bluuebunny/crossref_metadata_2025 huggingface dataset:
Manganese Reactions and Availability as Influenced by pH and Pyrophosphate Content of Ammonium Phosphate Fertilizers
Authors: Hossner L. R. , Blanchar R. W.
Published: July 2010

Ammonium phosphate, composed of mixtures of ammonium ortho‐ and pyrophosphate, were tested to determine their effectiveness as carriers of Mn. The mixtures contained 0, 20, 40, 60, 80, or 100% of their total P as pyrophosphate with the remainder being orthophosphate. Each series of mixtures was prepared at saturated pH values of 3.6, 4.0, 5.0, 6.0, 7.0, and 8.0. Residues, formed when the ammonium phosphates were blended with MnSO4 · H2O and reacted with the soil, were analyzed to determine their composition.

Essentially all of the applied Mn precipitated as manganese ammonium phosphate when the pH of the fertilizer was greater than 6.0. As the pH was decreased from 5.0 to 3.6 there was a decrease in precipitated manganese with decreasing pyro‐ to orthophosphate content at each pH value. When the fertilizer pH was 3.6 or 4.0 and the P was present as 100% orthophosphate there was no residue formed indicating complete movement of Mn from the site of placement.

Four manganese ammonium phosphates were identified in the residue samples. The compound Mn(NH4)2H4(P2O7)2·2H2O was present at pH 3.6 and 4.0 and a pyrophosphate content of 40% or greater. Mn3(NH4)2(P2O7)2·2H2O formed at pH values of 5.0 or less and with pyrophosphate contents of 20% or greater. When the fertilizer pH was 5.0 or greater Mn(NH4)2P2O7·H2O was the dominant compound identified in the residues. The only manganese orthophosphate identified was MnNH4PO4·H2O which precipitated at pH values above 5.0 when 80% or more of the P was present as orthophosphate.

Plant utilization of Mn spot‐placed with ortho‐pyrophosphate mixtures as measured with 54MnSO4·H2O was proportional to decreasing precipitation of applied Mn. Maximum uptake of applied Mn occurred at a pH of 3.6 and 100% orthophosphate. Residual uptake of Mn from reaction products blended with the soil was high from all treatments. There was a tendency for a reduction in Mn uptake with increasing pyrophosphate at each level.
Crop Response to Soil Acidity Factors in Ultisols and Oxisols: I. Tobacco
Authors: Abruña‐Rodríguez Fernando , Vicente‐Chandler José , Pearson Robert W. , Silva Servando
Published: July 2010

Yields of tobacco (Nicotiana tabacum L.) on three Ultisols in Puerto Rico increased with liming up to about pH 5.0. There was a highly significant inverse relationship between yield and exchangeable Al. Maximum yield was generally reached as exchangeable Al approached 0 and at base saturation values of around 60%. Yields on an Oxisol increased with liming to about the same pH and base saturation level, although only traces of exchangeable Al were found. Leaf analysis indicated that Mn toxicity was a probable factor in the Oxisol. Tobacco root growth, studied in one of the Ultisols, was directly affected by low soil pH. Al toxicity appeared to be the chief cause of restricted growth but Ca deficiency was a possible contributing factor.
Some Relations Among Coastal Plain Soils and Geomorphic Surfaces in North Carolina
Authors: Daniels R. B. , Gamble E. E. , Cady J. G.
Published: July 2010

Soils on the upper and middle Coastal Plain surfaces in North Carolina have been exposed to surface weathering for about 3‐ to 10‐million years. This makes it possible to evaluate the effect of soil formation of long duration on soil properties. Solum thickness, percentage of soils with plinthite, and gibbsite content increase from the youngest to the oldest surface, but kaolinite content and percentage of soils with Be bodies decrease in this direction. Solum thickness, percent of soils with plinthite, gibbsite and kaolinite content and percentage of soils with Be bodies have a curvilinear change with time. Soil properties are not always related to the total time of subaerial weathering because some soil processes do not begin for a million or more years after weathering starts. Changing internal soil environments produced by changing water‐table regimes is a major factor influencing soil formation in these soils. Changing water‐table regimes probably are produced largely by landscape evolution.
Effects of Added Nitrogen on the Availability of Phosphorus to Slash Pine on Two Lower Coastal Plain Soils
Authors: Maftoun M. , Pritchett W. L.
Published: July 2010

Applications of 50 to 400 ppm N as NaNO3 or (NH4)2SO4 suppressed growth, total P uptake, and recovery of fertilizer P by young slash pine (Pinus elliottii var. elliottii Engelm.) in two P‐deficient coastal plain soils. At the higher N rates (200 and 400 ppm) growth was limited severely by (NH4)2SO4 and all seedlings were killed by these rates of NaNO3 in pot experiments. Growth suppressions following N fertilization were associated with reductions in P availability, as measured by total P uptake.

Reducations in total P uptake apparently were not a result of anion antagonism, as there were only small differences in P uptake associated with the two N sources. Incubation studies indicated very low rates of nitrifications in these soils and N applications did not increase microbial activity (CO2 production), which could have temporarily reduced P availability.

