bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Cesium Uptake in Wheat Seedlings Cultured with Ammonium
Authors: Minotti Peter L. , Craig Doris , Jackson W. A. 
Published: July 2010

AbstractWheat seedlings grown exclusively on NH4‐N, relative to those grown exclusively on NO3‐N or without N, consistently demonstrated a markedly high capacity for subsequent Cs absorption from solutions labelled with Cs137. In addition, previous nitrogen nutrition greatly influenced the relative distribution of absorbed Cs, with percentage transport of Cs to tops being greatest in seedlings cultured with NO3. The results could not be explained on the basis of either K content or respiratory substrate levels prior to the uptake periods.
Preparation of Thin Sections from Moist Organic Soil Materials
Authors: Langton John E. , Lee Gerhard B. 
Published: July 2010

AbstractMicromorphologic investigation of Histosols requires use of thin sections prepared in such a way as to minimize shrinkage and disruption of natural soil fabric. A method which meets these requirements is described. Moist samples are impregnated with Carbowax 6,000, mounted with Castoglas, and ground and polished by special techniques. Little shrinkage or destruction of soil fabric occurred in thin sections prepared by this method from a variety of organic soil materials.
The Significance of Nonsymbiotic Nitrogen Fixation
Authors: Knowles R. 
Published: July 2010

AbstractEstimates of the rate of nonsymbiotic fixation of N215 were calculated on an area basis for several natural woodland and cultivated field soils. Results supported the conclusion that much of the nitrogen gain in the field may be associated with periods or regions of anaerobiosis, or with localized available energy sources. There was agreement with many earlier conclusions drawn from nitrogen balance experiments.
The Effect of Soil Temperature on the Availability of Indigenous Soil Zinc
Authors: Bauer A. , Lindsay W. L. 
Published: July 2010

AbstractA short‐term growth chamber experiment was used to study the effect of soil temperature on the availability of indigenous soil zinc. Zinc‐deficient weld loam was incubated for periods of 0, 1, 3 and 6 weeks at temperatures of 5, 17, 31 and 43C and treated with 0 and 0.75 ppm Zn as ZnSO4·7H2O, immediately before plant‐soil contact. Two‐week‐old corn plants (Zea mays) used as the assay crop were allowed to exploit the previously incubated soil for a 2‐week uptake period.During this period both yield and the uptake of Zn was increased from soil previously incubated at 43C for 1 to 3 weeks. The 6‐week incubation period tended to reduce available Zn over shorter periods. The addition of Zn fertilizer showed that Zn was a limiting factor in growth at the lower temperatures. Chemical extractions commonly used as soil tests for Zn were not sufficiently sensitive to detect the Zn made available to plants by soil incubation.
Effect of Underlying Residua on Chemical and Mineralogical Properties of Soils Developed in a Uniform Loess Overlay
Authors: Hutcheson T. B. , Bailey H. H. 
Published: July 2010

AbstractChemical properties; sand, silt and clay mineralogy; and particle size distributions are compared and found to support the concept that Lexington, Wellston, Bewleyville, and Dewey soil series were developed in wiedly different residua overlain by a rather uniform loess mantle. Data presented indicate greater weathering of the loess mantle when it is underlain by coarser textured residual material as well as illuviation of materials from the loess mantle into and/or through the coarse textured residuum. Thinner loess overlays tend to exhibit significant mixing with underlying materials from the residuum.
Effect of Phosphorus on Some Physical Properties of Soils: I. Modulus of Rupture
Authors: Lutz J. F. , Pinto Rafael A. 
Published: July 2010

AbstractApplications of phosphorus, both as phosphoric acid and as monocalcium phosphate, to three soils were very effective in reducing the hardness of soils as measured by modulus of rupture. Phosphoric acid was more effective than monocalcium phosphate on all three soils. Both sources of P were more effective on Iredell soil, which consists predominantly of montmorillonite with some kaolinite, than on White Store soil, which contains montmorillonite and kaolinite but with some illite. Even though both sources of P produced significant decreases in modulus of rupture on the Georgeville soil, which contained predominately 1:1 clay minerals, the results were not as striking as on the Iredell. The greatest effect per unit of P was produced by the smaller increments, especially by the 50‐ppm rate. This is especially important from both agronomic and economic standpoints since 50 to 100 lb/acre are feasible rates.
Quantitative Determination of Vermiculite in Soils
Authors: Alexiades C. A. , Jackson M. L. 
Published: July 2010

