bluuebunny/crossref_metadata_2025 huggingface dataset:
Transformations and Movement of Urea in Soils
Authors: Broadbent F. E. , Hill G. N. , Tyler K. B.
Published: July 2010

Samples of several California soils were incubated in a controlled environment chamber after addition of varying amounts of urea in solution. Samples were analyzed after time intervals ranging from 1 day to 8 weeks. In short‐term experiments analyses for residual urea were performed at frequent, short intervals, and in longer‐term experiments nitrification of the hydrolysis product was followed. At 45°F., 200‐ and 400‐ppm. amounts of urea were completely hydrolyzed after 7 days, although some urea remained after 3 days. At 75°F., no urea remained after 2 days when the initial application was 400 ppm or less. At 800 ppm., considerable urea remained at 3 days but none at 14 days.

Urea was rapidly nitrified in all soils at moderate levels of application but was inhibited in the poorly buffered Hanford sandy loam by the 800‐ppm. application, due to the high pH produced.

Leaching experiments with soil columns showed that urea moves less rapidly than nitrate, partly because of rapidly hydrolysis to ammonia and partly because urea itself is held by weak absorption forces.
Restoration of Soil Structure with Redtop and Other Sod Crops
Authors: Wisniewski Adam J. , Salomon Milton , Smith John B.
Published: July 2010

Water‐stable aggregates, soil organic matter, bulk densities, and soil moisture retention at 50‐cm. tension were determined for a Bridgehampton silt loam following various treatments involving sod crops in rotation with potatoes and continous potatoes.

An overall positive correlation was found between organic matter and aggregation. Although plots that were in a redtop‐potato rotation were significantly better aggregated than those in a red clover‐potato rotation and plots in continous potatoes, increased aggregation was not always accompanied by an increase in total soil organic matter. This implied that the type of soil organic matter resulting from the decomposition of redtop is more effective in promoting water‐stable aggregates than either the native organic matter or that resulting from the decomposition of other plant residues studied. Potato yields appear to be more a function of aggregation than of total soil organic matter. Some evidence exists that the decomposition of native organic matter has been hastened by the addition of redtop residues. A microscopic examination of aggregates > 5 mm. shows that roots are partly responsible for binding some of the smaller aggregates into larger ones.
Soil Nitrogen Accumulation Under Black Locust
Authors: Ike A. F. , Stone E. L.
Published: July 2010

Soil nitrogen accumulation beneath stands of black locust, a leguminous tree, was studied at four locations in Tompkins County, N. Y. Adjacent areas identical in prior treatment served as controls. Significant increases were found under three 16‐ to 20‐year‐old plantations but not under a 5‐ to 10‐year stand. These changes extended below the 0‐ to 7‐inch depth, with total nitrogen increases of approximately 600 pounds per acre in the 0‐ to 20‐inch layer.

In a greenhouse study of availability, Sudangrass cultures were able to absorb somewhat larger amounts of nitrogen from soils under locust. Measurement of nitrogen in ground vegetation and estimates of return by locust foliage indicate an annual turnover in excess of 50 pounds per acre.
Urea‐Formaldehyde Fertilizer as a Source of Nitrogen for Cotton and Corn
Authors: Scarsbrook C. E.
Published: July 2010

Three formulations of experimental 12‐12‐12 grade fertilizer, each containing a portion of the nitrogen as ureaformaldehyde, were compared with ammonium nitrate as sources of nitrogen for cotton and corn. The 12‐12‐12 used in 1955 contained 38% of the nitrogen as urea‐formaldehyde with an availability index of 20; in 1956 two formulations were used with urea‐formaldehyde percentages of 35 and 36 and availability indices of 49 and 57, respectively. Ammonium nitrate produced higher yields than equivalent rates of nitrogen from fertilizer containing urea‐formal‐dehyde. Nitrogen contents of corn leaf samples and of grain were higher where ammonium nitrate was the source of nitrogen. The residual value of nitrogen on oat forage following cotton was determined. Urea‐formaldehyde with an availability index of 49 had the greatest residual effect. However, the residual effect from ammonium nitrate was greater than from the index‐20 material.
A Study of Fragipans in Some Southern Indiana Soils
Authors: Anderson J. U. , White J. L.
Published: July 2010

Fragipans or “X” horizons have been recognized in highly weathered soils of southern Indiana for more than 30 years. They occur at depths of 2 to 4 feet, and are most common in imperfectly and moderately well‐drained soils.

Profiles of three highly weathered soils of the residual area of southern Indiana were selected for study. A fourth profile which did not have a fragipan, but was formed from similar parent material was sampled for comparison. Detailed chemical and mineralogical studies were made on the nonfragipan profile and one of the fragipan profiles.

Each of the soils with fragipans had a pH of 4.5 or less in the B horizon. The profile without a fragipan had a minimum pH of 5.6. Horizons of one fragipan profile were shown to contain iron oxide as a cementing agent. The clay of the fragipan was found to be lower in montmorillonite than the clay from comparable horizons of the profile without a fragipan. Only a small portion of this montmorillonite from the fragipan was capable of expansion without sample pretreatment.
Chemical Behavior of Monocalcium Phosphate Monohydrate in Soils
Authors: Lehr James R. , Brown Walter E. , Brown Earl H.
Published: July 2010

To gain an insight into the phenomena that are initiated when superphosphate is placed in soil, tablets containing monocalcium phosphate monohydrate were placed in several soils and observed directly. Petrographic examinations and supporting chemical studies gave information on chemical reactions associated with the dissolution process and on the transport of materials to and from the tablet—factors that bear upon the distribution and chemical combination of the phosphorus and thus upon agronomic response.