Root development was restricted by the N fertilizers to a greater extent than was top growth. The root suppression evidently resulted from increased concentrations of Na or total salts in the soil. Although it appeared from these studies that Na was involved in the reduction in P uptake by the seedlings, it was not clear whether the small suppressions following N fertilization were associated with reductions in P uptake.
Equations for Approximating Vertical Nonsteady‐State Drainage of Soil Columns
Authors: Jackson Ray D. , Whisler Frank D.
Published: July 2010

Equations are derived, from a capillary tube model, that predict vertical nonsteady‐state drainage from soil columns over the entire time of drainage for which experimental data are available. The model assumes that a soil column is a bundle of capillaries of various radii with the effective conductivity of the column decreasing as drainage progresses. The conductivity is first considered to be a linear function of the average water level in the column, and then considered to be a quadratic function of the water level. Both resulting equations predict drainage reasonably well when particular values are assigned to the ratio of the average height of capillary rise to the column length. A simplified expression is obtained by neglecting an insignificant term and assigning values to constants in the equation in which the conductivity was taken as a quadratic function of the average water level. The equations are compared with experimental data.
Crystalline Phosphates Produced By Interaction of Orthophosphate Fertilizers With Slightly Acid and Alkaline Soils
Authors: Bell L. C. , Black C. A.
Published: July 2010

Petrographic and X‐ray diffraction methods were used to identify the phosphates formed when Ca(H2PO4)2 · H2O, NH4H2PO4, and (NH4)2HPO4 were allowed to move individually into columns of slightly acid and alkaline soils from a layer of the solid phosphate salt placed at the bottom. The soil columns were examined after 4, 16, and 48 weeks of incubation. With Ca(H2PO4)2 · H2O as the fertilizer, the dominant phosphate identified in all soils was CaHPO4 · 2H2O. Minor amounts of CaHPO4 were found in the soils within 2 mm of the fertilizer. With NH4H2PO4 as the fertilizer, CaHPO4 · 2H2O was again the dominant phosphate identified in all soils, the amount increasing with the amount of calcium present initially in exchangeable and carbonate forms. No CaHPO4 was found. In one soil containing 12 meq of exchangeable magnesium per 100 g, the CaHPO4 · 2H2O was accompanied by MgNH4PO4 · 6H2O, which, with time, dissolved to form Mg3(PO4)2 · 22H2O. With (NH4)2HPO4 as the fertilizer, the amounts of crystalline phosphates found were smaller, but the number of different phosphates was larger than with the other fertilizers. Phosphates identified were Ca(NH4)2(HPO4)2 · H2O (dimorph B), Ca8H2(PO4)6 · 5H2O, CaHPO4 · 2H2O, and MgNH4PO4 · 6H2O, but no one phosphate was identified in all soils. CaHPO4 · 2H2O was the dominant phosphate in high‐calcium soils (except for a highly calcareous soil in which only Ca8H2(PO4)6 · 5H2O was identified), but was present only in traces in low‐calcium soils. Ca(NH4)2(HPO4)2 · H2O (dimorph B) was identified in most soils at 4 weeks; it disappeared with time, leaving a residue of CaHPO4 · 2H2O. MgNH4PO4 · 6H2O occurred at 4 weeks in a soil high in exchangeable magnesium; only a trace remained at 48 weeks. Ca8H2(PO4)6 · 5H2O occurred as an initial product in a soil containing 22% CaCO3 equivalent and as a product of alteration of CaHPO4 · 2H2O in a number of soils with pH values of 6.3 or higher. Once formed, it seemed stable with time.
Effect of Clod Size in the Seedbed on Development and Yield of Sugarcane
Authors: Jain N. K. , Agrawal J. P.
Published: July 2010

Topsoil was replaced to a depth of 22.8 cm with clod separates, to correspond to Yoder's pulverization moduli, in an experiment conducted with sugarcane (Saccharum officinarum L.) during 1965–1966 and 1966–1967 at the Government Agricultural College, Kanpur, India. Soil bulk density, used as a measure of soil pore space, was lowest at pulverization modulus 2 which represented a clod size of 3.2 to 6.4 mm. Increased pore space at this pulverization modulus resulted in a higher germination percentage, increased the number of shoot roots, enhanced the uptake of nitrogen and, consequently, benefited all measured indices of sugarcane crop response. These included plant height, number of tillers, number of millable canes, and cane yield. To some extent, juice quality of sugarcane was also improved by optimum soil preparation. Deviation from an optimum to a coarser seedbed was less harmful than deviation to a finer seedbed.
Nitrate Volatilization from Soils
Authors: Thomas G. W. , Kissel D. E.
Published: July 2010

Nitrate losses from several soils were studied with regard to soil acidity, temperature, and time of heating. Much higher losses of NO3 were observed from soils containing KCl‐exchangeable Al3+ + H+ than from those with no replaceable acidity. Losses at 85 and 110C were much higher than at lower temperatures, suggesting that losses in the field would be moderate. There was a general increase in NO3 loss with time of heating.

The reaction explaining most of the loss was thought to be:
urn:x-wiley:03615995:saj2sssaj197003615995003400050043x:equation:saj2sssaj197003615995003400050043x-math-0001 However, there was an additional small loss of NO3 from all soils used which could not be explained by the above reaction.
A Variable‐Intensity Sprinkling Infiltrometer
Authors: Amerman C. R. , Hillel D. I. , Peterson A. E.
Published: July 2010

A rotating disk with four open, adjustable slots was mounted on a portable single‐nozzle sprinkling infiltrometer. When spun at about 60 rpm, essentially uninterrupted artificial precipitation reached the ground surface. At intensities ranging from 1 mm/hr to more than 150 mm/hr, uniformity coefficients were little different from those achieved by the nozzle itself.
Miscible Displacement Measurements within Laboratory Columns Using the Gamma‐photoneutron Method
Authors: Corey J. C. , Hawkins R. H. , Overman R. F. , Green R. E.
Published: July 2010