AbstractA chemical method based on potassium fixation was developed for quantitative determination of vermiculite in soils. The cation‐exchange capacity (CEC) of a sample is determined by washing with CaCl2 and replacement of Ca with MgCl2. The sample is then washed with KCl, heated to 110C overnight to dehydrate and collapse the layers of vermiculite and to fix K. The K remaining exchangeable is determined by NH4Cl washings. The difference between these two CEC values gives the interlayer charge of vermiculite. A number of vermiculite standards and soil samples of widely different clay mineral compositions give remarkably near 100% totals when the vermiculite content is based on the average value of interlayer charge of 154 meq/100 g of vermiculite and when the other minerals present are appropriately determined (mica by K2O, chlorite by ignition loss, montmorillonite by CEC measured by non‐fixed K, quartz and feldspar by Na2S2O7 fusion, allophane, kaolinite, and halloysite by selective dissolution in NaOH). The total CEC of vermiculite is 159 meq/100 g when the allocated external surface charge of 5 meq is included.
Effect of pH on Leaching Losses of Potassium Applied to Forest Nursery Soils
Authors: Krause H. H. 
Published: July 2010

AbstractA lysimeter experiment was conducted to determine the effect of soil pH on adsorption and leaching of applied K. The experimental soil was a fine sand. The pH was adjusted to 4.3, 5.1, and 6.4. The soils of different reaction were treated at increasing rates with K2SO4 and exposed to rainfall and irrigation. Periodic collection and analysis of leachates over 1 year showed that K losses from strongly acid (pH 4.3) soil were 1.7 to 2.4 times higher than losses from moderately acid (pH 5.1) soil, and 2.5 to 3.5 times higher than losses from weakly acid (pH 6.4) soil. Seasons of greatest K leaching were late fall, early spring, and wet periods during summer.The results show a need for an adjustment of rate and frequency of K fertilization according to pH and base saturation of individual nursery soils, and stress the importance of liming of strongly acid nursery soils.
Recording CO2 in Soil‐Root Systems with a Potentiometric Membrane Electrode
Authors: Jensen C. R. , Van Gundy S. D. , Stolzy L. H. 
Published: July 2010

AbstractA commercial electrode was evaluated for measuring the partial pressure of CO2 in soil. Carbon dioxide was monitored in containers of Yolo silt loam, with and without a growing tomato plant (Lycopersicum esculentum), and compared with gas chromatograph measurements of simultaneous soil air samples. A linear correlation coefficient of 0.98 between the two methods was obtained, although the electrode departs slightly from linearity below 2% CO2. Small increases of CO2 pressure in the soil were observed immediately following small additions of water; these increases could be followed continuously by the electrode. The CO2 electrode should prove practical for both greenhouse and field measurements.
The Influence of Soil Moisture, Soil Texture, Drying Conditions, and Exchangeable Cations on Soil Strength
Authors: Gerard C. J. 
Published: July 2010

AbstractEmpirical relationships expressing soil strength for different combinations of silt‐clay and sand mixtures as functions of soil moisture, drying conditions, and exchangeable Na+ content of the silt‐clay fraction were determined. Soil strength data indicate that moisture content, drying conditions, texture, and kind and level of exchangeable cations of the soil and interactions of these factors play significant roles on soil strength and the soil strength‐moisture relationships. Strength of briquets increases (i) with decreasing soil moisture, reaching a maximum when moisture content was reduced to 2 to 3 monomolecular layers of water; (ii) with increasing silt and clay and exchangeable Na+ content; and (iii) by slow drying. The cohesive actions of water molecules during slow drying, similar to the dispersing action of Na+, increase close‐packing of soil particles and, therefore, soil strength. Fast drying produces briquets of lower strength due to disruptive action of rapidly escaping water molecules on the arrangement of soil particles.
Release of Potassium from Soil Fractions During Cropping
Authors: Doll E. C. , Mortland M. M. , Lawton K. , Ellis B. G. 
Published: July 2010

