bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Soil pH on the Availability of Magnesium to Corn (Zea mays L.) from Magnesium Sulfate and High Magnesium Liming Materials
Authors: Usherwood Noble R. , Miller James R.
Published: July 2010

The effect of soil pH on the availability of Mg to corn from magnesium sulfate and several high Mg liming materials was studied in the greenhouse using a Keyport fine sandy loam soil. The soil pH was adjusted from 4.4 to 5.3, 5.7, 6.2, and 6.7 with CaCO2 containing less than 0.005% Mg. Magnesium was applied at rates of 0, 7.5, 15, 30, and 60 ppm of Mg as magnesium sulfate (9.9% Mg), coarse dolomitic limestone (12.0% Mg, 24% through a 100‐mesh sieve), fine dolomitic limestone (12.4% Mg, 80% through a 100‐mesh sieve), hydrated lime (18.7% Mg), and burnt lime (21.0% Mg). Corn (Zea mays L.) was grown for 30 days after emergence and the dry matter yields were determined. The plant tissue was analyzed for Mg.

With the exception of coarse dolomitic limestone the application of 7.5 to 15 ppm of Mg to the soil significantly (5% level) increased the dry matter yield of the corn, regardless of the Mg source of soil pH level. Higher Mg rates caused no further significant yield increase. In most cases, fine dolomitic limestone, hydrated lime, and burnt lime were as effective as magnesium sulfate for increasing corn yields, while coarse dolomitic lime‐stone was often inferior to the other sources studied.

An increase in soil pH from 5.3 to 6.7 significantly decreased the uptake of Mg by corn from soil treated with coarse and fine dolomitic limestone but in most cases had no significant effect on Mg uptake from magnesium sulfate. Total Mg uptake from fine dolomitic limestone was significantly greater than from coarse dolomitic limestone applied at rates of 15, 30, and 60 ppm of Mg to soil of pH 5.3 to 6.7, but was usually significantly lower than Mg uptake from magnesium sulfate, hydrated lime, or burnt lime. Very little difference in total Mg uptake existed between magnesium sulfate and hydrated or burnt lime.
The Occurrence of Carbazole in a Peat Soil
Authors: Braids O. C. , Himes F. L. , Volk G. W.
Published: July 2010

A sample of Rifle peat soil was extracted with benzene‐methanol (10:1). The yield of extracted material was 1.5% (dry soil weight). This material was fractionated according to solubility in petroleum ether and ethanol. Carbazole was identified in the fraction soluble in both solvents.
Layer Thickness Changes in a Clay‐Rich Soil in Relation to Soil Water Content Changes
Authors: Jamison V. C. , Thompson G. A.
Published: July 2010

Changes in soil water content and layer thickness of a soil with clay‐enriched horizons will depend upon the rooting depth and seasonal growth characteristics of the plant cover, as well as the nature of the soil itself. Soil anchors fitted with sleeves were turned to different depths in Mexico silt loam under bluegrass and alfalfa. Elevation measurements were made at each location with respect to benchmarks consisting of 3.7‐meter, sleeve‐fitted rods driven into the soil. Soil water measurements were made with a neutron meter. High corre'ations were found between water content and layer thickness of the clay‐rich layers. