bluuebunny/crossref_metadata_2025_split huggingface dataset:
Management of Nonleguminous Green Manures and Crop Residues to Improve the Infiltration Rate of an Irrigated Soil
Authors: Williams William A. 
Published: July 2010

AbstractThe effects of nonleguminous green manures and crop residues on the rate of infiltration were studied in field experiments on an irrigated soil.The increase in infiltration rate resulting from the green manure species was inversely related to their nitrogen concentration at the time of incorporation. The effect of the low nitrogen green manures persisted throughout the 28‐month trial period. Nitrogen fertilization of crop residue reduced infiltration rate in one experiment, but had no significant effect in another. Barley (Hordeum vulgare) crop residue and the resultant increase in infiltration rate were associated with an increase of 7 cwt of sugar produced/acre by the following crop of sugar beet (Beta vulgaris).
Moisture Release Characteristics of Forested Sand Entisols In Northern Lower Michigan
Authors: Zahner Robert , Hedrich David R. 
Published: July 2010

AbstractForest growth is better on Grayling fine sand than on Grayling medium sand. Moisture release curves were constructed for samples from these two types and for pure sand fractions separated from the samples. Examples of the fine sand soil retained 10% and the medium sand soil retained 7% water by weight at field capacity (.06 atm tension), while both soils retained equal amounts, 2.5%, of water at 15 atm tension. Of the pure sand fractions, very fine sand retained substantially more water at low tensions than did the larger fractions amounting to more than five times the amount of readily available water. The fine sand soil type contained six times the amount of very fine sand fraction than did the medium sand soil type, 12% vs. 2% by weight. Thus, much of the difference in water retention between the two examples is attributed to the very fine sand fraction, probably also accounting for much of the difference in tree growth.
A Portable Low‐Intensity Rain Simulator for Field and Laboratory Use
Authors: Steinhardt Reuven , Hillel Daniel 
Published: July 2010

AbstractA design is presented for construction of a dripping‐type rain simulator that is useful for study of infiltration characteristics of surface‐crusted soils and comparison of surface treatments for runoff inducement. The apparatus is lightweight, portable, and easily assumbled. Rain intensity can be varied between 4 and 100 mm/hr with adequate uniformity of distribution. Raindrop size and impact velocity, as well as rainfall intensity, can be controlled independently.
Soil Freezing and Soil Water Characteristic Curves
Authors: Koopmans R. W. R. , Miller R. D. 
Published: July 2010

AbstractAn earlier paper suggested that the soil water characteristic (SWC) of soil should have an analogue to be called the soil freezing characteristic (SFC) that could be obtained by freezing saturated soil in an apparatus functionally related to the pressure plate apparatus. The analogy for granular soil, free of colloids, is on a different basis (capillary effects) than for soil that is wholly colloidal (absorption effects). Different rules are needed to demonstrate the analogies for the respective types. Apparatus was devised to permit SFC and SWC data to be obtained, in turn, with each material placed in the apparatus. Two silt fractions, a sodium‐montmorillonite paste, and a whole soil were used. The results confirm the expected analogies and indicate that in these experiments, the ratio of the specific surface energy of an airwater interface at 20C to that of an ice‐water interface near 0C was as 72.7:33.1. The results demonstrate significant mobility for unfrozen water at temperatures as low as −0.15C even in clean silt fractions. It is concluded that the inherent instability of some of the residual water in soils during drying does not significantly affect the SWC in the range 0 to 4 bars of matric suction.
Soil Adsorption of Linear Alkylate Sulfonate
Authors: Murti G. S. R. Krishna , Volk V. V. , Jackson M. L. 
Published: July 2010