When fluid in a porous medium is displaced by a second fluid that is miscible with the first, a transition zone exists between the two. The length and location of this transition zone in a soil column is difficult to measure in situ. When one of the fluids contains D2O as the major component, a new procedure, the gamma‐photoneutron method, readily measures this transition zone. This method permits precise measurements of the average concentration of heavy water (D2O) at selected locations in a soil column. The utility of the method is illustrated by two experiments; the downward displacement of D2O (specific gravity of 1.105 g/cm3) by H2O, and the downward displacement of H2O by D2O + NaNO3 (specific gravity of 1.291 g/cm3). The mathematical model which describes the shape of the transition zone between the miscible fluids requires the apparent diffusion coefficients to be constant. The experiment showed the apparent diffusion coefficient was not constant as the zone moved through a 100‐cm column. Unstable flow due to viscosity differences between fluids was probably responsible for increases in the apparent diffusion coefficient when H2O displaced D2O.
Sources of Phosphorus for Plants Grown in Soils with Differing Phosphorus Fixation Tendencies
Authors: McLean E. O. , Logan T. J.
Published: July 2010

Several phosphates of varying water solubilities were evaluated as sources of P for plants grown in soils with different degrees of P fixation. With relatively low fixation, P content of corn (Zea mays) seedlings increased in direct proportion to water solubility of “available” P. With high fixation, P content decreased with increased water solubility of P. Under the latter conditions, liming the soil or banding the P decreased P fixation; but the amounts were small relative to total P fixed. On slightly acid soils (pH 5.6 to 6.5) where response was obtained to applied P by six crops (corn, alfalfa, German millet, buck‐wheat, wheat, or rice under both field and growth chamber conditions) 20% acidulated material was superior to 100% acidulated material in 16 cases, equal to 100% acidulated material in 55 cases, and inferior to 100% acidulated in only 17 cases. Where yields from the two materials differed significantly, differences were also observed in the effect of added P on soil available P (Bray P‐1). Since the efficiency of solubilization of P in rock phosphate by H3PO4 decreases with rate of acidulation, and the unreacted rock phosphate evidently enhances plant recovery of soluble P, partially (20%) acidulated rock phosphate is a reasonable choice for soils of high P fixing tendency.
Soils and Stratigraphy of a Portion of the Gola River Fan of Uttar Pradesh, India
Authors: Hurelbrink Richard L. , Fehrenbacher J. B.
Published: July 2010

The Gola River fan, formed at the base of the Himalayan Mountains in Nainital District of Uttar Pradesh, India, is composed of strongly to moderately sloping, thin, coarse‐textured sediments over stony layers near the foothills and gently sloping, moderately thick to thick, medium‐textured sediments over sand and gravel beyond some 8 to 10 km below the foothills. The two portions of the fan are separated by a spring line.

The soils of the upper portion of the fan, which is known as the bhabar, are thin and drouthy. Soils of the lower portion of the fan, which is called the tarai, have good moisture storage capacity and are highly productive. All soils are weakly developed with high pH values and high base saturation. Some leaching of bases, translocation of iron, and formation of structure has taken place in these soils, but clay movement has been very slight. Mineral alteration has not been great, the high chlorite and mica clay mineral content being inherited from the soil parent materials. Most of the soils in the tarai have mollic epipedons and cambic horizons and are Mollisols. Soils in the bhabar tend to have thinner, dark‐colored surface horizons than those in the tarai, and those near the apex of the fan and the foothills are Inceptisols and Entisols.
Adsorption of Boron by Ferromagnesian Minerals and Magnesium Hydroxide
Authors: Rhoades J. D. , Ingvalson R. D. , Hatcher J. T.
Published: July 2010

Arid‐zone soils are found to have appreciable boron‐sorption capacities in their silt and sand fractions. The site of this sorption is hypothesized to be magnesium‐hydroxy clusters and coatings that exist on the weathering surfaces of ferromagnesian minerals such as olivine, enstatite, diopside, augite, tremolite, and hornblende as well as micaceous layer‐silicate minerals.
Photoelectric Tachometer for Precise Centrifuge Speed Determination
Authors: Fisher H. D. , Brown M. J.
Published: July 2010

Certain chemical and physical investigations such as the mechanical analysis of soils by centrifugation require that the speed of rotation of the centrifuge be precisely determined. For a cost of approximately $40.00, when used with instrumentation normally available in research laboratories, the system outlined provides a vivid, unambiguous indication of the speed of rotation, the accuracy of which is limited only by the frequency standard used.
Soil Hydraulic Conductivity Measurement by Field Monoliths
Authors: Stibbe Ehud , Thiel T. J. , Taylor G. S.
Published: July 2010

A method is described for evaluating the saturated hydraulic conductivity (K) of field soils. Vertical water flow in relatively large, in situ monoliths provides K values that are reproducible and agree well with other techniques for evaluating K.
The Diffusion and Consumption of Oxygen in Submerged Soils
Authors: Howeler R. H. , Bouldin D. R.
Published: July 2010

Six O2 diffusion models, which included several oxygen consumption processes, were evaluated by measuring O2 consumption rates under conditions which approached the steady state and under transient‐state conditions. Consumption rates under approximately steady‐state conditions were determined by placing undisturbed lake‐bottom cores in water and measuring the decrease in O2 concentration of the water. Transient‐state consumption rates were determined from the amount of O2 gas that had to be injected above an initially reduced soil to maintain a constant O2 concentration at the soil surface. The distribution of extractable Fe in the cores was obtained by sectioning frozen soil cores and extracting the sections with NaOAc at pH 2.8 and with dithionite in EDTA.

