bluuebunny/crossref_metadata_2025 huggingface dataset:
Void Changes in Allophane Soils Determining Water Retention and Transmission
Authors: Maeda T. , Warkentin B. P.
Published: July 2010

Water retention and transmission were measured on eight samples of allophane soils from the West Indies and Japan. Standard methods of pressure plate, horizontal infiltration and steady‐state horizontal flux were used.

Soils with high allophane content have a sigmoid water content vs. log suction curve. Drying does not change the shape of the curve, but decreases the water content at any suction. Soils with low allophane content show a more linear water content vs. log suction curve, resembling that of clay soils with crystalline minerals.

Water transmission in undried allophane soils is slow because of the high proportion of microvoids. Air‐dried or oven‐dried samples have a higher proportion of macrovoids, and more rapid infiltration of water. This change in void size distribution is large enough to dominate the effect of greater volume of voids to be filled with water in an initially dry soil, with the result that water movement in allophanes increases as initial water content decreases.
The Influence of Size Distribution on the Bulk Density of Uniformly Packed Glass Particles
Authors: Staple W. J.
Published: July 2010

The theory of Westman and Hugill was used to predict the bulk density of uniformly packed mixtures of different sizes of glass beads. The density of packing depended on the number, the concentration, and the diameter ratio of the size components making up the mixture. Agreement between theory and experiment was good for binary mixtures but became less precise as the number of size components increased.
Steady Infiltration from Buried, Surface, and Perched Point and Line Sources in Heterogeneous Soils: II. Flow Details and Discussion
Authors: Philip J. R. , Forrester R. I.
Published: July 2010

Part I (Philip, 1972) developed physically relevant source solutions of the quasilinearized steady infiltration equation, generalized to apply to heterogeneous soils with conductivity depending exponentially on both moisture potential and depth. This paper discusses the results in further detail, and includes graphs of a wide range of solutions.
Variations in Picloram Leaching Patterns for Several Soils
Authors: Ping C. L. , Cheng H. H. , McNeal B. L.
Published: July 2010

Laboratory studies of picloram (4‐amino‐3,5,6‐trichloropicolinic acid) leaching under saturated conditions were conducted for four soils. Leaching patterns could be related to variations in soil texture and pore uniformity for three soils from arid and semiarid regions. Diffusion from conducting pores into adjacent micropores appeared to be the most plausible explanation of leaching patterns obtained for an Oxisol of volcanic origin from Hawaii. Evidence supporting the presence of the postulated micropore structure in this tropical soil was obtained from constancy in flow rate, from scanning electron micrographs, and from picloram recovery at a reduced leaching rate.
Effects of Beef‐Feedlot Manure and Lagoon Water on Iron, Zinc, Manganese and Copper Content in Corn and in DTPA Soil Extracts
Authors: Wallingford G. W. , Murphy L. S. , Powers W. L. , Manges H. L.
Published: July 2010

The effects of beef‐feedlot manure and lagoon water on DTPA‐extractable iron, zinc, manganese, and copper of a silty clay loam soil, concentrations of these elements in corn (Zea mays L.) forage and leaf tissue, and their uptake by corn forage were studied in the field. DTPA extractions were performed on the surface 1 m of soil cores collected from sets of plots that had received two annual applications of manure and three annual applications of feedlot lagoon water. Corn‐forage composition and nutrient uptake were measured from all plots for 3 years; corn leaf tissue composition was measured for 3 years on the manure plots only.

Both manure and lagoon water increased DTPA‐extractable Fe, Zn, and Mn in the soil, but extractable Cu was increased only by the highest manure treatments. Corn and leaf concentrations of Zn and Mn and corn forage uptake of Mn were enhanced by the manure application. Corn‐forage Mn content was increased linearly by applied lagoon water. The feedlot manure and lagoon water were shown to be sources of Fe, Zn, and Mn.
Differential Magnesium Efficiency in Corn Inbreds: I. Dry‐Matter Yields and Mineral Element Composition
Authors: Clark R. B.
Published: July 2010

In nutrient solutions, the corn (Zea mays L.) inbred B57 grew considerably better at low Mg levels and was more Mg‐efficient than the inbred Oh40B. B57 produced maximum dry‐matter yields near 0.12mM of Mg whereas Oh40B continued to increase dry‐matter up to 4.1mM of Mg. Roots of B57 contained lower Mg concentrations than roots of Oh40B at Mg levels below 1.2mM and slightly higher Mg concentrations at higher Mg levels. However, B57 leaves contained nearly twice as much Mg as Oh40B leaves did when plants were grown at the various Mg levels. With few exceptions, the root and leaf concentrations of the various essential mineral elements in both inbreds decreased as the Mg treatment increased. In nearly all plants, the decrease in B57 was greater at the lower levels of Mg than in Oh40B. Root concentrations of P, Mn, Fe, Cu, and Mo and leaf concentrations of Ca, P, Mn, Zn, B, and Cu were lower for B57 than for Oh40B. When B57 and Oh40B were grown together in the same container at various plant ratios and 0.062mM of Mg, B57 grew markedly better than Oh40B. The plant ratio did not significantly affect dry‐matter yield and mineral element concentration in the roots and leaves of either inbred.
Soil Properties Influencing Swelling in Canfield and Geeburg Soils
Authors: McCormack D. E. , Wilding L. P.
Published: July 2010