AbstractLinear alkylate sulfonate (LAS) adsorption was studied in relation to the pH, cation‐exchange capacity, clay, organic matter, extractable Fe and Al, exchangeable Al, and Fe2O3 contents of several soils. The LAS adsorption correlated highly significantly with the organic matter content (r = 0.81) and the P fixing capacity (r = 0.75) of the soils. With the removal of sesquioxides as the final pretreatment on chloritic, kaolinitic and allophanic soils the LAS adsorption decreased from values of 19 to 48 µ g/g on the untreated soil to a value of zero. When treated with a terminal H2O2 treatment, the adsorption values on the same soils ranged from 17 to 65 µ g/g. The increase apparently occurred as a result of Fe and Al released from organic chelates. The increase in the LAS adsorption from 7 to 27 µ g/g on the untreated soil to 8 to 50 µ g/g after the removal of both the organic matter and sesquioxides in a number of montmorillonitic Wisconsin soils indicates the importance of montmorillonite in LAS adsorption.
Conductance of Adsorbed Alkali Cations in Aqueous and Alcoholic Bentonite Pastes
Authors: Shainberg Isaac , Kemper W. D. 
Published: July 2010

AbstractEquivalent conductivities of the alkali cations adsorbed on bentonite clay in water, and in methanol and ethanol gels, were determined and compared with their equivalent conductivities in bulk solution. The mobilities of adsorbed cations were reduced to about one‐half their mobilities in bulk solution in water systems and to much smaller fractions of their bulk solution mobilities in alcohol gels. The reduction in mobility was independent of the clay concentration in the range studied, and was characteristic of the cation. It was pointed out that “specific forces” between the cation and the clay surface are not possible unless the cations reside directly on the clay surface (without a watermolecule between the ion and the clay). The fraction of adsorbed cations not participating in electrical transport was in reasonable agreement with the portion of adsorbed ions residing directly on the surface as calculated considering both hydration and electrical potential energies in the Boltzmann distribution equation. An electrostatic interaction is discussed which would cause reduction in mobility of cations that are in the first molecular layer of solvent.
Ionic Relationships in the Pedogenesis of Hawaiian Soils
Authors: Swindale L. D. , Uehara G. 
Published: July 2010

AbstractA pedogenic mica is believed to be present in a sequence of Hawaiian soils, the lower, drier members of which are Oxisols and the upper, wetter members Ultisols. The mica decreases with depth within each soil and increases generally with increasing rainfall and elevation. Direct relationships exist between the amount of mica in the soils and the amount of exchangeable potassium per unit of base saturation, and between the amount of mica and the concentration of potassium in the soil solution. The parameters, log [K+]/[H+] and log [H4SiO4], of the mass action equations between mica, kaolin, and gibbsite, when measured for the soil solutions, are useful indicators of the probable stabilities of the minerals in the soils. Tests of physical models of the chemical system involved indicate that the exchangeable potassium and the potassium in the soil solutions as measured are not in equilibrium with the minerals in the soils.
Fractionation and Characterization of Naturally Occurring Organo‐Clay Complexes
Authors: Arshad M. A. , Lowe L. E. 
Published: July 2010

AbstractClay separated from a Solonetz Bnt horizon was fractionated lnto coarse (2–0.2 µ), medium (0.2–0.14 µ), fine (0.14–0.08 µ) and very fine (<0.08 µ) size fractions. Organic matter from these fractions was obtained by extractions with 0.1M Na4P2O7 (pH 11.0), followed by extractions with 0.1N NaOH. The residue was then repeatedly treated with an HF‐HCl mixture and the remaining organic fraction was extracted with 0.1M Na4P2O7 (pH 11.0). The organic and clay fractions were analyzed for C and N contents, and by X‐ray diffraction, electron microscopy and infrared spectroscopy.Experimental data indicated that the largest portion of the complexed organic matter was associated with the coarse clay fraction which contained relatively large amounts of kaolinite, whereas a small percentage was associated with the fine clay fraction where kaolinite occurred as traces. The percentage of extractable organic matter increased with decrease in clay particle size. No evidence was found for the adsorption of organic matter in the interlamellar spaces as reported by some previous workers.Study of humic acids isolated from the clay fractions showed that aliphatic structures were more common in humic acids derived from fine clay than in those separated from the coarse clay fraction. Aromatic structures of the humic acids increased in the order of pyrophosphate humic acid→alkali humic acid→residual humic acid. The humic acids unextractable by the solvents commonly employed appeared to be highly humified and aromatic in nature.
Numerical Method for Analyzing Hysteresis‐Affected, Post‐Infiltration Redistribution of Soil Moisture
Authors: Rubin J. 
Published: July 2010