Considerable amounts of Fe2+ were found to diffuse from the reduced zone to the oxidized zone where it accumulated as precipitated Fe3+. The oxygen consumption was best described by models which included consumption by microbial respiration in the aerobic zone and oxidation of mobile and nonmobile reductants such as Fe2+. The latter components of oxygen consumption accounted for about 50% of the consumption by cores after 11 days when the cores were initially uniformly reduced.
Wheat Straw Decomposition in the Field
Authors: Smith J. H. , Douglas C. L.
Published: July 2010

Wheat (Triticum aestivum) varieties ‘Nugaines’ and ‘Lemhi’ were grown on Portneuf silt loam soil with three nitrogen and three irrigation treatments in 1967. After harvest, 84 kg N/ha was applied to half of each plot before plowing. Uniform straw samples were enclosed in fiberglass cloth bags and buried in the plots September 7. The straw placed in N‐treated plots received sufficient N in solution to increase the straw N from about 0.29 to 1.5%. Straw samples were recovered November 15, after the soil had cooled below 4C, and at three later sampling dates to October 3, 1968, after a bean crop (Phaseolus spp.) was harvested. Weight loss and total N were determined on all samplings and total C on the first sampling. Decomposition was greater with N than without it for the November sampling and the March sampling for Nugaines but not at other samplings for both varieties. The weight of N in both N‐treated straw varieties decreased 55% by November 15, while in the non‐N‐treated Nugaines and Lemhi straw, N weight increased 12 and 32%, respectively, by March 22. Later, N moved out of all the straw samples when the N percentages were much lower than the theoretical equilibrium value.
Chemical and Physical Stability of Microbially Stabilized Aggregates
Authors: Aspiras R. B. , Allen O. N. , Chesters G. , Harris R. F.
Published: July 2010

Chemical properties of microbially bound aggregates were determined by organic solvent extraction and by the rate of sonic dispersion of the aggregates. Seven fungi, six streptomycetes, and four bacteria, produced in situ chemically different binding agents which conferred different chemical and physical properties on soil aggregates. A. tenuis, S. atra, and two species of Penicillium apparently bound soil aggregates by the production of humic‐like binding materials. Six streptomycetes and two Aspergillus species obtained their effectiveness by production of a combination of humic‐like components and polysaccharides. Components of lignin‐like character were involved in the stabilization of aggregates bound by two Aspergillus species. B. polymyxa, R. trifolii, and two species of Agrobacterium bound soil aggregates largely by NaIO4‐oxidizable polysaccharide gums. M. hiemalis was the only organism that bound aggregates by waxy or fatty components.

Microorganisms differ widely in their ability to affect mechanical stability of water‐stable soil aggregates. The ability of each microorganism to bind mechanically stable aggregates varied between soil types. Aggregates bound by A. tenuis and S. atra, B. polymyxa, and A. radiobacter were more stable than those bound by other microorganisms, as evidenced by the longer exposure time required for sonic dispersion. The aggregates produced by S. purpurascens and S. coelicolor were less resistant to sonic dispersion. Aggregates of three soils bound by A. zonatus and M. hiemalis were destroyed easily by sonication. Microbially‐bound Kewaunee clay aggregates were generally the most resistant to sonic dispersion.
Ionic Effect of Salts on Mineral Nitrogen Release in an Allophanic Soil
Authors: Agarwal A. S. , Singh B. R. , Kanehiro Y.
Published: July 2010

A comparison of the effects of sulfate and chloride salts on N release and microbial activity in Akaka soil showed that only sulfate salts at low concentrations increased CO2 evolution. The chlorides were more effective than sulfates in effecting NH4‐N release in the soil. The addition of CaCl2·2H2O resulted in the greatest NH4‐N release, followed by that of KCl and NaCl. Among sulfates, K2SO4 ranked first, followed by Na2SO4 and CaSO4 · 2H2O. The idea that certain chemical reactions and/or processes are involved in splitting NH4‐N from organo‐inorganic complexes of a soil and that NH4+ ions are subsequently exchanged with cations in the surrounding soil solution was further substantiated by results of this investigation. The exchange reaction was noted to depend on the nature and valence of the cation, concentration in the soil solution, length of reaction, and the anionic species associated with the cation. The capacity of the cations for releasing NH4‐N decreased in the order Ca > K > Na for the chloride series.

Unlike the NH4‐N release pattern, sulfates were more effective than chlorides in promoting nitrification. In general, all salts, excepting CaSO4 · 2H2O, at higher concentrations curtailed nitrification. The results indicated a real participation of anions in soil N release. Two salts containing the same cation but different anions released different magnitudes of N at an equivalent concentration. Thus, the results of this investigation provide further support for the role of cations in soil N release and, in addition, furnish reasonable evidence of the participation of anionic species. A consideration of the overall values of NH4‐ and NO3‐N at various salt concentrations led to the series, CaCl2 · 2H2O > KCl > NaCl > K2SO4 > Na2SO4 > CaSO4 · 2H2O, in order of decreasing N release power.
Phosphorus Adsorption and Movement in Some Sandy Forest Soils
Authors: Humphreys F. R. , Pritchett W. L.
Published: July 2010

