditioner of the type VAMA (Vinyl acetate‐maleic acid) in stabilizing the structure of alkali soils, is reflected in the permeability ratio determination.The permeability ratio for soils varies over a range of from slightly greater than 1 to 10,000 or more. This large range permits effective appraisal of soil treatments that affect soil stability.On the basis of the reported tests, it appears that at the 20 to 1 level of odds, single determinations of the permeability ratio will distinguish a 45% difference for fragmented samples and a 185% difference for cores.The permeability ratio expresses in a single dimensionless number the effects of many factors and processes that influence the stability of soil structure. It is an integrated measure of the effects of swelling, slaking, dispersion, and other processes that take place to change soil structure as a result of wetting with water.
Mica Weathering Sequence in the Highfield and Chester Soil Profiles
Authors: Jeffries C. D. , Rolfe B. N. , Kunze G. W. 
Published: July 2010

AbstractThe paper consists of the description of a procedure for determining the nature of the micas in soils and the application of this procedure to the study of the weathering characteristics of the micas in the Highfield soil profile from Pennsylvania and the Chester soil profile from Virginia. The results of this study indicate a definite type of weathering sequence of the micas, which consists of mica — mica intermediate, to hydrated mica to chlorite — kaolin.
The Feeding Power of Plants for Phosphates
Authors: Fried Maurice 
Published: July 2010

AbstractPlant species were compared as to their feeding power for both monocalcium phosphate and rock phosphate. Even after the effect of size and extensiveness of the root absorbing surface was eliminated, species differed in their capacity to absorb phosphorus from basic calcium phosphates. The phosphorus of rock phosphate was most available to buckwheat and was more available to the legumes, alfalfa, crotalaria, and ladino clover, than to the grasses, orchard grass, bromegrass, perennial ryegrass, millet and oats.
Iron Oxide Removal from Soils and Clays
Authors: Aguilera N. H. , Jackson M. L. 
Published: July 2010

AbstractIron oxide coatings or crystals must be removed from soils in which they are found in many mineralogical techniques for identification of colloidal layer silicates as well as the identification of silt and sand grains with the polarizing microscope. A procedure is presented which employs sodium dithionite (Na2S2O4, hyposulfite, or “hydrosulfite”) as the reductor, and 0.3 molar citrate with or without Fe‐3 specific Versene as the chelating reagent. It is a neutral system the pH of which is kept at 7.3. The reaction is fast, as much as 20% of iron oxides (hematite, geothite, or limonite but not magnetite or ilmenite) being removed from a soil in 15 minutes, and does not precipitate either elemental sulfur or iron sulfides. Like other procedures, it causes some decrease of exchange capacity of layer silicates which contain iron, and at the same time may increase the exchange capacity of kaolinic soils.
Influence of Rate of Plant Residue Addition in Accelerating the Decomposition of Soil Organic Matter
Authors: Hallam M. J. , Bartholomew W. V. 
Published: July 2010

AbstractThe addition of corn and soybean residues to soils increased the rate of decomposition of the native soil organic matter. The residues were comparable to green manure crops and the data provide an explanation for the failure of green manures to be helpful in building or maintaining the organic matter content of soils.Plant materials containing radioactive carbon were added to soils at the rates of 2.5, 10 and 50 tons per acre. The use of the isotopes permitted a partition of the evolved CO2 into that coming from the plant residue and that coming from the soil organic matter.The high rates of residue addition resulted in greater losses of native soil organic matter than did the low rate. Corn and soybeans were similar in their influence on the decomposition of soil carbon.The rate of plant residue addition had a marked influence upon the rate of residue decomposition. At the rate of 2.5 and 10 tons per acre the decomposition of residue was considerably more rapid than when added to soil at the rate of 50 tons per acre. Residues apart from soil decomposed at about the same rate as when added to soil at the rate of 50 tons per acre.
Characteristics of Certain Soils in the Dominican Republic
Authors: Veale P. T. 
Published: July 2010

AbstractThis study summarizes the first soil survey on sugar estates in the Dominican Republic. The soils are characterized and classified. Illustrations of soil profiles, and diagrams showing their topographic occurrence are included. A rather close relationship was found between soil characteristics and root growth of cane. Study of root growth in relation to soil properties was helpful in evaluating the agriculture potentialities of the various soils.
A Basis for Improving the Soil Classification in the Seaward Portion of the Atlantic Coastal Plain
Authors: Ligon W. S. , Lyford W. H. 
Published: July 2010

AbstractField studies and historical reviews of some 47 soil series in the seaward portion of the northern Atlantic Coastal Plain led to the use of five general principles in improving the soil classification in that particular area:

The older, widely known soil series names shall be given preference over newer ones whenever feasible.

Soil series shall not be differentiated on the basis of marine terrace height (or age) per se.

