bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of Paleosols and the Fort Hall Geosol in Southeastern Idaho Loess Deposits
Authors: McDole Robert E. , Lewis Glenn C. , Fosberg Maynard A.
Published: July 2010

Information on the origin and history of the southeastern Idaho loess deposits was obtained through examination of 11 loess sections for evidence of paleosols. These sections comprised three transects traversing the loess deposits adjacent to the Snake River flood plain near Pocatello, Idaho. Characteristics identifying paleosols were found in 7 of the 11 sections. The paleosols were identified by zones in the loess section having one or more of the following properties: (i) a twofold increase in calcium carbonate equivalent, (ii) a sharp increase to a strong maximum in soluble salts, and (iii) an increase of 5 to 10% in the amount of clay. The paleosols show as strong or stronger development than the present modern soil.

When a paleosol can be positively identified as occurring at more than one site, it becomes a marker used in the study of geologic formations such as loess deposits. A paleosol that serves this purpose is termed a geosol, and becomes a valuable tool in correlation of soil parent materials.

The Fort Hall Geosol was identified in loess sections at 7 of the 11 study sites. The Fort Hall Geosol differed from the rest of the loess section and the other paleosols by having higher total clay content and finer clay, more montmorillonite, higher amounts of coarse silt, very fine sand and coarser sands (1.0 to 0.1 mm); and higher calcium carbonate and total salts.

These identifying characteristics infer the nature of events which took place to form these paleosols. The characteristics suggest polypedogenesis. The initial event in the formation of the paleosols resulted in accumulations of relatively insoluble carbonates and clays. The Fort Hall Geosol represents a much stronger set of soil forming factors than those responsible for the formation of the existing modern soil or the other palesols in the section. Later, soluble salts accumulated in or above the zone of carbonate and clay accumulation. The soluble salts appear to be related to a subsequent deposition followed by a period of leaching.
The Problem of Assessing the Erosive Power of Rainfall from Meteorological Observations
Authors: Kinnell P. I. A.
Published: July 2010

A number of rainfall parameters have been proposed in the past as bases for indexes of erosivity. Values for three such parameters—momentum, kinetic energy, and kinetic energy per unit horizontal area of the drop—were calculated from drop‐size data and relationships between rainfall intensity and the parameter values were developed. Examination of these relationships showed that both raintype and geographic location influenced the parameter values. This suggests that the detachment ability of rainfall, at a given rainfall intensity, may vary between raintypes and geographic locations. However, the degree and direction of the influence depended on which parameter was being considered. The ordering of five raintypes at Miami, Florida, determined by values obtained at given rainfall intensity from the intensity‐parameter regressions for momentum and kinetic energy was reversed for kinetic energy per unit horizontal area of the drop. Therefore, in the absence of data on the rate of soil detachment, it is not possible at present to classify the raintypes at a geographic location according to their detachment power. In the view that runoff is a major factor in controlling the transport phase of soil erosion, the observations indicate that rainfall parameters may only be evaluated as indexes of the detachment power of rainfall if they are determined directly and simultaneously with soil loss, and provided that the influence of runoff on soil loss is taken into account.
Electron Microprobe Analysis of Phosphates in Soils and Sediments
Authors: Sawhney B. L.
Published: July 2010

Electron microprobe analyses of discrete phosphate grains in soils and sediments revealed that precipitated phosphates occur mostly as complex compounds containing Al, Fe, Si, Ca, and P. The composition of these complex phosphates varied over a wide range.
Simultaneous Extraction of Hydroxyatrazine, Atrazine, and Ametryne from Some Hawaiian Soils
Authors: Goswami Kishore P. , Green Richard E.
Published: July 2010

A simple procedure is described for simultaneous extraction from soil of 2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine (atrazine), 2‐methylthio‐4‐ethylamino‐6‐isopropylamino‐s‐triazine (ametryne) and their common hydrolysate (hydroxyatrazine = HA). The procedure involves extraction by shaking in acidified methanol, centrifugation, and subsequent quantitative separation of HA from the parent triazines by liquid‐liquid partitioning. The pH of methanol was adjusted with 4N HCl to obtain a final pH of 2.5 in the soil extract, using a 1:10 soil/solvent ratio. HA recovery with one extraction was 94% for both Molokai (Typic Torrox) and Hilo (Hydrandept) soils having soil extract pH values of 2.4 and 3.4, respectively. In all cases atrazine and ametryne were quantitatively recovered in soil extracts. After protonation HA was quantitatively separated from the mixture of HA and atrazine or ametryne by partitioning in an aqueous methanolic soil‐extract/chloroform system when the water/methanol extract ratio was 1.25. HA extraction from soil was extremely pH dependent. Dissolution of calcium chloride in acidified methanol decreased recovery of added HA from 94% to 76% for Hilo soil but had no effect on % HA recovery from Molokai soil; the electrolyte was found to increase the pH of Hilo soil extract, a result of the net positive charge of this soil at low pH. The recovery of added HA from Ca‐montmorillonite was 33%, suggesting that the procedure may be less suitable for soils with high permanent negative charge.
Genesis, Morphology, and Classification of Mounded Soils in Eastern Oklahoma
Authors: Allgood F. P. , Gray Fenton
Published: July 2010

Numerous small mounds are unique features of landscapes that extend from the southern part of Missouri to the coast of Texas. Many hectares of eastern Oklahoma are included in this vast area. The mounds occur in densities of 8 to 16/ha.

