bluuebunny/crossref_metadata_2025 huggingface dataset:
Psychrometric Measurements of Soil Samples Equilibrated on Pressure Membranes
Authors: Richards L. A. , Ogata Gen
Published: July 2010

The osmotic pressure or solute suction (SS) of the extract from a “saturated” soil paste can be measured with a thermoelectric psychrometer which is calibrated by use of standard osmotic solutions. The same psychrometric procedure can be used to measure the total soil‐moisture stress or total suction (TS) of water in soil that has been equilibrated with a pressure membrane at known soil‐moisture tension or matric suction (MS). From membranous and psychrometric measurements, the difference ΔS = TS ‐ (MS + SS) was evaluated for 134 samples of Pachappa soil at three SS levels (0.3, 2.5, and 5 bar) attained by leaching with calcium chloride solutions and three MS levels (5, 10, and 15 bar). Mean ΔS values at 5, 10, and 15 bar MS were, respectively, −0.6, −0.4, and −0.1 bar. Mean ΔS values at 0.3, 2.5, and 5 bar SS were, respectively, −1.0, +0.04, and +0.5 bar. Standard deviation values for MS, SS, and TS, respectively, were 0.07, 0.1, and 0.5 bar.
Relationships Between Particle Size and Potassium Release From Biotite and Its Analogues
Authors: Mortland M. M. , Lawton K.
Published: July 2010

The relationships of particle size of biotite to K release, oxidation state of iron, cation‐exchange capacity, and total charge of the mineral were studied. The first stage of alteration, accomplished by leaching 15 minutes with 0.1N NaCl, showed a marked relationship to particle size. At this point, the only K removed was that on the external surfaces of the particles, and consequently the fine particles lost a larger percentage of their total K at this stage than did the larger particles. However, by the last stage where 50% of the total K had been removed, the large particles generally had lost as much as the fine. Once the initially exchangeable K has been removed, the release of matrix K from the particles is suggested to be controlled by the concentration gradient and the geometry of the diffusion path available for the exchanging ions, Na and K. The equilibrium concentration of K in 0.1N NaCl was shown to be proportional to the total K content of biotite which had been altered to different levels of total K. The oxidation state of iron in the biotite was shown to be a function of particle size and extent of alteration.
The Effect of Surface Soil Thickness on Corn Yields: I. As Determined by a Series of Field Experiments in Farmer‐Operated Fields
Authors: Engelstad O. P. , Shrader W. D. , Dumenil L. C.
Published: July 2010

A study was conducted to determine the effect of surface soil thickness on yields of corn and to learn whether nitrogen fertilizer would substitute for surface soil thickness in producing yields of corn on the minimal Brunizem soils of southwestern Iowa.

During 1957 and 1958, 55 nitrogen fertilizer experiments were distributed over the existing range of surface soil thickness. The corn yield obtained from each of 5 nitrogen fertilizer rates was measured at each site. By means of a multiple regression analysis it was found that application of nitrogen fertilizer at the rate of 100 pounds per acre for corn completely substituted for surface soil in 1957 but failed to do so in 1958. Under the soil and climatic conditions that prevail in the area studied, nitrogen fertilizer can substitute completely for surface soil thickness in some years but not in others. Apparently, climatic factors influence the degree of such substitution.
Water Infiltration into Stratified Soil
Authors: Miller D. E. , Gardner W. H.
Published: July 2010

A laboratory investigation was made of the effects of textural and structural stratification within the profile on rate of water infiltration into soil. A recording infiltrometer was devised and a method developed for obtaining uniformly packed tubes of soil. Infiltration data were obtained for soil conditioner treated Palouse silt loam. These data were used to test several infiltration equations found in the literature. It was observed that none of the equations tested adequately describe the experimental data.

Effects of strata within soil were related to the pore characteristic differences between the layering material and the surrounding soil. When most of the pores in a layer were larger than those in the surrounding soil, infiltration was temporarily inhibited after the wetting front reached the layer. The degree of inhibition was increased when the pore sizes in the layer were increased. Water must accumulate at a layer‐soil interface until it is at a tension low enough to allow it to move into pores in the layer. Water movement into the surface is reduced while the accumulation takes place.
Retention and Cation‐Exchange Properties of Organic Matter in Coastal Plain Soils
Authors: Kamprath E. J. , Welch C. D.
Published: July 2010

Soil organic matter is quite important as a source of cation‐exchange capacity in Coastal Plain soils. The amount of organic matter in well‐drained soils is directly related to the clay content. In the very poorly drained soils this direct relationship was not apparent.

The cation‐exchange capacity of soil organic matter varied from 62 to 279 me. per 100 g. The nature of the exchangeable hydrogen of organic matter was measured by the use of several replacing solutions. A portion of the exchangeable hydrogen in soil organic matter was found to come from strong acid groups.
Evaluation of Air‐to‐Water Permeability Ratio for Measuring Differences in Soil Structural Stability Under Ten Cropping Systems
Authors: Cohen O. P. , Strickling E.
Published: July 2010