Range in subsoil texture of each series shall be consistent and of reasonable magnitude.

Each drainage sequence shall consist of soil series reasonably comparable in subsoil texture.

Differences in substratum texture that constitute the sole differentiating feature between soils shall be considered as phase differentia rather than series differentia.

Each of these principles is discussed with reference to problems of soil classification in the area and a partial key showing drainage and subsoil texture relationships among 30 of the soil series is given.
Correlation of Phosphorus Content of Alfalfa with pH and Forms of Soil Phosphorus
Authors: Hallock D. L. , Attoe O. J. 
Published: July 2010

AbstractA study was made of the availability to alfalfa of acid soluble and alkali soluble inorganic and organic soil phosphorus. Samples of both soil and alfalfa were taken from experimental plots and farm fields located on eight soil types.In the case of the plot samples, it was found that the content of acid soluble soil phosphorus in 1948 and soil pH in 1949 were the variables most closely related to the phosphorus content of the alfalfa. Out of 22 cases of significant correlations of the phosphorus, 2 were with soil pH, 8 each with the acid soluble and alkali soluble inorganic forms and 4 with the alkali soluble organic form.When the silt loam soils were divided into two pH groups, those below 7.0 and those of 7.0 and above, the contents of acid soluble and alkali soluble inorganic phosphorus were the forms most closely (and about equally) correlated with the phosphorus content of the alfalfa for both groups.
A Comparison of the Effects of Exchangeable Sodium and Potassium upon the Physical Condition of Soils
Authors: Reeve R. C. , Bower C. A. , Brooks R. H. , Gschwend F. B. 
Published: July 2010

AbstractThe effects of exchangeable sodium and of exchangeable potassium upon soil physical condition were compared by means of permeability ratio, air to water, and modulus of rupture determinations. The permeability ratio is a measure of the change in pore‐size distribution due to the action of water and the modulus of rupture is a measure of soil crusting. The permeability ratio and modulus of rupture increased markedly with increasing exchangeable‐sodium‐percentage, whereas, increases in the exchangeable‐potassium‐percentage had little effect. The relation of the permeability ratio to exchangeable‐sodium‐percentage can be expressed by an exponential equation of the form, y = aebx, whereas, the modulus of rupture is linearly related to exchangeable‐sodium‐percentage by the equation y' = mx + c. The parameters a, b, m and c of the respective equations are positively correlated with cation exchange capacity and total specific surface.
Sand‐Model Experiments on the Distribution of Water‐Pressure under an Unlined Canal
Authors: Day Paul R. , Luthin James N. 
Published: July 2010

AbstractA study has been made of the seepage of water by capillary flow (movement at pressures less than that of the atmosphere). The analysis differs markedly from previous theories of seepage which ignore capillary movement.An idealized flow system, which consisted of parallel furrows in soil overlying a gravel substratum, was postulated in the theory and simulated experimentally in a sand model. Pressures were measured tensiometrically. The water pressure found at various points in the sand model in the steady state agreed approximately with values calculated from theory.The theory is applicable only to certain simple cases. However, the results show clearly that under certain conditions capillary flow accounts for the entire seepage flux. In such cases, the reduced pressure of the water prevents its entry into test holes placed in the seepage zone.
A Study of Adaptation in Azotobacter
Authors: Harris John O. 
Published: July 2010

AbstractThe age of cells was shown to be an important factor in the rate at which Azotobacter chroococcum adapts its respiratory mechanism to the utilization of different substrates. These organisms are able to utilize dilute (M/400) solutions of glucose or mannitol for respiration. Experiments measuring oxygen uptake and dehydrogenase activity of intact cells indicated that simultaneous oxidation of two substrates is possible by partially adapted cells. Studies of enzymatically active cell‐free extracts showed that the Kreb's cycle of terminal oxidation probably occurs in Azotobacter chroococcum. Glucose and mannitol dehydrogenases appeared to be formed only when these compounds were present. This was interpreted as evidence that at least part of the adaptation process is due to formation of new enzyme systems.
Modification in Chemical Properties of Straw during Decomposition
Authors: Broadbent F. E. 
Published: July 2010

AbstractOat straw samples were allowed to decompose for periods varying up to 15 months; changes in functional groups and chemical properties followed as a function of time. Carbon increased in the whole residues and decreased in the lignin fraction while hydrogen decreased in both. Selective demethylation occurred in the lignin but methoxyl content of the complete residues remained about constant. Carboxyl groups as determined by esterification increased progressively, accompanied by decreases in hydroxyl. Carboxyl in the lignin fraction was in good agreement with exchangeable hydrogen determined by an iodometric titration procedure in contrast to lack of agreement between corresponding values in the whole residues. Cation exchange capacity of the straw residues and of their lignin component increased as decomposition progressed.Absorption of oxygen by alkaline suspensions of the residues was determined in a Warburg respirometer and found to increase with length of decomposition period. Most of the total oxygen uptake during an arbitrary 8‐hour period could be attributed to the lignin fraction.Some chemical properties of organic matter preparations from five soils were compared with corresponding values for the decomposed residues.
The Adsorption and Reactions of Enzymes and Proteins on Kaolinite. II
Authors: McLaren A. Douglas 
Published: July 2010