The results suggest that capillary flow was a principal mechanism in the movement of phosphate solution away from the tablet. Vapor‐phase transport of water to the tablet apparently controlled the rate of dissolution. A significant part of the P remained at the tablet site as dicalcium phosphate, anhydrous or dihydrated. The dissolution process was affected by soil type, soil moisture content, humus content, microbiological activity, capillarity of soil and tablet, time, and temperature.
Determination of Sodium in Saline Solutions With a Glass Electrode
Authors: Bower C. A.
Published: July 2010

An experimental sodium alumino‐silicate glass electrode supplied by Beckman Instruments, Inc., was studied to determine its sensitivity to the cations commonly found in irrigation waters and in water extracts of soils. The electrode was found to be insensitive to Ca++ and Mg++ but sensitive to Na+, K+ and H+, giving theoretical relations between EMF's and cationic activities for the latter.

A procedure for determining Na in waters and saturation extracts with the electrode is described. It involves dilution of the sample so that the total cation concentration does not exceed about 10 me. per liter, adjustment of the pH value to approximately 7, and precipitation of K as K tetraphenylboron. The Na concentrations of irrigation waters and saturation extracts of soils as determined by the electrode and by flame photometry agree closely.
Strontium and Calcium Contents of Crop Plants in Relation to Exchangeable Strontium and Calcium of the Soil
Authors: Menzel R. G. , Heald W. R.
Published: July 2010

The relative uptakes of Sr and Ca were determined for crops grown in the field and greenhouse. Exchangeable Sr and Ca contents were determined in 93 plow layer samples representing 51 soil types in 11 widely scattered states. The average ratio was 1.3, with a range of 0.2 to 4.0, Sr atoms per 1,000 Ca atoms. The ratio varied more according to area than according to type of parent rock, and was similar to the ratio in surface water supplies. The ratios of Sr and Ca in alfalfa or wheat grown in the field were nearly equal to those in the exchangeable cations of the soil. Ten species of cultivated plants grown on 4 soils in the greenhouse had Sr and Ca ratios averaging 0.7 times those of the exchangeable cations in the soils. Small, but statistically significant, differences in relative Sr and Ca uptakes were found with different crops and soils.
Phosphorus Solubility in Calcareous Soils: II. Effects of Exchangeable Phosphorus and Soil Texture on Phosphorus Solubility
Authors: Cole C. V. , Olsen S. R.
Published: July 2010

P solubility expressed as the mean activity of dicalcium phosphate in equilibrium solutions increases regularly with the amounts of P adsorbed in the monolayer region on the surfaces of various materials likely to be present in calcareous soils. Values of the mean activity of dicalcium phosphate in equilibrium soil solutions increased as a direct function of the amount of phosphate added as concentrated superphosphate. Differences in P solubility behavior between soils of varying texture are explained by measurements of the surface area and the capacity of the soils for monolayer adsorption of P.
Some Growth Responses of Tomatoes to Soil Compaction
Authors: Flocker W. J. , Vomocil J. A. , Howard F. D.
Published: July 2010

Compression of soil reduces the size and arrangement of soil air spaces. When this process is carried beyond certain limits it results in an overall inhibition of some of the physiological processes of plant growth.

A greenhouse experiment was designed to determine some of the effects of reduced soil air spaces on growth of tomatoes. Three soils—Yolo fine sandy loam, Salinas clay loam, and Sacramento clay—were compressed hydraulically into 1‐gallon cans to air spaces varying from 42 to 2%. Percentage of germination, velocity of emergence, blossoming, rate of growth, and yield data were taken. Results showed that compacting soil to a certain density increased percentage of germination, but that compression beyond this point seriously reduced the percentage of germination. Compacting the soil increased the time required for seedlings to emerge. Blossoming was delayed as density increased for all three soils tested. Growth curves were plotted for some densities on the soils with the maximum rate of growth occurring at different plant ages, depending on soil air space. Reduced air space retarded growth in all three soils as measured by total height and the weekly change in height.

The relationship between soil air space and total plant height was plotted. A curvilinear regression was found to be highly significant. Optimum air space for maximum height was calculated to be about 30%.
The Relation of Temperature and Phosphate Placement to Growth of Clover
Authors: Robinson R. R. , Sprague V. G. , Gross C. F.
Published: July 2010

The effect of placement of mono‐calcium phosphate on P availability to red clover seedlings was determined at 50°, 60°, 70°, and 80°F. in controlled temperature chambers. Band applications of phosphate, as compared with phosphate mixed with the soil, were much more effective at low temperatures than at higher temperatures. This is attributed to the effect of temperature on rate of P uptake by the plant. Where only small amounts of phosphate were mixed with the soil, the level of available phosphate was low and growth at low temperature was very poor. With increasing temperature, the rate of P uptake increased markedly and plant growth increased. It would appear that the more rapid uptake of P at higher temperature is associated with the temperature coefficient of absorption rather than with an increase in P concentration in the soil solution. Thus, as the temperature increases, plants apparently are able to absorb P more rapidly from soil solutions containing very small amounts of P. Band applications of phosphate greatly increase the concentration of phosphate in the root zone, and therefore the effects of temperature on rate of P uptake become less important.
Soil Organic Matter: I. Electrophoretic Separation of Acid‐Resistant Components
Authors: Johnston Harry H.
Published: July 2010