Aggregate and structural stabilities were determined on samples taken under 10 cropping systems on Beltsville silt loam soil. Water stability of aggregates from 2 mm. to 4.76 mm. in diameter was measured by the wet‐sieving method of Bryant, Bendixen, and Slater. Structural stability was determined on samples < 2 mm. and < 1 mm. by the air‐to‐water permeability ratio method of Reeve. The measurement of soil aggregate stability by wet‐sieving distinguished six different groups of cropping systems according to Duncan's Range Test (4). The order of placement of the cropping systems was in agreement with other experimental results of Wilson et al. concerning the effect of cultivation and forage crops on aggregate stability. The measurement of structural stability by the air‐to‐water permeability ratio method did not distinguish soil structural differences associated with the cropping systems. Attempts to increase the sensitivity of the air‐to‐water permeability ratio failed. Water permeability offers some promise as a measurement of structural stability differences associated with cropping systems.
Problems in Clay Mineral Identification by X‐Ray Diffraction
Authors: Harward M. E. , Theisen A. A.
Published: July 2010

X‐ray diffraction studies of Oregon soil clays during the past few years have resulted in the observance of a number of phenomena that were somewhat disconcerting. Results of a number of different studies have indicated that the clay minerals identified in a given sample are dependent upon specimen carriers, method of Fe removal, dispersion reagents, cation saturation of clay, and in some cases, peeling of specimens. Further, the situation is complicated by the fact that the effects vary not only with different soils, but also to some extent with different size fractions of the same soil.

Data obtained lead to consideration of the possible extent that clay mineral identification by X‐ray diffraction may be arbitrary and empirical. A question is raised as to differentiation of clay minerals which may occur naturally in a given soil from those which may appear as a result of sample preparation. Certainly, the results reported here strongly suggest the need of a combined and intensive effort to establish clay mineral identification on a better and more universal foundation than appears to be the case at the present time.
The Solubility of Gibbsite in Aqueous Solutions and Soil Extracts
Authors: Frink C. R. , Peech Michael
Published: July 2010

The solubility of gibbsite was determined in supersaturated and undersaturated AlCl3 solutions as well as in 0.01M CaCl2 soil extracts. The rate of dissolution of gibbsite in undersaturated solutions was extremely slow. In supersaturated solutions that were seeded with gibbsite, equilibrium was established after 1 to 3 months. The solubility product, expressed as pKsp, was found to be 33.5 at 25°C., which agrees well with a value of 33.8 calculated from thermodynamic data. Owing to the relatively large amount of adsorbed aluminum ions as compared to that present in solution, the time necessary to reach the solubility product of gibbsite was found to be much longer in a clay or soil suspension than in an aqueous solution having the same pH value.
Molecular and Equivalent Weights of the Organic Matter of a Podzol
Authors: Schnitzer M. , Desjardins J. G.
Published: July 2010

The number‐average molecular weights of the organic matter of the A0 and Bh horiozons of a Podzol, determined by freezing point depression in sulfolane, were 1684 and 669, respectively. From the molecular weights, in conjunction with ultimate and functional group analyses, molecular formulae were calculated. These were C75H33O17N3 (COOH)3(OH)12(CO)2 for the A0 and C21H12(COOH)6(OH)5(CO)2 for the Bh organic matter. The presence of relatively large numbers of functional groups in the Bh molecule offers interesting possibilities for metallo‐organic interactions.

The equivalent weights of the same organic matter preparations, measured by discontinuous potentiometric titrations, were 165 for the A0 and 76 for the Bh organic matter. The ratio of molecular to equivalent weight was 10 for the A0 and 9 for the Bh material. These ratios were in both cases equal to the sum of carboxyl plus phenolic hydroxyl groups in the two molecules.
Response of Slash Pine to Nitrogen and Phosphorus Fertilization
Authors: Walker L. C. , Youngberg C. T.
Published: July 2010

A slash pine plantation in the lower Coastal Plain of Georgia was fertilized at age 9 with 200 pounds per acre of N, 44 pounds per acre of P, and with both elements. Diameter and basal area growth response to N was obtained for each of the first 3 years following treatment, but maximum stimulation occurred the year after fertilization. Diameter growth of the largest 400 trees per acre was also significantly increased by N treatment. P supplements gave no response in the deep sandy soil. Height growth responses were not apparent.

Concentration of N in needles was increased 1 year after treatment, but by the end of the third growing season, no differences were apparent for N, P, K, and Ca content in foliage. Chemical analyses are also given for L and F layers, the latter being high in N. Neither needle lengths nor soil analyses differed between treatments after 3 years.
Simplified Accounting for Membrane Impedance in Capillary Conductivity Determinations
Authors: Kunze Raymond J. , Kirkham Don
Published: July 2010

Miller and Elrick's method of computing capillary conductivity for nonnegligible membrane impedance has been modified to reduce the amount of calculation required for converting pressure plate outflow data to capillary conductivities. Plate impedance need not be measured and variable contact impedance is accounted for. The method is most practical if accurate time and outflow measurements can be made shortly after making a small step change in pressure. An apparatus is described to make such measurements. To minimize diffusivity changes associated with moisture outflow, only the initial portion of the outflow data resulting from the step change in pressure is used. The relationship between capillary conductivity and moisture content is shown for two soils.
Evidence of Polymolecular Film Formation During the Adsorption of Water and Ethylene Dibromide on Glass Spheres
Authors: Jurinak J. J. , Waldron L. J. , Vomocil J. A.
Published: July 2010