These mounds were studied with special emphasis on the genesis, morphology, and classification of associated soil pedons. Laboratory measurements included particle size distributions, bulk density, extractable cations, and organic matter extractions.

Soil morphological features and laboratory analyses indicated that the development of the mounded soils differs from that of the associated intermound pedons by being highly altered by the many organisms of the landscape that assemble in the selected elevated soil to escape seasonal wet soil conditions.

Mounded soils of Site I are classified as Aquic Paleudolls or Aquic Argiudolls in the present system of soil classification (12). But most of the mounded soils which were studied would be better classified with a vermic modifier.
Effective Available Water and Its Relation to Evapotranspiration Rate, Depth of Wetting, and Soil Texture
Authors: Miller D. E. , Aarstad J. S.
Published: July 2010

The effect of evapotranspiration (Et) rate on effective available water (EAW) was evaluated for three soils ranging in texture from sand to silt loam, at evapotranspiration rates of about 0.4 to 1.3 cm per day, and at two depths of wetting. In all cases, as evapotranspiration rate increased, drainage following irrigation decreased and as a result EAW increased. The increase in EAW due to Et rate was relatively greater in the sand than in the finer textured soils. If only midsummer Et rates are considered, EAW is estimated quite well from a usual field capacity test, provided soil depth and soil texture are considered in determining the sampling time for characterizing field capacity. If one considers usable water referenced to some safe depletion level rather than available water referenced to the 15‐bar percentage, the effect of Et is more important. EAW is influenced differently by depth of wetting in different textured soils.
The Water‐Ice Phase Composition of Clay‐Water Systems: I. The Kaolinite‐Water System
Authors: Anderson Duwayne M. , Tice Allen R. , Banin Amos
Published: July 2010

Previous work has indicated that when water‐ice phase composition curves are normalized to unit surface area, unfrozen water content values at all temperatures are higher for the kaolinite‐water system than for other clay‐water systems. In addition, the water‐ice phase composition curve for this system appeared to be the resultant of the superposition of two power curves of the form Wu = αθβ. The measurements have been repeated using an improved isothermal calorimeter and the earlier results confirmed. Values of Wu per unit surface area for the kaolinite‐water systems are more than twice as large as those for the montmorillonite‐water systems. Addition of polyox (polyethylene oxide) to the kaolinite‐water system had little effect on Wu in the range of 0 < θ < 1.7 but diminished Wu significantly at values of θ > 1.7. The observations are explained qualitatively in terms of a domain model of clayimbibed water.
Sorption of Nitrogen Dioxide by Calcareous Soils
Authors: Prather Robert J. , Miyamoto Seiichi , Bohn Hinrich L.
Published: July 2010

The NO2 sorption capacity and rate of calcareous soils, a calcic soil, and a granular limestone were measured at room temperature by passing air or nitrogen gas containing NO2 through them. In dry air (humidity < 5%), NO2 sorption reached an equilibrium value within 2.5 min. In moist air (humidity > 95%), NO2 sorption increased to as much as 10‐fold that in dry air and approximately equaled the acid‐titratable basicity of calcareous soils. The sorption rate was proportional to the unreacted fraction of the capacity with sorption rate constants ranging from 0.015 to 0.03 min‐1 at a NO2 concentration of 0.5% volume. At a concentration of 0.1%, the sorption rate was slower but the capacity remained unchanged. Sorption of NO2 was similar when either air or a nitrogen carrier was used.
Variation of 15N in Corn and Soil Following Application of Fertilizer Nitrogen
Authors: Kohl D. H. , Shearer G. B. , Commoner B.
Published: July 2010

Samples of corn (Zea mays L.) plant tissue (grain and leaf) were obtained from the University of Illinois South Farm plots and from the University of Illinois Morrow plots. Soil samples were also obtained from each of the South Farm plots. The 15N:14N ratio of the nitrogen in these corn plants is shown to be sensitive to the source of nitrogen taken up by the plants. A systematic decline in δ15N (per mill excess 15N) was observed within a narrow range of variation (about 4 δ15N units) with increasing applications of commercial nitrogen fertilizer. This result is consistent with increasing contributions of fertilizer nitrogen to the plant, as the fertilizer had a δ15N value close to zero. Similarly, the influence of a small amount of manure nitrogen (40 kg nitrogen/ha) applied over many years was detected in samples grown on the University of Illinois' historic Morrow plots. The results indicate that the nitrogen of grain and the leaf tissue of young plants is derived at least in part from different pools reflecting different proportions of fertilizer and soil nitrogen or fertilizer nitrogen of different δ15N, due to the time course of its fractionation. Unexplained differences between the influence of soybeans and clover on δ15N were also observed. Neither the quantity nor the δ15N of the total nitrogen was influenced by short term (3 years) addition of large quantities of nitrogen (448 kg/ha) to the soil on the South Farm plots.