Two acid‐resistant fractions were isolated from three soils, a Sims clay loam, a Houston Black clay, and a Xenia silt loam. The fractions were separated by paper electrophoresis and analyzed for functional groups by infrared spectra. One component was a dark‐colored nonfluorescent material and the other a yellow fluorescent water‐soluble material. Chemical analysis of the darker humic acid obtained from the Xenia silt loam gave the following results: C, 52.48%; O, 38.38%; H, 4.65%; N, 1.98%. This material was found to contain 6.7% methoxy groups. Infrared spectra of the two fractions showed them having a different structure, but both materials were throught to contain hydroxyl and carbonyl groups. The N content of the dark‐colored fraction separated by electrophoresis was 1.98% for the Xenia and Sims soils and 1.79% for the Houston soil. Because of the similarity of these materials in infrared spectra and N content, it is believed that these acids are of fundamental importance in the structure of soil organic matter.
Evaluation of Two Methods of Measuring Available Soil Copper and the Effects of Soil pH and Extractable Aluminum on Copper Uptake by Plants
Authors: Blevins R. L. , Massey H. F.
Published: July 2010

The relationship between Cu uptake by millet grown in the greenhouse on 34 Kentucky soils and the available Cu in the soil as determined by the versenate procedure of Cheng and Bray and an adaptation of the dithizone procedure for Zn of Shaw and Dean was studied. The pH of the soil and the Al extracted by 0.1N CaCl2 were also correlated with Cu uptake.

Highly significant correlations between both methods for available Cu and Cu uptake by the millet plants were obtained, but the relatively low values of the correlation coefficients indicate that neither procedure adequately measures available soil Cu. There was no correlation between soil pH and Cu uptake. Al extracted by 0.1N CaCl2 was inversely correlated with Cu uptake. The uptake of Cu by wheat plants was decreased by Al concentrations of 0.4 to 1.0 ppm. in short term solution‐culture experiments. An Al concentration of 0.1 ppm. appeared to increase the uptake of Cu.
Diffusivity of Soil Water During Sorption as Affected by Temperature
Authors: Gardner W. R.
Published: July 2010

The sorption diffusivity at saturation and at the air‐dry water content has been measured for five soils of different textures as a function of temperature. Near saturation, the viscosity effect is predominant. At low water contents, the effect of temperature upon the suction becomes important and in some cases exceeds the viscosity effect. The hysteresis effect is often as large or larger than the temperature effect. For many purposes it may be acceptable to assume the diffusivity and capillary conductivity to be independent of temperature, at least at normal laboratory and field temperatures.
Drain Depth and Spacing Effects on Water Removal from a Gray‐Brown Podzolic Soil
Authors: Goins Truman , Taylor George S.
Published: July 2010

The effect of two depths and two spacings of drains on tile flow rates and drawdown in a glaciated Ohio soil were evaluated. Drain depths were 2 and 3 feet, and the spacings were 30 and 60 feet.

Flow rates were linearly related to the water table (WT) level at the midpoint between drain lines. Tile flow was more closely related to the position of the WT in the profile than to the height of the WT above the drain, indicating the strong influence of the conductivity profile in drainage. The highest flow rates were obtained from drains at the 2‐foot depth; while spacing had no significant influence on maximum flow rates. Drains at the 2‐foot depth lowered the WT faster in the upper 18 inches of soil than did those at the 3‐foot depth; and drains spaced 30 feet apart were more effective in lowering the WT than those spaced 60 feet. The relative performance of the drains at 2‐ and 3‐foot depths was a result of decreased soil hydraulic conductivity with depth.

Estimates of soil hydraulic conductivity based on drain flow and WT levels showed that the auger hole and the O'Neal methods underestimated the conductivity by factors no smaller than 4 and 2, respectively.
Equilibrium of Soil Grains at the Threshold of Movement by Wind
Authors: Chepil W. S.
Published: July 2010

This paper, based on wind tunnel studies, presents an analysis of the nature and magnitude of forces on soil grains at the threshold of their movement by wind. Forces of drag, lift, and gravity were analyzed in relation to each other.

The equilibrium between these forces and the soil grains was found to be influenced by the diameter, shape, and immersed density of the grains, the angle of repose ø′ of the grains with respect to the mean drag level of the fluid, the closeness of packing η of top grains on the sediment bed, and the impulses of fluid turbulence TD and TL associated with drag and lift, respectively. All those factors were measured and related with actual and theoretical forces involved.

New approaches to measurement of η, ø′, TD and TL are presented. Analyses indicate that the magnitude of pressure impulses of both TD and TL is statistically distributed according to the somewhat skewed normal error law. The ratio of mean pressure to standard deviation σ was constant for any size of grains or fluid velocity and could be expressed by equation σ = cP̄ in which P̄ is the mean pressure of lift or drag and c is a constant which was found to have a mean value of 0.49.
Nature of the Reactions of Monocalcium Phosphate Monohydrate in Soils: IV. Repeated Reactions With Metastable Triple‐Point Solution
Authors: Lindsay W. L. , Stephenson H. F.
Published: July 2010

A series of soil samples was reacted repeatedly, first with solution saturated with respect to Ca(H2PO4)2 · H2O and CaHPO4 · 2H2O (MTPS), and later with water, in an attempt to simulate the changing chemical environment of soil surrounding a superphosphate granule.

The reaction of MTPS with soil was accompanied by increase in pH and precipitation of Fe, Al, and Ca phosphates from solution. Soil repeatedly contacted by MTPS gradually became more acidic and showed continued dissolution of Fe and Al. Subsequent additions of water to the soil residues remaining after reaction with MTPS increased the pH and caused further precipitation of phosphate from solution. Many filtrates obtained during these reactions yielded precipitates upon standing. The following crystalline compounds were identified from these precipitates: CaHPO4 · 2H2O, H6K3Al5(PO4)8 · 18H2O, H8K(Al,Fe)3(PO4)6 · 6H2O, and CaHPO4. The indications are that these compounds may form as initial phosphate reaction products of superphosphate fertilizers in soils. Tentative conclusions are presented regarding the nature of the reactions of Ca(H2PO4)2 · H2O in soils.
Organic Matter Decomposition and Plant Nutrient Release from Incorporations of Soybean Hay and Wheat Straw in a Holston Sandy Loam in Outdoor Lysimeters
Authors: Shaw W. M. , Robinson Brooks
Published: July 2010

An acid Holston sandy loam, unlimed and limed to 60 and 100% base saturation, without organic matter and with soybean hay and wheat straw was placed in 1/20,000‐acre outdoor lysimeters which were exposed to weather and kept free of vegetation for a period of 3 years. Soil samples were taken at the end of each year and analyzed for organic matter and total N content. The leachates were analyzed for the annual outgo of Ca, Mg, K, S, N, and soluble organic matter.

A 2% soybean hay incorporation in a Holston sandy loam after a 3‐year exposure to weather and leaching has resulted in a net gain to the soil in percentages of the additives: 20% of organic carbon, 40 to 60% of N, and about 70% of the mineral nutrients. The soybean hay treatment resulted in a 10% increase in cation‐exchange capacity of the soil.

A shallow incorporation of the soybean hay (4 inches) resulted in a 50% greater retention, and a smaller (1/3) loss by volatilization of the nutrient N as compared to full‐depth incorporation.
Solubility of Dicalcium Phosphate Dihydrate in Aqueous Systems
Authors: Moreno Edgard C. , Brown Walter E. , Osborn Glen
Published: July 2010

The metastable solubility isotherm for dicalcium phosphate dihydrate, CaHPO4·2H2O, (DCPD), in the pH range 3.5 to 7.5 was established by (a) leaching solutions of dilute phosphoric acid through columns of DCPD, and (b) by shaking suspensions of DCPD in dilute phosphoric acid solutions.

In other experiments, equilibrium was approached both from undersaturated and supersaturated conditions. In both cases the final solution compositions were represented by points on the isotherm obtained by the methods mentioned above, and dissolution or precipitation occurred with a Ca/P ratio equal to one.

The solubility product constant of DCPD was found to be 2.77 × 10‐7 for all concentrations tested when appropriate corrections were made in the calculation of ionic activities.
Stability of Dicalcium Phosphate Dihydrate in Aqueous Solutions and Solubility of Octocalcium Phosphate
Authors: Moreno Edgard C. , Brown Walter E. , Osborn Glen
Published: July 2010

The hydrolysis of dicalcium phosphate dihydrate, CaHPO4·2H2O, in dilute phosphoric acid solutions and in water was investigated at 25° C. in the absence of CO2. Octocalcium phosphate, Ca4H(PO4)3·3H2O, was found to precipitate when the pH of the solution was higher than 6.38. The extent of the hydrolysis was larger the higher the initial pH of the solution. The solution composition followed the metastable solubility isotherm for dicalcium phosphate dihydrate until a singular point between octocalcium phosphate and dicalcium phosphate dihydrate was reached. At this point the solution had a pH of 6.38 and Ca and P concentrations of 1.36 × 10‐3M and 2.21 × 10‐3M, respectively. The solubility product of octocalcium phosphate was calculated to be (Ca)4(H)(PO4)3 = 1.25 × 10‐47.

Relative rates of solution and precipitation of both dicalcium and octocalcium phosphates are discussed. No formation of anhydrous dicalcium phosphate or hydroxyapative was detected in equilibrations for as long as 90 days, even though both of these compounds are more stable than dicalcium phosphate dihydrate under the experimental conditions.
Behavior of Free Amino Acids in Soil
Authors: Schmidt E. L. , Putnam H. D. , Paul E. A.
Published: July 2010

The behavior of a mixture of amino acids in a soil environment was studied. Extractions were made with 80% ethanol. The extract was concentrated and then was analyzed for amino acids by gradient elution chromatography. After 1 hour of soil contact in the cold, at least some of each amino acid could be recovered, but the extraction was not efficient. Replicate soil flasks to which amino acids had been added were incubated at 28° C. under conditions that allowed for both CO2 and amino acid analysis of the same flask. After 24 hours, substantial degradation had occurred but at least trace amounts of each of the added amino acids except threonine could still be detected. Beta alanine appeared on the 24‐hour chromatogram although it was not among the amino acids added initially. Results of both chromatographic analysis and CO2 collection suggested that nearly all of the added amino acids were degraded by the end of 96 hours. Separate studies using microbiological assay failed to confirm the persistence of threonine in soil as reported in the literature. The possibility that the beta alanine found in the soil environment was formed from aspartic acid decarboxylation was explored, but large additions of aspartic acid to soil did not result in substantial increases in beta alanine.
Ponderosa Pine Productivity in Relation to Soil and Landform in Western Montana
Authors: Cox G. S. , McConnell R. C. , Matthew L. M.
Published: July 2010

Forest soil productivity for growth of ponderosa pine (Pinus ponderosa Dougl.) in Montana west of the Continental Divide was studied. Data were obtained on 255 plots located in medium‐ to well‐stocked stands on 28 soil series and 9 landform types. Mean site indices for the soils studied ranged from 54 to 99 feet at 100 years.

