bluuebunny/crossref_metadata_2025 huggingface dataset:
The Use of Spheres to Measure Lift and Drag on Wind‐Eroded Soil Grains
Authors: Chepil W. S.
Published: July 2010

Experiments were conducted to determine the relative magnitude of lift and drag on small spheres, similar to soil grains, at different heights in a fluid boundary surface and to determine if these forces are related to movement of soil grains in saltation.

Lift on the average was about 75% that of drag when a sphere was at zero height. Lift decreased with height and virtually ceased a short distance above ground. The greater the ground roughness and drag velocity, and therefore the steeper the velocity gradient, the higher lift extended. It is concluded that lift is caused by a steep wind velocity gradient near the ground.

Drag on the spheres was generally much greater than lift. Drag increased directly with an increase in wind velocity and was apparently due to direct pressure of the wind against the sphere.

It is evident from these experiments that lift alone is too small to cause the saltating grains to rise, as they do, essentially vertically. The predominantly vertical rise apparently is the way the saltating grains rebound from the ground.
Determination of Arsenic in Flue‐Cured Tobacco and in Soils
Authors: Small H. G. , McCants C. B.
Published: July 2010

Procedures are described for the semimicro analysis for arsenic in flue‐cured tobacco and in soils. The plant material is digested with a mixture of nitric, sulfuric and perchloric acids and the soil with sulfuric and perchloric acids. Arsenic is distilled directly from the digestion flask, absorbed in an iodine solution and determined colorimetrically by the molybdenum‐blue method.

The data show that good recovery of arsenic and reproducibility of results were obtained with the described procedures. The acid digestion method for plant material gave results which were comparable to those obtained by oxidation in an oxygen bomb. The evidence from soils indicates that the digestion and distillation procedure employed removed essentially all of the arsenic.
Clay Skin Genesis in Wisconsin Soils
Authors: Buol S. W. , Hole F. D.
Published: July 2010

Clay skins separated from the B3 horizon of the “Ockley‐like” silt loam, a Gray‐Brown Podzolic soil, were further analyzed and found to contain 186% as much total phosphorus and 177% as much total manganese as the bulk of the same horizon. More than 200 thin sections were made of samples from a variety of Wisconsin soils, including soils of the Podzol, Gray‐Brown Podzolic, Brunizem and Humic‐Gley great soil groups. A study of volume of clay skins, as determined from microscopic views of thin sections, and soluble salt concentration revealed that in the “Ockley‐like” profile maxima of both occurred in the C1 horizon. By alternately leaching with percolate from a leaching column and drying with a water aspirator, artificial clay skins were produced in “unweathered” loess material. From observations made during this study a definition of the term “clay skin” is proposed and it is concluded that clay skins in Wisconsin soils are formed by the percolation of dilute clay suspension, from which clay is deposited at or below the bottom of the solum as percolation ceases and the larger pores are emptied of water.
The Apparent Swelling Behavior of Some Moderately Dispersed Bentonites
Authors: Rollins Myron B. , Hallam Merrill J. , Myers Victor I.
Published: July 2010

A study was conducted to measure the swelling rate of various dispersed bentonites. The purpose was to characterize the role of continued swelling of clay micelles in the sealing of irrigation conveyance channels with seepage‐transported bentonite.

Centrifugal forces were used to separate hydrated, expanded bentonite micelles from the free water of a dispersed system. Eight bentonite samples were successfully settled and their hydrated volumes measured. Seven of the eight bentonites measured continued to swell with time, although most of the samples reached a large percentage of their total expansion within 15 minutes after dispersion. Some bentonites showed a substantial amount of continued swelling. The time required to reach maximum volume for the seven bentonites varied from 3 to 21 days.

The results suggest that the phenomenon of continued swelling of bentonites may have a role in the sealing of irrigation conveyance channels with seepage‐transported bentonite.
Root Growth and Diffusion Rates as Functions of Oxygen Concentration
Authors: Stolzy L. H. , Letey J. , Szuszkiewicz T. E. , Lunt O. R.
Published: July 2010

This paper deals with two aspects of soil‐oxygen‐plant relationships: (1) the effect of O2 concentration on O2 diffusion rates, and (2) the O2 diffusion rate in relation to root growth of established plants. The study was designed to minimize the effects of CO2 on root growth during the experiment while studying the effects of oxygen supply and root growth.

An average O2 concentration of 0.7% above the soil surface virtually stopped root growth while only a few new roots were initiated at the 2% level. Depth of rooting and the O2 diffusion rate associated with this depth were proportional to the concentration of O2 at the soil surface. Root initiation was reduced or stopped when oxygen diffusion rates in the soil were in the range of 18 to 23 × 10‐8 g. cm.‐2 min.‐1. Diffusion rates above 23 × 10‐8 g. cm.‐2 min.‐1 permitted relatively good root growth.
Some Physical, Chemical, and Mineralogical Properties of Compacted and Adjacent Soil Layers in Coarse‐Textured Soils
Authors: Milford M. H. , Kunze G. W. , Bloodworth M. E.
Published: July 2010