Seven to 11 years after rock or superphosphate was applied to young slash pine (Pinus elliottii Engelm. var. elliottii) plantations on seven soils of the Lower Coastal Plains, significant growth responses were evident in five of the seven tests. However, there were indications that the effect of the fertilizer was diminishing in certain soils. Foliage P, soil P intensity measurements, P sorption characteristics, and the Chang and Jackson sequential extraction procedure were used to ascertain the present availability of fertilizer residues at different soil depths. Little or no residual P from superphosphate remained in the top 20 cm of soils with no P sorption or buffering capacity, such as Leon fine sand. However, almost all of the superphosphate remained in an available form in the rooting zone in soils with a low P sorption and buffering capacity. In a soil with a high P sorption and buffering capacity most of the added P was retained in the surface horizon in a poorly available form. Little rock phosphate had been leached from any of the soils. Some transformation of P to adsorbed forms, as with superphosphate, had occurred, but availability was very high in each case. Some observations are made concerning the types and amounts of phosphate fertilizers suitable for these and similar soils.
Testing Sodium Hazard Predictions
Authors: O'Connor G. A.
Published: July 2010

Greenhouse data were used to test a series of equations developed by Rhoades to predict the sodium hazard of irrigation waters. Two equations used to calculate values of LRSAR were found to successfully predict excess sodium accumulation in treatments where LF < LRSAR. Equations used to calculate SARdw values gave good quantitative agreement for systems apparently in equilibrium when the soil‐mineral weathering coefficient was assumed to be 0.65.
Effect of Waterlogging and Organic Matter on the Loss of Applied Sulfur
Authors: Jones M. B. , Williams W. A. , Martin W. E.
Published: July 2010

Gypsum and elemental S (56 kg/ha) were applied to lysimeters before the first fall rains. Waterlogging and barley straw (Hordeum vulgare L.) (11,200 kg/ha) were additional variables imposed in all possible combinations. Nitrogen was applied uniformly to all tanks, and cereal and grass were grown during two seasons. In the first year after application of gypsum, 45 and 41 kg/ha S were recovered in the leachate from freely drained soil with and without straw, respectively. The free draining tanks treated with elemental S gave values of 10 and 7 kg/ha S recovered in the leachate for the straw and no straw treatments. Waterlogging decreased leaching loss of sulfur by an average of 40%. Oats (Avena sativa L.) planted when waterlogging was discontinued took up more S in the absence of straw and also more S was leached than on the freely drained treatment. However, no significant increase in uptake occurred in the succeeding grass crop as a result of the sulfur conserved by the waterlogging. It is concluded that where waterlogging occurs during the winter months in annual‐type range soils, SO4‐S leached from either applied or natural sources of sulfur is likely to be decreased, but also that sulfur conservation by this means is unlikely to aid the production of grasslands in California.
A Statistical Comparison of pH Values of some English Soils after Measurement in both Water and 0.01M Calcium Chloride
Authors: Davies Brian E.
Published: July 2010

Published pH values of British soils, determined both by equilibration with water and 0.01M CaCl2 solution have been analyzed by statistical techniques. Values from the two determinations are linearly related with a highly significant positive correlation. A pH of 6.5 is conveniently regarded as neutrality when soil reaction is determined with CaCl2 solution.
Reaction of Copper Tetrammine With Bentonite Clay
Authors: El‐Sayed M. H. , Burau R. G. , Babcock K. L.
Published: July 2010

Copper (II) tetrammine was accumulated by bentonite in amounts greatly exceeding its cation exchange capacity. Analyses of sorption isotherms disclosed that at least two distinct reactions were involved. The first was completed at low equilibrium concentration and appeared to be insensitive to temperature changes. The second was an endothermic process that simulated compound formation. Exchangeable Cu(NH3)42+ on the clay was evaluated by isotopic dilution and its exchange reaction with calcium was investigated. It is doubtful that Cu(NH3)42+ can be used directly to assess copper exchange capacity of clays.
Efficiency of Different Nitrogen Forms As Tested By Barley Seedlings
Authors: Balba A. Monem , Shabanah M. R.
Published: July 2010

A study using modified Neubauer technique was carried out to evaluate the efficiency of the soil organic N and the soil‐fixed NH4+ to supply barley seedlings (Hordeum vulgare L.) with N in the absence and presence of nitrate increments.

The results showed that in the absence of NO3‐ increments, the seedlings absorbed the mineralized soil organic N at the rate of 0.065 mg N/mg soil organic N and the soil‐fixed N at the rate of 0.27 mg N/mg fixed N. The efficiency of the soil‐fixed NH4+ was 4.18 times that of the soil organic N.

The absorption of the fixed N and the mineralized organic N increased with increments of NO3‐, at the rate of 1.20 mg of fixed N and 0.88 mg of soil N/mg N added as NO3‐. An equation representing the uptake of N from the three sources was established and their contribution to the plant content of N was calculated.
Chemical Characteristics of the Coppice Dune Soils in Paradise Valley, Nevada
Authors: Stuart D. M. , Schuman G. E. , Dylla A. S.
Published: July 2010

The coppice dune and associated barren playa soils of Paradise Valley, Nevada contain large amounts of soluble salts, exchangeable sodium, and boron. The concentrations of salts and sodium are variable. Sodium and Cl appear to be the principal soluble ions. The pH at the surface is high (usually 9+). Exchangeable sodium percentage is high at the surface (30% +) and decreases with depth. Boron, while highly variable, is high enough at several locations to limit the growth of even tolerant species. Silica in the saturated extracts increases as the soil pH increases. Because of the salts, high pH, exchangeable sodium, and toxic concentrations of boron, even partial reclamation of these soils would prove difficult without an adequate supply of water, large amounts of amendments, and considerable expense.
Similarities of Two Major Haplaquepts Mapped Along Tributaries of the Ohio River in Northwestern Kentucky
Authors: Bailey H. H. , Barnhisel R. I. , Rice H. B.
Published: July 2010