The importance of adsorptive forces in monodispersed glass bead systems, at high relative pressures, was studied during the adsorption of water and ethylene dibromide by microscopic Pyrex and alkali glass beads, i.e., ideal soil. The analysis of the adsorption data by the Frenkel‐Halsey‐Hill isotherm equation, applicable at high surface coverages, allowed differentiation between capillary condensation and multilayer adsorption. Polymolecular adsorption accounted for all adsorption of water up to P/P0 = 0.98 with no indication of condensation. The type of glass had a marked effect on the nature of water interaction. Evidence is presented which indicates that both ethylene dibromide and ethyl alcohol (data from literature) exhibit phase transitions in the multilayer region of adsorption.
Some Chemical Characteristics of Submerged and Reclaimed Sediments of the San Francisco Bay System
Authors: Grass Luther B. , Aronovici V. S. , Muckel Dean C.
Published: July 2010

Samples of water, and of sediments deposited under the influence of sea water, were taken from the San Francisco Bay system. Samples of both reclaimed and unreclaimed sediments were taken from areas immediately adjacent to the bay for comparative purposes. Total sulfur and organic matter were determined and the saturation extracts analyzed for Ca, Mg, Na, and K.

These analyses show that the submerged sediments were in equilibrium with the water from which they were collected. The relative concentrations of cations in the water were: Ca, 3.8%; Mg, 20%; Na, 75%; and K, 1.2%. The total cation concentration was 470 me. per liter. Increased accumulation of sulfur during the emergence of the sediments from the water and the oxidation of reduced sulfur to H2SO4 accounts for the reduction in pH in reclaimed sediments. A curve was developed for use in predicting ultimate pH from sulfur analyses of the sediments.
Total Sulfur and Sulfate Sulfur Content in Subterranean Clover as Related to Sulfur Responses
Authors: Jones Milton B.
Published: July 2010

Subclover was grown on sulfur deficient soil in the greenhouse and in the field with various rates of S applied. Plants were harvested in the greenhouse when the first, third, and fifth flower per stem appeared, and the plant material was separated into leaflets, petioles and stems. The total S and SO4‐S concentrations in the plant did not change significantly over the three stages of growth.

The first 20 pounds per acre increased yield and the organic‐S concentration, but did not change the SO4‐S concentration in the plant. Rates of S > 20 pounds per acre did not increase the yield, but increased the SO‐4S more than the organic S fraction in the plant. More SO4‐S accumulated in the stems than in the petioles or leaflets at high rates of applied S, but at low levels of S there was little difference between the SO4‐S concentration of the three plant parts. There was more organic‐S in the leaflets than the other plant parts at all levels of applied S.

The SO4‐S concentration was determined in whole subclover tops grown in the greenhouse on 13 soils fertilized with sulfur and phosphorus. Eight of the soils produced clover with SO4‐S concentrations of 170 ppm. or less when unfertilized and each of these soils produced more clover when sulfur was applied if adequate phosphorus was available. The SO4‐S concentration in whole subclover plants showed the same relation to yield in the field as in the greenhouse. The SO4‐S concentration in subclover identified plants deficient in S, but did not indicate the degree of S deficiency.
A Study of the Morphology and Pedogenesis of a Medial Chernozem Developed in Loess
Authors: Bourne W. C. , Whiteside E. P.
Published: July 2010

Bozeman silty clay loam is a well‐drained, medial northern Chernozem. The A horizons are very dark grayish brown and granular; the B are dark grayish brown to dark brown and compound prismatic‐blocky; the C are calcareous, pale brown, massive silt loams. Particle‐size distributions of the associated loess deposits indicate that local floodplains contributed significantly to their silt and sand fractions, and that some stratification must have occurred during their deposition. During pedogenesis, marked changes have occurred in the microfabric of the soil and acid‐soluble material, mostly lime, has been moved into and through the Cca horizon. The principal clays are montmorillonite and illite. During pedogenesis, there has been an increase in total clay in the solum, a movement of some clay downward, and a reconstitution of much of the clay of the A horizons to randomly interstratified forms. Calculations show the relative rate of clay formation to be highest in the lower A.
Soil Layering and Compaction Effects on Unsaturated Moisture Movement
Authors: Eagleman J. R. , Jamison V. C.
Published: July 2010

Measurements of the velocity of flow and hydraulic gradients were obtained in the suction range of 0 to 700 cm. of water across the plane of contact for three different soil textural pairs, two of which were sampled from naturally occurring textural breaks in alluvial soil profiles. The hydraulic conductivity values across the textural breaks indicated that the soil properties were favorable for moisture transfer from large pores to smaller pores, but that a barrier existed for water movement from smaller pores to large pores. The barrier developed as the suction increased in a coarse layer in contact with finer material. With water removal from the larger pores at moderately low suctions, flow from the fine soil layer into the coarse material was reduced. In the naturally occurring breaks in soil texture it was found that the compaction of the different soil layers determined the degree of expression of the barrier to water movement.
A Greenhouse Study of Relations between Nutrient Movement and Conversion in a Sandy Soil and the Nutrition of Slash Pine Seedlings
Authors: Bengtson George W. , Voigt Garth K.
Published: July 2010

A greenhouse lysimeter study was made of plant‐soil‐water relations determining the availability of N, P, and K from different fertilizer sources to slash pine seedlings growing in Lakeland fine sand.

Leachate analyses showed that virtually all NH4NO3 and KCl applied to the surface of the soil in bare lysimeters was leached from the upper 12 inches of the profile within 4 weeks when water was applied at the rate of 4 inches per week. At the same watering rate, urea‐formaldehyde and potassium calcium pyrophosphate showed substantially lower leaching losses. No significant leaching of P was observed.