Some physical, chemical, and mineralogical properties of compacted and adjacent soil layers, which were selected from cultivated and virgin Willacy fine sandy loam soils in the lower Rio Grande Valley of Texas, were studied to attain a better understanding of the compacted zone and its development. Hydraulic conductivity measurements and field studies substantiated the presence of a hardpan layer, which was first encountered at a depth of 3½ to 7 inches and ranged to a depth of 7½ to 12 inches, at each of the five sites sampled. Clay content increased with depth, while sand content decreased. The fine (0.25 to 0.1 mm.) and very fine sand (0.1 to 0.05 mm.) fractions, for all samples, comprised at least 95% of the total sand and more than 60% of the total soil. Soil reaction (pH), organic matter content, cation‐exchange capacity, exchangeable cations, and extractable silica, aluminum, and iron were determined. Extractable cementing materials were not found in important quantities in any of the layers. Mineralogical analyses of the samples showed that quartz and lesser amounts of feldspar composed the sand and silt fractions, while illite and poorly ordered, weathered micaceous materials dominated the clay fraction. No pronounced differences in the chemical and mineralogical properties of the hardpan layers as compared to the layers above and below the hardpan were found.
Experimental Consideration of Diffusion Analysis in Unsaturated Flow Problems
Authors: Nielsen D. R. , Biggar J. W. , Davidson J. M.
Published: July 2010

An experimental investigation of the applicability of the diffusion equation to soil water movement is reported using soils and sandstone with water and oil. The fluids were allowed to enter at different negative pressures into air‐dry horizontal columns of several lengths. The equation predicted the water movement when the entry pressure was −2 millibars. The inability of the equation to predict water movement for greater negative pressures is discussed.
Approximate Solution of a Non‐Steady‐State Drainage Problem
Authors: Gardner W. R.
Published: July 2010

Flow in the unsaturated zone during one‐dimensional drainage is taken into account approximately by assuming the water content to be a linear function of the hydraulic head. The problem is then treated as one in unsaturated flow. After a brief initial period, the rate of outflow should decrease exponentially with time, with the outflow rate proportional to the soil‐water diffusivity. Agreement with experimentally determined outflow rates is reasonable; however, the exact water content distribution cannot be calculated. The treatment is extended to two dimensions by the equivalent of the Dupuit‐Forchheimer assumption. The total amount of water in the profile at any horizontal distance from a drain is calculated rather than the position of the water table. The theoretical outflow is in good agreement with results of sand tank and field measurements.
Effect of Anions in the System on the Amount of Cations Adsorbed by Soil Materials
Authors: Sommerfeldt Theron G.
Published: July 2010

Wells fine sandy loam and Utah bentonite (noncalcareous) were equilibrated in solutions of NaOH, NaCl, Na2CO3 and Na2SO4 to determine the effect of the different anions on the amount of cations retained by these materials.

Total exchangeable cations, exchangeable sodium and exchangeable calcium plus magnesium, as extracted by NH4OAc method, were greatly affected by the anions in the systems.

Various possibilities for these results have been discussed. It was concluded that the adsorption capacity of the materials had not remained constant, but varied with the anion environment, and that this was the most important factor responsible for these results.
Some Aspects of Zinc and Copper Phosphate Formation in Aqueous Systems
Authors: Jurinak J. J. , Inouye T. S.
Published: July 2010

Zinc and copper systems were titrated with NaOH in the presence of varying amounts of KH2PO4. The data indicated zinc formed the orthophosphate, Zn3(PO4)2 · 4H2O while copper precipitated as the basic phosphate, Cu5(H2PO4)2(OH)8. The pKsp calculated from the dissociation of these phosphates at their respective isoelectric pH values were 47.9 and 92.5 for zinc and copper phosphate, respectively. Basic copper phosphate was less soluble than zinc orthophosphate at all pH levels studied.
Chemical Relationships Affecting the Water‐Holding Capacities of Clays
Authors: Thomas Grant W. , Moody John E.
Published: July 2010

The relation between water‐holding capacity and clay properties was studied on Wyoming bentonite and four Virginia soil clays ranging in mineralogical type from montmorillonite to kaolinite. The amount of water held at 1/3 atm. pressure was closely related to clay type and cation saturation; the Na‐montmorillonites containing much more water than any other clays. At 15‐atm. pressure there was little difference in water held between any of the clays regardless of cation saturation or clay type. The only exception was Na‐bentonite which held 71% H2O compared to a mean of 48.6 ± 3.2% among all the other clays. Analyses of displaced solutions from the clay suspensions showed that only in Na‐montmorillonites was the predicted double‐layer pattern of reduced anion concentration at lower water contents followed. This and the fact that other clays apparently did not imbibe much water between layers support the idea that the double‐layer theory is applicable only to freely‐expandable clay minerals.
Inefficiency of Fertilizer Use Resulting from Nonuniform Spatial Distribution: III. Fractional Segregation in Fertilizer Materials
Authors: Jensen Don , Pesek John
Published: July 2010

Partial stratification of dry‐blended fertilizer materials may occur as a result of different physical properties of the component nutrient carriers. Nonuniform nutrient distributions arise, in spite of uniform application of the mixture, because nutrient ratios and analyses vary among strata. Nutrient segregation is illustrated by a linear relation between nutrient rate and distance traveled by a fertilizer applicator.

Fertilizer distributions may also be influenced by spreading characteristics of the fertilizer applicator. Yields associated with nonuniform application of a segregated mixture were evaluated by substituting an appropriate distribution function into a specific yield equation and integrating over the treated area.