Swelling phenomena were measured on Saran3‐coated undisturbed clods, trimmed undisturbed samples in a consolidation frame, and on remolded compacted samples in the Percent volume change (PVC) meter and in a consolidation frame. Three horizons of the Canfield series and two horizons of the Geeburg series were studied at each of five sites. Swelling pressures of 1.5 to 2.0 kg/cm2 were measured for the clayey Geeburg samples; in the loamy Canfield samples swelling pressure was generally < 1.0 kg/cm2. Percent swell ranges from 5 to 8% in Geeburg soils and is generally < 1% in Canfield soils. Where other parameters are held constant, most of the variation in swelling is explained by variation in clay content. Values of r2 as high as 0.93 were derived. Coarse clay content is more highly correlated with swelling than fine clay content, possibly because of the effect of the higher charge density of the coarse clay on the thickness of oriented water films. Results indicate that expansive soils continue to swell at moisture contents above ⅓‐bar tension, and continue to shrink at moisture contents below 15‐bar tension and below the shrinkage limit.
Two‐Dimensional Solutes Transfer during Nonsteady Infiltration: Laboratory Test of Mathematical Model
Authors: Bresler Eshel , Russo David
Published: July 2010

The theory of two‐dimensional transport of solutes during nonsteady infiltration from trickle sources, as developed previously, was compared with experimental results. A laboratory experiment was conducted under conditions similar to those assumed in the two‐dimensional plane flow model. The agreement between theory and experiment as expressed by salt concentration distribution and location of wetting fronts, is generally good. This suggests that the theory is applicable to many situations similar to the conditions studied.
Leaching of Adsorbed Potassium from Humid Tropical Soils
Authors: Bower C. A.
Published: July 2010

Equilibrium between solution and adsorbed K in humid tropical soils leached by rainfall was found to be described by the Langmuir adsorption equation. The product of the two constants in the Langmuir equation k1 and k2, which is equal to the reciprocal of the intercept of the Langmuir isotherm, is a direct measure of the tendency of soil to retain adsorbed K against leaching. Retentivity was greatest in soil containing montmorillonite clay and least in soils derived from volcanic ash having clay dominated by amorphous silicates. Soils whose clay consisted of goethite, gibbsite, and kaolinite were intermediate in retentivity. As a consequence of the applicability of the Langmuir equation, it has also been found that the concentrations of solution and adsorbed K at any depth in the soil as a function of depth of water passing the depth during leaching can be satisfactorily predicted by simplified, approximate solutions of equations derived by Thomas, and Hiester and Vermeulen.
Anthraquinones and Phenols as Intermediates in the Formation of Dark‐Colored, Humic Acid‐Like Pigments by Eurotium echinulatum
Authors: Saiz‐Jimenez C. , Haider K. , Martin J. P.
Published: July 2010

Eurotium echinulatum, a fungus isolated from a vertisol in southern Spain, formed humic acid‐like pigments during growth in glucose‐asparagine or glucose‐NaNO3 media. After 6 to 7 days the phenols, orsellinic, p‐hydroxycinnamic, and p‐hydroxybenzoic acids, and the anthraquinones, endocrocin, emodin, and physicion were detected in the culture media. Upon further development of the mycelial mats additional aromatic compounds were produced and after 4 to 6 weeks more than 50 different ether‐extractable phenols and anthraquinones were detected. With further incubation the amounts and number of these compounds decreased and pigment formation in the media increased. After 2 to 3 months the culture media were dark brown to black and about 1 to 3.5 g/liter of polymer could be recovered upon acidification of the culture medium. Sodium amalgam reduction of this polymer yielded numerous phenols, anthraquinones, anthrones, and possibly anthracene derivatives. Treatment with sodium dithionite yielded largely anthraquinones. The polymer contained 1 to 4.5% N depending upon the N source. From 50 to 60% of this N was released in the form of amino acids upon acid hydrolysis. With both asparagine and NaNO3 as N sources the same amino acids were isolated from 6N HCl hydrolysates. Quantitatively, however, there were differences in the percentage distribution of the amino acids.
Effect of Degree of Soil Profile Disruption on Plant Growth and Soil Water Extraction
Authors: Rakov K. , Eck H. V.
Published: July 2010

Modification of slowly permeable soil profiles has been effective in ameliorating undesirable soil conditions. Various methods and depths of modification have been studied but little attention has been given to (i) the degree of disruption necessary to accomplish satisfactory profile modification or (ii) the relative merits of topsoil‐subsoil mixing and stockpiling and returning topsoil to the surface after profile modification. We studied seven degrees of profile disruption (clod size distributions in the B22t and mixing of topsoil with that horizon) in simulated soil profiles in the greenhouse. Grain sorghum (Sorghum bicolor) was grown on Pullman clay loam. Disturbance of the B22t layer increased yields but once that layer was disturbed, degree of disturbance had no further effect on yield. Compared with retaining topsoil on the surface, mixing it with the B22t did not affect yields.
The Effect of Ammonia and Ammonia‐sulfur Solutions on Nitrification Rates and Chemical Properties of a Calcareous Soil
Authors: Stevens R. G. , Reuss J. O.
Published: July 2010

Nitrification rates and changes in chemical properties of a calcareous soil were investigated after injection of liquid anhydrous NH3 and anhydrous NH3‐S solutions.

Nitrification rates (on a whole pot basis) of 15.7, 25.3, and 32.2 mg of N per pot per day were found with the application of 200, 400, and 600 mg of N/pot, respectively. These nitrification rates were recorded during the initial 14 days of the study when total NO3‐ accumulation appeared to be linear.

Ammonium depletion from zones 1 cm in thickness measured outward from the injection point appear to obey a first‐order rate law. Half life values ranged from 12.4 to 1.4 days. They were longest at the injection point with the highest NH3 rate and decreased with decreasing rate of application and with increasing distance from the injection point. There were no differences in the nitrification rates of the two sources as measured by either nitrate accumulation on a whole pot basis or ammonium depletion of individual zones.