AbstractSoil fractions from six soils known to vary in ability to supply K to field crops were cropped intensively in greenhouse experiments. All soils and soil fractions were Mg‐saturated prior to conducting the experiments. The K content of the clay and of the silt was linearly correlated with the logarithm of the K uptake for each fraction, except for the silt fraction of one soil. No correlation was noted between the uptake of K and the K content of the entire soil. In equilibrium experiments, K in solution in 1.0n MgOAc after 90 days was linearly correlated to the K content of the clay. A similar correlation was obtained with the entire soil. The different pattern of K release during cropping tests as compared to the equilibrium studies is attributed to rate processes which would govern release during cropping, but which would not be a factor in the equilibrium experiment. X‐ray analyses indicated the formation of expanding lattice clays upon the removal of interlayer K by cropping. Large amounts of K were removed from the coarse clay (2.0–0.2µ), intermediate amounts from the medium clay (0.2–0.08µ), and small amounts from the fine fraction (<0.08µ). This differential release of K by the different size clay fractions can be explained by a decrease in the activity of interlayer K when the K content of the clay is decreased.
Potassium Availability in Nason Soil as Influenced by Ammonium and Lime
Authors: Murdock L. W. , Rich C. I. 
Published: July 2010

AbstractA greenhouse experiment was established to find if NH4+ increases K+ availability when Nason silt loam is limed to pH 7.0 as suggested by previous laboratory studies.Two oat crops were grown in soil at 3 lime levels (1, 5, and 15 g/1,000 g), 2 K levels (0 and 0.5 meq/100 g) and 2 N sources [Mg(NO3)2 and NH4NO3]. At high soil pH, potassium uptake was significantly greater where the N source was NH4NO3 as compared to Mg(NO3)2. The results support soil extraction data which show that at about pH 7.0, NH4+ ions are considerably more efficient in displacing K+ from this soil than are Mg2+ ions. It is concluded that the smaller NH4+ ions are able to penetrate to exchange positions not accessible to large hydrated Mg2+ ions.The results do not support an explanation of the differential K uptake based on the antagonistic effect of Mg2+ ions on K+ nor due to an effect caused by lower soil pH with NH4NO3 fertilization.Although K fixation occurs at high pH in this soil, this fixation does not appear to be associated with greater collapse of expansible vermiculite. In fact, it is shown that liming caused the vermiculite to be less subject to collapse on K saturation. The reason for the greater fixation at high pH may be that there is less competition for the specific sites by H3O+ ions and thus greater opportunity for selection of K+ ions which are of similar size.
Estimating Soil and Saturation Extract Composition by a Computer Method
Authors: Paul J. L. , Tanji K. K. , Anderson W. D. 
Published: July 2010

AbstractFive soil samples were salinized with NaCl and CaSO4.2H2O. They were extracted at 1:1 and saturation moisture content, and the chemical composition of the soils and extracts was determined. Exchange constants, for Na‐Ca and Mg‐Ca exchange, in combination with chemical data derived from samples at 1:1 moisture content were used in a computer program to predict soil and extract composition at saturation. The computer procedure, developed by Dutt, proved very satisfactory in estimating chemical makeup at saturation.
Factors Controlling the Extractability of Soil Zinc
Authors: Martens D. C. , Chesters G. , Peterson L. A. 
Published: July 2010

AbstractThe effect of total zinc, pH, and contents of clay and organic C on the extractability of soil Zn by Aspergillus niger, 0.1n HCl, dithizone, and 0.2m MgSO4 for 57 Wisconsin soils was evaluated by simple, partial, and multiple correlation.The relative amount of soil Zn extracted by the Zn tests was in the order A. niger > 0.1n HCl > dithizone > 0.2m MgSO4 extractable Zn. Simple, partial, and multiple correlation data indicated that the fungus extracts a fixed fraction of the total soil Zn. Consequently, total Zn and A. niger‐extractable Zn were of approximately equal importance in the prediction of Zn uptake by plants. Statistical interactions between clay and organic C content in relation to the amount of Zn extracted by 0.1n HCl were explained on the basis of organo‐clay complex formation. An increase in organic matter content at constant levels of clay increased the amount of Zn bound by the organo‐clay complex thereby resulting in increased extractability of soil Zn by 0.1n HCl. On the basis of correlation data and the greater extractability of Zn by 0.1n HCl than dithizone, it was concluded that much of the Zn extracted by 0.1n HCl over dithizone is not extractable by plants. It was shown that the amount of Zn extracted by 0.2m MgSO4 varied inversely with pH; clay and organic C contents had less effect on the relationship suggesting that 0.2m MgSO4 extracts only solution and readily exchangeable Zn.
Optimum Nutrient Levels in Potato Leaves (Solanum tuberosum L.)
Authors: MacKay D. C. , MacEachern C. R. , Bishop R. F. 
Published: July 2010