Algebraic results of the derivations are illustrated numerically for corn produced on a calcareous Ida silt loam in Iowa. Yield losses induced by nutrient segregation alone may reach 5 bushels per acre for selected degrees of severity of stratification. For the particular distribution patterns considered, additional yield losses of up to 6.1 bushels per acre may result from nonuniform application of a segregated fertilizer mixture.
Nitrification of Ammonium Sulfate in a Calcareous Soil as Influenced by Combinations of Moisture, Temperature, and Levels of Added Nitrogen
Authors: Justice John Keith , Smith R. L.
Published: July 2010

(NH4)2SO4 at levels of 0, 150, and 450 ppm. N was incubated in a calcareous soil at 2°, 10°, and 22° C. at 10, 1, and 0.3 bars moisture tension using periodic aeration. A second incubation study included 4 other moisture levels (7, 15, 115, and 415 bars moisture tension) and continuous aeration. Good control of the moisture was attained with the continuous aeration by humidifying the incoming air over saturated salt solutions known to give the required relative humidity. The soil used, Millville loam from the Agronomy farm, is a highly calcareous (47% CaCO3 equivalent) fertile soil with a saturated paste pH of 7.8, and moisture contents at field capacity (0.3 bar tension), permanent wilting percentage (15 bars tension), and air dry of 18.0, 6.9, and 1.6%, respectively.

The only evidence of nitrification at 2°C. was the production of NO2‐N which was not converted to NO3‐N in 10 weeks. At 10°C. there was nitrification at ⅓, 1, and 10 bars tension where the lowest moisture (10 bars tension) apparently only delayed the initiation of nitrification and did increase the period of NO2‐N accumulation. At 25°C. nitrification was completely inhibited at 415 and 115 bars tension. At 15 bars tension 50% of the 150 ppm. N was oxidized to NO3‐N in 28 days, while at 10, 7, and 1 bars tension the nitrification was complete in about 28, 20, and 12 days. In this soil, 35°C. was less favorable for nitrification than 25°C. NO2‐N accumulated at this temperature and persisted throughout the 8 weeks. Temperature (both high and low) and lowered moisture had a greater inhibiting effect on NO2‐N oxidizers than on NH4‐N oxidizers.

There was a decrease in the total inorganic N recovered when unfavorable nitrification conditions were encountered. This loss of inorganic N was apparently from the NH4‐N pool.
Effect of Soil pH and Texture on the Availability of Water‐Soluble Boron in the Soil
Authors: Wear John I. , Patterson R. M.
Published: July 2010

A greenhouse study was conducted with alfalfa to determine the relationship between water‐soluble B in the soil and plant uptake as affected by soil texture and pH. Soils used were Norfolk sandy loam, Hartsells fine sandy loam, and Decatur silty clay representing coarse‐, medium‐, and fine‐textured soils. Treatments included five rates of B at three pH levels. Yields and B content of plants were measured. After the plants were harvested, soils were analyzed for water‐soluble B and pH. Results showed that alfalfa grown on the coarse‐textured soil had the highest uptake of B per unit of water‐soluble B in the soil and the plants from the fine‐textured soil had the least. The medium‐textured soil was intermediate. As the acidity decreased from a pH value of 5 to 7, less B was available at any level of water‐soluble B in all three soil types. These results indicate that texture and pH must be considered when water‐soluble B is used as a measure of availability to plants.
A Rapid Method for Measuring Lime Requirement of Red‐Yellow Podzolic Soils
Authors: Adams Fred , Evans C. E.
Published: July 2010

The exchangeable acidity determined by neutral 1N NH4OAc was compared to that measured in a buffered solution on 348 soil samples from profiles of Red‐Yellow Podzolic soils in Alabama. The soil pH values ranged from 4.1 to 6.5 and cation‐exchange capacities from 0.8 to 13.0 me. per 100 g. The methods measured comparable amounts of acidity. An equation was calculated by the method of least squares for the relationship between soil pH and percent base unsaturation for all samples. The amount of CaCO3 needed to bring soil pH to desired level was calculated by estimating percent base unsaturation from soil pH values in water and by measuring exchangeable acidity of soil by pH values in a buffered solution. The validity of this procedure was tested by incubating soils with increments of Ca(OH)2 and measuring the change in soil pH.
Determination of Phosphorus Fixation Capacity in Organic Soil
Authors: Harris C. I. , Warren G. F.
Published: July 2010

In a study of 15 organic soils the reduction in phosphorus concentration in aqueous solutions shaken with the soils gave a good indication of their phosphorus fixation capacities. An equally good indicator in soils that had had prior phosphorus fertilization was the level of water‐extractable phosphorus. Total iron, aluminum, calcium, and phosphorus content of the soils did not relate significantly to phosphorus fixation capacity.
Soil Morphology and Genesis at Higher Elevations of the Great Smoky Mountains
Authors: McCracken R. J. , Shanks R. E. , Clebsch E. E. C.
Published: July 2010

Properties of soils representative of the elevation from 4,500 to 6,600 feet in the Smokies along the North Carolina‐Tennessee border are reported.

Mean annual rainfall exceeds 80 inches. Mean air temperatures are: annual 45° to 49°F.; January, 31° to 35°F., July, 59° to 63°F. Parent rock is feldspathic sandstone and conglomerate. These soils can be placed in two groups: (1) lacking A2 horizons with thin A1 and “color B” horizons, and (2) with A2 horizons, Bir horizons, and relatively thick mor layers. Soils of the first group ordinarily occupy well‐drained sites under spruce‐fir forest. Those of the second group occupy less well‐drained sites under heath bald or rhododendron understory of sprucefir, with some indication that they tend to form from more quartzose conglomeratic rock.