Less than 10% of the applied sulfur was recovered as SO42‐ during the incubation period. Little difference was found in the effect of the two sources on pH, DTPA extractable Zn or Fe, or NaHCO3 extractable P. DTPA‐extractable Mn was higher near the injection point in the NH3‐S treatments.
Micaceous Vermiculite, Glauconite, and Mixed‐Layered Kaolinite‐Montmorillonite Examination by Ultramicrotomy and High Resolution Electron Microscopy
Authors: Lee S. Y. , Jackson M. L. , Brown J. L.
Published: July 2010

Electron optical fringes of the layer structures of micaceous vermiculite (Colorado), glauconite (Wisconsin), and mixed‐lavered kaolinite‐montmorillonite (Mexico) were observed after separation of clay fractions, saturation with various cations, embedment in Epoxy, thin sectioning normal to the (001) planes by a diamond‐knife ultramicrotome, and high resolution, diffraction contrast electron microscopy.

In the thin section of Cs‐saturated micaceous vermiculite, the electron optical fringes at 10Å may represent the basal crystallographic spacing of unweathered K mica; fringes at 11Å and 5.5Å may represent the (001) and (002) crystallographic basal orders of Cs vermiculite with the interlayers nearly closed; and fringes at 12.5Å may represent incompletely collapsed vermiculite (possibly lower layer charge and/or hydrous metal oxideinterlayered). The K‐saturated glauconite particles occur as thin crystal packets consisting of 5 to 20 layers of mica + vermiculite + montmorillonite with 10Å spacing; occasional interstratified 14Å spacings are believed to represent the Raman‐Jackson chlorite. A Mg‐saturated, mixed‐layer kaolinite‐montmorillonite from Mexico showed interleaving among the electron optical (001) fringes of kaolinite (7Å), montmorillonite (12 to 14Å), micaceous vermiculite (10Å), and regularly interstratified kaolinite‐montmorillonite (19Å). The mixing among the minerals in the Mexico sample appears to involve (i) a whole series of interstratifications along the Z axis, and (ii) mixing across planes defined by the X and Y axes, including regularly alternating, irregularly mixed, and zones of specific minerals.
Pirimiphos Ethyl‐Clay Surface Interactions
Authors: Mingelgrin U. , Gerstl Z. , Yaron B.
Published: July 2010

Pirimiphos ethyl (PE) losses on Na‐kaolinite and Na‐bentonite were investigated, and the effect of moisture and temperature on the clay‐pesticide interactions determined. The behavior of PE on clay surfaces is discussed in view of the behavior of other organo‐phosphorus pesticides, and the mechanism of the hydrolysis of organo‐phosphorus pesticides catalyzed by clay surfaces. The data suggest that the dominant mode of loss is the hydrolysis of the phosphate ester bond with the pyrimidine ring of pirimiphos ethyl. Hydrolysis occurred at a significant rate on air‐dried Na‐kaolinite at 23C and 47C and on oven‐dried as well as air‐dried Na‐bentonite at 47C.
Charge Characteristics and Nitrate Retention By Two Andepts from South‐Central Chile
Authors: Espinoza W. , Gast R. G. , Adams R. S.
Published: July 2010

Charge characteristics of two Andepts, or volcanic‐ash‐derived soils, from south‐central Chile were studied using a combination of nitrate retention, pH dependent cation exchange capacity and pH titration curves. Nitrate retention was determined by washing the soil with KNO3 solutions having the appropriate concentration and pH and determining the amount of nitrate adsorbed. Net surface charge was determined from potentiometric titration curves conducted using a batch technique.

Results show that both soils have a complex mixture of pH dependent and permanent charge surfaces. The maximum pH dependent charge is in the range of 15 to 20 meq/100g at either very low or very high pH and high electrolyte concentration. The permanent negative charge is in the range of 45 meq/100g and is apparently the result of ion substitutions and lattice vacancies in X‐ray amorphous oxides and hydrous oxides rather than 2:1 type clay minerals.
The Chemistry of Lead and Cadmium in Soil: Solid Phase Formation
Authors: Santillan‐Medrano Javier , Jurinak J. J.
Published: July 2010

Equilibrium batch studies were conducted to obtain solubility data of Pb and Cd in soils. The data were plotted on equilibrium solubility diagrams using pH as the master variable. In the construction of the diagram the hydroxide, carbonate, and phosphate compounds of Pb and Cd were given particular attention. Both Pb and Cd solubility decreased in the soils as pH increased. The lowest values were obtained in the calcareous soil. Under a given set of conditions, however, Cd activity in solution was always notably greater than that of Pb. In noncalcareous soils the solubility of Pb appeared to be regulated by Pb(OH)2, Pb3(PO4)2, Pb4O(PO4)2, Pb5(PO4)3OH, depending on the pH. In calcareous soils, PbCO3 also assumed importance. At higher Cd concentrations the precipitation of Cd3(PO4)2 and/or CdCO3 regulated cadmium solubility. At low Cd concentrations the equilibrium solution was undersaturated with regards to both Cd3(PO4)2 and CdCO3.
Characteristics of Computerized Soil Maps
Authors: Nichols Joe D.
Published: July 2010

In computer‐generated interpretive soil maps, a detailed soil map is generalized by selecting the dominant soil by estimation within a grid or unit cell. The soil mapping unit from the detailed soil map is retained for its higher predictive value.