A relatively high value of δ15N was obtained for NO3‐ in the soil profile in the fall following spring application of 448 kg nitrogen/ha. This suggests that the observed nitrate nitrogen was not derived from nitrogen molecules applied as fertilizer in the spring, but originated rather from the exchange of fertilizer nitrogen for soil nitrogen and/or the “priming effect” (release of extra soil nitrogen as a result of the application of fertilizer nitrogen).
Thermodynamics of Ion Exchange
Authors: Ravina Israela , DeBock Joseph
Published: July 2010

The local formulation of nonequilibrium thermodynamics is used to define the electrochemical potentials in the ion‐clay‐water system, thus enabling development of an improved nonempirical approach to cation‐exchange processes. The presence of the electrical field in the system is expressed by a proportional increase of the pressure in the double layer. The effect of the electrical field on the chemical potentials of the exchangeable cations is divided into the common electrostatic term and a term dependent on their polarizabilities. For systems containing a mixture of monovalent ions it can be assumed that the electrostatic effect of the electrical field is the same for each of the exchangeable cations. Using values of the polarizabilities and intrinsic volumes of the alkali metal cations, the free energies of exchange with sodium in montmorillonite were calculated. The calculated free energies were found to be in good agreement with experimental values.
Survival of Two Strains of Rhizobium in Soil
Authors: Danso S. K. A. , Alexander M.
Published: July 2010

A sensitive method was devised for determining the abundance of strains of Rhizobium meliloti and R. trifolii introduced into soil. This method relies on the use of streptomycin‐resistant mutants which, after inoculation into soil, are counted on a medium supplemented with streptomycin at concentrations sufficient to inhibit most soil microorganisms.

Viability of streptomycin‐resistant strains of R. meliloti and R. trifolii did not fall markedly when the bacteria were introduced into moist soils. Various organic matter amendments did not significantly alter the decline rate of the rhizobia. R. meliloti populations did not lose viability readily in moist sand, in desiccated soils, or in solutions free of organic nutrients, but the population density fell rapidly when the bacteria were inoculated into desiccated sand. The rate of decline in cell number was enhanced with increasing temperature. Both rhizobia survived well in dry, nonsterile soil.
An Isokinetic Sampler for Wind Erosible Silt and Clay Particle Measurement
Authors: Arkin Gerald F. , Perrier Eugene R.
Published: July 2010

The general theory, design details, and soil particle concentration data for an isokinetic fine particulate sampler for soil erosion studies are presented. This isokinetic sampler enables rapid measurement of a totally representative profile distribution of soil particles entrained in a turbulent boundary layer within a wind tunnel test section. Differences between mass flux, soil particle concentration, and particle size distribution measured at the sampling point and in the air stream are minimized by isokinetic sampling.
Count‐Rate Instability in Gamma‐Ray Transmission Equipment
Authors: Reginato Robert J.
Published: July 2010

Significant errors in measuring the bulk density and water content of soils can result from a procedure commonly used with gamma‐ray transmission equipment. The detector probe can be exposed directly to the unattenuated gamma‐ray source when moving from a standard absorber to the soil. Under this high‐exposure condition, 20 to 30 min may be required before the system will stabilize and reliable count rates can be taken. To avoid this difficulty, three alternative techniques are suggested. The alternative found most desirable for existing conditions was to take a standard count rate in the soil pedon where the bulk density remained constant, thus eliminating the necessity of exposing the detector to the unattenuated gamma‐ray source.
Influence of Organic Nitrogen on Soil Nitrogen, Nodulation, Nitrogen Fixation, and Yield of Soybeans
Authors: Bezdicek D. F. , Mulford R. F. , Magee B. H.
Published: July 2010

Nitrogen was applied on a previous rye (Secale Cereale L.) cover crop for later determination of the effect of organic N on soybean (Glycine max L.) N2‐fixation rate, plant dry matter, N uptake, and yield. Nitrogen was applied at 0, 56, 112, and 224 kg N/ha as NH4NO3 or urea either on rye in mid‐March or at soybean planting time in a 4 × 2 × 2 factorial design. In both years of study, N2‐fixation rate as estimated from acetylene reduction was reduced throughout the season by increased fertilization rate. For 1 year, interactions showed that N2‐fixation rate and nodule mass were stimulated late in the season from increased N fertilizer applied to the rye but not at soybean planting. Interactions between NH4NO3 and urea and time of application showed that NH4NO3 as compared with urea applied on rye significantly increased soybean dry matter, N uptake, and yield. Urea applied at planting increased these parameters in comparison with NH4NO3. The observed increases in dry matter, N uptake and yield from rye‐applied NH4NO3 were not accompanied by a corresponding increase in N2‐fixation rate or nodule mass. This would suggest that the N2 fixing system was not responsible for the increase of dry matter, N uptake, and yield. Soil organic N was not measurably influenced by the treatments imposed.
Afforestation Alters Prairie Soil Nitrogen Status
Authors: Fisher R. F. , Eastburn R. P.
Published: July 2010

Two prairie soils were examined after 20‐years of occupancy by four tree species to determine what alterations had occurred. Bulk density, exchangeable bases, pH, and organic carbon had not changed in the 0 to 10‐cm soil layer. Red pine (Pinus resinosa) and Japanese larch (Larix leptolepis) caused significant increases in total N and a change in N form. Tulip tree (Liriodendron tulipifera) caused a significant change in N form while basswood (Tilia americana) caused no significant alteration. From this we conclude that alteration in soil N form is one of the first changes to occur following afforestation.
Insolubilization of Inorganic Phosphate by Anoxic Lake Sediment
Authors: Norvell W. A.
Published: July 2010

The insolubilization of soluble phosphate by anoxic lake sediments was studied at 4 to 5C under oxygen‐free conditions. After 3 to 4 weeks of reaction between added phosphate and two sediments, samples of the interstitial solution were recovered and analyzed. Sediment samples were extracted to determine exchangeable cations, CEC, and readily soluble phosphate. Insolubilization of added phosphate was accompanied by decreases in the concentrations of all major cations in the interstitial solution. Soluble cations and phosphate were lost in essentially charge‐equivalent amounts. Calcium, iron, and manganese were lost from both soluble and exchangeable forms. Soluble Mg, Na, K, and NH4 decreased also but only because these cations occupied exchange sites vacated by Ca, Fe, and Mn. The fraction of soluble and exchangeable Mn lost was greater than for any other cation. No significant changes in pH, CEC, or concentrations of indigenous anions were found at any level of added phosphate. Essentially all insolubilized phosphate was recovered as inorganic phosphate by mild extractants suggesting that inorganic chemical reactions were responsible for the losses of added phosphate. The results suggest that phosphate compounds of Ca, Fe, and Mn were precipitated.
Soil Temperatures in Selected Southeastern Idaho Soils: I. Evaluation of Sampling Techniques and Classification of Soils
Authors: McDole Robert E. , Fosberg Maynard A.
Published: July 2010

An intensive 2‐year study of mean annual soil temperatures (MAST) was conducted in an attempt to more accurately classify the soils of the Fort Hall Area, Idaho, Soil Survey into the new Soil Taxonomy. Temperature data was obtained from 21 sites partly from deep samplings (7 to 9 m) with an extension auger and partly from monthly readings taken at depths of 0.6, 0.9, 1.2, and 1.5 m.

Sites were selected under native vegetation to include a range in elevations (1,330 to 1,860 m), drainage, soil texture, and slope. Drainage classes ranged from excessively drained to very poorly drained; textures ranged from loamy coarse sand to silt loam with one site a peat; slopes were nearly level with one 11% south slope and a 20% north slope.

Soils having MAST less than 8C (47F) occurred only above 1,830 m (6,000 ft) elevation or only under very poorly drained conditions. MAST was generally 2.5 to 3C (4.5 to 5.5F) warmer than the mean annual air temperature in the study area except where influenced by slope, texture, or drainage.

Mean summer soil temperature (MSST) of all well‐drained soils was above 15C.
Soil Temperatures in Selected Southeastern Idaho Soils: II. Relation to Soil and Site Characteristics
Authors: McDole Robert E. , Fosberg Maynard A.
Published: July 2010

Development of the new Soil Taxonomy (Soils Survey Staff, 1970) and classification of soils in the new system has brought about renewed activity in collecting soil temperature data in the past few years. However, little of this data has been published to date.

In an attempt to properly classify soils of the Fort Hall Area, Idaho, Soil Survey, an extensive study of soil temperatures was conducted over a 2‐year period. The temperature data collected furnished information on soil temperature as it relates to such characteristics as elevation, slope, texture, drainage, and ground‐water temperature.

Mean annual soil temperature (MAST) is strongly influenced by elevation. An increase in elevation of 300 m reduces the MAST by 2.5 to 2.7C. Presence of a water table having an average temperature of 9.6C in the 150‐cm soil profile resulted in lowering the MAST from the 10 to 12C typical of well‐drained soils in the area to a low of 7.5C on a very poorly drained soil. Mean summer soil temperature (MSST) decreases in going from a well‐drained soil to a very poorly drained soil. In contrast, the mean winter soil temperature (MWST) is higher in the more poorly drained soils than in better drained soils.

South‐facing slopes and coarse texures give indications of slightly increased MAST over nearly level slopes and medium textures, although results from this study are not conclusive. North‐facing slopes show decreased MAST when compared to nearly level slopes.
Evaluating Penetration Resistance and Wheel Sinkage Response to Soil Water Suction Changes in a Draining Clay Soil
Authors: Steinhardt Reuven
Published: July 2010

To facilitate the development of subsurface drainage design criteria for the reduction of soil compaction, the relation between the bearing capacity of nearly saturated soil and its water suction(s) is analyzed for a cone penetrating into the soil and for a sinking tractor wheel. Approximate equations are developed, from basic soil mechanic theory, for certain soils under a limited range of suction and loading conditions. The main assumptions are attainment of plastic equilibrium during dynamic loading and independence of the soil deformation process and its shear failure pattern of suction. The penetration resistance‐suction model shows that a linear response to suction changes can be expected, characterized by a modified bearing capacity‐suction factor (Ns) which may be estimated from the mechanical and water properties of the soil. The wheel sinkagesuction model predicts the relative change in wheel rut depth in response to loading (inflation pressure) and suction changes, by means of the same Ns parameter. Tests were conducted in plowed (P1) and unplowed (P0) irrigated plots of a clay soil, utilizing a cone penetrometer and a tractor with differentially loaded and differentially inflated rear wheels. Variations in penetration resistance with suction were successfully predicted, assuming local, intermediate, and general shear failure in the subsoil, and in the plow‐layers of P1 and P0, respectively. The relative change in wheel rut depth with suction was found predictable, provided S > Smin. The transition from S > Smin to S < Smin was characterized by an inversion of sinkage response in P0, and by a transition from vertical to horizontal soil compaction or flow in P1.
Soil Water Content: Microwave Oven Method
Authors: Miller R. J. , Smith R. B. , Biggar J. W.
Published: July 2010

The moisture content of two soils was determined rapidly with a microwave technique. Equations were developed for estimating soil drying times for two soils of different texture at different moisture contents and for different sample sizes. Results indicate that drying soil by microwave oven also may have a limited use as a method for soil preparation prior to chemical analyses.
Heating Sample Plate for X‐Ray Diffraction Studies of Clays
Authors: Weed S. B. , Leonard R. A.
Published: July 2010