Soils of the first group are ascribed to the Sol Brun Acide great soil group on the basis of very low base status and high exchangeable Al, C/N levels, lack of relative accumulation of free iron and of layer silicates, and lack of A2 horizons. Second group soils are excluded from the Sol Brun Acide group, due to the presence of A2 horizons, differential iron accumulation, and C/N levels, and are interpreted as Podzols.

Possible mechanisms are proposed to account for contrasting properties of the Sol Brun Acide and Podzol soils described, and the anomalous absence of A2 in the Sol Brun Acide of the Smokies. Extreme acid hydrolysis, producing intergradational three‐layer silicates plus kaolinite and gibbsite weathering end products, is postulated for these soils.
Occurrence of Chlorite‐Like Intergrade Clay Minerals in Coastal Plain, Piedmont, and Mountain Soils of North Carolina
Authors: Weed S. B. , Nelson L. A.
Published: July 2010

Soils of the Coastal Plain, Piedmont, and Mountain regions of North Carolina were examined for the occurrence of chlorite‐like intergrade clay minerals. The intergrade clay minerals were found to be very common constitutents of soils examined, ranging in occurrence from trace to major amounts. Degree of interlayering, as estimated from response of clays to acid NH4F treatment, was related to position of the clay in the profile, usually, though not always, decreasing with depth. The amount of 3‐layer clay, as estimated by X‐ray diffraction, was greatest in the surface horizons and decreased with depth. For soils formed on similar parent material, 3‐layer clays from well‐drained, highly oxidized soils were usually more difficult to collapse than those from less oxidized soils. Chemical and mineralogical studies suggest that the intergrade clay minerals originated from mica precursors.
The Effect of Soil Saturation Upon the Dry Weight, Ash Content, and Nutrient Absorption of Various Bottomland Tree Seedlings
Authors: Hosner John F. , Leaf Albert L.
Published: July 2010

Current year seedlings of 14 bottomland tree species surviving 60 days of completely water‐saturated soil conditions were compared to check seedlings grown under well‐watered but nonsaturated soil conditions. Comparisons were made of the following: dry weight per seedling top, and contents of ash, N, P, K, Ca, and Mg. Based on root and shoot growth and nutrient absorption, the species are grouped according to their relative tolerances to watersaturated soil conditions as follows: Tolerant—Nyssa aquatica, Fraxinus profunda, Salix nigra, Fraxinus pennsylvanica; Intermediate—Quercus palustris, Populus deltodis, Platinus occidentalis, Acer negundo, Acer rubrum, Acer saccharinum; Intolerant—Ulmus americana, Celtis occidentalis, Liquidambar styraciflua, Celtis laevigata.
A Comparison of Selected Methods for Expressing Soil Aggregate Stability
Authors: Conaway Andrew W. , Strickling Edward
Published: July 2010

Aggregate stability was determined on samples taken from plots under 10 cropping systems on a Beltsville silt loam and on samples taken from selected soil types in Maryland, North Carolina, South Dakota, Texas, and Wisconsin. Complete aggregate and mechanical analysis curves were determined on the 2.0‐ to 4.76‐mm. fraction from each soil sample. The method of Bryant et al. (2) was also used to determine water stability of this fraction.

These data were used to calculate soil aggregate stability by 24 different methods. Duncan's multiple range test was used to determine the ability of each method to distinguish between changes in soil aggregate stability produced by the cropping systems.

In general, simple summation fractions of the water‐stable soil aggregates distinguished well between cropping systems and were as sensitive as more time‐consuming methods. It was found that changes in aggregate stability were reflected most by the 0.5‐ to 2.0‐mm. aggregates.
Kinetics of Potassium Release from Biotite and Muscovite in Sodium Tetraphenylboron Solutions
Authors: Reed M. G. , Scott A. D.
Published: July 2010

A mathematical expression that describes the release of interlayer K from mica particles in NaCl‐NaTPB solutions was derived. The mica particles were assumed to be circular discs and the rate determining process for the release of K was considered to be the simultaneous diffusion of K and Na within the particle. Therefore, this derivation involved the solution of a two‐dimensional radial diffusion problem in which K diffuses from a receding weathering front to the periphery of the particle.

The validity of these assumptions and the resulting expression was evaluated with experimentally determined K release data. The experimental data were obtained with different size fractions of biotite and muscovite placed in NaCl‐NaTPB solutions for different periods of time. The results obtained with each size fraction were accurately described by the theoretical expression. In the case of a 50 to 62µ biotite fraction, this was true even though 90% of the K was released in a period of 113 hours. On the other hand, the expression did not account for the effect of particle size. A modification of the expression, based on the experimental results, however, accounted for the effects of both time and particle size.
Identification of Reaction Products from Phosphate Fertilizers in Soils
Authors: Lindsay W. L. , Frazier A. W. , Stephenson H. F.
Published: July 2010