Interpretive maps are generated by computer translation of the dominant soil in each unit cell to a rating and then printing the result on unlined paper as a graphic display. A study was made of the agreement between detailed soil maps and those generalized using various cell sizes. On a soil survey map with a medium amount of cartographic detail, the average agreement was 70.5, 64.4, and 48.4% for unit cell sizes of 8.64 ha (21.33 acres), 16.20 ha (40 acres), and 64.80 ha (160 acres). On soil maps with low, medium, and high amounts of cartographic detail, the average agreement was 71.6, 64.4, and 41.3%, respectively, for a standard unit cell size of 16.20 ha (40 acres). The t test was used to test the agreement between the acreage of soil mapping units obtained from the MIADS program versus the acreage measured by dot counting. The test showed no differences in sample means of the two methods for samples tested.
A Lithosequence in the Mountains of Southwestern Oregon
Authors: Parsons R. B. , Herriman R. C.
Published: July 2010

A lithosequence derived from granite, schist, and pyroclastics was studied on gently sloping and steep mountain slopes. Each soil exhibits lithologic discontinuities related to increments of slope alluvium and identified on the basis of the depth distribution and weathering of rock fragments over saprolite. Soils developed from granite have coarse textures, low base saturation and cation exchange capacity, and no argillic horizons. Soils from pyroclastic rocks are fine‐textured, have argillic horizons, and have the highest base saturation and cation exchange capacity, whereas soils from schist may or may not have argillic horizons and have intermediate chemical properties. The soils developed from pyroclastics have higher woodland productivity and fewer watershed management and construction problems than soils developed from schist or granite. Soil landscapes underlain by schist are especially susceptible to mass movement.
Possible Mutual Prediction Between Black Cherry and Sugar Maple Foliar Analysis Data
Authors: Leaf Albert L. , Bickelhaupt Donald H.
Published: July 2010

Fertilizer treatments were established in duplicate in a 75‐ to 80‐year‐old mixed stand of sugar maple (Acer saccharum Marsh.) and black cherry (Prunus serotina Ehrh.) on Cookport silt loam soil in a randomized‐blocks‐with‐split‐plot experimental design. The main unit treatments were control, N‐only, P‐only, NP, and NPK, and the subunit treatments were nonlime and lime. Foliage samples were obtained from 5 dominant‐codominant trees of each species in each plot for 1 pretreatment year and 3 consecutive years following treatments. Regression analysis of foliar mean values from each treatment plot and year was used to determine if a statistically significant relationship existed for concentrations of N, P, K, Ca, Mg, Na, and Mn of the sample trees. The mutual prediction between black cherry and sugar maple foliage analysis data was statistically significant for several of the parameters investigated.
Solute Travel‐Time Estimates for Tile‐Drained Fields: II. Application to Experimental Studies
Authors: Jury W. A.
Published: July 2010

The model of Jury (1975) for estimating travel time from surface application to point of discharge for tile‐drained fields is applied to data from published studies of tile‐drain effluent concentrations and solute flux. In all systems the observed values are consistent with model calculations, and in circumstances where an exact comparison is possible the agreement between measured and predicted values is very good. Measures proposed for improving water quality by requiring standards for affluent discharge levels are discussed and criticized, and model simulations of projected monitoring policies of typical field systems are used to demonstrate the potential for misinterpreting the relationship between surface inputs and output levels.
Predicting Ionic Distributions in Large Soil Columns
Authors: Wierenga P. J. , Shaffer M. J. , Gomez S. P. , O'Connor G. A.
Published: July 2010

The distribution of various cations and anions was measured with depth and time in a large lysimeter column periodically irrigated with saline water. Samples of the soil solution were removed with extraction cups placed at depths of 25, 50, 75, 100, 125, and 150 cm below the soil surface in the lysimeters. Observed ionic distributions were compared with calculated values obtained by combining a transient water flow model with a chemical plate theory model. Good agreement was obtained between observed and predicted depth distribution profiles for SO42‐, Cl‐, Na+, and Ca2+. Soluble Mg2+ and HCO2‐ concentrations were overpredicted suggesting that further refinement of the chemical subroutine may be needed.
Potassium in an Arid Loessial Soil: Characterization by Equilibrium Release‐Absorption to Strong Salt Solutions
Authors: James D. W. , Weaver W. H.
Published: July 2010

Shano silt loam soil developed from loessial and volcanic materials of recent origin under mild weathering conditions. It contains < 5% of clay, and 60% or more of silt. The rate of release of mineral K (Km) in this soil to 1N Cl solutions decreased in the order Na > Ca > Mg ≫ NH4. Release of Km may have involved some framework silicates, but for practical purposes the layer silicates controlled Km activity. Release of exchangeable K (Kx) graded imperceptably into Km release and apparently depended on the relative accessibility of edge‐interlattice adsorption sites. The classical method for estimating Kx (three extractions with NH4) evidently released some Km because the conformation of the cumulative solution K (Ks) curves was the same for initial NH4 extractions as for NH4 extractions following removal of Kx with Ca, Mg or Na. Based on the proportions and K‐releasing abilities of several soil size fractions, it was concluded that the preponderance of Km release activity originated in the silt fraction. A lesser amount of Km activity was associated with the sand with only a small portion of the Km release attributable to the clay. Equilibrium between Km, Kx, and Ks in the Shano soil was essentially complete within 24 hours.