The presence of pine seedlings in the lysimeters prevented or reduced leaching of N and K at low and intermediate watering levels but at the high level the seedlings were relatively ineffective in reducing nutrient losses.

Chemical analyses of the seedlings showed greater nutrient uptake over a 17‐week period from the readily soluble N and K sources at 1 and 2 inches of water per week. At the higher watering rate (4 inches per week) more N and K was taken up from the slowly soluble sources. These differences were reflected in seedling growth.

Fertilized seedlings transpired from 30 to 80% more water than the controls, yet their water use per gram of dry matter produced was 25 to 50% less than that of control seedlings.
Miscible Displacement: IV. Mixing in Glass Beads
Authors: Nielsen D. R. , Biggar J. W.
Published: July 2010

A column of 390µ glass beads was used in a series of miscible displacement experiments to investigate over a wide range of flow velocities the contributions of diffusion and variations in pore‐water velocities to mixing. The two fluids were aqueous solutions of Na2SO4 and NaCl having equal densities and with tritium added to the NaCl. A desired minimum solute‐solid interaction was obtained as indicated by the data. It was found that diffusion causes a significant amount of mixing during displacement. An application of the information to the movement of nutrients in the soil moisture stream is discussed.
Effects of Past Agricultural Practices on the Survival and Growth of Planted Trees
Authors: Gilmore A. R. , Boggess W. R.
Published: July 2010

Four pine species (loblolly, shortleaf, red, and white) and three hardwood species (sycamore, green ash, and yellow‐poplar) were planted on a recently abandoned agronomic experimental field in southern Illinois that had been used for 40 years to test crop rotations with various soil and fertilizer practices. After 7 growing seasons, pine survival and growth were poorest on the old limed plots (attributed to competition from weeds). After 6 growing seasons, hardwood survival and growth were best on the old limed plots. The effect of the tree species and the past fertilizer practices upon the chemical composition of the soil are given. Five years after plots were planted to pines, soil organic matter remained approximately the same on fertilized plots but nearly doubled on unfertilized plots.
Potassium and Ammonium Taranakites, Amorphous Aluminum Phosphate, and Variscite as Sources of Phosphate for Plants
Authors: Taylor A. W. , Lindsay W. L. , Huffman E. O. , Gurney E. L.
Published: July 2010

As shown by the response of three successive crops of corn, the effectiveness of potassium and ammonium taranakites as sources of phosphorus increased with prolonged contact with the soil. This effect was independent of the soil pH. Potassium taranakite was a consistently better source of phosphorus than ammonium taranakite.

On acid soil, amorphous aluminum phosphate was a moderately effective source of phosphorus, whereas crystalline variscite was ineffective. On calcareous soil, amorphous aluminum phosphate, variscite, and both taranakites were as effective as monocalcium phosphate, and on this soil the particle size of the aluminum phosphate was the controlling factor in their effectiveness.
Saprophytic Activity of Rhizoctonia as Affected by the Carbon‐Nitrogen Balance of Certain Organic Soil Amendments
Authors: Davey C. B. , Papavizas G. C.
Published: July 2010

Carbon (C) from cellulose added to soil slightly suppressed the competitive saprophytic activity of Rhizoctonia, whereas nitrogen (N) from NH4NO3 increased it. Cellulose and NH4NO3, combined to produce a wide range of C/N ratios and incorporated in soil, suppressed Rhizoctonia activity at most C/N ratios. With certain exceptions, soil bacteria and fungi increased in numbers with decreasing C/N ratios. Soil streptomycetes were not greatly affected. Oat straw and soybean hay enriched with NH4NO3suppressed Rhizoctonia activity at all C/N ratios tested. The cellulolytic fungus Humicola greatly increased in numbers in the presence of decomposing oat straw whereas Trichoderma was not affected.
Complexing of Metals by Soil Organic Matter
Authors: Mortensen J. L.
Published: July 2010

Soil organic matter forms complexes with metals by ionexchange, surface adsorption, chelation, and complex coagulation and peptization reactions. Little is known concerning the nature of the ligands in polymeric components of soil organic matter which chelate metals, but carboxyl, hydroxy, and amide groups are probably involved. A number of low molecular weight compounds capable of chelating metals have been isolated from soils.

Metallo‐organic matter complexes must be identified and characterized before unequivocal evidence for their formation in soils can be obtained.
Recovery of Fixed Ammonium by Corn in Greenhouse Studies
Authors: Walsh L. M. , Murdock J. T.
Published: July 2010

The availability of native fixed NH4 and applied NH4 fixed in the Ap and B1 horizons of a Dodge silt loam was investigated. In addition, the effect of freezing on the fixation of applied NH4 was studied. By applying K and N to either the same or separate layers of soil in green‐house pots it was also possible to evaluate the effect of K on the release of fixed NH4. When NH4 and K were applied in the same layer of soil, the Ap and Bl horizons fixed 5 and 15% of the added NH4, respectively. An additional 5% of the added NH4 was fixed in each horizon when the soil was frozen after applying NH4. However, when NH4 and K were applied to separate layers of soil, negligible amounts of NH4 were fixed. Highly significant correlations between exchangeable K in the moist soil after cropping and the amount of applied NH4 fixed as measured by differential N uptake showed that the level of exchangeable K in the soil controlled the release of fixed NH4 to the crop. Correlations between two methods of measuring fixation of applied NH4, namely, differential N uptake and analysis of the soil after cropping, were highly significant.