Approximately 30 crystalline phosphate compounds, in addition to colloidal precipitates of variable composition, were identified as reaction products following the addition of various fertilizer solutions to soils and soil constitutents. The identifications were made by means of X‐ray, petrographic, and chemical analyses. The findings help to clarify the mechanism of phosphate reactions in soils, which includes the dissolution of fertilizer and soil constituents and the precipitation of new products.
Comparative Rates of Decomposition in Soil of Wood and Bark Particles of Several Hardwood Species
Authors: Allison Franklin E. , Murphy Raymond M.
Published: July 2010

The decomposition rates of the finely‐ground woods and barks of 9 species of hardwoods were determined in the laboratory at two nitrogen levels. Carbon dioxide was measured at frequent intervals during periods varying from 72 to 580 days. The following species were studied: black oak, white oak, red oak, post oak, hickory, red gum, yellow poplar, chestnut, and black walnut. During the first 60 days an average of 30.3% of the wood carbon was released as CO2 in the absence of fertilizer nitrogen, and 45.1% was released in its presence; the corresponding values for the barks were 22.4 and 24.5%. The variations in the rates of CO2 release from the woods were not great, but hickory and black walnut barks decomposed much slower than the other barks. The hardwoods were attacked much more readily than most of the softwoods used in an earlier study, and consequently more nitrogen was required by the microorganisms that decomposed them. There were no indications that any of these wood products was toxic to the decay organisms.
Factors Responsible for Poor Response of Corn and Grain Sorghum to Phosphorus Fertilization: II. Lime and P Placement Effects on P‐Zn Relations
Authors: Langin E. J. , Ward R. C. , Olson R. A. , Rhoades H. F.
Published: July 2010

Soil factors controlling Zn concentration in the corn plant are very complex, including among others a beneficial action of applied N and a detrimental action of P or lime inherently present or added to the soil. It is apparent that Zn deficiency is likely to be aggravated or created by row application at low rates or heavier mixed applications of readily available P fertilizer. The problem is greatest on soils that are calcareous and especially on those of high inherent P supply where plant Zn concentration already may be approaching a critical level.

The more effectively the applied P is utilized by the crop, the more severe is the reduction in Zn utilization. Thus the calcareous soil with tendency for Zn deficiency perhaps should not be treated so as to afford maximum early uptake and utilization of applied P. It also seems evident that low P rates rather than heavy, infrequent applications are likely to give less damaging effects. Alternative to these procedures is to apply supplemental Zn whenever P is added to soil where the level of Zn availability is uncertain.

The damaging effect of P on Zn utilization is considered to be largely physiological in nature, probably a plant root cell absorption phenomenon, and not an external Zn phosphate precipitation. It is recognized, however, that root proliferation in the band of row‐placed P may be a contributing factor due to inadequate exploration of a soil body where enough available Zn may exist.
Controlled Release of Fertilizer Minerals by Incapsulating Membranes: II. Efficiency of Recovery, Influence of Soil Moisture, Mode of Application, and Other Considerations Related to Use
Authors: Lunt O. R. , Oertli J. J.
Published: July 2010

It was shown using membrane‐coated granular fertilizer, in which the membrane constituted 11 or 12.5% of the weight of the granules, that: (a) moisture levels, exceeding the range of permanent wilting percentage to field capacity in a loam soil, did not appreciably affect the rate of transfer of minerals through the membrane of coated fertilizer mixed in the soil, (b) the time for transfer of a given fraction of fertilizer through membranes is substantially extended if the fertilizer is topdressed on a soil as compared to incorporated (presumably due to intermittent drying between leachings), and (c) an efficiency of recovery ranging from about 25 to 45% was obtained from a single application, incorporated in the sand, of coated ammonium nitrate by corn during a 3‐month growing period. In the latter study a sand was used containing < 1% of clay and as much as 7 feet of water passed through the root zone during the period of the study. Implications of the coating technique for controlling fertilizer availability are briefly considered.
Weathering of Sodium‐Potassium Mica in Soils of the Virginia Piedmont
Authors: Cook M. G. , Rich C. I.
Published: July 2010

The occurrence of paragonite, the Na‐analogue of muscovite, in intimate association with muscovite was observed in two soils and their parent materials in the Virginia Piedmont. A relatively constant Na/K molar ratio of approximately 1 was maintained in both the parent rocks and soils. This indicated that equal molar quantities of paragonite and muscovite were present and that the weathering rates of the two micas were similar.

Vermiculite and kaolinite were the weathering products formed upon weathering of the mixed Na‐K mica. The vermiculite had the same expansion and contraction characteristics as that formed from a predominantly K‐mica. Consequently, the kind of weathering of muscovite and paragonite also appears to be similar.

Paragonite is believed to be of more widespread occurrence than previous work has indicated. Its possible influence on soil genesis, morphology, and classification may be significant.
Aluminum Bonding in Soils: a Unifying Principle in Soil Science
Authors: Jackson M. L.
Published: July 2010