It appears that Km may be more important than Kx in this soil as pertaining to K intensity and capacity. In neutral and calcareous soils Ca and Mg are present in large amounts as exchangeable ions and as soluble and/or slightly soluble salts. Therefore, the activity ratio Ks/Nas potentially has greater significance in neutral to calcareous soils than do the potassium adsorption ratio K/[(Ca + Mg)/2]½ or quantity‐intensity relations, ΔKs vs. [K/(Ca + Mg/2)]½.
Potassium in an Arid Loessial Soil: Changes in Availability as Related to Cropping and Fertilization
Authors: James D. W. , Weaver W. H. , Roberts S. , Hunter A. H.
Published: July 2010

Two K fertilizer experiments were initiated in 1961 in arid central Washington on a Shano silt loam soil site that had been leveled to accommodate irrigation. The experiments were continued for 3 years and utilized rates of K fertilizer up to 320 kg K/ha in a randomized complete block design. By 1964 there existed a wide range of Kst (soil test K) as a result of the fixed random K treatments and the partial exposure of K‐deficient subsoils. That year the experiments were altered to completely randomized designs using both Kst and K fertilizer rates as controlled variables. The experiments were continued through 1970, providing an evaluation of the effects of crop management and K fertilization on soil K reserves.

High Kst, both indigenous and fertilizer induced, decreased rapidly as a result of crop removal, with the rate of decline decreasing to zero as Kst fell below 100 ppm. The decrease in Kst was strongly modified by the type of crop (rooting habit and total K uptake) and by the method of crop residue disposition. Forage crops maximized the changes, whereas grain crops (with seed only removed) had a minimal effect, causing an apparent increase in K availability as a result of surface soil enrichment with K from the subsoil via the stubble. Decreases in Kst were stopped or reversed by K fertilization. Large amounts of K were removed by crops when Kst was low and static.

At low levels of Kst soil mineral K (Km) had a dominating influence, strongly buffering Kst changes involved with K removal (cropping) and K addition (fertilization). Whereas Kst serves as a good first approximation of soil K supply potential, supplemental information is required to fully describe the intensity and capacity factors in the K‐soil‐plant system. At comparable levels of Kst, the Shano silt loam profile is essentially homogeneous in regard to K availability. Therefore, special efforts to sample subsoils need not be made in routine fertility diagnosis of this soil series.
Growth of Turfgrasses as Affected by Soil Phosphorus and Arsenic
Authors: Carrow R. N. , Rieke P. E. , Ellis B. G.
Published: July 2010

The influence of soil phosphorus (P) level on the growth of turfgrasses and on the Bray P1 extractable arsenic (As) were investigated. In the first study five rates of As (0, 0.44, 0.88, 1.76, and 3.53 kg As/100 m2) and four rates of P (0, 1, 2, and 4 kg P/100 m2) were applied to a soil low in natural P. In the second study four rates of As (0, 0.88, 1.76, and 3.53 kg As/100 m2) were applied to a soil collected from a long‐term P study. Several cool season turfgrasses were seeded in each study.

Arsenic had no effect on seed germination of any of the grasses when the As was applied and incubated 7 weeks prior to seeding. Increasing As levels decreased the growth of all grasses regardless of P level. Poa annua L. was most affected by As. Phosphorus had little or no effect on As toxicity as exhibited by turfgrass growth even at very high P levels.

Adding As increased the Bray P1 extractable As fraction. The Bray P1 extractable As level was negatively correlated to turfgrass growth. Phosphorus had no effect on As activity as measured by the Bray P1 extractable As. However, As markedly increased the P soil test results due to interference.
Loess in Ohio in Relation to Several Possible Source Areas: II. Elemental and Mineralogical Composition
Authors: Rutledge E. M. , Wilding L. P. , Hall G. F. , Holowaychuk N.
Published: July 2010

This study presents the elemental and mineralogical composition of thin loessial deposits eastward of three rivers in Ohio. In general, elemental contents (Ca, Fe, K, Ti, and Zr) of medium and coarse silts of the Late Wisconsin‐age loesses were of the same magnitude in each area. These elements showed remarkably slight weathering profiles which were essentially comparable among areas. Weathering profiles of Fe were more strongly expressed than those of K and Ca; depth‐distributions of Zr and Ti were most uniform. Contents of Ca within a Loveland loess paleosol were remarkably constant with depth and notably low, especially in the coarse silt fraction (mean of 0.06%). Mineralogy did not reflect bedrock lithologies among the different assumed loess source areas. Clay fractions from the parent loess in the first two transects were dominated by mica followed by vermiculite and quartz with less expandables and kaolinite. Clay fractions of surface and subsurface horizons in these transects contained about equal amounts of mica, vermiculite, and quartz with less expandables and kaolinite. In the third transect, weathered loessial materials generally contained less mica and more interstratified 10–14Å components. Clay‐free particle‐size distribution was the most sensitive parameter of parent material uniformity; total Zr and Ti in silt fractions, and Ti/Zr ratios were less sensitive in that order.
Vegetative History of Cinnabar Park in Medicine Bow National Forest, Wyoming
Authors: Miles S. R. , Singleton P. C.
Published: July 2010

A study was initiated to determine the vegetative history and boundary stability of Cinnabar Park, a small park located in Medicine Bow National Forest, Albany County, Wyoming, typical of many high altitude parks scattered throughout our National Forest Lands.

The park and the forest immediately surrounding the park occur on an erosional remnant of uplifted Tertiary aged sediments at an elevation of 2,758 m. The soils of the park are classified as Cryoborolls, and those of the forest surrounding the park are Cryochrepts. Vegetation in the park consists of a variety of forbs, shrubs, and grasses, while that of the surrounding forest is mainly lodgepole pine (Pinus contorta Dougl.), with some Engelmann's spruce (Picea engelmanni (Parry) Engelm.) intermixed.