An inexpensive heating sample plate for X‐ray diffraction studies of clay minerals is described. The plate is supported on a machined massive pyrophyllite base which fits in the sample mount of an X‐ray diffractometer. Temperatures up to 450C are readily attained.
Microbial Growth Rate in Glucose‐Amended Soil
Authors: Behera B. , Wagner G. H.
Published: July 2010

Microbial growth in soil amended with glucose was evaluated. Following the incorporation of glucose into soil, rapid evolution of CO2 occurred and was accompanied by a similar increase in bacterial numbers. It appeared that the amendment was utilized primarily by bacteria and was wholly expended within the first 2 days of incubation. Subsequently fungal growth was noted at the time the bacterial count declined. The developing bacterial population followed the typical sigmoid growth curve and a minimum generation time of 2 hours was obtained during the period 5 to 10 hours after adding the glucose. It was determined that the yield coefficient of bacteria produced relative to substrate consumed was 0.39 g of cell C/g substrate C. The energy expended by the population for functions other than production of new cell material, referred to as specific maintenance, was estimated to be 0.0036 hour‐1.
Utilization of Organic Compounds by Germinating Soybean Seeds
Authors: Zwarun A. A.
Published: July 2010

Surface‐sterilized soybean seeds (Glycine max L.) were placed inside sterile vials containing 5 ml of sterile, deionized water and 1µCi amounts of various 14C‐labeled organic compounds. The atmosphere inside the sealed vials was analyzed for 14CO2 every hour for 12 hours. The compounds tested were uniformly labeled glucose, fructose, maltose, lysine, glycerol, and urea; glycine labeled in the 1 or the 2 position; and citric acid labeled in the 1 and 5 positions. All compounds tested were metabolized by germinating soybean seeds as evidenced by 14CO2 evolution. However, with the exception of urea, the amount of 14CO2 produced was small. Urea was metabolized very rapidly and very extensively. It appears that soybean seeds can metabolize external organic molecules within 1 hour of exposure to moisture.
Effect of Macronutrient Ions on the Availability of Iron from a Chelated Source
Authors: Oertli J. J. , Opoku A. A.
Published: July 2010

The uptake of Fe from FeEDDHA [ferric chelate of ethylenediamine di (o‐hydroxyphenylacetic acid)] during periods of 1 to 2 days was studied with 10‐ to 11‐day‐old corn plants (Zea mays L.) grown in nutrient solutions. The Fe in roots and tops was markedly affected by the composition of the nutrient solution. Cations stimulated Fe in plants in the following order: K> Na > Mg > Ca, and anions SO4 > Cl > NO3. The stimulation was the greater the more the pH declined during the absorption experiment; hence it was concluded that the effect of nutrient solution composition on Fe nutrition must be attributed to the imbalance of cation and anion uptake rather than to a specific nutrient. The pH decline and, in general, the associated stimulation of Fe uptake were enhanced by increasing concentrations of the interfering ions and by time. However, when the pH fell toward a value of 4, injury to roots occurred and Fe uptake was reduced in spite of a higher supply. The composition of the nutrient solution was also effective in long‐term experiments in regulating Fe uptake. A decrease in pH resulting from excess cation uptake favors the formation of less dissociated forms of the free ligand, namely of (ligand‐H)3‐, (ligand‐H2)2‐, etc., instead of the reactive ligand, (ligand)4‐ and equilibrium can be maintained only if more FeEDDHA dissociates, liberating Fe3+ for uptake.
Ammonia Volatilization from Surface Applications of Ammonium Compounds on Calcareous Soils: II. Effects of Temperature and Rate of Ammonium Nitrogen Application
Authors: Fenn L. B. , Kissel D. E.
Published: July 2010

The effects of temperature and rate of application on NH3‐N volatilization from NH4+ salts applied to the surface of a calcareous soil were investigated in the laboratory. Total NH3‐N losses were only slightly influenced by temperature over a broad range of NH4+‐N application rates with a precipitate forming NH4+ compound such as (NH4)2SO4 in a calcareous soil. The rates of NH3‐N loss were highly influenced by temperature. High temperatures increased the initial rates of NH3‐N loss although they were proportionally reduced at later stages. The lowest temperature resulted in the lowest initial NH3‐N loss rate but became highest for the last 76 hours. Total ammonia nitrogen losses were dependent on the rate of NH4+‐N application. The quantity of NH3‐N loss varied from 19 to 50% of the applied NH4+‐N at 33 to 550 kg NH4+‐N/ha, respectively.

The increasing temperature increased losses of NH3‐N from NH4NO3 which does not form precipitates with CaCO3 or appreciable (NH4)2CO3. In 100 hours, NH4NO3 lost 14, 18, and 26% of the applied NH4+‐N at 12, 22, and 32C, respectively. Both the total 100‐hour NH3‐N losses and rates of NH3‐N loss were increased by increased temperatures; however, the percent of NH3‐N volatilized was unaffected by rates of NH4+‐N application.