The aluminum ion bonds through oxygen to form a variety of functional groups underlying diverse properties of soils. One aluminum‐bond functional group provides the cation exchange site of soil layer silicate clays. Pauling's m‐rule of acid strength for oxy‐acids, (HO)nOmC, applied to the 2:1 layer silicate clay formula of beidellite, considering all structural cations, yields m = 1.6, characteristic of a medium to strong acid strength (on an m‐scale: 1 = weak; 2 = strong). The solubility product of Al(OH)3, k1 of Al(OH2)63+, and the Pauling k1/k2 ratio of 105 are applied to calculate concentrations of aluminohydronium monomeric cation species of valence of 3, 2, and 1. These concentrations relate to cation exchange and interlayer aluminum polymerization reactions in soils during chemical weathering. The latter and mineral colloid composition changes are summarized in the generalized bonding equation: Al ‐ O ⇌ Al ‐ OH, which provides the ultimate buffer, setting the lower and upper limits of the pH range of soils except in the presence of strong acidforming compounds such as S and FeS2. Aluminum bonding is central to soil acidity, through not only the acidic aluminohexahydronium monomeric cations, but also through the weakly acid Al‐OH2 … OH pair at edges of polymerized (“precipitated”) hydroxy aluminum structures. The aluminum toxicity of soil acidity may involve aluminum bonding and solubility product relations at the soil‐root interface and in solutions in soil and sap. Retention by soils of anions such as phosphate and sulfate is closely related to aluminum bonding of these anions (OH replacement). Some aspects of soil aggregate structure involve hydroxy aluminum bonding; loss of aggregates follows intensive cheluviation in the A2 horizon. Aluminum bonding in a real sense supplies a unifying principle for understanding many properties of the soil system, much as hydrogen bonding has served to unify understanding of many properties of water and of aqueous organic systems including living matter.
Effect of Exchangeable Potassium Level and Drying on Release and Fixation of Potassium by Soils as Related to Clay Mineralogy
Authors: Dowdy R. H. , Hutcheson T. B.
Published: July 2010

The effect of exchangeable K level and drying over H2SO4 upon K release and fixation by six soil series was studied in the laboratory. Differences in behavior seemed to be related very closely to clay mineralogy of the soils. Illite appeared to be the source of K released by drying, whereas fixation at moisture levels higher than 4% was associated with vermiculite and fixation at lower moisture levels with montmorillonite.

Further evidence indicates the moist K equilibrium value of these soils to be 0.45 ± 0.10 me. exchangeable K per 100 g. of soil. When exchangeable K values are above that level for field‐moist samples, K is fixed on drying, whereas it is released when the initial K level is lower. The magnitude of release or fixation appears to be directly related to the clay mineralogy.
A Characterization and Genetic Study of Two Modal Reddish Prairie Soils
Authors: Molthan H. D. , Gray Fenton
Published: July 2010

The Zaneis and Kingfisher series are both developed from Permian “Red Bed” deposits and occur primarily in the Reddish Prairie Provinces of Oklahoma, Kansas, and Texas.

Four profiles of the Zaneis series and two profiles of the Kingfisher series were sampled in detail. Chemical and physical studies were made on each subhorizon. Clay mineralogical studies were made for each major horizon. The clay was separated into two fractions: 2 to 0.2µ and < 0.2µ. Ethylene glycol retention, nonexchangeable K, cation‐exchange capacity, differential thermal, and X‐ray diffraction analyses were made.

Results show the clay fractions of all six profiles contain a high percentage of particles < 0.2µ in diameter. Montmorillonitic‐type minerals dominate the fine clays of all six profiles while illite, vermiculite, and kaolinite are dominant in the coarse clays. Very little evidence of weathering of clay minerals was found. Apparently the clay minerals present in the solum are, for the most part, inherited directly from the clay minerals present in the parent materials.

The parent materials of the Kingfisher soils were found to differ in character from those of the Zaneis. The soil materials of the Kingfisher soil appear to have been deposited in brackish water; whereas, those of the Zaneis were deposited in more fresh water.
Vegetative and Nonvegetative Materials to Control Wind and Water Erosion
Authors: Chepil W. S. , Woodruff N. P. , Siddoway F. H. , Fryrear D. W. , Armbrust D. V.
Published: July 2010

Fine, medium, and coarse gravel spread uniformly at rates of 20, 50, and 100 tons per acre, respectively, adequately controlled wind erosion of smooth, bare, Sarpy sandy loam where no traffic was involved.

Resin emulsion sprayed at 600 gallons of concentrate per acre and asphalt emulsion and cutback asphalt sprayed at 1,200 gallons of concentrate per acre adequately controlled wind erosion on level Sarpy sandy loam at estimated respective costs of $213, $247, and $335 per acre on a carload basis, in drums, at Manhattan, Kansas. Under similar conditions, 4,000 pounds of wheat straw mulch per acre anchored with a rolling disk packer was equally effective at an estimated cost of $89 per acre.

Quantities of latex emulsion sprayed at rates up to 225 gallons of concentrate per acre were not sufficient to control wind or water erosion on level or sloping ground. Starch treatments were also ineffective to control wind erosion under the conditions of the experiment.

On a 3:1 construction slope, at least 1,200 gallons of asphalt emulsion per acre sprayed uniformly on the surface were needed to control rill erosion. The treatment cost $335 per acre. In previous experiments on a 3:1 construction slope, prairie hay mulch at 4,000 pounds per acre uniformly spread and anchored with 400 gallons of asphalt emulsion per acre was equally effective at a cost of about $200 per acre.
Soil‐Moisture Depletion by a Hardwood Forest during Drouth Years
Authors: Fletcher Peter W. , Lull Howard W.
Published: July 2010

Daily soil‐moisture readings were taken during two drouth years with fiberglas units installed on each of 8 plots at 8 depths in the upper 40 inches of soil in a polesize mixed oak and hickory stand, Butler County, Missouri. On two plots the trees were cut and removed and the litter burned (bare); on two the trees were cut and removed and litter was left intact (litter‐only); on two the litter was burned (trees‐only), and two plots were left undisturbed (trees‐and‐litter).