Soils identified as belonging to the Alligator and Sharkey series are of wide distribution and importance on portions of the Lower Ohio River Valley Flood Plain. Previous morphological and chemical studies indicated a close similarity of these soils. Further studies of physical properties, including particle size distribution, aggregate stability, bulk density, plastic limits, pore space, available moisture, percolation rates, along with sand, silt, and clay mineralogy, indicate that in most characteristics there are greater ranges between profiles within a series than between series. These data strongly support the hypothesis that these soils should be included in the same classification and mapping category in the Lower Ohio River Valley; namely, Vertic Haplaquepts: fine montmorillonitic, nonacid, mesic. The suggested classification is in the Karnak series.
Remote Soil‐Water Sampling Technique
Authors: Wengel R. W. , Griffin G. F.
Published: July 2010

Commercial soil‐water samplers have been modified by using small diameter nylon tubing and toggle valves to achieve remote sampling. Particular benefits of this technique are: (i) elimination of traffic at the sampler site, thus preventing excessive soil compaction and plant damage at the site which could alter the experimental results; (ii) facilitation of multiple sampling and/or frequent sampling; and (iii) reduction of inter‐sample contamination caused by residual solution in long lines. Field equipment is shown and discussed.
Effects of Chromium on Growth and Mineral Nutrition of Soybeans
Authors: Turner M. A. , Rust R. H.
Published: July 2010

Chromium additions [0–5 ppm Cr(VI)] to soybeans, Glycine max (L) Merrill, grown in nutrient culture resulted in decreased concentrations and total uptake of Ca, K, P, Fe, and Mn in tops and of K, Mg, P, Fe, and Mn in roots. These effects were often apparent at Cr treatments as low as 0.5 ppm.

In soil culture Cr additions [0–60 ppm Cr(VI)] appeared to interfere with the accumulation of Ca, K, Mg, P, B, and Cu by soybean tops, with little or no effect on Fe, Mn, or Zn uptake. These effects were generally first observed at the 5‐ppm Cr treatment.

The initial symptoms of Cr toxicity appeared as severe wilting of tops of treated plants.

It could not be concluded from the results of these experiments that Cr, as the hexavalent anion, specifically interfered with uptake of Fe or P by plants, as earlier reported.
Microrelief, Soil Water Regime, and Loblolly Pine Growth on a Wet, Mounded Site
Authors: Lorio Peter L. , Hodges J. D.
Published: July 2010

Microrelief and associated soil characteristics were related to differences in soil water regime and diameter growth response of 40‐year‐old loblolly pines (Pinus taeda L.). Growth on flat sites between mounds about 0.6 m high greatly exceeded that on the mounds, but variability in growth rate was likewise greater on flats. Soil water recharge from summer or fall showers was related to microrelief and antecedent water status. Recharge on flat sites resulted in accelerated growth evidenced by dendrometer band measurements and by zones of earlywood‐type cells within the latewood. The soil water regime and tree growth responses indicate an unstable environment on flat sites that probably affects tree rooting and, in time, tree susceptibility to bark beetle attack.
Biosynthesis of Sugars in Soils Incubated with 14C Glucose and 14C Dextran
Authors: Oades J. M. , Wagner G. H.
Published: July 2010

Samples of soil were incubated for 28 days after the addition of 14C‐labeled glucose or 14C‐labeled dextran. Decomposition was monitored by measuring the release of CO2 and determining its radioactivity throughout the incubation period. Soil samples were removed from the incubation at intervals, hydrolyzed to release individual monosaccharides, and the radioactivity of each sugar was measured.

The 14C from glucose or dextran was rapidly incorporated into galactose and mannose during the incubations; but xylose, arabinose, rhamnose and fucose embodied smaller amounts of 14C or none at all.

At the end of 28 days, 75% and 66% of the 14C had been liberated as CO2 from the glucose and dextran incubations, respectively. Of the residual 14C in the soils after 28 days, about 6% from the glucose incubation and 15% from the dextran incubation, was present in saccharides and predominantly found in the hexoses.

A portion of the dextran was apparently protected from decomposition during the incubation.
Influence of Nitrogen Source and Clay on Growth and Phenolic Polymer Production by Stachybotrys Species, Hendersonula toruloidea, and Aspergillus sydowi
Authors: Bondietti E. , Martin J. P. , Haider K.
Published: July 2010

Additions of montmorillonite (0.25–1.0%) and vermiculite and kaolinite (0.25%) to aerobic cultures of Hendersonula toruloidea, Stachybotrys spp., and Aspergillus sydowi, greatly accelerated growth, glucose utilization, CO2 evolution, phenol synthesis and phenolic polymer formation. In some tests the clay increased total biomass formed, while in others the biomass of the checks eventually attained values of the cultures with clay. Montmorillonite was more effective than vermiculite or kaolinite. Nitrate‐N was a poor N source for Stachybotrys spp., but was a relatively good source of N in the presence of montmorillonite. The presence of clays in the culture media exerted little effect on the N content, C content, exchange capacity, total acidity, phenols released upon Na‐amalgam reduction, and decomposition rate in soil of the polymers formed. Phenolic polymers formed in cultures containing inorganic nitrogen contained about ⅓ to ½ the N of those produced in cultures with asparagine or peptone. The percentage of the N of the polymers released as alpha amino N upon 6N HCl hydrolysis was about 30–40% and was not influenced by the N content of the polymers.
Measuring Radiance Characteristics of Soil with a Field Spectroradiometer
Authors: Cipra J. E. , Baumgardner M. F. , Stoner E. R. , MacDonald R. B.
Published: July 2010