Ammonium sulfate losses from a noncalcareous Wilson clay loam buffered to the pH of the calcareous soil produced NH3‐N losses equivalent to NH4NO3 at 12C and lower than NH4NO3 at 32C. Ammonia nitrogen losses, both total NH3‐N and rates of NH3‐N loss, were similar to losses of NH4NO3 from the calcareous soils. Therefore in the calcareous Houston Black clay the NH3‐N loss caused by reaction of (NH4)2SO4 with CaCO3 ranged from 0 to 70 or 80%.

Regression equations were developed that predict NH3‐N losses at certain temperatures, time, and rate of NH4+‐N application.
Availability of Fertilizer Zinc to Corn in a Calcareous Mineral Soil
Authors: MacGregor J. M. , Sajjapongse A. , Gunderson O. M.
Published: July 2010

Powdered ZnSO4 · 7H2O was plowed down for corn (Zea mays L.) in a Zn‐deficient Fieldon silty clay loam at five rates, row banded, or banded at four rates after mixing with NH4NO3. The effect of dusting corn seed with Na2Zn‐EDTA was also compared, using leaf Zn and grain yields for 5 years as criteria. Soil analyses and greenhouse studies with 65Zn, eight years after Zn fertilization, were conducted to determine possible cause(s) of extreme variations in field availability of indigenous soil Zn for corn, and the residual effect remaining where Zn fertilizer was used eight years previously.

Plowing down ZnSO4 · 7H2O at higher rates resulted in higher leaf Zn in all 5 years, whereas initially effective lower treatment rates decreased with time. Banded Zn and/or N had little or no effect on leaf Zn. Grain yields were increased by both plow down and band ZnSO4 · 7H2O treatments until the fifth year. Dusting corn seed with Na2Zn‐EDTA had no effect on leaf Zn or on annual grain yield, but increased the 5‐year yield.

Soil analyses 8 years after Zn fertilization showed that vegetative Zn‐deficiency symptoms of corn in the field and subsequent low grain yields were significantly related to high extractable P/extractable Zn ratios in the surface 30.5‐cm soil depth. There was no observed effect of temperature, moisture, pH, conductivity, calcium carbonate equivalent, or exchangeable K. More Zn was extracted from the surface soils where Zn had been applied nearly 8 years previously, but “A values” were larger only in soils receiving the heaviest 1962 Zn treatment of 44.8 kg/ha.
A Study of Six “Latosols” from Costa Rica to Elucidate the Problems of Classification, Productivity and Management of Tropical Soils
Authors: Martini J. A. , Macias M.
Published: July 2010

Six deep, red, clayey, acid soils from the hot and humid tropics of Costa Rica, previously classified as “Latosols” were studied. Special attention was given to the diagnostic horizons and properties to elucidate the problems of classification, productivity, and management of tropical soils. Physical, chemical and mineralogical properties showed that these soils were as highly weathered as indicated by their morphological properties and other field observations. However, they were predominantly Ultisols and not Oxisols, as it is sometimes assumed, and they did not fully fit C. E. Kellogg's original definition of “Latosol.” Although physical properties were found to be adequate, chemical properties were indicative of poor soil productivity and difficult management.
Difficult Eroded Planting Sites in North Mississippi Evaluated by Discriminant Analysis
Authors: Duffy Paul D. , McClurkin D. C.
Published: July 2010

A discriminant analysis of physical and chemical characteristics of the upper 23 cm of the soil was computed for 24 sites where bar‐planted loblolly pines (Pinus taeda L.) had failed and at 15 successful plantations near the fail sites. Screening of 17 soil properties indicated that bulk density is the best variable for classifying sites. A function based only on bulk density correctly classified 74% of the sites as fail or success, regardless of microrelief. On sites where bulk density equaled or exceeded 1.45 g/cm3 bar planting was predicted to fail. Information on a site's proximity to the rim or bottom of a deep gully improved accuracy of classification. Since other soil properties differed relatively little between success and fail sites, results suggest that high bulk density substantially contributed to pine mortality, either through physical impedance of root growth or poor aeration or by interference with proper planting.
A Modified Shop Press for Use in Soil Compaction Studies
Authors: Tanabe M. J. , Murdoch C. L.
Published: July 2010

A system was developed at the University of Hawaii for studying effects of compaction on hydraulic conductivity of soil mixtures. A major advantage of this system was the ability of the compacting unit to apply a specific amount of pressure for any desired length of time. The permeameter used also decreased possible error in hydraulic conductivity measurements.
Small Tensiometers for Field and Laboratory Studies
Authors: Rogers J. S.
Published: July 2010

A small tensiometer was constructed and used in field and laboratory studies. The units are suitable only for low suctions, but have the fast response time that is desirable for measuring short‐term changes in field and laboratory studies of drainage. Several tensiometers have been in use for over 4 years and continue to perform very satisfactorily.
Predicting Exchangeable Sodium Ratios in Irrigated Tropical Vertisols
Authors: Sinanuwong S. , El‐Swaify S. A.
Published: July 2010

Batch equilibrium studies were used to investigate Nadivalent exchange and to derive Gapon constants for three Hawaii Vertisols. Obtained regression coefficient values indicated that a linear relationship exists between exchangeable sodium ratios (ESR) and sodium adsorption ratios (SAR) for tropical Vertisols. ESR values obtained for two of the soils were slightly lower than the values predicted by Bower's equation (3) and higher than those predicted by the U.S. Salinity Laboratory's equation (11). ESR values obtained for the third soil were lower than those predicted by either equation. Generally, the higher preferences of surface than of subsurface horizons for Na was confirmed. Prevailing electrolyte concentration levels were found more important than any other experimental variable in affecting the precision of ESR estimates for a given SAR. Although ESR values were generally higher at 0.1N than at 0.01N, the valence‐dilution effect was reversed for the surface horizon of one Vertisol during Mg‐Na exchange.