Various soil characteristics of the park were compared with those of the surrounding forest in an effort to obtain clues which might point to the vegetative history of this area. The content of plant opal and the pH of the soils, together with field observations, led to the conclusion that the park boundaries are slowly shifting in an eastward direction. Strong prevailing westerly winds and drifting snow appear to be the forces responsible for the boundary movement.
The Use of a Specific Ion Electrode for Determination of Bromide in Soils
Authors: Onken Arthur B. , Hargrove R. S. , Wendt C. W. , Wilke O. C.
Published: July 2010

Bromide has desirable characteristics for use as a tracer for NO3‐ in some soil studies. However, its quantitative determination in the presence of Cl‐, which occurs in interfering quantities in many soils, requires lengthy procedures. Further, Br‐ interferes with the quantitative determination of Cl‐ for which concentrations may also need to be determined. To facilitate the use of Br‐ as a tracer in such tests, a procedure for the rapid and accurate determination of water‐extractable Br‐ in the presence of Cl‐ and Cl‐ in the presence of Br‐ was developed. These quantitative determinations over a wide range of concentrations were accomplished by use of standard curves, interference curves, and successive approximations. Bromide added to soil over a wide range of concentrations was quantitatively recovered.
Bulk Density, Saturation Water Content and Rate of Wetting of Soil Aggregates
Authors: Gumbs F. A. , Warkentin B. P.
Published: July 2010

Bulk density, degree of saturation, volume increase on wetting, and rate of wetting were measured for aggregates and clods of Ormstown silty clay loam (Humaquept) of sizes from 5 cm to 0.036 cm diameter.

Bulk density increased with a decrease in diameter. For 2.2‐mm to 0.36‐mm diameter aggregates this increase was due to a surface area effect, i.e., loss in porosity as a result of subdividing larger aggregates. Both surface area effects and increased porosity from root channels and fissures were required to explain the increase for clods between 5 and 1 cm diameter.

An evaporation and a sorption technique are described and used to estimate the water content of aggregates at saturation, i.e., the intra‐aggregate water content. The evaporation technique gave reliable results at specific rates of evaporation, but the sorption technique was not as useful. Clods and aggregates of the soil and of pumice samples did not fully saturate; entrapped air accounted for 25 to 27% of the total pore volume.

Aggregates of 1 and 2.2 mm diameter and clods of 1.0 and 5.0 cm diameter took about 1, 1.7, 45, and 1,000 seconds, respectively, to saturate. This rapid wetting would minimize differences in potential between inter‐and intra‐aggregate water during infiltration.
Gaseous Loss of Ammonia from Sulfur‐coated Urea, Ammonium Sulfate, and Urea Applied to Calcareous Soil (pH 7.3)
Authors: Prasad M.
Published: July 2010

Laboratory incubation experiments were conducted to study the comparative volatilization loss of NH3 in a calcareous soil from sulfur‐coated urea (SCU) with fast (F), medium (M), and slow (S) dissolution rates, ammonium sulfate (AS) and urea, at two temperatures 22 and 32C, and at three soil moisture levels 25, 50, and 80% of the water‐holding capacity of the soil. The effect of the addition of organic amendment (filter press mud) to soil on NH3 loss from these N‐sources was also studied. Losses were studied up to 21 days. At both temperatures increasing soil moisture levels led to reduction of NH3 loss regardless of the N‐source, despite the fact that the soil analysis showed higher dissolution of N from SCU at high soil moisture.

Higher temperature increased the NH3 losses from all N‐sources. Losses usually followed the order of Urea > AS > SCU(F) > SCU(M) > SCU(S). At 32C losses from uncoated urea and AS at low, medium, and high moisture were 20.6 and 16.7%; 14.5 and 13.1%, and 8.4 and 6.6% of the N application rate, respectively. Losses from SCU(F) and SCU(M) as percentage loss of uncoated urea varied from 34% and 26% at low moisture, 29% and 23% at medium moisture, and 28% and 23% at high moisture, respectively. At 22C losses from uncoated urea and AS at low, medium, and high moisture were 11.1 and 10.2%; 7.7 and 8.8%, and 4.2 and 3.5% of the N application rate, respectively. Losses from SCU(F) and SCU(M) at three moisture levels were 26 and 17%, 18 and 10%, and 24 and 16%, respectively.

Incorporation of filter press mud to the soil resulted in reduction of volatilization loss of NH3 from all N‐sources which was partly due to exchange reaction and biological immobilization of NH4‐N and partly due to reduction of urease activity.
Soils and Stratigraphy of Mid to Lower Slopes in the Southwestern Uplands of Nigeria
Authors: Ojanuga A. G. , Lee Gerhard B. , Folster H.
Published: July 2010

Pedogenic and geomorphologic studies along mid to lower slopes of typical landforms in southwestern Nigeria revealed simple to complex stratification of pedisediments derived through cyclic erosional and depositional phenomena that evolved the inselberg landscapes in the region. The most recent pedimentation of slopes and hence, the deposition of the youngest soil parent material, is believed to have occurred about 2360 ± 120 years before the present. Contemporary soils owe many of their major properties to depositional processes. Pedogenic processes that could be inferred from existing soil properties include: the addition of organic matter to surface horizons, strong leaching of bases, eluviation of iron oxides from surface layers, lateral translocation of iron oxides, incrustation of subsoil concretionary materials to form petroferric horizons (hardpan) in lower slope positions, and clay migration.
Drainage System Effects on Physical Properties of a Lakebed Clay Soil
Authors: Hundal S. S. , Schwab G. O. , Taylor G. S.
Published: July 2010

The long‐term effects of drainage on physical properties of a lakebed silty clay soil were evaluated 16 years after initiation of a field experiment. The treatments were undrained, surface drainage, subsurface drainage, and a combination of surface and subsurface drainage. Soil conditions were characterized by surface penetration resistance and by unconfined compressive strength, hydraulic conductivity, and pore size distribution in the 0–30 cm depth. Subsurface drainage resulted in greater soil hydraulic conductivity, less unconfined compressive strength, and less surface crust resistance than treatments without subsurface drainage. Subsurface drainage also decreased bulk density and increased the volume of air‐filled pores at 0.02 to 1.0‐bar suctions, but these effects were of smaller magnitude.