AbstractField experiments involving six rates of each of the nutrients N, P, and K were conducted at 18 locations over a 3‐year period. Comparison of polynomial response curves for tuber yields with those for nutrient content of uppermost mature leaves collected at the 10% bloom stage suggested optimum levels of 6.5, 0.50, and 3.9% for N, P, and K, respectively.The optimum level for K was the most satisfactory of the three nutrients because moderate yield deficiencies resulted in large differences in leaf concentrations. However, on soils high in exchangeable K, responses to K fertilization were obtained at higher leaf levels than on soils low in K.The optimum level derived for N appeared to be fairly stable. On coarse‐textured soils, or where a combination of factors produced unusually high yields, somewhat higher leaf levels, at the stage sampled, were apparently necessary to prevent deficiency.The optimum level obtained for P was the least satisfactory, since there was considerable variation as a result of season and soil series. However, where yields were < 90% of the maximum, the P content was invariably well below the overall optimum value.
An Evaluation of the Mechanisms Governing the Supply of Ca, Mg, K, and Na to Soybean Roots (Glycine max)
Authors: Oliver S. , Barber S. A. 
Published: July 2010

AbstractThree mechanisms, root interception, mass‐flow, and diffusion, govern the rate of supply of nutrients from the soil mass to the plant root. Two experiments were conducted to evaluate methods developed for calculating the supply of ions to the root by mass‐flow and by root interception. Root interception values were calculated by assuming that all the exchangeable and soluble ions were in the pore space and that the roots intercepted an amount in proportion to their volume. Mass‐flow was calculated by multiplying the amount of water uptake of the plant by the concentration of ions in this water as determined from analysis of a saturation extract.Contributions of mass‐flow were varied by creating three rates of transpiration. The results indicated that mass‐flow was significant for supplying Ca and Mg but was of little importance for Na and K in the soil used. Increases in mass‐flow of Ca and Mg were highly correlated with increases in the uptake of Ca and Mg by the plant.In a second experiment, root interception of Ca and Mg was varied by using soil‐sand mixtures varying from 100% soil to 20% soil and 80% sand. Mass‐flow was minimized by leaching the soil before use. The results indicated that the calculated Ca uptake by root interception gave a reasonably close approximation to uptake of Ca minus mass‐flow Ca.
Source and Placement of Zinc and Phosphorus for Corn (Zea mays L.)
Authors: Brown A. L. , Krantz B. A. 
Published: July 2010

AbstractThe effects of source and placement of zinc and phosphorus were studied in several greenhouse experiments. A Zn and P deficient soil was utilized and sweet corn was grown as the test plant.When Zn fertilizer materials were mixed well with the soil ZnSO4 and organic sources such as ZnEDTA and Rayplex‐Zn were equivalent in their effectiveness for the correction of Zn deficiency. However, if the fertilizer was banded under the seed, ZnEDTA was more effective than the inorganic sources.A small amount of mixing appeared to improve the effectiveness of Zn, or P, or both fertilizers markedly.Granulation greatly reduced the effectiveness of ZnSO4, ZnNH4PO4, and Rayplex‐Zn.
Closed‐System Freezing of Unsaturated Soil
Authors: Dirksen C. , Miller R. D. 
Published: July 2010

AbstractRecent developments in the theory of soil freezing and frost heaving led to the conclusion that pores directly adjacent to a growing ice lens ought to be filled with water. The literature contains fragmentary reports of heaving of soils that were not saturated with water and which lacked an external source of water. It was thought that this apparent anomaly might be explained by postulating that before lens growth and heaving began, local saturation was achieved by thermal water transfer.Experiments confirm that heaving sometimes occurs in moist closed soil columns, initially at uniform temperature and water content, when the temperature at one end is lowered below the ice point and kept at that temperature while the other end is held at the original temperature. The region just ahead of the advancing ice front does not become saturated in the expected manner, but instead suffers a net loss of water. Water lost from the unfrozen soil enters the frozen soil, and causes its water (ice) content to increase for a considerable distance behind the 0 C isotherm. This transport within the frozen soil exceeded by several orders of magnitude that which can be accounted for as vapor movement through the unfilled pore space and thus, it was concluded, must take place in the liquid phase. Whenever and wherever the degree of saturation reaches about 0.9, a further increase in water content is accompanied by heaving. The frozen soil actively extracts water from the unfrozen soil, supposedly due to attenuation of the iquid water films associated with ice surfaces. The resultant water content gradient in the unfrozen soil induces hydraulic flow toward the frozen soil. During the early stages of the experiments thermal transport in the unfrozen soil is inconsequential compared with this hydraulic flow. Later the rate of ice accumulation diminishes, the hydraulic gradient is dissipated, and the thermal water transport becomes relatively more important, by default. By that time heaving has virtually ceased. Thermal water transport is, therefore, not essential for heaving in moist soils that lack an external source of water.
Soil Aggregate Stabilization by the Indigenous Microflora as Affected by Temperature
Authors: Harris R. F. , Chesters G. , Allen O. N. 
Published: July 2010