AbstractAn especially devised numerical procedure applied to the Darcian model of soil moisture flow makes it possible to analyze the post‐infiltration redistribution of water in semi‐infinite, vertical soil columns. The method takes into account the effects of hysteresis by making it possible to find, within the hysteretic system of curves, the unique curve which characterizes moisture transformations at each soil depth. The method can be applied to cases in which the moisture flux at soil surface is zero as well as to those in which the redistribut on is accompanied by constantrate evaporation.The results obtained by applying the new method to data on moisture retention and conductivity of a sandy soil demonstrate the importance of hysteresis in the redistribution processes.
Analysis of Gamma‐Ray Spectra From Soils and Plants: II. Effect of Trees on the Distribution of Fallout
Authors: Franklin R. E. , Gersper P. L. , Holowaychuk N. 
Published: July 2010

AbstractA detailed study of the distribution of fallout in soil from a forested area has been initiated. Surface soil samples (0 to 7.5 cm) collected at several distances from the stems of beech‐(Fagus grandifolia), sugar maple (Acer saccharum), tulip (Liriodendron tulipfera), scarlet oak (Quercus coccinea), hickory (Carya glabra), and white oak (Quercus alba) trees were analyzed by gamma‐ray spectroscopy. The concentration of Cs137 in the soil near the stem of a beech tree was about five times higher than at other positions under the canopy. This effect was about one‐half as great for sugar maple and much less for the other species. The magnitude of this concentration is apparently related to the quantity of stemflow water, which may be appreciable with some species and negligible with others. Samples collected at four depth intervals (0 to 7.5, 7.5 to 15, 15 to 22.5 and 22.5 to 30 cm), in an area which included three of the trees, were also analyzed. Considerable leaching of Cs137 occurred in soil adjacent to tree stems, apparently as a result of stemflow.
Atrazine Hydrolysis in Soil
Authors: Armstrong D. E. , Chesters G. , Harris R. F. 
Published: July 2010

AbstractAn important pathway of atrazine degradation in perfusion systems of three soils was chemical hydrolysis to hydroxyatrazine. Ultraviolet spectrophotometric analyses of the perfusates showed the presence and accumulation of hydroxyatrazine. Atrazine degradation followed first‐order kinetics in soil‐free, sterilized soil and perfusion systems. An increased rate of atrazine hydrolysis in an acid soil was consistent with the effect of pH on hydrolysis. No microbial degradation of atrazine was detected following inoculation of a soil‐free atrazine medium with perfusates. An increased rate of hydrolysis in the presence of sterilized soil was postulated to result from soil adsorption of atrazine. Soil pH and organic matter content largely controlled the rate of atrazine hydrolysis; for soils of similar pH, atrazine degradation rates increased with increased atrazine adsorption.
Extraction of Organic Nitrogen and Ammonium From Soil with Hydrofluoric Acid
Authors: Stevenson F. J. , Kidder G. , Tilo S. N. 
Published: July 2010

AbstractFrom about one‐fifth to one‐half of the organic N in some surface soils, and over two‐thirds of that in some subsurface soils, occurred in compounds capable of being extracted with HF. The NH4+‐N/organic N ratios in HF extracts were generally highest in soils where the predominant clay minerals were illitic, intermediate in soils where the predominant clay minerals were montmorillonitic, and lowest in soils where the clay fraction contained high amounts of amorphous (allophanic) material. The presence of organic N compounds within the lattice structures of clay minerals was indicated. Analyses of the Morrow Plot soils showed that a considerably higher fraction of the organic N in the heavily cropped soils was extractable with HF than in soils where organic matter had been maintained at high levels by periodic application of manure or through growth of legumes. Evidence was obtained in support of the view that many soils contain significant amounts of naturally occurring fixed NH4+.
Some Till‐Derived Chernozem Soils in Eastern North Dakota: I. Morphology, Genesis, and Classification
Authors: Redmond C. E. , Omodt H. W. 
Published: July 2010