The litter‐only plots remained wettest throughout both growing seasons, and bare plots occupied a position of medium wetness. The trees‐only plots and the trees‐and‐litter plots had driest and similar soil moisture contents. Daily rates of soil profile drying during rainless periods were linearly related to moisture contents of the 40‐inch depth for all but the litter‐only plots. Drying rates decreased with increasing profile depth. As compared with undisturbed forest soil at field capacity, litter removal increased soil drying rates about 10%; tree removal decreased them about two‐thirds. Removal of both trees and litter decreased soil drying rates about one‐third.
The Release of Nonexchangeable Soil Potassium to Cation‐Exchange Resins as Influenced by Temperature, Moisture and Exchanging Ion
Authors: Haagsma T. , Miller M. H.
Published: July 2010

The release of nonexchangeable potassium (K) from a Haldimand clay to H‐saturated Dowex 50‐W cation‐exchange resin was found to increase with increasing temperature although the increase in release was greater for a temperature increase from 50° to 80°C. than from 5° to 50°C. A decrease in moisture content decreased the rate of K‐release at the higher temperature range but had little effect at 5° and 25°C. The effect of moisture content apparently resulted from an influence on movement of K from the point of release to the resin particle rather than on the release of K from the soil particles.

No release of nonexchangeable K to Na‐ or Ca‐saturated Dowex 50‐W resin occurred but the release increased linearly with the proportion of H‐saturated resin added in combination with Na‐ or Ca‐saturated resin. It appeared that the presence of the H+ ion was required for release. It could not be determined whether the mechanism of release involved an exchange of H+ or Al3+ for K in the mineral lattices or an acid decomposition of the K‐bearing minerals.
Biosynthesis of Soil Polysaccharides: I. Glucose and Alfalfa Tissue Substrates
Authors: Keefer R. F. , Mortensen J. L.
Published: July 2010

Glucose, galactose, mannose, arabinose, xylose, rhamnose, fucose, ribose (trace), uronic acid, and five unidentified sugars were chromatographically separated from hydrolysates of polysaccharides extracted from soil which had been incubated with glucose‐1‐C‐14 or C14‐alfalfa tissue. All sugars in the polysaccharide became labeled during the incubation period, but glucose, galactose, and mannose contained more carbon‐14 than other sugars. Xylose was present in greatest concentration. Concentrations of glucose, galactose, mannose, arabinose, and rhamnose were similar.
Effect of Placement on the Absorption of Rb86 and P32 from Soil by Corn Roots
Authors: Vasey E. H. , Barber Stanley A.
Published: July 2010

Placement of Rb86 and P32 in the soil affected their relative uptake by corn roots. Autoradiographic techniques were used to determine the uptake processes involved. Banding of the fertilizer rather than mixing with the soil affected Rb86 uptake more than P32 uptake. The diffusion rate for Rb86 in the soil was much larger than for P32. Also, Rb86 was translocated more extensively throughout the corn root than was P32.

The greater uptake of Rb86 from band applications appeared to be due to both a greater facility for uptake by a small portion of the root and a greater diffusion of Rb86 out of the band.
Mineralogy of Soils on Basalt in North Queensland
Authors: Simonett David S. , Bauleke Maynard P.
Published: July 2010

Data from X‐ray diffraction, elemental, differential thermal analyses, and differential dissolution were used to correlate the relationship between rainfall and clay mineral formation in the < 2 µ fraction of latosolic soils of North Queensland, Australia. Rainfall varied from 36 to 147 inches per year. Application of the weathering mean showed that the weathering intensity increased with increasing rainfall, being most pronounced in the surface layers. Poorly crystalline kaolinite is the dominant clay mineral (79 to 52%). Halloysite may be present in the higher rainfall areas. Total iron content moderately increased with rainfall (12 to 20%). No positive evidence for allophane was found. Gibbsite content varied (0 to 19%). The mineral composition of the silt fractions was also estimated.
The Pedon and the Polypedon
Authors: Johnson William M.
Published: July 2010

One of the great difficulties in soil classification is that soils rarely exist as discrete individuals with clear boundaries. Instead, they grade to other soils across broad transition belts and their boundaries are determined by definition. Two new concepts, the pedon and the soil individual, have been proposed to help clarify relations between the soil continuum and soil taxonomic classes.

Pedons are real, natural soil volumes just large enough to show all the soil horizons present and their relationships. Boundaries of pedons do not depend on reference to any taxonomic scheme. A soil individual (polypedon) is also a real soil body; it is a parcel of contiguous pedons all of which have characteristics lying within the defined limits of a single soil series.

Pedons may be considered as building blocks that make up both soil taxonomic classes and soil mapping units. Most pedons are too small to exhibit all the characteristics of a soil individual; for example, usually they do not show shape of the soil nor nature of its boundaries with other soils.