An alfalfa (Medicago sativa L.)‐timothy (Phleum pratense) mixture was grown during the period of these measurements. The survival of alfalfa and the total hay yield decreased in the order: combined surface and subsurface drained, subsurface drained, surface drained, and undrained treatments.
Polymerization of Aromatic Molecules on Smectite
Authors: Mortland M. M. , Halloran L. J.
Published: July 2010

When benzene or phenol are adsorbed on smectite containing Fe(III) or Cu(II) on the exchange complex, higher molecular weight products are formed. Evidence for these products is provided by mass spectroscopy. In the case of benzene most of the reaction products cannot be attributed to coupled benzene rings, while extensive coupling occurs for phenol. Electron spin resonance spectroscopy provides evidence for radical cation formation of the aromatic molecules. The involvement of these radical cations is thus proposed in the formation of the higher molecular weight species. The relevance of these reactions to the natural systems of soils and sediments is suggested.
Influence of Cation Content on the Biological Activity of Fensulfothion in Plainfield Sand
Authors: Harris C. R. , Bowman B. T.
Published: July 2010

A study was conducted to assess the influence of cations on the biological activity of the organophosphorus insecticide, fensulfothion (O, O‐diethylO‐[p‐(methylsulfinyl)phenyl] phosphorothioate)(Dasanit®) in soil. Bioassays were done using first stage crickets, Gryllus spp. as test insects and a Plainfield sand without and amended with various concentrations of reagent chloride salts of NH4+, K+, Ca2+, Fe3+, and Al3+. The toxicity of fensulfothion decreased with increasing cation content, with the effect being most pronounced with trivalent > divalent > monovalent cations. Results of the bioactivity study paralleled those of an earlier adsorption study on fensulfothion‐cation montmorillonite suspensions.
Biosynthetic Alteration in a British Columbia Soil by Ants (Formica fusca Linné)
Authors: Wiken E. B. , Broersma K. , Lavkulich L. M. , Farstad L.
Published: July 2010

The occurrence and pedological effects of active and recently active (inactive) ant mounds are compared with apparently unaffected soils in the subalpine region of Mt. Tatlow in British Columbia, Canada. The unaffected soils in the area are classified as Orthic Dystric Brunisols (Dystrochrepts). The soils have developed from post‐Pleistocene glaciofluvial deposits and support a lodgepole pine‐pine grass vegetative community. Comparison of the active and inactive colonies with the surrounding unaffected soils showed marked changes in particle size distribution, chemical properties, and structure formation. The biosynthetic alteration generated by ants (Formica fusca Linné) appears to reverse the general pedogenetic processes of leaching and horizonation. This process is only temporary as the inactive sites are similar to the surrounding unaffected soils.
Effect of Water Supply, Nitrogen, and Seedbed Density on White Spruce Seedling Growth
Authors: McClain K. M. , Armson K. A.
Published: July 2010

Seedling dry weight, height, and root area index were measured during the second (2 + 0) growing season for white spruce (Picea glauca (Moench) Voss) seedlings grown in a field nursery at two seedbed densities, three levels of moisture supply, and four levels of N. All measures of growth increased with rise in N supply. Increases were more pronounced at the lower than at the higher seedbed density. Growth responses to increases in moisture supply varied in relation to N level but were consistently greater at the lower density. Seedling foliage at final harvest was analyzed and concentrations of the major elements (N, P, K, Ca, and Mg) determined. Nitrogen concentrations increased with increasing N supply and decreasing moisture. Other nutrient elements were variably affected, but did not limit growth.
The Effect of Controlled‐Availability Nitrogen Fertilizers on Mature Pecan Trees
Authors: Sullivan D. T. , O'Connor G. A. , Herrera‐Aguirre E.
Published: July 2010

Two controlled‐availability N fertilizers, sulfur‐coated urea (SCU) and NH4NO3 plus N‐Serve, were compared with NH4NO3 alone applied to 30‐year‐old pecan trees (Carya illinoensis Koch) in a 2‐year study. Leaf N contents were increased in both years by N fertilization, but yield and nut weight were not significantly affected. Yields in 1973 were correlated with 1972 leaf N contents, but not with 1973 leaf N contents. The SCU treatment was effective in controlling N release in 1973, but not in 1974. The N‐Serve treatment was ineffective both years of the study. The ineffectiveness of the controlled N sources were attributed to: (i) poor incorporation of the materials, (ii) inherent slow response of mature pecan tree to N fertilization, and/or (iii) sufficient variability within treatments to mask fertilizer source difference.
Changes in the Physical Properties of Soil Clays due to Precipitated Aluminum and Iron Hydroxides: II. Colloidal Interactions in the Absence of Drying
Authors: El‐Swaify S. A.
Published: July 2010