AbstractThe macromorphology of several groups of well‐drained Chernozems in Eastern North Dakota that have developed in glacial till are described. A general map shows the areas where these soils occur and the location of sites sampled. Laboratory analyses of two profiles representative of each of three of these soil groups include: particle size distribution, pH, organic carbon, CaCO3 equivalent, clay size carbonates, free iron oxides, and the shale and chert content of the sand fractions.The processes involved in the development of these soils from the glacial materials include: accumulation of organic matter and associated structure formation; redistribution of carbonates and more soluble salts; color changes; and formation of prismatic, finer textured B horizons primarily by alternate wetting and drying and weathering ‘in situ.’ Differences in the magnitude of these changes and in the original materials account for the Forman, Intermediate, and Barnes soils.
Trafficability of Four Loess Soils
Authors: Bassett J. R. , McDaniel A. R. 
Published: July 2010

AbstractStrength of the 15‐ to 30‐cm layer of 65 modal sites on Loring, Grenada, Calloway, and Henry silt loams varied as much within series as between. Thus, little accuracy of strength prediction was lost by grouping the series for trafficability purposes. The group equation relating strength to moisture content accounted for 66% of the strength variation.
The Effect of Nonuniform Water Application on Soil Moisture Content, Moisture Depletion, and Irrigation Efficiency
Authors: Cohen O. P. , Bresler E. 
Published: July 2010

AbstractSoil moisture measurements with a neutron probe indicated considerable non‐uniformity of moisture application in a citrus grove. Surface recharge was well correlated (r = 0.89) with interna recharge immediate'y after irrigation, but the coefficient of correlation decreased (r = 0.68) as the moisture was redistributed in the soil. Higher terminal moisture contents after irrigation, and higher rates of moisture depletion during the initial period of subsequent drying cycles, were measured in the soil volumes receiving higher rates of moisture application. Even though moisture application was nonuniform, irrigation efficiency was high, since the terminal moisture content was affected and the maximum wetting depth remained within the root zone. These effects of nonuniform moisture application must be considered during moisture requirement experiments if gross errors are to be avoided.
Ion Distribution, Moisture Content and Density of Soil Columns Measured with Gamma Radiation
Authors: Shalhevet J. , Yaron B. 
Published: July 2010

AbstractAnion distribution in soil columns was measured nondestructively by using a radioactive tracer, 60Co (CN)63‐. The breakthrough curves of Cl‐ and 60Co (CN)63‐ were very similar, indicating the possible use of the 60Co complex ion as a qualitative model for anion movement. The external measurement of gamma activity was compared to measurements of 1:1 water extracts of the sectioned columns. The gamma activity of the tracer was measured along uniformly packed soil columns through a few drying and wetting cycles. Drying was done with a stream of warmed air that passed around and through the perforated soil columns. Moisture content and density of the soil in the columns were measured simultaneously by the gamma attenuation method. An equation, the parameters of which were determined empirically, giving density as a linear function of moisture content, may be introduced into the attenuation equation to correct for the variation of density with moisture content.
Characteristics of Ammonia Adsorption by Homo‐Ionic Clays
Authors: du Plessis M. C. F. , Kroontje Wybe 
Published: July 2010

AbstractAdsorption of ammonia by aluminum‐saturated bentonite and kaolinite was described by Langmuir's adsorption equation. The inverse values of the slopes of the two straight line segments of each adsorption isotherm approximate the permanent charge and the total charge or cation exchange capacity at a particular pH (above 6), respectively.Ammonia was presumably adsorbed as NH4+ to the full extent of the permanent charge and in addition ammonia appeared to be chemisorbed at pH‐dependent sites. Exchangeable Al3+ as well as hydroxy aluminum compounds may be precipitated as Al(OH)2 provided that the concentration of ammonia is high enough.For homo‐ionic calcium, magnesium, sodium and potassium clays Langmuir's adsorption equation did not characterize chemisorption of ammonia from aqueous ammonia solutions satisfactorily. The S‐shaped ammonia adsorption isotherms obtained do not necessarily support the theory of physical multilayer adsorption.
Properties of the Available and the Soluble Molybdenum Fractions in a Raub Silt Loam
Authors: Follett R. F. , Barber S. A. 
Published: July 2010