These studies also indicated that about 15% (0.12 me. per 100 g.) of the native fixed NH4 in the Bl horizon was released when the level of exchangeable K in the soil was very low. However, very little native fixed NH4 was released from the Ap horizon, presumably because sufficient K remained in the soil of this horizon to block release of fixed NH4. These studies indicate that even under the most advantageous conditions very little of the native fixed NH4 is available to crops.
Some Geographic Aspects of the Seventh Approximation
Authors: Orvedal Arnold C. , Austin Morris E.
Published: July 2010

The Seventh Approximation sharpens the relationship between soil classification and soil geography; and it is likely to lead to more valid geographic correlations between genetic factors and soil morphology. Although the Seventh Approximation is expected to bring about only a few changes on large‐scale, detailed soil maps, the opposite is true for small‐scale, general soil maps. Even on the general maps, however, many, perhaps most, soil boundaries will appear where they would have appeared using the current soil classification; but the changes will be drastic in the nomenclature. The fact that substantive names are, or will be, provided for all classes in all categories makes soil classes of all categories available for use on maps. This fact makes possible a better matching of categorical and cartographic levels of generalization. The Seventh Approximation does not alter the need for the concepts of soil phases and soil associations.
Influence of Variations in the Diffusivity‐Water Content Relation on Infiltration
Authors: Hanks R. J. , Bowers S. A.
Published: July 2010

Estimates of the influence of variations in the diffusivity (or conductivity)‐water content relation on infiltration were made using a numerical method. Where the diffusivity was increased or decreased up to a factor of two at saturation, infiltration was markedly changed. However, variations of the diffusivity by a factor of 100 at drier moisture contents had no significant influence on infiltration. This implies that infiltration is governed, to a large extent, by the soil properties at water contents near saturation and is little influenced by soil properties at drier water contents.
Factors Responsible for Poor Response of Corn and Grain Sorghum to Phosphorus Fertilization: III. Effects of Soil Compaction, Moisture Level and Other Properties on P‐Zn Relations
Authors: Ward R. C. , Langin E. J. , Olson R. A. , Stukenholtz D. D.
Published: July 2010

Greenhouse experiments were used to study soil compaction, moisture level, soluble P and Zn, pH, organic matter and clay contents, K saturation and titratable alkalinity as these soil factors influenced P‐Zn relationships in corn. Some of the resulting observations help to explain why starter fertilizers containing P may on occasions cause depressions in plant growth.

Fertilizer P applied in the row markedly reduced Zn concentration of corn. Increasing soil compaction and soil moisture level caused further depressions of Zn concentration. The combination of irrigation practice on newly graded (and compacted) land, especially when soil P is high, would seem to portend Zn deficiency problems.

Soil K saturation also appears to have a decided influence on P‐Zn relations in the plant. The higher the percent K saturation of the soil, the less did applied P reduce plant utilization of Zn in these experiments.
Morphology and Genesis of a Sol Brun Acide with Fragipan in Uniform Silty Material
Authors: Jha P. P. , Cline M. G.
Published: July 2010

The physical, chemical, and mineralogical data assembled indicate that physical phenomena have been major factors involved in the development of genetic horizons of a Sol Brun Acide with a fragipan. Gross mineralogy is primarily inherited; chemical alteration is confined mainly to fine fractions in zones of maximum permeability above the fragipan and along connecting fracture planes. Evidence is presented that compaction by glacial ice, periglacial phenomena, or weight of overburden is not essential for development of density in fragipans. Density and firmness are attributed to reorganization of particles upon alternate dessication and wetting, possibly augmented by seasonal frost action and some illuviation of clay. Dessication is suggested as the major factor in development of polygonal fracture planes. Clay destruction by weathering is suggested as a major factor contributing to the character of zones of apparent eluviation. It is suggested that the fragipan is being degraded both from the top and from the fracture planes.
Miscible Displacement: V. Exchange Processes
Authors: Biggar J. W. , Nielsen D. R.
Published: July 2010

Miscible displacement experiments have shown that the physical processes associated with microscopic flow velocities should be included in any theory of exchange during flow through soils. Water contents and average‐flow velocities were controlled in Oakely soil columns initially saturated with Ca ion. Without disturbing the water content and flow velocity, Ca acetate of 0.1N and 0.05N concentration was displaced by MgCl2 solutions of similar concentration. The distribution of Mg2+ and Cl‐ ion in the effluent was related to the volume passing through. Mg2+ ion appeared in the effluent well in advance of that predicted on the basis of exchange theory. Three mathematical models that include the exchange process were compared with the data to ascertain their usefulness in predicting positions and shapes of breakthrough curves. Although the theories were generally inadequate, they did serve to emphasize the important contribution of microscopic flow velocity and ionic diffusion to the mixing or dispersion of solutions in porous media and to exchange processes.
The Effect of Soil Moisture Content Upon the Uptake of Molybdenum, Copper, and Cobalt by Alsike Clover
Authors: Kubota Joe , Lemon E. R. , Allaway W. H.
Published: July 2010

