bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactions of Ammonium Ortho‐ and Polyphosphate Fertilizers in Soil: I. Mobility of Phosphorus
Authors: Khasawneh F. E. , Sample E. C. , Hashimoto Isao
Published: July 2010

The mobility of P applied as diammonium orthophosphate (DAP), triammonium pyrophosphate (TPP), or ammonium polyphosphate (APP) was studied in columns of Hartsells fine sandy loam. The fertilizer dissolved in soil moisture that moved towards the application site. This water movement was sometimes against a gradient in soil moisture content, but it was along a gradient in the total potential of soil water.

The extent of P movement from all three sources was similar, but the distribution patterns were different. The extent of P movement was influenced more by the initial soil moisture content than by the source of P.

A higher fraction of the added P was precipitated when the source was TPP or APP than when it was DAP. The ability of the polyphosphates to sequester soil Fe and Al did not prevent the precipitation of these phosphates nor did it make them more mobile than the orthophosphates. It only delayed the precipitation reaction to a degree that depended on the polyphosphate content of the fertilizer material.
Influence of Genetic Variability on Zinc Response in Wheat
Authors: Shukla U. C. , Raj Hans
Published: July 2010

Influence of genetic variability on Zn response in wheat (Triticum sp.) was evaluated in the greenhouse. There was considerable difference among 21 varieties in the time of appearance and intensity of deficiency symptoms, yield depression, and Zn concentration under Zn stress conditions. Without supplemental Zn, dry matter yields of shoot and roots were 8.6 to 33.5% and 9.4 to 36.8% lower, respectively, than at 5 ppm Zn level. Zinc concentration of varieties ranged from 4.2 to 28.3 ppm under zinc deficiency conditions. The differential response among the varieties was found closely linked to their efficiency in Zn utilization from the soil.
Solution to the One‐Dimensional Linear Moisture Flow Equation with Water Extraction
Authors: Warrick A. W.
Published: July 2010

The one‐dimensional, steady‐state moisture flow equation is solved for arbitrary plant water withdrawal functions using the matric flux potential of earlier investigators to obtain a linearized form. A semi‐infinite flow medium and a finite‐depth medium overlying a shallow water table are considered with the surface boundary condition taken as a flux. Tables are presented giving the matric flux potential (from which the pressure head is easily determined) for several withdrawal functions. Numerical examples show the effects of different surface fluxes and rooting depths on the matric flux potential and pressure‐head profiles. The results are particularly relevant for high‐frequency irrigation.
A Postulated Mechanism for Increasing the Efficiency of Organic Soil Conditioners
Authors: Koch J. T. , Kay B. D. , Lange G. L.
Published: July 2010

A mechanism whereby organic polymers may be made more effective in maintaining the water stability of soil aggregates is postulated. The proposed mechanism employs coupling agents which chemically bond parts of the organic and inorganic phases of the aggregate together.

Various silane coupling agents and other compounds of similar structure were added to soil aggregates. Predictions based on the proposed mechanism were tested by recording the effects of the compounds on aggregate stability as measured by the wet‐sieving technique. Addition of silicon—functional compounds resulted in a marked increase in the water stability of soil aggregates. However, it was not possible to prove conclusively that the organic functionality of NH2(CH2)3Si(OC2H5)3 participated in the postulated mechanism of strength improvement.
Two‐Dimensional Displacement into or from Water‐Filled Ditches
Authors: Miyamoto S. , Warrick A. W.
Published: July 2010

Piston‐type displacement of solutes for steady‐state saturated flow into or from water‐filled ditches is analyzed mathematically and by a sand‐tank model. The displacement front into the drains advances much faster near the drains than in the region midway between them. The presence of an impermeable sublayer accentuates this trend. The front bcomes nearly horizontal for a wider surface impermeable spoil bank or if water is ponded away from the drains. Such a spoil bank may be useful for reducing the amount of water required to leach salts or for minimizing the loss of water‐applied fertilizers into drains. The displacement front for water moving from the ditches into a field (such as for salt intrusion from open ditches) advances in an ellipsoidal pattern. The analysis is also useful for predicting the displacement patterns for localized initial solute distributions. Experimental data obtained from a sand‐tank model agree with the predicted fronts.
Effect of Hydrochloric Acid‐Hydrogen Fluoride Pretreatments on Solubilization of Organic Matter by a Cation‐Exchange Resin
Authors: Pietz R. I. , Adams R. S.
Published: July 2010

Soil was pretreated with HCl‐HF solutions prior to organic matter solubilization by an iminodiacetic acid type cation‐exchange resin (Chelex 100). As the normality of HCl‐HF solutions increased from 0.05N to 0.5N, the identifiable soil mineral content of the extracted organic matter decreased and the inorganic element content increased. Pretreatments with 0.1N and 0.3N HCl‐0.3N HF solutions resulted in the highest element concentrations in the extracted organic matter, while the 0.5N HCl‐0.5N HF pretreatment resulted in the smallest soil mineral content. Elemental analysis of the ashed organic matter indicated that it had a high affinity for P, Al, Fe, Zn, Cu, and B solubilized by HCl‐HF. Infrared spectra of the extracted material suggested that metal‐organic complexing occurred through electrovalent bonding between ionized carboxyl groups and solubilized inorganic elements and their hydrous oxides. However, analysis of the supernatant from the HCl‐HF pretreatments indicated that most of the solubilized soil elements remained in solution.
Radar Theory Applied to Reconnaissance Soil Surveys
Authors: Morain S. A. , Campbell J. B.
Published: July 2010