Effective depth of soil in which tree roots might develop was the principal factor influencing tree growth. Four depth factors limited development of roots: depth to gravel or loose sand, depth to a slowly permeable layer, depth to bedrock, and depth to lime. Areas receiving supplementary moisture from seepage or high water tables were good sites for tree growth regardless of the type of soil involved.
Soil Capillary Conductivity: Comparison of Measured and Calculated Values
Authors: Nielsen D. R. , Kirkham Don , Perrier E. R.
Published: July 2010

Capillary conductivities were measured for two loess soils and two glacial till soils at four depths and at five values of water suction, up to and including 100 cm. of suction. For the same soils, curves of moisture content vs. suction were obtained and, from the latter data, capillary conductivities were calculated by the Childs and Collis‐George method and by the Marshall method. The values obtained by the Marshall method were all considerably higher than the measured values. Those obtained by the former method—a method which utilizes a matching constant to fit the experimental data at one point—agreed satisfactorily for the loess soils, but not for the glacial soils. Suctions as small as 25 cm. of water reduced capillary conductivities by as much as 10‐4 for the glacial soils. The reduction was not as marked for the loess soils. The theories tested had been developed for nonshrinking materials such as sieved sand and slate dust. The present results show that the use of one of the theories may be extended to agricultural soils, and that the other theory could also be so extended, if a matching constant were used.
Crystalline and Amorphous Soil Minerals of the Mississippi Coastal Terrace
Authors: DeMumbrum L. E.
Published: July 2010

Vernniculite and “allophane” are predominant clays of poorly drained Gulf coastal soils, while vermiculite and gibbsite are found in the better drained soil studied. Vermiculite present in both situations is interlayered with alumina, somewhat similar to that described by Rich in Virginia soils. Removal of the interlayer alumina allows collapse of the mineral, but no expansion beyond 14Å. The ability to fix large amounts of K was also induced by the treatment, indicating the vermiculitic nature of the mineral.

The presence of an amorphous, aluminous mineral was evident from the nature of the X‐ray diffraction patterns, chemical analyses and from electron photographs. The most direct means for its determination, however, was the use of an infrared absorption technique. A very strong 2.78 micron hydroxyl absorption maximum was observed in the colloid containing large amounts of alumina. The intensity of the absorption maximum was lessened as amount of the substance decreased.

Presence of these clays in soils derived from Recent or late‐Pleistocene marine sands may be explained by either of two alternate hypotheses: (a) glauconite weathering or (b) deposition of weathered micas in the presence of aluminous precipitate in semimarine environment. Either or both processes may have been operative.
Solubility and Availability of Micronutrients in Relation to Phosphorus Fertilization
Authors: Bingham Frank T. , Garber M. J.
Published: July 2010

Availability of B, Cu, Fe, Mn, Mo, and Zn in relation to excesses of Ca(H2PO4)2 was studied with sour orange seedlings as indicators for induced interactions created in 19 different soils. To separate the effect of the carrier from that due to phosphorus, Ca(H2PO4)2, H3PO4, KH2PO4, and NH4H2PO4 sources were also used in a separate experiment. Chemical analyses of water extracts from the latter experiment provided the solubility data as controlled by excesses of P.

Regardless of sources, excess P resulted in acute Cu deficiency; and in the case of acid soils, reduced uptake of B and Zn usually followed excess P fertilization. Excessive P fertilization of acid soils resulted in increased Mn and Mo uptake, whereas in alkaline soils excessive P reduced the availability of Mo. Solubility of Mn, B, and Mo Paralleled uptake data. Cu and Zn Solubilities were increased by excessive P fertilization. Mechanisms pertinent to the various P interactions are discussed with the major emphasis placed on P‐Cu antagonism.
Nitrate Production in the Field by Incubating the Soil in Polyethylene Bags
Authors: Eno Charles F.
Published: July 2010

Nitrate production was studied in the field by incubation of the soil in pint polyethylene bags during the 1958–59 winter season. This technique permits the diurnal changes in soil temperature to be taken into consideration in studying microbial processes, such as nitrification.

Laboratory studies showed that the rate of nitrification in soil contained in the bags was equal to that contained in ventilated bottles. The bags were tightly closed against the soil and secured with rubber bands. Only slight losses in soil moisture occurred during a 6‐week period of incubation. Polyethylene is permeable to oxygen and carbon dioxide. No nitrate difused through the polyethylene bags in a 24‐week period.

Field studies were made using bags of soil buried at a depth of 4 inches for periods of 1 to 6 weeks. Although soil temperatures at this depth were never below freezing, they varied sufficiently to result in considerable changes in the rate of nitrate production.