While little difference was noted between Ca‐Na and Mg‐Na exchange in one of the soils, in the other two significantly smaller ESR values were obtained for the first than for the second reaction. An unexpected type of hysteresis effect was noted, whereby divalent‐soils exhibited greater preference for Na than did Na‐soils. Possible reasons for this effect are discussed.
Nitrogen‐15‐Depleted versus Nitrogen‐15‐Enriched Ammonium Sulfate as Tracers in Nitrogen Uptake Studies
Authors: Edwards A. P. , Hauck R. D.
Published: July 2010

Fertilizer particles were prepared from ammonium sulfate with a lower (0.031) than natural (0.366) atom percentage of 15N. The 15N‐depleted material was compared with ammonium sulfate of a comparable level of 15N enrichment (0.734 atom %) in a greenhouse pot experiment which measured plant recovery of applied N. There was no statistical difference in N recovery values for five harvests taken over an 18‐week period at three rates of applied tracer N, with on exception. Accurate and precise measurement of tracer N in plant tissue was obtained for both 15N‐depleted and 15N‐enriched materials, using two mass spectrometers with different measurement and rcording systems. A nontracer technique gave lower first harvest and higher combined harvest values of percentage recovery of applied N than either tracer technique.
Salt Tolerance of Mexican Wheat: II. Relation to Variable Sodium Chloride and Length of Growing Season
Authors: Bernal Carlos Torres , Bingham F. T. , Oertli J.
Published: July 2010

Germination, seedling growth, and grain production of four short‐season, one intermediate‐season, and three long‐season varieties of Mexican wheat (Triticum aestivum) were studied in relation to variable NaCl salinity. Germination counts after 7 days exposure to NaCl solutions in petri dishes revealed that the wheats as a group are relatively tolerant, germinating freely in the presence of −16‐ to −20‐atm osmotic potential. ‘Nadadores,’ ‘Potam,’ ‘Sonora,’ and ‘Nuri’ were the most tolerant; ‘Ciano,’ ‘Cajeme,’ and ‘Yecora,’ the least at germination. Tolerance at germination was not associated with any obvious properties such as length of growing season or seed hardness. The eight wheat varieties were grown from seedling stage to maturity in sand cultures with a complete nutrient solution containing sufficient NaCl to produce total osmotic potentials of −0.5, −2.5, and −4.5 atm. Leaf samples were collected at spike emergence for chemical analysis including NO3‐N, Cl, and Na. Plots of relative grain yield in relation to osmotic potential of substrate revealed two general relationships, one for the short‐season varieties and one for the long‐season varieties. Fifty percent yield decrements were associated with −3 atm and −6 atm for short‐season and long‐season varieties, respectively. Further, relative grain yields under a given NaCl stress were correlated with the length of the maturity period. Chemical analyses of leaf samples collected at spike emergence showed higher Na and Cl contents in short‐season varieties than in long‐season varieties. Thus, Na and Cl toxicities may be involved in growth depressions. Also, leaf analysis data revealed an inhibitory effect of Cl upon NO3‐N accumulation.
Evaluation of Six Extractants for their Ability to Predict Manganese Concentrations in Wheat and Soybeans
Authors: Shuman L. M. , Anderson O. E.
Published: July 2010

Six extractant procedures were evaluated for their ability to relate soil Mn to Mn concentrations in wheat (Triticum aestivum) and soybeans (Glycine max L. Merr.) over three soil pH levels (pH 4.8, 5.8 and 6.8) and three rates of Mn addition. Eight Southeastern soils were treated with 0, 25, and 50 ppm Mn for wheat and 0, 2.5, and 25 ppm Mn for soybeans and the crops were grown 40 days in the greenhouse. Correlation coefficients were computed for plant Mn in relation to soil Mn extracted using six extractants: water, neutral 1N NH4OAc (with and without 0.2% hydroquinone), “double acid,” diethylenetriaminepentaacetic acid (DTPA) and ethylenediaminedi‐o‐hydroxyphenylacetic acid (EDDHA). For wheat the correlations between soil Mn extracted with both water and 1N NH4OAc and plant Mn were consistently high over the entire pH range. However, for soybeans only water had a high coefficient at pH 4.8 while DTPA and the “double acid” extractants gave food correlations at the higher two pH levels. For wheat, DTPA also gave consistently good correlations. Considering both crops studied, it was concluded that at pH 5.8 and 6.8 DTPA gives the best measure of plant available Mn in acid Southeastern soils. At pH 4.8, water would be the extractant of choice. Double acid, EDDHA, and 1N NH4OAc were intermediate in their ability to predict plant Mn concentrations and 1N NH4OAc plus hydroquinone was inferior for both crops.
The Exhaustive Alkaline Cupric Oxide Oxidation of Humic Acid and Fulvic Acid
Authors: Neyroud J. A. , Schnitzer M.
Published: July 2010

A humic acid and a fulvic acid were subjected to successive oxidations with alkaline cupric oxide at 170C for 3 hours until identifiable degradation products were no longer formed. Resistant humic acid and fulvic acid residues were then oxidized with alkaline permanganate. Following each oxidation, the degradation products were extracted into ethyl acetate, methylated, separated by column, thin‐layer and gas‐chromatography and identified by mass spectrometry and micro‐IR spectro‐photometry.