This paper describes the use of radar imagery as a base for reconnaissance soil surveys. Attention is focused on the interpretation of tone patterns as resultants of microwave interactions with terrain. The tone appearance of soils and associated landscape features is governed in large part by surface roughness, moisture content, system resolution and viewing angle. These factors are reviewed in both theoretical and applied terms. For cartographic purposes the resolution of existing imaging radar systems appears adequate for reconnaissance surveys. For interpreting soil attributes, however, both resolution and viewing angle are important considerations. Images from arid and humid environments are interpreted as examples of the application of radar theory to reconnaissance mapping. As with photo interpretation, most soil information is obtained by using a combination of radar reflectance theory and landscape inference. Once the theory is understood, however, radar imagery can offer advantages over black and white photography in terms of timeliness and scale of coverage.
Modified Penman Equation to Provide the Upper Boundary Condition in Computing Evaporation from Soil
Authors: Staple W. J.
Published: July 2010

Penman's equation for potential evaporation was modified by including in it the relative vapor pressure h of partially dried surface soil. The modified equation was used to predict evaporative flux from drying soil as a boundary condition in the finite difference solution of the flow equation. The method gave satisfactory agreement in a 20‐day test in which evaporation was measured from short columns of soil in a fallowed plot.
Content and Adsorption of Phosphorus in Black Hills Prairie and Forest Soils
Authors: White E. M. , Gartner F. R. , Thompson W. W.
Published: July 2010

Prairie areas within forested areas of the western United States have been attributed to the phosphorus content being higher or lower than the adjacent forested soils. Black Hills forest and prairie soils in South Dakota have about the same quantity of total and available P. Langmuir adsorption and desorption isotherms for PO4‐P are not distinctly different for the prairie and forest soils, which suggests the chemical systems are the same in both soils. Thus, prairie areas in the ponderosa pine (Pinus ponderosa, Laws) forest of the Black Hills are not caused by differences in the phosphorus chemistry of the soils.
Effect of Application Rate, Initial Soil Wetness, and Redistribution Time on Salt Displacement by Water
Authors: Ghuman B. S. , Verma S. M. , Prihar S. S.
Published: July 2010

Certain concepts regarding the displacement and profile‐spread of surface‐salts with applied water and the leaching efficiency of the latter were experimentally verified using soil columns. Treatments included different amounts and rates of water application and different initial soil water contents. Salt and water profiles were determined by destructive sampling in 2‐cm depth intervals after variable times of redistribution.

Salt front coincided with the water front in the initially dry soil and lagged behind it in the initially moist soil. Salt peak immediately after infiltration and after redistribution, for all initial soil water contents, occurred at a depth above which total water storage equalled infiltration. But the salt spread in the profile increased as the initial water content increased.

Immediately following infiltration, salt was displaced deeper with slower than with faster rates of water application. But when the application plus redistribution time was matched, the salt showed deeper movement with water added at faster than at slower rates. These results show that slower rates of water application may not increase the leaching efficiency of water under field conditions.
Potassium Status of Some Costa Rican Latosols and Andosols and their Response to Potassium Fertilization Under Greenhouse Conditions
Authors: Martini J. A. , Suárez A.
Published: July 2010

Exchangeable, nonexchangeable, and structural K were determined in A and B horizons of seven Latosols and seven Andosols. Responses to K fertilization using tomato (Lycopersicum sculentum) as indicator plant under greenhouse conditions were studied. Forms of K were correlated with each other as well as with crop response to native and applied K.

Responses to K fertilization, as measured by plant growth and K uptake, were greater for Latosols than for Andosols and greater in B than in A horizons. Larger responses to K for the Latosols, particularly in B horizons, were associated with lower levels of all forms of soil K and higher (Ca + Mg)/K ratios. Conversely, lower responses to K for the Andosols, particularly in A horizons, were associated with higher levels of all forms of soil K and lower (Ca + Mg)/K ratios.
Soil Water Measurement with an Inexpensive Spectrophotometer
Authors: Bowers S. A. , Smith S. J. , Fisher H. D. , Miller G. E.
Published: July 2010

A small, portable, battery‐powered, spectrophotometer was developed to measure soil water content rapidly. Soil water contents of 16 soils were related to the absorbance at 1.94 µm by a soil‐methanol extract by the curvilinear equation
urn:x-wiley:03615995:saj2sssaj197503615995003900030014x:equation:saj2sssaj197503615995003900030014x-math-0001

With the exception of Houston Black Clay, one equation could be used for all soils. Determination time for individual samples was approximately 15 min.
Diurnal and Seasonal Soil Water Uptake and Flux within a Bermudagrass Root Zone
Authors: Rice R. C.
Published: July 2010

Diurnal water movement within a bermudagrass [Cynodon dactylon (L.) Pers.] root zone and the uptake of water by the roots was studied in a field plot. A fast response tensiometer‐pressure‐transducer system was used to measure the hydraulic heads. The relations of pressure head to water content and to hydraulic conductivity were determined in situ. Diurnal water content and soil water flux profiles were derived by using the established hydraulic properties. The fast response tensiometer system enabled calculation of flux and water content changes over 2‐hour intervals. Diurnal water extraction rates calculated for different depths and times during the growing season yielded evapotranspiration rates that agreed well with rates measured on similar days in previous years using a lysimeter.
A One‐Step Wetting Procedure for Determining Both Water Characteristic and Hydraulic Conductivity of a Soil Core
Authors: Ahuja L. R.
Published: July 2010

Reasonable simplifications are used to obtain both the suction‐water content and unsaturated hydraulic conductivity relationships from data measured during wetting of a relatively dry soil core through a high‐hydraulic‐resistance porous plate. For soil‐water contents below the bubbling‐pressure value, the two functions are assumed to be of previously known power forms. The resulting similarity is then utilized to obtain these functions from cumulative inflow and wetting‐front position data, using an iterative numerical solution of the ordinary differential equations. Accuracy of the solution is tested on a set of generated data. Tests of the technique as a whole on generated data for one soil and experimental data for another show it to be promising. For water contents above the bubbling‐pressure value, a method is suggested to obtain the two hydrologic properties from cumulative inflow and soil‐water suction at the other end of the core.
A Field Study of Soil Water Depletion Patterns in Presence of Growing Soybean Roots: III. Rooting Characteristics and Root Extraction of Soil Water
Authors: Arya L. M. , Blake G. R. , Farrell D. A.
Published: July 2010

Rooting characteristics and water extraction patterns in the root zone of a mature soybean (Glycine max L.) crop were determined in the field. Although rooting density for liter samples of soil varied from 0.07 to 5.0 cm/cm3, nearly 60% of the root zone exhibited densities in the 1.0 to 2.0 cm/cm3 range. Densities near the plant row and at depths of 20 to 45 cm in the interrow space tended to be well above average. Elsewhere densities varied in a random manner. Total root length per plant was about 680 m. Mean root diameters ranged from 120 to 500 µm with the 150 to 300 µm range being the most common. Maximum fresh weight concentration was in the 30‐ to 40‐cm zone. The dry root weight monotonically decreased with depth. The ratio of fresh to dry weight increased with depth.

Rates of water extraction by the roots in the various 10‐cm intervals were computed over an irrigation‐drying cycle, 81 to 91 days after planting. In the 10‐ to 30‐ and 60‐ to 70‐cm layers the extraction rate decreased with time. In the 30‐ to 60‐cm layer an initial decrease was followed by a substantial increase later in the cycle. Total extraction between 40 and 240 hours after irrigation decreased with depth—1.32 cm in the 10‐ to 20‐cm layers and 0.25 cm in the 60‐ to 70‐cm layers. Extraction rate for the 10‐ to 70‐cm soil during the 47‐ to 56‐ and 81‐ to 91‐days growth periods showed an initially rapid decrease following irrigation but reached constant levels of 0.48 and 0.39 cm/day, respectively.

In the light of Philip's (1957) extraction model, our rooting characteristics and water uptake measurements suggest that soil‐water pressure between roots (ΨB) and on root surfaces (ΨR), effective conductivity of the soil (K̄), sink strength (rz), and rooting density (Lv) are related by
urn:x-wiley:03615995:saj2sssaj197503615995003900030023x:equation:saj2sssaj197503615995003900030023x-math-0001

Estimates of were negligibly small suggesting that rhizosphere resistance was not a significant factor in our experiments.

Patterns of water movement in the two‐dimensional root zone space show considerable deviation of flow direction from the vertical. These deviations suggest that with row crops more sophisticated analyses and more detailed soil and root measurements will be needed for the meaningful interpretation of field data.
Mathematical Analysis of Steady Saturated Flow through a Multilayered Soil with a Sloping Surface
Authors: Selim H. M. , Selim M. Sami , Kirkham Don
Published: July 2010

An analytical solution is presented for a two‐dimensional multilayered hillside seepage problem. The soil is horizontally stratified with each layer having a different permeability. The flow medium is assumed to be water‐saturated to the soil surface, bounded below by an impermeable barrier at a finite depth, and bounded laterally by vertical streamlines. Seepage occurs into the flow medium along the upper part and out along the lower part of the sloping soil surface. Two situations are analyzed, one with a constant slope soil surface and another with an abritrarily shaped soil surface. The potential and stream functions for the problem are developed by starting with a general series solution to Laplace's equation and using a modified Gram‐Schmidt method to determine the series coefficients. Solutions are derived for two‐layered and three‐layered soils. From these derivations, solutions for soils with more than three layers can be readily deduced. The results presented include flow nets, seepage velocities and infiltration rates for two‐layered and three‐layered soils.
In Situ Hydraulic Conductivity at Four Hillslope Locations in a Closed Drainage System
Authors: Matzdorf K. D. , Cassel D. K. , Worcester B. K. , Malo D. D.
Published: July 2010

Virtually no information has been published concerning the hydraulic properties of large acreages of till plain soils associated with “Potholes” in Northcentral United States and Canada. The objectives of this research were to measure and compare in situ hydraulic conductivities and selected soil physical properties at several depths in four soil profiles on a till plain in southeastern North Dakota. In addition, theoretical hydraulic conductivity values were calculated and compared with the in situ conductivities.

Unsaturated soil hydraulic conductivity vs. depth was measured in situ at four sites on a toposequence developed from a glacial till. Water was allowed to infiltrate the soil at each site and the soil surface covered to prevent evaporation. During the ensuing drainage periods soil water pressure was monitored with triplicate tensiometers at each of six depths. These depths were not arbitrary as in previously reported studies but were selected on the basis of soil morphology. Soil water characteristics, determined on triplicate 7.6‐ by 7.6‐cm cores taken from the same depth as the tensiometer cups, were used in conjunction with the soil water pressure data to compute hydraulic conductivities. Hydraulic conductivity generally increased with depth to about 90 cm. Below this depth, hydraulic conductivity tended to decrease. In addition, hydraulic conductivity values at each depth for each site were computed by the Green and Corey Method. When the matching factor was selected from the midpoint of the measured hydraulic conductivity range, the conductivities computed by Green and Corey's method compared favorably with those measured in situ.
A Procedure for the Sampling and Testing of Large Soil Cores
Authors: Watson K. K. , Lees S. J.
Published: July 2010

The significance of acquiring reliable data on the soil‐water characteristics of field soils is discussed in relation to the input requirements of computer‐based numerical models of the unsaturated flow process. A specification outlining the conditions to be fulfilled in sampling and testing a large soil core is then detailed. Equipment used in extracting a 40‐cm‐diam soil core is described together with relevant laboratory instrumentation.
Rate of Dissolution of Phosphate from Minerals and Soils
Authors: Olsen R. A.
Published: July 2010

A laboratory technique was devised for conveniently measuring the rate of dissolution of phosphates in minerals and soils. The conditions imposed upon the samples were believed to be similar in several important respects to those in the close proximity of plant roots. An equation was derived which was reasonably descriptive of the dissolution process even in widely different soils. The technique was used to measure the rate of dissolution of a number of well‐characterized rock phosphate samples and of many soils. The data were found to rate the samples very well with regard to their value as a source of phosphate to plants. There was no apparent advantage of measuring rates of dissolution, however, over measuring amounts “available” by means of conventional single extraction techniques. Based upon the technique studied, a simple and apparently reliable extraction technique for routine evaluations of soil as a source of phosphate is described.
Chemical Conversion of Parathion on Soil Surfaces
Authors: Yaron Bruno
Published: July 2010

Chemical conversion of parathion was studied on a range of sterile soils widely different in organic matter content and clay mineralogy. After 130 days' incubation at room temperature, conversion ranged between 3–23% for air‐dried samples and was < 10% for moist ones in all the soils studied. The conversion was found to proceed via hydrolysis of the phosphate ester bond. A conversion mechanism is proposed. The conversion was affected by soil constituents like clay and organic matter—the rate decreasing in the order:—kaolinite > montmorillonite > organic matter, this being inversely related to the adsorption affinity of these materials for parathion. This phenomenon is explained by assuming that surface catalysis of parathion occurs at specific active sites only. For almost all the soils studied, the presence of water apparently blocked the active sites required for parathion decomposition, indicating that the soils' catalytic activity is moisture dependent.
Microbial Degradation of Ametryn in Hawaiian Torrox and Hydrandept Surface Soils
Authors: Goswami Kishore P. , Green Richard E.
Published: July 2010

Degradation of ring‐14C ametryn in autoclaved and inoculated surface soils with added C and N sources was measured for 60 days in a 14C balance study. The study involved periodic analysis for (i) total methanol‐extractable 14C, (ii) 14C‐polar products separated from the methanol extract by liquid‐liquid partitioning with chlorform, (iii) 14CO2 evolution, and (iv) 14C‐nonextractable residue by combustion. The results confirm that unlike the chemical breakdown of chloro‐s‐triazines, ametryn degradation in soil is predominantly a microbiological process which proceeds mainly through the initial N‐dealkylation pathway with some simultaneous formation of hydroxyatrazine. Gas chromatographic analysis showed partitioning of two possible N‐dealkylated products of ametryn metabolism into the aqueous phase of the chloroform/aqueous‐methanol system. Less than 7% of the applied ametryn was lost in autoclaved soils, but ametryn was rapidly degraded in inoculated soils. Ametryn disappearance was much faster in the Hilo soil (Typic Hydrandept) with 8.7% remaining at 60 days than in the Molokai soil (Typic Torrox) with 63.7% remaining. The extremely high surface area and high organic matter content of the Hydrandept surface soil were considered conducive to higher microbial activity in this soil. The major fraction of 14C‐degradation products was recovered in polar compounds with a lesser quantity residing in a nonextractable fraction; less than 0.2% was evolved as 14CO2. Evolution of 14CO2 at a given time was not governed either by the quantity of parent ametryn remaining nor by the concentration of polar products.
Nutrient Dilution—Antagonism Effects in Corn and Snap Beans in Relation to Rate and Source of Applied Potassium
Authors: Terman G. L. , Allen S. E. , Bradford B. N.
Published: July 2010

Greenhouse pot experiments were conducted to compare responses of corn (Zea mays L.) and snap beans (Phaseolus vulgaris L.) to 0 to 1,600 mg of K/pot as KNO3, KCl, and K2SO4 on K‐deficient soils (3 kg of soil/pot). Marked responses were obtained to applied K, which were similar among sources, except for a toxic salt effect of 1,600 mg of K as KCl. Marked reciprocal K‐N, K‐P, K‐Ca, and K‐Mg relationships with yield response to rates of applied K were attributed to both dilution and ion antagonism. The latter was most pronounced at higher K rates giving little or no additional yield response and resulting in decreased Ca, Mg, or P uptake. There was a close relationship between total N and total cation concentrations in corn leaves but not in bean leaves. This difference is attributed to absorption of much of the N as NO3‐N by corn and as biologically fixed NH2‐N by snap beans.
Application of Soil Taxonomy in Tidal Areas of the Southeastern United States
Authors: Coover J. R. , Bartelli Lindo J. , Lynn Warren C.
Published: July 2010

Several million hectares of soils of the southeastern United States are subject to inundation by tidal action. The influence of seawater is reflected in the higher proportions of Na and Mg in these soils than in surrounding upland soils or soils in fresh water marshes. Rise in sea level and subsidence of some coastal areas have combined to submerge soils. Diagnostic features such as argillic and spodic horizons were formed prior to submergence. Sulfides have accumulated in some soils. Other soils have features resulting from continuous saturation of sediments deposited in water. Organic materials have accumulated over extensive areas. Additions to Soil Taxonomy are proposed for further testing, including subgroups of Hydraquents and Sulfaquents and halic great groups of Alfisols, Entisols, and Histosols. Field observations indicate a need for refinement of the definition of sulfidic materials. Soil surveys of tidal areas are designed to meet the needs of potential users.
Effect of Added Salts on Nitrogen Release and Nitrate Levels in Forest Soils of the Washington Coastal Area
Authors: Heilman Paul
Published: July 2010

The release and mineralization of N was studied in incubated samples of 10 forested soils from the Washington Coast which had been treated with a variety of salts. Salts were added in solution at 0.005, 0.05, and 0.2M concentrations and the samples were incubated at 27C for 7, 14, and 21 days. Release of NH4‐N plus NO3‐N increased with increase in the duration of incubation and concentration. The lowest concentration of salt increased N release over that from distilled water. The order of the effect of salts on release of N was AlCl3 > CaCl2 > KCl > K2SO4 > K2CO3 > K2HPO4.

At the lowest concentration, salts had little effect on nitrate levels, but at higher concentrations, nitrification was reduced in all soils by chloride salts. Nitrification was also reduced by K2SO4 but the reduction was evident only at the highest concentration. In contrast, nitrification was increased in the majority of these soils by K2CO3 at the two higher concentrations and by K2HPO4 at the highest concentration. Of the four soils in which nitrification was not increased, three had the highest nitrification capability of all soils studied, as evidenced by the high levels of nitrate produced when incubated with water.

Implications of the study concern the influence of fertilizers, lime, and ash from burning on availability of native soil N and formation of nitrate, and the effect in these soils of different N fertilizers on mineralization of soil N and nitrate levels.
Crop Response to Manganese Sources Applied with Ortho‐ and Polyphosphate Fertilizers
Authors: Mortvedt J. J. , Giordano P. M.
Published: July 2010

Fine MnSO4, MnO, and MnEDTA were applied alone or with various granular and fluid ortho‐ and polyphosphate fertilizers to a Mn‐deficient Maumee 1s in three greenhouse pot experiments. Other nutrients were applied uniformly to the soil at nonlimiting rates. Forage yields and Mn uptake by oats (Avena sativa L.) were increased by all Mn applications. All three Mn sources applied alone were equally effective, but forage yields and Mn uptake were generally higher when these sources were applied with the phosphates. The Mn‐containing fertilizers were more effective with banded than with mixed application. The granular fertilizers in decreasing order of effectiveness as carriers of MnSO4 or MnO were: monoammonium phosphate, diammonium phosphate, and ammonium polyphosphate. Fluid polyphosphates generally were less effective than granular fertilizers as carriers of MnSO4 or MnO. This was related to formation of Mn‐phosphate reaction products of differing plant availability. Chelated Mn (MnEDTA) did not react with polyphosphates and was quite effective for plants when applied with all phosphate fertilizers.
Testing the Accuracy of Field Textures
Authors: Foss J. E. , Wright W. R. , Coles R. H.
Published: July 2010

Soil texture influences a wide variety of pedological, physical, chemical, and biological processes; thus, this property is a natural criterion to use in a soil classification scheme. Although laboratory analyses provide data on soil textures, most of the determinations occur in the field. Accuracy of field textures is therefore an important part of separating soils on the landscape and predicting their suitability for various uses. The accuracy of 598 field textures from Maryland was 50%; that is, in 50% of the cases, the field‐textural class was in agreement with the USDA textural classification as determined by laboratory results. The highest accuracy was found with the sand, clay, sandy loam, and silt loam classes, with the agreement being 74, 73, 68, and 63%, respectively. When allowing an arbitrary 4% deviation around the textural class, the overall agreement increased to 67%. Errant field textures were generally associated with high contents of coarse fragments, free iron, organic matter, and very fine or coarse sands.
Use of Sorption‐Isotherms for Evaluating Potassium Requirements of Plants
Authors: Singh B. B. , Jones J. P.
Published: July 2010

A sorption‐isotherm technique was used to evaluate plant‐available K for potatoes (Solanum tuberosum var. ‘Russet Burbank’), celery (Apium graveolens ‘Utah Pascal No. 15’), tomatoes (Lycopersicon esculentum var. ‘Owyhee’) and beans (Phaseolus lunatus var. ‘Fordhook’) in a greenhouse study. Sorption equilibrium was reached after 24 hours. Desorption equilibrium was reached after 1 hour. A 95% yield of beans, tomatoes, celery, and potatoes was achieved with 7.2, 7.4, 11.1, and 13.6 µg/ml K in sorption‐equilibrium solution and 2.6, 2.7, 3.5, and 4.7 µg/ml K in desorption‐equilibrium solution, respectively. The energies of exchange, Ek, for these sorption equilibrium solution K levels were −2,500, −2,485, −2,360, and −2,300 calories/M, respectively. Increase in the equilibrium‐K levels beyond the level needed for 95% yield resulted in little or no change in the growth of these crops. The desorption‐equilibrium solution K levels for maximum yields in this study are in close agreement with the solution K levels of nutrient‐culture studies reported earlier. Tissue‐K concentrations for 95% yield were 1.78, 3.30, 3.60, and 4.65% in beans, celery, potatoes, and tomatoes, respectively. Potential use of this technique for determination of K requirement is discussed.
Potassium Release Characteristics of Selected Peruvian Soils
Authors: Oelsligle D. D. , Doll E. C. , Valverde C.
Published: July 2010

To evaluate K release, 16 Peruvian soils were intensively cropped in growth chambers using the Stanford‐DeMent technique, and K was extracted with sodium tetraphenylboron (NaTPB) for varying periods. When 1‐g soil samples were equilibrated with solutions containing NaTPB for 0.25, 1, 10, 100, 1,000, and 2,000 hours, K extracted with NaTPB was linearly correlated with the logarithm of time from 10 to 1,000 hours. Rates of K release varied from −0.03 to 7.43 meq K/100 g soil per week. Large differences in the total amount of K removed in 2,000 hours (1.9 to 66.9 meq K/100 g soil) were related to the presence and apparent degree of crystallinity of illite in the clay fraction of the soils.

Amounts of plant‐available K, as determined from cumulative K uptake by five successive 2‐week‐old oat (Avena sativa) crops, varied from 0.35 to 3.24 meq K/100 g soil, and rates of K uptake varied from 0.016 to 0.215 meq K/100 g soil per week. Omitting three soils which released relatively large amounts of K (two at low and one at high levels of exchangeable soil K), the uptake of K by the first oat crop was highly correlated with initial exchangeable soil K.
Mapping Accuracy of a Contemporary Soil Survey in an Urbanizing Area
Authors: Amos D. F. , Whiteside E. P.
Published: July 2010

Mapping unit homogeneity was determined by the point‐intercept transect method for 12 mapping units representing nearly 60% of the land area in a contemporary soil survey of an urbanizing county in south‐central Michigan. By assigning a contrast value to each inclusion a “weighted contrast value” was established for each unit permitting a comparison of homogeneity among the units. Comparison of Miami drainage‐sequence map units revealed a deficiency in the concept of the moderately well drained member.

At the series level “observation‐mapping unit agreement” improved an average of 22% when the mapping units were renamed to more accurately reflect their actual composition. Continuing refinement of taxa together with increased interpretive demand on the cartographic delineation would seem to necessitate quantification of mapping units in subsequent soil surveys.
Soil Changes Resulting from Cropping
Authors: Skidmore E. L. , Carstenson W. A. , Banbury E. E.
Published: July 2010

The need to document further the changes in soil properties from various cropping systems and the uniqueness of a long‐time cultivated field adjacent to buffalograss (Buchloe dactyloides) pasture prompted us to evaluate soil‐property changes of a Keith silt loam (fine‐silty, mixed, mesic, Aridic Argiustolls), characteristic of that pasture and field. In the fall of 1973, we broke the sod of the buffalograss pasture for analysis. Soil samples were obtained from the pasture (newly broken sod) and the adjacent cultivated field. The wet aggregates from the pasture were stabler as compared with the cultivated field for both flash and vacuum wetting. However, the dry aggregates from the cultivated field were slightly stabler than those from the pasture. The average clod densities were 1.7 and 1.3 g cm‐3 from the tilled and pasture soils, respectively. The pasture soil was also much more permeable. The constant infiltration rate (after 6 hours of infiltration) averaged 0.95 and 0.13 cm hr‐1 for pasture and cultivated soils, respectively. Because of the general deterioration of many of the physical properties of its soil, the cultivated field will require special management consideration.
A Technique for Installing Induction Coils in a Profile with Minimum Soil Disturbance
Authors: Spotts J. W. , Brown K. W.
Published: July 2010

Details of a technique are given which can be used to position induction coils in an undisturbed soil profile to study the shrinking and swelling within the soil profile with changing moisture content. The specially designed apparatus consists of a soil cutting blade which can be advanced horizontally from an access hole into the soil at the desired depth. The induction coils are installed in the slots after the holes have been cut. Installations have been made successfully at depths as great as 2 m.
A Device for Isolating Field Soil Columns with Minimum Disturbance
Authors: Brown K. W.
Published: July 2010

A device is described which can be used to dig a ditch to isolate soil blocks in the field. The ditch can be as deep as 1.5 m with a width of 2.5 cm thus minimizing the amount of soil disturbance in individual blocks. The necessary equipment can be fabricated in a well equipped shop with a minimum of expense.
Injecting and Sampling Equipment for Studying Mobility of Pesticides in a Soil Profile
Authors: Wilson L. E. , Lavy T. L.
Published: July 2010

The injecting equipment described allows one to conveniently and accurately apply a liquid treatment to an exact location and specific soil depth. The sampling equipment facilitates the precise relocation of the point of injection. By sampling at 2.5‐cm vertical intervals, the extent of downward movement can be accurately determined. The equipment was designed to minimize smear and compaction which can occur during sampling of moist soils.
A Model for the Simultaneous Production and Diffusion of Ferrous Iron in Submerged Soils
Authors: Harmsen K. , van Breemen N.
Published: July 2010

The model describes the distribution of dissolved ferrous iron as a function of time and depth in a flooded soil profile consisting of three distinct horizons. In this soil profile, the production of dissolved ferrous iron is high and constant with depth in the surface horizon, low and constant with depth in the subsoil, and varies linearly with depth between these two values in the intermediate horizon. The Fe2+ concentration is found as the difference of the rate of ferrous iron production, integrated over time and a diffusion term consisting of an infinite series of the third and fifth repeated integral of the complementary error function. The parameters considered are (i) three constants specifying the dependence of the ferrous iron formation on time and depth, (ii) the depths of the three horizons, and (iii) the apparent diffusion coefficient. As shown by one example, the general solution can be greatly simplified for many cases of practical interest. The inherent assumptions of the model and its application to actual water‐logged soils are discussed.
Reclamation of Soils Contaminated with Radioactive Strontium
Authors: Lagerwerff J. V. , Kemper W. D.
Published: July 2010

Evesboro loamy sand, Sassafras sandy loam, and Fort Collins silt loam were treated with a mixed Ca‐Sr solution to give about 95% saturation with Ca and 5% saturation with Sr. Samples of these soils were placed in acrylic cylinders and leached with 0.06N CaCl2 to remove Sr. The leachings were mechanically controlled at various rates for different periods of time. Extracting the leached soil samples with 1N HCl yielded residual Sr equal to 0.43, 0.47, and 0% of the Sr exchange capacity of the Evesboro, Sassafras, and Fort Collins soils, respectively. There was general agreement between Sr concentrations measured at various depths and those calculated on the basis of the Lapidus‐Amundson equation, especially so with heavier soils. The Evesboro and Fort Collins soils were also tagged with carrier‐free 85Sr and, mounted in columns, leached with 0.06N solutions of either CaCl2 or SrCl2. The removal of 85Sr was more complete from the Evesboro than from the Fort Collins soil, and from the center than from the edge of the columns. Short‐term leaching capability of SrCl2 exceeded that of CaCl2 where 85Sr was present in amounts small enough to be adsorbed mostly on specific soil adsorption sites. Where larger amounts of 85Sr had been adsorbed, Ca was equally effective as Sr in replacing the contaminant.
Distribution and Some Properties of Loess in Southeentral and Southeastern Idaho
Authors: Lewis G. C. , Fosberg M. A. , McDole R. E. , Chugg J. C.
Published: July 2010

The extensive loess deposits of southcentral and southeastern Idaho have been delineated and mapped. Depth of the loess over much of this area is between 50 to 100 cm thick. The thickest loess deposits are south and east of the Snake River where depths of loess up to 36 m have been measured. Thickest loess deposits are parallel and immediately adjacent to the Snake River. Loess source in the uplands in southeastern Idaho appears to be the Snake River Plain. No pattern of loess sorting was evident on the Snake River Plain; however, there was sorting in the uplands to the southeast of the plain and perpendicular to the Snake River.
Relationship of Geomorphology to Origin and Distribution of a High Charge Vermiculitie Soil Clay
Authors: Lietzke D. A. , Mortland M. M. , Whiteside E. P.
Published: July 2010

A large quantity, up to 560 kg/ha, of elemental K fertilizer was required to obtain optimum yields and quality of tomatoes (Lycopersicon esculentum Mill.) in a fertility trial. The fertility trial was on a low well‐drained terrace of the St. Joseph River at Sodus Horticultural Experiment Farm located in Berrien County, Michigan.

The surface layer of the soil contained 15% clay with a Ca/Mg cation exchange capacity of 115 meq/100 g. This clay was capable of fixing about 94% of the applied K fertilizer.

A study of the glacial geology and more recent geomorphology in the area was done in order to determine the distribution and possible origin of the vermicultic soil clay at the study site.

The geomorphic study showed that the oldest land surface had acid leached soils with the surface layer containing considerable chloritized vermiculitic clays but little or no vermiculite. In contrast the younger well‐ and moderately well‐drained river terraces had soils that were higher in pH, and the surface layers contained vermiculitic clay but very little chloritized vermiculite.

Analysis of the soils on the river terraces showed a relationship of vermiculitic clay content to soil pH. If the soil pH was > 7.5 or < about 6.3 the vermiculite content of the surface layer dropped sharply.

The vermiculite in the river terrace soils is apparently derived from chloritized vermiculitic soil clays that were eroded from the older upland soils. The change in pH of the environment from acid to neutral or mildly alkaline plus abundant organic matter, under suitable conditions, evidently triggers a dechloritization reaction involving an aluminate or organic complexing mechanism.
Thick Bh Horizons in the North Carolina Coastal Plain: II. Physical and Chemical Properties and Rates of Organic Additions from Surface Sources
Authors: Holzhey C. S. , Daniels R. B. , Gamble E. E.
Published: July 2010

Thick Bh horizons in siliceous sands of the North Carolina Coastal Plain have essentially no extractable iron, and very small quantities of calcium, magnesium, and potassium. Aluminum is the dominant cation and the exchange properties of the Bh horizons are dominated by Al and organic carbon.