This technique should also prove to be of considerable value in evaluating nitrification in climates where the soil is frozen or at a temperature near freezing during a portion of the year.
Relationships of Atterberg Limits to Some Other Properties of Illinois Soils
Authors: Odell R. T. , Thornburn T. H. , McKenzie L. J.
Published: July 2010

Multiple correlations were determined between liquid limit, plastic limit, and plasticity index and various combinations of standard physical and chemical determinations (cation‐exchange capacity, percent of organic carbon, percent of <0.002‐mm. clay, percent of montmorillonite in the clay separate, percent of illite in the clay separate, and percent of 0.05‐ to 0.002‐mm. silt) on a wide range of Illinois soils.

Multiple correlation coefficients of 0.959, 0.887, and 0.938 were obtained between liquid limit, plastic limit, and plasticity index, respectively, and three soil properties (percent of organic carbon, percent of clay, and percent of montmorillonite in the clay separaate), indicating that there is a very close relationship between Atterberg limits and these three soil properties. If additional soil properties, such as percent of silt and percent of illite in the clay separate, are included in the analysis the correlation coefficients are increased only slightly. Lower, but highly significant correlations were also obtained between each of the Atterberg limits and cation‐exchange capacity, and a combination of percent of organic carbon and percent of clay.
Oxidation‐Reduction Studies on the Mechanism of B Horizon Formation in Podzols
Authors: McKenzie L. J. , Whiteside E. P. , Erickson A. E.
Published: July 2010

Oxidation‐reduction potentials in situ have been measured in a hydro‐sequence of soils in the Podzol region of Michigan with variations in time and space. The soils were well‐drained Kalkaska sand, imperfectly drained Saugatuck sand and poorly drained Roscommon sand. The distribution of citrate‐oxidizing organisms and iron‐oxidizing organisms in horizons of Kalkaska and Saugatuck sands was also studied.

Redox potentials were observed to vary with moisture, temperature and soil horizons. The population of citrate‐oxidizing organisms decreased with depth and iron‐oxidizing organisms were isolated from the Bir horizons of both Kalkaska and Saugatuck sands.

The results indicate that certain mechanisms of Podzol formation may be active in the soils studied.
Laboratory Studies and Genesis of a Clay‐Enriched Horizon in the Lowest Part of the Solum of Some Brunizem and Gray‐Brown Podzolic Soils in Illinois
Authors: Bartelli L. J. , Odell R. T.
Published: July 2010

Results are presented from laboratory investigations of Beta horizons (clay‐enriched layers found below the B2 horizons) of selected soils in the Wisconsin‐age glaciated region of northern Illinois.

Stereoscopic microscopic investigations indicated the peds were microconstructional. This was interpreted to be the result of not only the arrangement of skeletal material in situ, but also the effect of colloidal material which has moved into the horizon from above and deposited on surfaces of grains, peds, and walls of pores to alter the microconfiguration and porosity. Microscopic studies of thin sections showed a rather porous fabric with a large percentage of the clay being strongly oriented in layers along surfaces of mineral grains, walls of pores and root channels, and surfaces of peds. Thin sections of sand columns through which clay suspensions had been passed had a fabric markedly similar to that of Beta horizons. These micromorphological investigations strongly suggest that the Beta horizon is primarily a zone of clay illuviation.

Mechanical analyses indicated that the total clay fraction (< 0.002 mm.) was at a maximum in the B2 horizon and that fine clay was at a maximum in the Beta horizon of each profile. Amounts of organic matter by weight were about the same in the B2 and Beta horizons. On the other hand, if amounts of clay and organic matter were expressed on a specific surface area basis, the Beta horizon was appreciably higher than the B2 horizon of the same profile.

Clay mineral analyses indicated that the Beta horizons are characterized by a montmorillonitic suite more closely associated with the loess‐influenced material in the upper part of the soil than an illitic clay suite which characterizes the drift material below.

The reaction ranged from pH 6.0 to 7.7 for most of the Beta horizons with the lower portion of the horizon having the highest pH.

Clay migration was suggested as the dominant process in the development of the Beta horizon and it was closely related to the discontinuity in moisture flow at the boundary of the coarser textured substrata and finer textured subsoil.
Morphology and Genesis of Some Soils Containing Fragipans in Northern Michigan
Authors: Yassoglou N. J. , Whiteside E. P.
Published: July 2010

Detailed physical, chemical, and mineralogical studies were made on profiles representative of the McBride, Isabella, and Nester series. These are soils that were formed in calcareous sandy loam, sandy clay loam, and clay loam tills, respectively, in northern Michigan. They are bisequal profiles representative of the zonal Podzol group, intergrading to Gray Wooded soils. They each contain eluvial fragipan horizons (Eq) between the overlying illuvial humus sesquioxide horizon (Ihi) and the underlying illuvial silicate clay or textural horizon (It). Genesis of the Podzol sequum is characterized by high physical, chemical, and biological activities, while the underlying Gray Wooded sequum is characterized mainly by leaching of soluble materials and high physical activity such as eluviation, illuviation, contraction, and rearrangements of soil particles.

The fragipan is most strongly developed in the McBride. The fragipans occur at depths of 8 to 20 inches beneath the surface and are 6 to 24 inches thick. They are deeper and thicker in the soils formed in the moderately coarsetextured primary materials. The fragipans are grayer and more compact than adjoining layers. They have high bulk densities, are hard when dry and firm when moist. When moist, the resistance of the materials studied to the penetration of a metal cone increases with clay contents up to about 15%. With higher clay contents their resistance decreases rapidly. The clay in these horizons is largely illitic but some chlorite and kaolinite are also present. The clay and silt form a dense matrix or bridges between the sand grains.