The effect of soil moisture level on the uptake of Mo, Cu, and Co by alsike clover was investigated in a greenhouse experiment with two Brown Podzolic soils from New Hampshire and a Weisenboden and a Brown soil from Nevada. A wet soil condition increased the Mo in the soil solution and plant Mo content on all four soils. The Co concentration in the soil solution was higher in pots maintained at the high moisture level than at the low moisture level. This increase in Co concentration with soil wetness was reflected in alsike clover, over four cuttings, on the two Brown Podzolic soils, but not in plants from the two Nevada soils. Copper contents in the plants and in the soil solution did not differ consistently because of soil wetness.
A Field Measurement of Total Porosity and Surface Microrelief of Soils
Authors: Burwell R. E. , Allmaras R. R. , Amemiya M.
Published: July 2010

Total porosity of the layer to be plowed was estimated from undisturbed cores collected before primary tillage. Using a point quadrant instrument, soil surface elevation measurements were made before and after preplant tillage, and after each cultivation to determine the effects of tillage on total porosity of the plowed layer. Large apparent differences in capacity to detain water, as inferred from total porosity, were observed among preplant tillages and among particular combinations of preplant and postplant tillage that are used in the western Corn Belt.

When total porosity of the plowed layer was measured in the ensuing fall and spring, relatively small changes in total prosity were observed. This result suggests that this physical property persists over a long time in a Barnes loam.

To evaluate the effects of tillage on surface geometry and temporary water storage in surface depressions, macro and random surface roughness as measured by the point quadrant instrument are considered. Estimates of the standard error among logarithm of the elevation heights differed among tillage treatments. The standard error is suggested as an index of random roughness.
Monovalent‐Divalent Cation‐Exchange Equilibria in Soils in Relation to Organic Matter and Type of Clay
Authors: Pratt P. F. , Grover B. L.
Published: July 2010

Cation‐exchange equilibria at pH 7 were measured using ion pairs of Na‐Ca, Li‐Ca and Li‐Mg on each of 10 soils. Data on Li‐Mg and Na‐Ca ion pairs were nearly the same and data on Li‐Ca were highly correlated with exchange equilibria data on both Na‐Ca and Li‐Mg. Two soils containing largely amorphous clay minerals showed a higher preference for Li than soils containing dominantly crystalline clay minerals. Destruction of the organic matter in two soils increased the ratio of Na to Ca adsorption to a much greater extent than would be predicted by the decrease in measured surface charge density. At a sodium‐adsorption ratio (SAR) of 100 (mmole per liter)1/2, organic‐matter free soils containing dominantly montmorillonite and illite clays had ratios of Na to Ca adsorption of 1.66 to 1.94 (excluding one soil, 1.66 to 1.78). Two soils with dominantly amorphous minerals had ratios of 0.92 and 1.10, and one soil with a mixture of kaolinite, illite, and amorphous clays had a ratio of 1.35.
The Role of Hydrolysis in the Reaction of Heavy Metals with Soil‐Forming Materials
Authors: Hodgson J. F. , Tiller K. G. , Fellows Martha
Published: July 2010

The proposition that hydrolysis may account for the selective adsorption of heavy metals by clay surfaces is compared with an alternate explanation of specific exchange of the metal with weakly dissociable H+. It is shown that past evidence offered in support of the two hypotheses is somewhat ambiguous. Theoretical treatment is presented for the competition of ions in adsorption reactions which provides a means of distinguishing between the two alternatives through the effect of H+ on the metal‐clay reaction in the presence of a competing ion. Experimentally, the effect of H+ on the reaction of Co2+ with montmorillonite is studied in the presence and absence of Mg2+, a weakly competing ion. Ionic strength is held constant, and nonspecific reactions are minimized with an excess of CaCl2. The results are interpreted as favoring the hydrolysis hypothesis. Inherent assumptions are considered.
The Effect of Cation‐Exchange Capacity, Clay Content, and Fixation on Rubidium‐86 Diffusion in Soil and Kaolinite Systems
Authors: Evans S. D. , Barber S. A.
Published: July 2010

An investigation of the factors influencing the diffusion of Rb86 in eight soils showed that the more strongly Rb86 was absorbed by the soils the slower was the rate of diffusion. In leached soils that were dried after labeling, diffusion was correlated with the amount of Rb86 fixed against NH4OAc extraction. In leached soils that were kept moist after labeling, diffusion was closely related to clay content and exchange capacity. In dilute kaolinite systems, diffusion was related to the amount of Rb86 in solution.
The Effect of Rubidium‐86 Diffusion on the Uptake of Rubidium‐86 by Corn
Authors: Evans S. D. , Barber S. A.
Published: July 2010

Uptake of Rb86 by corn roots was highly correlated with the diffusion of Rb in soil and kaolinite systems. At values of Dp/b above 1 × 10‐6 cm.2 sec.‐1 the relationship was curvilinear whereas it was more nearly linear at rates less than this. The curvilinear relation at the higher rates of diffusion was attributed to the limitations of the rate of absorption of the root.
A Comparison of Mg2+, Ca2+, and Sr2+ as Exchange Ions for Mineralogical Studies of Clays
Authors: Weed S. B. , Leonard R. A.
Published: July 2010

Strontium‐, Ca2+‐, and Mg2+‐saturated clay minerals were studied with respect to X‐ray diffraction, differential thermal analysis, cation exchange capacity, and glycerol adsorption. In general, 3‐layer clay minerals saturated with Sr2+ lost interlayer water at lower temperatures and at higher vapor pressures than did Mg2+‐clays; Ca2+‐clays were intermediate. A clay mineral‐ion‐saturation interaction was apparent. Calcium‐ and Sr2+‐saturation of clays yielded similar values for cation exchange capacity. Strontium‐saturated 3‐layer clays retained more glycerol than did clays saturated with Ca2+. Expansion of vermiculite with glycerol and ethylene glycol was dependent on cation saturation and lattice charge. Strontium‐saturated vermiculites expanded to near 16Å. more readily than did Mg2+‐clays, and Ca2+‐clays were intermediate. Vermiculites with high lattice charge expanded less readily than did vermiculites with relatively low lattice charge.