One to two grams of total Ca, Mg, and Na/m2 per yr are being added to these soils by rainfall and recycling. From 3 to 40 g of carbon/m2 per yr is available to move into the solution below 10 cm. This is enough carbon to develop a Bh horizon 7 m thick in < 30,000 years.

The mechanism that immobilizes the carbon to form the Bh horizon is open to question. It is postulated that bases, pH changes, or other aspects of the chemical environment may have immobilized the carbon initially, but these causes have subsequently been removed or changed through leaching. Another alternative, is organo‐mineral bonding such as with silica on quartz surfaces that may be the major factor in the immobilization of carbon.
Fixation of Iron and Zinc Applied as Chelates Into a Soil Column During Leaching
Authors: Lahav N. , Hochberg M.
Published: July 2010

The movement of iron in the form of FeEDDHA and FeEDTA and zinc in the form of ZnEDTA was studied in columns of Rehovot sand under several flow rates and in the presence of either Ca(NO3)2 or KNO3 with the same ionic strength of 0.0375M/liter. Chloride was used as a tracer.

FeEDDHA was neither adsorbed nor fixed by the soil. Both ZnEDTA and FeEDTA were fixed in the soil column in the presence of Ca2+ but not in the presence of K+. ZnEDTA was not adsorbed significantly, whereas FeEDTA was adsorbed in the presence of either KNO3 or Ca(NO3)2 solutions. Reasonable agreement was obtained between experimental results and theoretical calculations of the breakthrough curves, based on the analytical solution of the general dispersion equation.
Dispersion of Clays in Ethanol Solutions
Authors: Leonard R. A. , Jackson W. A.
Published: July 2010

Kaolinite was found to disperse at critical electrolyte concentrations in ethanol solutions greater than 80 vol/vol% of 10‐5 to 10‐3M CaCl2 and 10‐5 to 10‐2M AlCl3. Cecil soil clay also dispersed under the same conditions, while montmorillonite did not disperse in these solutions. Kaolinite did not disperse in alcoholic NaCl solutions.

The dispersed kaolinite migrated toward the cathode in electrophoresis experiments which supported our hypothesis that cation adsorption from the alcohol solution into the Stern layer at the clay surface imparted a positive electrical charge and promoted dispersion.

Cationic reactions with clay surfaces in alcoholic media may provide additional insight concerning the nature of these surfaces. Dispersion of clays in alcohol may also be a useful technique for selectively concentrating clay for other characterization studies.
Effect of Method of Nitrogen Application on Corn (Zea Mays L.) Grown on Irrigated Sandy Soils
Authors: Rehm G. W. , Wiese R. A.
Published: July 2010

Studies were conducted in 1970 and 1972 to determine the influence of method of Nitrogen application on corn production (Zea Mays L.) on irrigated, sandy soils. Conventional preplant and sidedress treatments were compared to situations where either preplant or sidedress applications were supplemented with added N in the irrigation water. Grain yields were recorded and the NO3‐‐N distribution to 150 cm in the soil profile was measured at the end of the growing season. The influence of method of application on corn yields was related to the textural profile of the soil. For a sandy soil with no accumulation of fine textured material, the application of N with the irrigation water increased grain yields. Also, the corn crop recovered a higher proportion of the applied N when some fertilizer N was added with the irrigation water. For a soil type characterized by an accumulation of fine textured material at 50–70 cm below the surface, method of N application had no influence on yield since the downward movement and loss of NO3‐‐N was restricted by the layer of fine‐textured material. The data show that the application of a portion of the N fertilizer requirement with the irrigation water should be a recommended practice for corn production on sandy soils having no accumulation of fine‐textured material.
Landsat Data, Its Use in a Soil Survey Program
Authors: Westin Frederick C. , Frazee C. J.
Published: July 2010

This study's three objectives were: first, to investigate the unique characteristics of LANDSAT imagery as they aid in recognizing soil survey boundaries; second, to explore the use of LANDSAT imagery for low intensity soil surveys; and third, to investigate LANDSAT imagery as a base map for publishing thematic soils maps.

As an aid in recognizing soil boundaries, the following characteristics of LANDSAT imagery have a bearing on its use in a soil survey program: the synoptic view of 3.5 million ha on which the condition of the soils and stage of vegetative growth are recorded at nearly the same moment; the near‐orthographic character of the scenes, allowing for the construction of mosaics; the temporal feature, permitting study of soils and vegetation as they change with time and the multispectral capabilities which increase the possibilities of unique signatures for vegetation and soils.

Using many of the characteristics of LANDSAT imagery, a low intensity soil survey of Pennington County, South Dakota was completed in 1974. The purpose of this survey was to determine the feasibility of preparing an inexpensive soil map which could be used in the Great Plains areas of South Dakota which presently lack a detailed soil survey. The LANDSAT survey cost 2¢/ha and took about 5 weeks.

The first step using LANDSAT imagery as a base map for publishing thematic soil maps is to prepare a mosaic. Twenty LANDSAT scenes from several late spring passes in 1973 were selected and made into a mosaic of scale 1:1,000,000. Two LANDSAT mosaics of South Dakota containing soils information have now been published. On the first, the soil associations are keyed to information on land sale prices from 1967–1972. The result is a land value map on a LANDSAT mosaic. On the second, the soil associations are keyed to soil test results in South Dakota of the last 25 years for organic matter, P2O5, K2O and pH. Also given for each soil association is relief and texture. Each of these publications cost about $400 for 5000 copies.