The alterations of the primary materials necessary for the formation of the pedogenetic fragipan horizons include: leaching of lime, eluviation of the finer expanding lattice clays leaving a residual concentration of the coarser nonexpanding clay, compaction of the layers by weight of the overlying layers or the tap roots of plants, and possibly some weak reversible cementation with soluble alumina.

The fragipan layers interfere with the movement of water and plant roots in the soil profile. Roots branch little in these layers and tap roots of alfalfa commonly zigzag through cracks in them.
Statistical Parameters and Reproducibility of the Neutron Method of Measuring Soil Moisture
Authors: Stone John F. , Shaw R. H. , Kirkham Don
Published: July 2010

The neutron device used in the study was essentially that of Stone et al., Soil Sci. Sco. Am. Proc. 19:419‐423. 1955. Reproducibility (that is, repeat performance at a given location) of the neutron device was evaluated in the laboratory and in the field. Observed coefficients of variation for laboratory and field were about 1.5% to 2.5%. Random counting error component accounted for most of this percentage.

In comparing gravimetric sampling with neutron measurements at the same locations, a rather poor agreement was observed within locations, but overall average difference in indicated moisture was < 0.1 inch of water per 6‐inch soil depth. Poor individual agreement is believed to be due to limitations of bulk density determination and not to the neutron device.

A comparison of the relative abilities of the aravimetric and neutron methods to evaluate moisture in a set of plots where sampling locations were randomized indicates that use of seven gravimetric sites for each neutron site gives a comparable standard error of the mean.
A Microscopic Determination of Apatite and a Study of Phosphorus in Some Nebraska Soil Profiles
Authors: Shipp R. F. , Matelski R. P.
Published: July 2010

A microscopic method is described for the determination of apatite mineral frequencies. The technique was developed from further study and application of a method used to detect alkaline earth carbonates in soils. Essentially, the method consists of distributing soil heavy minerals over 2 to 3 drops of 10.7N H2SO4 on a glass slide. Needle‐like calcium sulfate crystals develop on the surface of the apatite grains making them easily recognized. The low birefringence of apatite is used as a further identifying characteristic.

A study of three Nebraska soils was made using this technique. Data on the occurrence and vertical distribution of apatite in these soils is presented. A general tendency for the apatite content to increase with depth was noted. This increase is shown to parallel the profile distribution of acid‐soluble phosphorus in these soils. There was a close correlation between the total phosphorus content of the sand and coarse silt and the percent of apatite as determined by this method.
Problems Relating to Research in Forest Fertilization With Southern Pines
Authors: Pritchett W. L. , Robertson W. L.
Published: July 2010

Recent interest in fertilization of forest soils has pointed up the need for improvements in investigational techniques in the field. Since methods developed for agronomic research often have little application to forestry, a series of experiments were conducted in slash pine plantations to check experimental technique. P32 measurements indicated 2‐, 3‐, and 5‐year‐old pine trees may feed out to about 19, 25 and 32 feet, respectively, on sandy soil. Root grafting, as determined by the use of P32, appeared to occur in trees 5 years or more in age. The size of plots depends upon the anticipated extent of the root system at the finish of the experiment. At least 30 trees should be included for measurements, with borders to prevent cross‐feeding. Except for experiments to be conducted for short periods on young trees, individual plots should be about ¼ to ½ acre in size.

Depth of feeding, method of fertilizer application, and season of application are discussed. Care must be exercised when applying fertilizer at time of transplanting to prevent burn. Concentrations exceeding the equivalent of 300 pounds of soluble nitrogen (N) or potash (K2O) per acre may result in reduced growth and stand of newly planted pine on sandy soil. It appears that fertilization should be delayed at least 1 year after transplanting in order to reduce the danger of burning, leaching losses, and competition from weeds.
Miscible Displacement in Soils: I. Experimental Information
Authors: Nielsen D. R. , Biggar J. W.
Published: July 2010

When a fluid containing a tracer in solution is displaced from a porous medium by the same fluid without a tracer, this miscible displacement results in a tracer concentration distribution which depends upon microscopic flow velocities, tracer diffusion rates and other chemical and physical processes. Miscible displacement has been studied in several porous materials under saturated and unsaturated conditions at different average flow velocities. The tracer appeared at the end of the soil column well in advance of that expected had no mixing occurred at the boundary of the tracer and tracer‐free water. Physical differences between porous materials were manifested by changes in shape and position of breakthrough curves owing to ionic diffusion. One of the more important physical features was the magnitude of the volume of water not readily displaced at saturation and its increase when the soil was desaturated. Because the total flux of water moving through field soils is generally small, the role played by hydrodynamic dispersion and diffusion in transporting dissolved solutes must be included in the theory of most soil‐water processes.
Behavior of Soil Humic Acids Towards Oxidation With Hydrogen Peroxide
Authors: Savage S. M. , Stevenson F. J.
Published: July 2010

Humic acids from two Brunizem soils were oxidized with a view to obtaining and detecting intermediate products which would provide clues to their structures. A comparison of optimum conditions for the production of intermediate products showed that humic acid extracted from soil with 0.1M sodium pyrophosphate (pH 9.0) was more susceptible to oxidation than humic acid extracted with 0.5N NaOH. Intermediate products obtained from pyrophosphate humic acid by oxidation were different chemically from those derived from alkali humic acid.