Strontium can satisfactorily substitute for Ca2+ and Mg2+ in routine mineralogical studies of clays though special care may be needed to control relative humidity. Additional information regarding lattice charge of 3‐layer clays may be obtained by using several divalent ion saturations.
Comparative Properties of Plant Lignins and Humic Materials of Soils. 1. Yields and Cation Exchange Properties of Plant Lignins Isolated by Different Techniques
Authors: Thompson S. O. , Chesters G. , Engelbert L. E.
Published: July 2010

Yields and cation‐exchange capacities for Ca and Cu were determined for lignin samples isolated with 72% H2SO4, HCl‐H3PO4 mixture, 5% aqueous NaOH, and 1,4‐dioxane. Yields varied with extractant in the order: acid‐ > dioxane‐ > NaOH‐extracted lignins. For equal time, a higher yield of dioxane pine lignin was obtained by fractional than by a one‐step extraction. In most cases cation‐exchange capacities varied with lignin source and with method of extraction as follows: (a) Straw lignins > wood lignins; (b) alkali‐ > dioxane‐ > acid‐extracted lignins.

Lignins isolated by fractional extraction with dioxane showed the later fractions to have higher exchange capacities. Values for the one‐step extracted isolates were intermediate with respect to the high and low values of the fractionally isolated samples. Lignin, like soil organic matter, had higher adsorptive capacity for Cu than for Ca, and the adsorptive capacity was pH dependent. All samples examined for the effect of pH on Cu adsorption showed the same relative change in adsorption for a given change in solution acidity.
Zinc Availability in Calcareous Michigan Soils as Influenced by Phosphorus Level and Temperature
Authors: Ellis Roscoe , Davis J. F. , Thurlow D. L.
Published: July 2010

Yield of corn was increased from 7,504 to 8,680 pounds per acre by an application of 4 pounds of Zn per acre to a calcareous Wisner clay loam in a field experiment. In a greenhouse experiment with the same soil, yield, Zn concentration in the plant tissue, and total Zn uptake by corn were decreased when soil temperature was decreased from 75 to 55°F. Ten pounds of Zn per acre increased the Zn concentration in the corn tops. In a greenhouse experiment with a Kawkawlin‐Wisner loam, 10 pounds of Zn per acre increased the yield of field beans when the treatments included high levels of either applied or residual P. In greenhouse experiments, applications of 437 and 655 pounds of P per acre decreased the Zn concentration in field beans and corn. In most experiments, a negative correlation was noted between Zn and P concentrations in the plant tissue.
Mobility of Water Adjacent to Mineral Surfaces
Authors: Kemper W. D. , Maasland D. E. L. , Porter L. K.
Published: July 2010

Mobility of water adjacent to Na‐ and Ca‐saturated bentonite surfaces was estimated from diffusion rates of deuterium hydroxide in oriented clay pastes at several moisture contents. The first molecular layer of adsorbed water on Na‐ and Ca‐clays had mobilities which were 30 and 5%, respectively, of the mobility of water molecules in bulk water. There was an indication of a slight reduction in mobility of water as far as 40Å. From the sodium‐saturated clay. However, water more than three molecular layers from the solid surface had mobilities which were 60% of the mobility in bulk water. The mobility data indicate that water outside the first adsorbed molecular layer does not have viscosities more than 2.5 times the viscosity of bulk water.
Importance of Volumetric Expression of Water Contents of Organic Soils
Authors: Boelter D. H. , Blake G. R.
Published: July 2010

Methods for evaluating water contents and bulk densities of several different peats are compared. Because bulk densities (saturated volume basis) of moss, herbaceous, and aggregated peats varied from 0.028 to 0.249 g. per cc., a highly distorted impression of the amount of water actually held under field conditions is given if water values are expressed on an oven‐dry weight basis.

On a wet‐volume basis, moss peat held only 10 to 20% more water at saturation than did herbaceous and aggregated peat and retained less water than they did at higher suctions. Between 0.1 and 15 bars, moss peat retained about one‐quarter the volume of water of a medium‐textured mineral soil, Barnes loam.

Since considerable volume reduction occurs on drying, bulk density of oven‐dry peat, Db (dry volume basis), represents an artificial condition rarely, if ever, occurring in undrained bogs. Bulk densities must, therefore, be calculated on the basis of the wet bulk volume and are referred to as Db (wet bulk volume). A more precise expression of degree of wetness may be substituted for “wet” in the wet volume basis term.
Some Variables Affecting the Measurement of “Catalase Activity” in Soil
Authors: Johnson John L. , Temple Kenneth L.
Published: July 2010

Hydrogen peroxide decomposition rates were measured on five soils after incubation with and without added organic matter and bentonite. The measurement was affected by soil type, addition of organic matter, addition of bentonite and drying of the sample. The two‐factor interactions of soil × organic additive, soil × added bentonite, soil × drying, organic additive × bentonite and bentonite × drying were highly significant. The three‐factor interaction of soil × organic additive × bentonite was significant. The reaction rate was greatly increased by incubation with powdered milk but only partly lowered by autoclaving.
The Effect of Soil Moisture and Rubidium Concentration on Diffusion and Uptake of Rubidium‐86
Authors: Place Gerald A. , Barber Stanley A.
Published: July 2010

An autoradiographic technique was used to study the effect of soil moisture and Rb concentration on Rb86 diffusion and uptake by corn plants. Changes in soil moisture influenced the rate of diffusion, rate of root elongation, and the incidence of root hairs. The self‐diffusion of Rb86 was linearly correlated (R2 = 0.89) positively with soil mositure, Rb concentration, and interaction of these two factors.

The correlation of Rb86 uptake from the soil was positively correlated with Rb86 diffusion values approximated from measurements made of the depleted areas about the roots. When the root diameter used in the calculation included the length of the root hairs, the r2 was 0.70 and when the root hairs were not included the r2 was 0.56. The correlation of uptake with the values of Dp/b from self‐diffusion studies gave an r2 of 0.99.

Uptake by roots without root hairs was linearly correlated (r2 = 0.98) with soil moisture, Rb concentration, and their interaction. Since the uptake relationships were similar whether or not the roots possessed root hairs, it was concluded that moisture's effect on rate of diffusion was of greater significance in its effect on Rb86 uptake than was its effect on root hair incidence in these experiments.
An Experiment in the Numerical Classification of Some Kansas Soils
Authors: Bidwell O. W. , Hole F. D.
Published: July 2010

Thirty soil characteristics were used to calculate numerical indices of similarity for 29 Kansas soils. The indices varied from 90 for Ladysmith and Irwin soils (100 = perfect similarity) to 34 for Bates and Colby. In general, the numerical classification substantiated the present classification and the concepts of these soils and their interrelationships.

This experiment suggests that the numerical classification of soils, like that of plants, animals, and insects, is possible. The necessary information for this kind of analysis is available for many of our soils. The major obstacle appears to be the selection and weighting, if any, of the characteristics to be considered. Once the characteristics are selected, the determination of numerical relationships is objective and repetitive.
Isolation and Characterization of Some Soil Allophanes
Authors: DeMumbrum L. E. , Chesters G.
Published: July 2010

A fractionation procedure based on H‐dispersion was used to concentrate inorganic amorphous colloidal materials from several soils. Concentrate was evaluated by use of X‐ray diffraction, infrared absorption, electron microscopy, and chemical techniques. The allophanes were shown to be metallic silicates, largely hydrous aluminum silicate, which may be a residue of chemical weathering within the soil profiles. In the B and C horizons examined, microcrystalline particles of halloysite were shown to be intimately mixed with the amorphous residues. The presence of amorphous Al(OH)3 (or related polymers) in the allophanes is suggested.
The Use of Liquid Scintillation for the Assay of Carbon‐14 in Clay and Soil Suspensions
Authors: Page A. L. , Sims James R. , Bingham F. T.
Published: July 2010

The use of liquid scintillation for the assay of C14 in layer silicate and soil suspensions is evaluated by various procedures with several scintillator media. The effects of sample weight, color, settling time, and the level of activity on the counting characteristics of scintillator media which contain soils and layer silicates are presented.

Highly statistically significant linear regressions, which differed for each solid tested, were obtained between the level of activity added and the observed activity. The differences between the materials tested were related predominantly to the color which the solid imparted to the scintillator medium.

A procedure for the determination of the retention of carbon compounds by layer silicates and soils is presented. The procedure described is specific, but can easily be modified to fit the needs of related studies.
Factors Influencing the Availability of Sulfur Fertilizers to Alfalfa and Corn
Authors: Fox R. L. , Atesalp H. M. , Kampbell D. H. , Rhoades H. F.
Published: July 2010

Field and greenhouse experiments indicated that 8‐mesh elemental S was frequently inferior to sulfate forms of S for alfalfa and corn production on S deficient, acid, sandy soils in Nebraska. There was a marked increase in utilization of S from the elemental form during the second year compared with the first year after application.

Sulfur flour mixed with the soil was as effective as gypsum either mixed with the soil or side‐banded at planting time for supplying S to young corn plants in the greenhouse. A sidebanded application of the S at planting time was much less effective than the same material mixed with the soil unless a small amount of CaCO3 was also applied in the band. Sulfur utilization by young corn plants was linearly related to approximate specific surface of S particles obtained from 8‐mesh material. The smallest particles, < 0.05 mm. in diameter, were slightly less effective than either S flour or gypsum applied at the same rate. The largest particles, 2.0 to 1.0 mm. in diameter, were relatively ineffective even at high rates of application. Superiority of S flour over 8‐mesh material, at least under some conditions, appears to be associated largely with relative sizes of particles in the two materials.
Earthworms and the Development of Coprogenous A1 Horizons in Forest Soils of Wisconsin
Authors: Nielsen Gerald A. , Hole Francis D.
Published: July 2010

Changes in weight, thickness, and distribution of litter were observed in forest stands of Wisconsin. The study included manipulations of litter over 5 years. Observations disclosed the influence of casting and midden‐building activities of earthworms on the course and the rate of development of the coprogenous A1 horizon of forested soils.