Colloidal stability diagrams were constructed for suspensions of an illite, a kaolinite, and a mixture of the two into which Al(OH)3 and Fe(OH)3 were precipitated. These diagrams covered a pH range from 2.5 to 12.5 and electrolyte concentrations up to the flocculation value. It was revealed, in accordance with expected interactions of colloids with widely different isoelectric points, that the colloidal stability of each mixture was dependent on the charge balance between its individual constituents. Therefore, as long as a system has not encountered a drying cycle, hydroxides may provide favorable (flocculating) or nonfavorable (colloidally stable) effects on soil structure depending on hydroxide type, its surface reactivity, and the clay mineral with which it may be associated. Generally, the two hydroxides provided equal enhancement of clay colloidal stability above their isoelectric points. However, Al(OH)3 was more active in inducing clay flocculation and charge reversal at low pH values.
Ammonia Volatilization and Nitrogen Utilization from Sulfur‐coated Ureas and Conventional Nitrogen Fertilizers
Authors: Matocha J. E.
Published: July 2010

Ammonia volatilization was measured on acid and calcareous soils receiving sulfur‐coated ureas (SCU) and highly soluble N fertilizers. Surface and mixed applications of SCU‐30 (30% dissolution rate), SCU‐20 (20% dissolution rate), uncoated (NH2)2CO, NH4NO3, and (NH4)2SO4 were made with and without lime to a fallowed acid fine sand. Without lime, top dressed NH4NO3, SCU‐20, SCU‐30, and (NH4)2SO4 lost < 1% while (NH2)2CO lost 18.5% of added N in 14 days. Topdressing lime with N caused more NH3 loss from (NH4)2SO4 than from (NH2)2CO during the intial 48 hours. However, accumulative losses for 14 days were 51.5, 22.5, 9.0, and 1.7% from (NH2)2CO, (NH4)2SO4, SCU‐30, and SCU‐20, respectively. Incorporating the lime with the soil prior to N addition reduced NH3 loss > 50% as compared to surface application, but mixing N with the limed acid soil did not reduce NH3‐N losses. Mixing SCU with the soil appeared to increase release rate of N over topdressing, but this effect was not detected in plant response. Nitrogen uptake by corn (Zea mays L.) on the acid soil substantiated some of the conclusions regarding measured NH3‐N losses.

Ammonia losses from N mixed with the finer textured calcareous clay loam were generally insignificant. Surface applied (NH2)2CO and (NH4)2SO4 lost significant amounts of NH3‐N, while losses from SCU and NH4NO3 were negligible.
Microcalorimeter Adaptation for Measurement of Heats of Adsorption at Solid‐Solution Interfaces
Authors: Harter Robert D. , Kilcullen Brian M.
Published: July 2010

The sensitivity of the Calvet Microcalorimeter makes feasible the measurement of very small heats of reaction. This capability is particularly useful when studying adsorption reactions at solid‐solution interfaces. The instrument must, however, be specially adapted for measurements of this type, since it contains no provision for equilibration and mixing of separate solutions. Previously developed adaptations of the instrument are not satisfactory, because they either do not stir the combined solutions adequately to overcome flocculation problems or their mechanical energy input is high. An instrument has been developed whereby two solutions can be equilibrated in the calorimeter cell, then mixed and stirred with a net mechanical energy input of −2 ± 0.4 mcalories. This instrument, therefore, makes possible the precise measurement of very small heats of reaction.
A Portable Rainfall Simulator for Erodibility and Infiltration Measurements on Rugged Terrain
Authors: Munn J. R. , Huntington G. L.
Published: July 2010

A portable rainfall simulator for field study of erosion potential and infiltration on mountainous terrain is described. Polyethylene tubes produce 3.2‐mm drops which fall 2.5 m onto a 61 by 61 cm plot. The maximum rainfall intensity is 23 cm/hour. A 16% intensity variation across the plot area was measured, but the variation between separate simulated storms was < 1% for identical intensity settings. The unit is suited to one man operation on slopes up to 60%.
Time‐dependent Linearized Infiltration: III. Strip and Disc Sources
Authors: Warrick A. W. , Lomen D. O.
Published: July 2010

Water flow from strip and disc surface sources is analyzed using an approach similar to previous investigations with line and point sources. A line of closely spaced trickle irrigation emitters often wets a surface strip of finite width; similarly, for a single emitter the surface wetted pattern is a disc. Lines of equal matric flux potential are wider and more shallow for these sources than wetting patterns for the line and point. The moisture regime is independent of the source shape and depends only on the total flow rate for regions beyond approximately two times the strip width or disc radius.
Scanning Electron Microscopy of a Humic Acid and of a Fulvic Acid and its Metal and Clay Complexes
Authors: Chen Y. , Schnitzer M.
Published: July 2010

A Scanning Electron Microscope was used to explore the effect of varying the pH on the shape, size, and degree of aggregation of humic and fulvic acid particles. The structure of the complexes formed by fulvic acid when reacted with Cu2+, Al3+, Fe2+, and Fe3+ was also studied, as was the reaction product of Na‐montmorillonite and fulvic acid.

At low pH (2–3), fulvic acid occurred mainly as elongated fibers and bundles of fibers, forming a relatively open structure. With increase in pH (4–7), the fibers tended to mesh into a finely‐woven network to yield a sponge‐like structure. Above pH 7, a distinct change in structural arrangement and improved orientation was observed. At pH 8, the fulvic acid formed sheets which tended to thicken at pH 9. At pH 10, fine, homogeneous grains were visible. The effect of pH on the humic acid structure was similar to that observed on fulvic acid except that because of low solubility in water, the pH range had to be narrowed to between 6 and 10 and the pH at which the major transitions occurred was higher.

Micrographs of fulvic acid‐metal and fulvic acid‐clay complexes show interesting possibilities for the use of this approach in investigations on metal‐ and clay‐humic complexes.