A field spectroradiometer was used to measure radiation from samples of seven Indiana soil series in a spectral range from 430 to 730 nanometers (nm). This range includes most of the visible portion of the spectrum. Percent reflectance of the soils was calculated as the ratio of the radiation of the target soil divided by the incident radiation. Reflectance curves were obtained for the soils in both wet and dry conditions with the crust broken and for some of the soils in a dry crusted condition. Preliminary results obtained during evaluation of the instrument indicated a capability for characterizing the radiance properties of various soil series.
Leaching of a Surface Layer of Sodium Chloride into Tile Drains in a Sand‐Tank Model
Authors: Mulqueen J. , Kirkham D.
Published: July 2010

A series of experiments was conducted to study the leaching of NaCl through tile drains from a surface layer of salinized sand in a sand‐tank model. The effects of two recharge rates, three salinities in the salted‐sand layer, and three drain spacings were evaluated. Each experiment was conducted with a steady‐state, arch‐shaped water table maintained by recharge from a battery of capillary tubes that gave a uniform infiltration over the model. All the salt was leached from the model. The salt was dyed blue so that the leaching front could be photographed. The salinity of the tank solution and of the drainage water was measured at regular intervals. Intense fingering developed in all experiments in which a salinized layer was used. Fingering caused a rapid and erratic redistribution of salt within the model and an erratic variation in the salinity of the drainage water until about 1 pore volume had drained. The higher the initial sand salinity, the more intense was the fingering, the longer were the fingers, and the higher were the finger velocities. The behavior of the fingering transition zone was controlled by the interaction between the density gradients and the hydraulic gradient; this latter depends on the recharge rate and the drain spacing. The salinity of the outflow drainage water rose quickly to a peak and then declined almost as quickly for a short period, after which it reduced more gradually. After about 1 pore volume had drained, the salinity of the drainage water declined exponentially in all salinized experiments. Experimental curves fitted closely to an exponential relationship except initially and where fingering resulted in erratic variations.
Alkali Metal Cation Exchange on Chambers Montmorillonite
Authors: Gast R. G.
Published: July 2010

Standard free energies of exchange, ΔG°, were determined for the exchange of Na with Li, K, Rb, and Cs on a 0.1–0.5 micron fraction of Chambers montmorillonite having an exchange capacity of 123 ± 2 meq/100 g. The ΔG° values ranged from +80 cal mole‐1 for Na→Li exchange to ‐1886 cal mole‐1 for Na→Cs exchange and were approximately twice as large as those found previously for similar exchange reactions on Wyoming bentonite having an exchange capacity of 92 ± 2 meq/100 g. The ΔG° values reflect cation selectivity differences of a factor of two to three between the two clays. In contrast, the standard heats of exchange, determined calorimetrically, were approximately the same for both clays and ranged from + 125 cal mole‐1 for Na→Li exchange to ‐2575 cal mole‐1 for Na→Cs exchange. These results indicate that the differences in free energies of exchange between the two clays are due to entropy effects.
Diffusion of Zinc in Soil: I. The Influence of Soil Moisture
Authors: Warncke D. D. , Barber S. A.
Published: July 2010

Effective Zn diffusion coefficients, De(Zn), were determined at several soil moistures on six soils by allowing 65Zn diffuse from the soil into cation exchange resin paper placed on the surface of the soil. At 13% volumetric moisture De(Zn) values ranged from 10‐11 to 10‐8 cm2/sec with the range narrowing as the soils approached moisture saturation. In five of six soils, the effect of increasing moisture level on De(Zn) could be explained by its effects on tortuosity and on solution Zn concentration. When solution Zn remained constant as moisture level increased, the relation between De(Zn) and volumetric moisture was hyperbolic. When solution Zn level dropped as moisture increased De(Zn) changed very little. In one soil where variation in De(Zn) with moisture level was not explained by these two factors, a third unknown factor apparently influenced De(Zn).
Contributions of Clay and Organic Matter to the Cation Exchange Capacity of Maryland Soils
Authors: Wright W. R. , Foss J. E.
Published: July 2010

Fifty‐seven profiles representing 19 soil series from the three physiographic regions of Maryland were described and sampled. The relative contributions of clay and organic matter to total cation‐exchange capacity (CEC) of various horizons were measured using multiple regression analysis. The independent variables were clay and organic matter, with the dependent variable being CEC by sum of cations. The average exchange capacities of organic matter and clay from Ap horizons were calculated to be 295 and 41 meq/100g, respectively. Standard partial regression coefficients indicated that organic matter was slightly more important than clay in predicting the CEC of surface horizons. Soils of the Coastal Plain region had higher correlations between variables than Piedmont or Appalachian soils. In fact, only the Coastal Plain soils exhibited significant correlations between clay and CEC for B and C horizons. Correlation coefficients of clay and organic matter with CEC in the Coastal Plain Ap horizons were 0.90 and 0.76, respectively, and 88% of the variation in CEC could be attributed to these components.
Fractionation of Cation Exchange Capacity for Assessing Soil and Water Sodicity
Authors: Bower C. A. , Rhoades J. D.
Published: July 2010