AbstractThe water‐stability of sucrose‐amended aggregates of Waupun silt loam incubated at 15, 25, and 35C, and the aggregate‐stabilizing characteristics of microorganisms isolated from these aggregates were evaluated. Aggregate water‐stability determined by wet‐sieving was expressed as the percentage of soil material bound into water‐stable aggregates 0.5 to 1 mm, 1 to 2 mm, and > 2 mm in size. Microbial development was investigated by microscopic and dilution plate techniques.Fungi isolated from the aggregates differed in their ability to effect aggregate stabilization in the presence and absence of sucrose. Stabil zation by effective fungi was a function mainly of the binding of soil particles into > 2‐mm water‐stable aggregates and was related closely to the onset and subsequent development of macroscopic mycelia on the aggregates. Stabilization of aggregates by sporeforming bacteria involved the production of a high percentage of <2‐mm aggregates, especially in the early stages of incubation. Bacterial stabilization was initiated earlier but was maintained for a shorter time as incubation temperature increased from 15 to 35C; maximum aggregate stability effected at 15 and 25C was almost twice that reached at 35C.Maximum stabilization by the indigenous microflora occurred within 4 days at all 3 temperatures; appreciable stability was maintained for 84, 14, and 4 days at 15, 25, and 35C, respectively. Bacteria were primarily responsible for the initial stabilization of aggregates incubated at 15 and 25C and contributed to the initial stabilization of aggregates incubated at 35C. The fungal species involved in aggregate stabilization varied with temperature.
Mineralization and Immobilization of Nitrogen in Bacterial Cells and in Certain Soil Organic Fractions
Authors: Chu J. P‐H. , Knowles R. 
Published: July 2010

AbstractNitrogen15‐enriched Pseudomonas cells and (NH4)2SO4 were added separately to a Chicot sandy loam and to a black spruce raw humus (F horizon). At intervals from zero to 100 days the soil N was fractionated (Cheng and Kurtz, 1963) into: exchangeable NH4+‐ + NO3‐‐N, fixed NH4+‐N, N in acid hydrolyzate (i.e. NH4+ from hydrolysis, amino sugar‐N, amino acid‐N, acid‐soluble alkali‐insoluble humin‐N), and acid insoluble humin‐N.At zero time 92.5 and 93.0% of the added NH4+‐N appeared in the exchangeable fraction of the two soils, respectively; 55.3 and 83.7% of the added cell‐N appeared in the amino acid fraction of the two soils, respectively. During incubation in both soils about 40% of the added NH4+‐N remained in the exchangeable fraction and 50 to 60% was immobilized in the amino acid fraction. In the raw humus about 13% of the added NH4+‐N appeared in the insoluble humin fraction. In both soils 20–30% of the added cell‐N was rapidly mineralized but at least 50% remained in the amino acid fraction. There was evidence of a “priming effect” or “N interchange” resulting in increased mineralization of native soil organic N. This effect was particularly pronounced in the raw humus.
Properties and Genesis of the Hayesville and Cecil Series of Georgia
Authors: Gibbs J. A. , Perkins H. F. 
Published: July 2010

AbstractCecil and Hayesville soils are Typic Normudults derived from acid crystalline rocks in the Piedmont Plateau and Southern Blue Ridge Soil Provinces, respectively. Morphological, chemical, and mineralogical properties were similar except for fine sand content and clay mineralogy. In general, the Hayesville series contained larger amounts of fine sand in the whole soil and more gibbsite and less kaolinite in the clay fraction than the Cecil series. Data obtained are insufficient to justify the two series as they are classified in Georgia.