The exhaustive alkaline cupric oxide oxidation of 1.0 g of humic acid yielded 109.0 mg of aliphatic compounds (mainly succinic acid and the n‐C16 and n‐C18 fatty acids), 94.9 mg of phenolic acids and 36.2 mg of benzene‐carboxylic acids. Oxidation of 1.0 g of fulvic acid produced 104.7 mg of aliphatic compounds, 146.7 mg of phenolic acids and 35.1 mg of benzene‐carboxylic acids. The resistant humic and fulvic acid residues yielded on further oxidation with alkaline permanganate additional amounts of benzene‐carboxylic acids.

Compared to other degradation methods, alkaline cupric oxide oxidation of humic substances was found to be an efficient procedure for the formation of relatively large amounts of aliphatic and phenolic degradation products but was less effective for degrading aromatic structures linked by C‐C bonds only. The main reaction governing the alkaline cupric oxide oxidation of the humic substances appeared to be alkaline hydrolysis. The data indicate general similarities in the chemical structures of the two humic materials but with the fulvic acid containing more phenolic structures than the humic acid.
Denitrification Losses from Humid Tropical Soils of Puerto Rico
Authors: Dubey H. D. , Fox R. H.
Published: July 2010

Profile samples from 5 depths (0–25, 25–50, 50–75, 75–100, and 100–125 cm) from 3 soil types (two Oxisols—Piña sandy loam and Catalina clay, and an Ultisol—Humatas clay) were incubated at 23±1C under field capacity and waterlogged conditions in an oxygen‐helium atmosphere. Evolved N2 and N2O were determined after 1 and 2 weeks by gas chromatography.

Denitrification was related to moisture level, organic matter content, pH, and denitrifying population. Gaseous‐N losses occurred almost exclusively from the surface soil (0–25 cm) under waterlogged conditions. Losses ranged from 8 to 31% of the applied NO3‐‐N. Some loss (7%) also occurred at field capacity from the surface horizon of the Oxisol having the highest organic matter content, Catalina clay. Losses were directly related to organic matter content. Raising the pH of the subsoil only enhanced denitrification slightly. Addition of a denitrifying population and mineral nutrients in the form of a soil inoculant to a subsoil with a raised pH and organic matter content increased denitrification equal to that of surface soil. The lack of denitrification at lower depths is believed to be due to an inadequate supply of rapidly available energy material, low pH and mineral nutrients, and consequent lack of a denitrifying population. Since the surface soil rarely gets waterlogged, it was concluded that little possibility of N losses by denitrification in these humid tropical soils exists.
Infrared Absorption Similarities between Hymatomelanic Acid and Methylated Humic Acid
Authors: Tan K. H.
Published: July 2010

Infrared analysis was conducted comparing hymatomelanic acid and methylated humic acid extracted from two Ultisols and one Inceptisol. The results revealed close similarities in spectrograms, leading to the assumption that hymatomelanic acid was not an artifact, but a naturally esterified or methylated fraction of the humic molecule liberated by ethanol extraction. Carbon‐14‐labeled ethanol extraction of humic acid yielding hymatomelanic acid showing radioactivity counts below the control supported the assumption for the natural occurrence of hymatomelanic acid. Methylation of humic and hymatomelanic acids increased the infrared absorption between 3000 to 2800 and at 1720, 1460, and 1400 cm‐1, for C‐H, carbonyl, CC‐H3, and carboxyl stretching vibrations, respectively. Separation of the ester group from the hymatomelanic acid molecule by dissolution with 2N NaOH and HCl eliminated its blocking effect on the carboxyl vibration in COO‐ form and the absorption at 1620 cm‐1 regained in intensity.
Lithologic Discontinuities in Loessial Soils of Southwestern Kentucky
Authors: Price T. W. , Blevins R. L. , Barnhisel R. I. , Bailey H. H.
Published: July 2010

Eleven soil pedons representing three soil series, commonly mapped as loess over contrasting residuum in southwestern Kentucky, were studied. Numerous tests were conducted to determine which parameters are most reliable in discerning loess from underlying residuum and at the same time to obtain more complete characterization of these soils. Soils studied include the Bedford (Typic Fragiudults), Crider (Typic Paleudalfs), and Zanesville (Typic Fragiudalfs) series. Quartz/feldspar ratios indicate that the three soil series are very similar in the upper horizons, but somewhat different in the lower horizons, and have clear lithologic discontinuities. The occurrence and location of this discontinuity in the soil pedon as determined by the quartz/feldspar parameter agree closely with the pedon morphology described in the field. Particle size distributions indicate that the upper horizons of all the pedons are very similar, particularly in silt content. Particle size distributions also indicate a clear lithologic discontinuity in each of the Bedford and Zanesville soil pedons but do not show a clear boundary for Crider soils. Results from particle size analysis, quartz/feldspar ratios and field observed morphology indicate the presence of a thin loess mantle over differing residuum in these southwestern Kentucky soils.
Curling Inhibition of Clays Mounted on Slides for X‐Ray Diffraction Analysis
Authors: Rich C. I.
Published: July 2010

A method is proposed which effectively inhibits curling of clay specimens on slides used for X‐ray diffraction. Glass wool is broken into short lengths and mixed with the clay suspension before drying. Heat treatments and K‐saturation can be performed without curling and loss of the sample.