AbstractThe available molybdenum (Mo) in a Raub silt loam, determined with the bioassay procedure using Aspergillus niger M., was 3% of the total Mo in the soil. Available Mo could be removed by daily displacement with water of the water held by the soil in a leaching column. Incubating the leached soil at room temperature and in a moist condition for 7 months following removal of the available Mo by leaching failed to cause an appreciable conversion of the Mo from the unavailable to the available form. The available Mo in the soil moved readily to the soluble form and at 4C and 26C followed a first‐order relationship.
Relation of Extractable Molybdenum to Soil Series and Parent Rock in Kentucky
Authors: Massey H. F. , Lowe R. H. , Bailey H. H. 
Published: July 2010

AbstractMolybdenum extracted by the ammonium oxalate procedure proposed by Grigg was determined on 73 Kentucky soils. The Mo extracted by this method was related to the parent rock. Soils formed from Devonian black fissile shale contained approximately 20 times as much Mo as any other soil. Among the other soils the parent rock averages varied from 0.44 ppm Mo for older Ordovician limestone (generally high phosphatic) to 0.08 ppm Mo for Pennsylvanian sandstones and shales. The parent rock group differences were highly significant. Grigg‐extractable Mo and soil pH give some indication of Mo availability in the soil, and it is suggested that knowledge of the general level of Grigg‐extractable Mo in soils of a given parent rock group may allow useful prediction of Mo availability on these soils. The data provide some indication of a degree of uniformity within soil series. If further work supports this indication, a more accurate prediction based on soil series should be possible.
Redistribution of Nutrient Elements in Corn (Zea mays L.): I. N, P, K, Ca and Mg Redistribution in the Absence of Nutrient Accumulation after Silking
Authors: Kissel D. E. , Ragland J. L. 
Published: July 2010

AbstractThe redistribution of N, P, K, Ca, and Mg by corn from its vegetative parts to the developing ear was measured. This was accomplished by comparing a set of plants grown outdoors and harvested approximately 12 days after silking with a similar set of plants whose nutrient supply was cut off at the same time but which were allowed to grow to maturity. The increase in dry weight of ears between the first and second harvest was 174 g. The mean ear weight of the plants comprising the second harvest was 219 g.Chemical analysis of the various plant parts permitted a measure of the losses and gains of mineral elements from the first to second harvests. Of the total present in all vegetative plant parts at harvest 1, the following percentages of the various plant nutrients had moved out of the vegetative parts by harvest 2: N, 65%; P, 76%; K, 23%; Ca, 0%; Mg, 45%: If all the plant nutrients redistributed from the vegetative parts between harvest 1 and 2 moved to the developing ear, the following percentages of the nutrients in the mature ear were supplied by the redistribution process: N, 97%; P, 116%; K, 180%; Ca, 0%; and Mg 133%.
Two‐Phase Experiments with Plants Growing in Phosphate‐Treated Soil
Authors: Matar A. E. , Paul J. L. , Jenny H. 
Published: July 2010

AbstractBarley (Hordeum vulgare) and rye (Lolium multiflorum) plant were grown in phosphate‐treated soiland in an equilibrium nutrient solution which circulated continuously through soil potsand sand pots. The plants in soils always grew better and accumulated more phosphorus than the plants in sand. Plant physiological tests showed that the sand plants did not measureably deplete the circulating solution; therefore, the cause of this two‐phase effect must have resided in the soil.
Water Disposition in a Stream Channel with Riparian Vegetation
Authors: Qashu Hasan K. , Evans D. D. 
Published: July 2010

AbstractWater losses along stream channels in the semiarid southwestern United States are of utmost importance when considering water disposition and water yields from a watershed. An analysis is described for estimating the disposition along a reach of a natural stream channel with a riparian vegetation and impermeable bedrock at a shallow depth. Results for one annual cycle are presented which indicate the quantity of water removed from the stream channel reach by various processes.Methods were adapted for the particular set of conditions to measure subsurface water flow and water storage in the channel alluvium. Subsurface water flow was calculated from Darcy's equation. Water storage was estimated from water content, water table elevation, specific yield and volume of alluvium measurements.Four distinct water‐use periods were apparent within a yearly cycle, each expressed by a separate water balance equation. Water losses by evapotranspiration were estimated from these equations. For example, 9 mm of water were estimated to be lost per day by transpiration of the riparian vegetation during the months of May and June, a time of water shortage in the area. Total depth of annual water loss by evapotranspiration from the channel reach was estimated to be 131 cm of water (4.3 acre‐feet/acre).