High vermiculite, arid zone soils whose cation exchange capacities (CEC) decrease more than 45% by K fixation have higher than usual regression coefficients for the relation between their exchangeable‐sodium ratio (ESR) and sodium‐adsorption ration (SAR). The regression coefficients are approximated by the equation: regression coefficient of ESR/SAR relation = (0.00043 × percentage decrease in CEC upon K fixation) ‐ 0.0045. For eight soils having a wide range of vermiculite contents, the exchangeable‐sodium percentage required to cause a 25% reduction in hydraulic conductivity at a salt concentration of about 10 meq/liter was highly correlated (r = 0.95) with CEC after K fixation.
Evaluation of a Reductiometric Titration Method for Determining Quinones in Soil Humus
Authors: Mathur S. P.
Published: July 2010

A SnCl2‐I2 reductometric titration method gave values of 4.2 and 3.5 meq quinoid carbonyls/g in a soil fulvic (FA) and humic acid, respectively. The results were supported by the analysis of a mixture of the FA and a napthaquinone, and were in agreement with earlier enzymatic and infrared studies of the soil humic compound. No reduction of the nonquinoid carbonyl of benzophenone by SnCl2 was observed.
D‐Chiro‐Inositol Phosphate in a Forest Soil
Authors: L'Annunziata Michael F. , Fuller Wallace H. , Brantley David S.
Published: July 2010

The previously unidentified “D,L”‐chiro‐inositol phosphate (L'Annunziata and Fuller, 1971) of a Tucson forest soil was identified as the dextrorotatory D‐chiro‐inositol phosphate. An infrared spectrum of the inositol moiety was obtained as evidence for the chiro isomer, additional to the previously reported paper chromatographic Rf values (L'Annunziata and Fuller, 1971). A positive polarimetric optical rotation verified the dextrorotatory character of this isomer.
Scaling of Horizontal Infiltration into Homogeneous Soils
Authors: Reichardt K. , Nielsen D. R. , Biggar J. W.
Published: July 2010

The horizontal infiltration of water into uniform air‐dry soil columns is examined experimentally and theoretically. The applicability of the similar media concept to the scaling of soils having a wide textural range is studied. The microscopic characteristic length is determined from plots of the distance to the wetting front as a function of the square root of time, in such a way that these plots coalesce into one line when expressed in terms of scaled coordinates. If the soil water diffusivity of one soil is known, values of the microscopic characteristic length determined by the above method can be used to estimate the soil water diffusivity of the other soils.
Transport of Picloram in Relation to Soil Physical Conditions and Pore‐Water Velocity
Authors: Davidson J. M. , Chang R. K.
Published: July 2010

Miscible displacement techniques were used to study the movement of a solution containing 4‐amino‐3, 5, 6‐trichloropicolinic acid (picloram) through an initially herbicide‐free Norge loam soil. Picloram mobility was reduced significantly by decreasing the average pore‐water velocity from 5.8 to 0.59 cm/hr. A variation in herbicide adsorption with pore‐water velocity was observed at each bulk density (1.55 and 1.65 g/cm3) and aggregate size (<2.0 and <0.42 mm) studied. For a specific bulk density, picloram adsorption was greater when the largest soil aggregate size was <0.42 mm than when the soil contained <2.0‐mm aggregates. Differences in the effluent concentration distribution owing to variations in aggregate size were more evident at the lower bulk density. The average pore‐water velocity influenced picloram movement more significantly than variations in bulk density or largest aggregate size at a given flow rate.
Estimation of Corn and Soybean Yields Utilizing Multiple Curvilinear Regression Methods
Authors: Gross E. R. , Rust R. H.
Published: July 2010

Analysis of crop yield and soil management records were made to determine relationships between yield, management, and climate. Detailed investigations were made of fertilization, plant population, planting date, soil moisture, and temperature with respect to crop yield and selected soil family groupings in Minnesota. The independent variables used were N, P, K, plant population, maturity rating, planting date, average monthly temperatures for May, June, July and August, and the average available soil moisture for June 1, July 1, August 1, and September 1. The available soil moisture was computed using estimated moisture holding capacity of the soil, the precipitation and the temperature. For corn records three soil groups based on family criteria were used. Variables most highly correlated with yield and retained with greater than 60% frequency were applied N, P, and K, plant population, planting date, May, June, and July temperature, and soil moisture June 1, August 1, and September 1. Substitution of independent management and climatic variables into the prediction equation produces reasonable increases in corn (Zea mays L.) and soybean (Glycine max L.) yields and could be used as a method of predicting crop yield.
Some Factors Affecting the Soluble Ammonium‐Nitrogen Content of a Black Spruce Humus
Authors: Roberge M. R.
Published: July 2010

The influence of exchangeable NH4‐N content, water content, and pH on the NH4‐N content of the solution of three layers (L, F1, and F2) of the surface organic horizon found under a black spruce (Picea mariana (Mill.) BSP.) stand was investigated under controlled conditions in the laboratory. In the solution obtained by centrifugation‐filtration of the layers at 15,000 × g for 10 min the quantity of soluble NH4‐N increased as the exchangeable NH4‐N and the moisture of the layers were increased, and as the pH of the layers was decreased. Different layers were characterized by different levels of soluble NH4‐N even when exchangeable NH4‐N, moisture content, and pH value were comparable in these layers. Greater decomposition of the organic matter of the layers was always associated with lower contents of soluble NH4‐N.