Paper partition chromatography of the low molecular weight acids obtained by oxidation, as well as column chromatography on silicic acid, failed to reveal the presence of the common aliphatic and benzenoid acids. In one preparation, phthalic and trimesic acids were identified tentatively by paper chromatography. Evidence obtained indicated that the intermediate products were polycarboxylic.

The intermediate products formed by H2O2 oxidation of humic acids contained N, suggesting that humic acids contain N as part of their molecular structures. Ultraviolet analyses of the intermediate products failed to reveal the presence of azo‐ or diazo‐N compounds, or of constituents which contain heterocyclic 6‐membered ring N.
Sulfur Acidity in South Carolina Tidal Marsh Soils
Authors: Fleming John F. , Alexander L. T.
Published: July 2010

Some soils of the South Carolina tidal marsh area develop high acidity when drained. On soil samples from these areas pH values were lowered as much as 3 units on drying. Final values often ranged from pH 3.0 to 2.0 with an occasional value below pH 2.0. These soils contain up to 5.5% total sulfur.

This investigation indicates that the sulfur acidity problem in these soils is similar to the problem in soils called Katteklei (cat's clay) in Holland and by various other names throughout the world. It is postulated that sulfur from sea water was reduced forming sulfides which oxidize to sulfate on exposure to air‐drying. If there are not enough alkaline earth carbonates, high acidity results.

Field identification can sometimes be made by the smell of H2S from the disturbed soil, but often it is necessary to determine pH values before and after drying. Total sulfur percentage is also indicative.
Evaluation of Phosphobacterin as a Soil Inoculant
Authors: Smith J. H. , Allison F. E. , Soulides D. A.
Published: July 2010

Characterization of Phosphobacterin obtained from the U.S.S.R. showed that it is a culture of Bacillus megaterium adsorbed on kaolinite at approximately 7 billion spores per gram. The bacteria readily decomposed glycerophosphate.

Two greenhouse experiments conducted at Beltsville, Maryland, in which tomatoes and wheat were grown on six neutral soils showed a 7.5% increase in tomato yield in the first experiment, where Phosphobacterin was applied, and no increase for wheat. No such increase in tomato yields was observed in the second experiment. Neither phosphorus concentration in the two crops nor fertilizer recovery, determined with P32, was favorably influenced by the inoculant in either experiment.

There are no indications from these experiments that Phosphobacterin inoculation of vegetable or field crops would be beneficial.
Fraction of Net Radiation Utilized in Evapotranspiration from a Corn Crop
Authors: Graham W. G. , King K. M.
Published: July 2010

The ratio of daily evapotranspiration to net radiation was determined at various stages in the development of a corn crop. Measurements, made near the center of a 266‐ by 340‐foot corn plot near Guelph, Ontario are reported for 16 days of observation during the summer of 1958. Soil moisture in the plot was maintained at a level exceeding 75% available. There was good agreement between the daily evapotranspiration determined by a floating lysimeter and the daily evapotranspiration computed hourly from the vertical heat budget method. The ratio of evapotranspiration to net radiation (E/Rn) averaged 0.81 ± .09 for the daytime period on days following rain when a large area was equally moist. Low values of E/Rn were associated with days of heavy cloud and high humidity. Values of E/Rn greater than unity during the daytime were obtained on some days when the corn plot was irrigated and the surroundings were dry. Freezing of the crop reduced E/Rn to 0.52. The stage of crop development prior to freezing did not have any effect on E/Rn under the soil moisture conditions of this experiment.
Studies on Nitrite Oxidizing Microorganisms: I. Nitrite Oxidation by Nitrobacter
Authors: Silver Warren S.
Published: July 2010

Quantities of Nitrobacter sufficient for whole cell and enzyme studies have been obtained by cultivation under forced aeration in a soluble mineral medium. That the nitrite oxidase activity of washed cells and extracts is intimately linked to the cytochrome system was shown by manometric, spectral and inhibition studies. Cytochrome inhibitors but not uncouplers readily inhibited nitrite oxidation. The nitrite‐oxidizing system of cell‐free extracts was of relatively low activity compared to washed cells.
Residual Effects of Phosphorus Fertilizer on an Eastern Oregon Soil
Authors: Hunter Albert S. , Hoffman E. N. , Yungen John A.
Published: July 2010

In each of three successive years a 6‐year rotation (barley‐3 years alfalfa‐corn‐sugar beets) was established on separate plots of Owyhee silt loam treated with 0, 26, 53, 105, and 210 pounds of P per acre and a uniform rate of N. Plots were split in the fifth year for differential N and in the sixth year for P and N treatments.

Yields and removal of P by crops were determined each year. In the sixth year measurements of soluble P in soil, percent P in plant derived from soil P, A‐values, and yield and compositional responses of sugar beets to added P fertilizer were employed to evaluate levels of available residual P in soil.

All methods of evaluation indicate that 210 pounds of P were adequate for all crops in the 6‐year rotation. Residual P from the 105‐pound rate was inadequate for maximum yield of beets. Essentially no residual P remained in the sixth year from the 26‐ and 53‐pound applications.

Accumulation of N by alfalfa was unaffected by initial rate of P. Fertilizer N substantially increased corn yields following 3 years of productive alfalfa.