AbstractSome preliminary data illustrating the role of adsorption of enzymes and proteins to kaolinite in enzyme‐substrate reactions are presented. The adsorption of trypsin and chymotrypsin on kaolinite is nearly complete within 2–3 minutes. Over 40 mg. of chymotrypsin (MW 27,000) is adsorbed per gram of kaolinite whereas only 28 mg. of lysozyme (MW 15,000) is adsorbed. Much less chymotrypsin is adsorbed on kaolinite previously nearly covered by lysozyme. Heat‐inactivated lysozyme either in solution or adsorbed on kaolinite is subject to hydrolysis by chymotrypsin. The rate of hydrolysis is slower in the adsorbed state, however. Adsorbed trypsin is slowly hydrolyzed by free trypsin in a suspension of kaolinite. Thus substrates adsorbed on kaolinite are subject to hydrolysis by enzymes in solution. Lysozyme and trypsin eluted from kaolinite with ethylamine are active as enzymes. The possible significance of such findings for an understanding of the microbial utilization of macromolecules in the presence of clay minerals is discussed.
The Origin of Mima Mound (Hogwallow) Microrelief in the Far Western States
Authors: Arkley Rodney J. , Brown Herrick C. 
Published: July 2010

AbstractThe origin of the mound microrelief known by such names as “hogwallows,” “pimple mounds” or “mima mounds” has long been a mystery; although many solutions have been proposed, none has yet received widespread acceptance.During the course of the soil surveys of eastern Merced and Stanislaus Counties of California, where mound microrelief is widespread, the phenomenon was studied over a period of eight years. All known theories were evaluated and compared with the evidence which could be observed in the field. The evidence includes the nature of the mounds such as shape, size, internal structure, distribution of gravel, the burrows of ants and rodents; the distribution of the microrelief with respect to soil types and the pattern of occurrence of mounds under various conditions.The theories of origin which were tested included erosional theories based on wind action and water action, fluviatile, submarine and sub‐lacustrine currents; eruptional theories suggesting gas‐vents, sand boils and hydrostatic pressure; and biological theories based upon the activity of ants, ground squirrels and pocket gophers.It is concluded that the evidence points clearly to a biological explanation, and that the pocket gopher is responsible for Mima mound microrelief.
The Regur Soils of India and Their Utilization
Authors: Simonson Roy W. 
Published: July 2010

AbstractThe Regur or Black Cotton soils of India seem to be members of the same great soil group as the Houston Black and Houston series of Texas, on the basis of field studies by the author in the Deccan plateau in 1951. Similarities between the soils on the separate continents are evident in morphology, contents of organic matter, clay minerals, carbonate content and distribution, and the high coefficients of expansion and contraction upon wetting and drying. Like Houston Black clay, the Regur soils are widely used for cotton, although much greater acreages of the soils, with a total area equal to that of the Corn Belt, are devoted to sorghum, pearl millet, pulses, and other food crops. Agricultural production is largely dependent upon animal power and human labor, with little benefit from products of heavy industry such as tractors, fertilizers, insecticides, and the like. Yield levels for most crops are low as compared to those in the United States, although yields have been stable at these low levels for centuries. Higher levels of production will require substantial changes in the agicultural arts and in the technological and industrial resources available to and used by the cultivators of the Regur soils.
Rainfall Intensity as a Measure of Storm Erosivity
Authors: Ekern P. C. 
Published: July 2010

AbstractThe erosivity of storms should be proportional to the additive kinetic energy from the impact of falling rain and shallow flow of water. The erosivity of shallow water should be proportional to the proximity of the maximum velocity thread to the soil surface and the square of that maximum velocity. Relations among velocity, slope, and discharge suggest the following function for erosivity:Erosivity = f [(discharge rate)1.0 (slope)1.0]Evaluation of data suggested that the relation was reasonable, though a slightly higher value than the first power of the discharge was generally found.When discharge in turn was related to rainfall intensity, the erosivity for shallow flow became:Erosivity = f [(storm intensity)1.46 (slope)1.0]The impact energy of rainfall was found to be a nearly identical function of intensity and slope so that the additive energy of shallow flow and drop impact should approximate the 1.5 power of the storm intensity.Examination of the envelope for maximum soil loss from fallow plots of silt loam on 16% slopes at LaCrosse, Wis., showed such a relation to the 1.5 power of the rainfall intensity.