Soil individuals (polypedons) are the subject of soil taxonomy; they are the real objects that are classified. They are comparable to individual pine trees, individual fish, and individual men.
The Nomenclature of Soils, or What's In A Name?
Authors: Heller John L.
Published: July 2010

A discussion of the principles to be followed in the assignment of names to any new object or series of objects and of the difficulties experienced by those who devised the nomenclature of the Seventh Approximation. The use of elements drawn from the classical languages is defended, and some of the compromises made in their selection and combination are explained. Suggestions for improvement are welcomed, provided they fit the requirements of the system.
Accumulation of Organic Matter and Soil Nitrogen Beneath A Plantation of Red Alder and Douglas‐Fir
Authors: Tarrant Robert F. , Miller Richard E.
Published: July 2010

Soil nitrogen accumulation beneath a plantation of red alder and Douglas‐fir was compared with that under a pure fir segment of the same 30‐year‐old stand on the Wind River Experimental Forest in southwestern Washington.

Beneath the mixed plantation, there were significantly greater amounts of nitrogen in the forest floor and in the upper 24 inches of the mineral soil. Organic matter content in the upper 12 inches of mineral soil was also greater and bulk density at 0 to 3 inches was significantly less. Beneath the alder‐fir stand, the carbon‐nitrogen ratio was less, both in the forest floor and at 0 to 3 inches.

There were 938 pounds more N per acre to a depth of 36 inches under the alder‐fir plantation. Consequently, an average of 36 pounds more soil N per acre per year has accumulated beneath the mixed stand than under pure fir.
Diffusion Theory Applied to Water Flow Data Obtained Using Gamma Ray Absorption
Authors: Ferguson Hayden , Gardner Walter H.
Published: July 2010

Unsaturated water flow data obtained using gamma ray equipment were not fit by the equation x = 2η (θ) t½. Thus, the data could not be used in the ordinary differential equation obtained by combination of x = 2η (θ) t½ and the second‐order differential equation of diffusion. The discrepancy between the data and x = 2η (θ) t½ was not great over much of the range; thus, it is possible that this equation could be used in much unsaturated flow work. The data did indicate that diffusivity was a function of water content alone over much of the time of water flow. The relationship between diffusivity and water content followed a nonexponential, curvilinear relationship. The data also suggest that a minimum gradient may be essential in order for unsaturated flow to occur.
Factors Affecting the Lime Requirements of Wisconsin Soils
Authors: Keeney D. R. , Corey R. B.
Published: July 2010

Soil factors which have been reported to affect lime requirement were measured on 26 Wisconsin Soils, and the importance of these factors in predicting lime requirement was determined by use of linear and multiple regression. The lime requirement was taken as the amount of < 200‐mesh dolomitic limestone necessary to raise the soil pH to 6.5 after 12 months of equilibration. Organic matter (% OM) was found to be significantly related to lime requirement (r = 0.620), and a function of a pH‐organic matter interaction, (pH 6.5 − soil pH) × (% OM) also correlated well (r = 0.884). Clay content, ranging from 5 to 27%, did not appear to be an important factor in determining lime requirement. Exchangeable Al contents were too low in these soils to contribute significantly, and pH 4.8 NH4OAc‐extractable Al did not appear to be an important factor. Lime requirement as indicated by the new buffer developed by Shoemaker, McLean, and Pratt was very highly correlated with lime requirement (r = 0.949), while the Woodruff buffer did not correlate as well (r = 0.818).
A Study of the Equilibria Between Three Categories of Potassium in an Illitic Soil
Authors: Bolt G. H. , Sumner M. E. , Kamphorst A.
Published: July 2010

The release of K from K‐Ca‐illites by repeated extraction with 0.5 N solutions of various salts was determined. From comparison between the action of NH4 ions and Na ions it could be deduced that the rapidly exchangeable K occupies two types of sites, which were named “planar” sites and “edge‐interlattice” sites, respectively. The very high preference for K of the edge‐interlattice sites explains why, e.g., Na ions and Ca ions are very ineffective in removing K from these sites as long as the released K ions are not removed from the system. NH4 ions are, in contrast, highly competitive for the edge‐interlattice sites, but their action is kept within bounds by the fact that the mineral lattice remains fairly well closed during the penetration of NH4 ions. An analysis of the exchange curve against Na ions yielded an estimate of the distribution and properties of the different types of sites, viz about 500 µeq. per g. rapidly exchangeable sites, of which 96% is situated on the external planar side of the lattice (preference factor for K about 2 in comparison to Ca ions), and 4% is located on the edges (preference factor for K about 500 in comparison to Na ions). In addition to this the illite studied contained about 700 µeq. K per g. in interlattice positions, which will lead to a very slow release of K if the chemical potential of K in solution is maintained at a low level.
Longevity and Efficiency of Rhizobial Cultures
Authors: Means Ura Mae , Erdman Lewis W.
Published: July 2010

More than 1,200 strains of legume bacteria from 225 species of leguminous plants are stored in the legume bacteria collection at Beltsville, Maryland. Observations were made on longevity and effectiveness of strains of Rhizobium stored under different conditions: (a) stored in a refrigerator on yeast‐mannitol agar; (b) stored under oil; and (c) lyophilized. Vegetative tests on 126 refrigerated strains acquired from 1911 to 1930 showed them viable and still able to fix at least some nitrogen (N). However, over a period of years many other strains had lost their ability to fix N and were discarded. After 7 years' storage under oil 190 of 620 strains were viable but they varied markedly by cross‐inoculation groups in survival and N fixation. Cross‐inoculation groups also showed variation in survival under lyophilization. Rank correlation coefficients for age of strain and decreasing N fixing ability were computed for 16 strain efficiency tests and the results showed a positive correlation only when a large number of new strains were being evaluated.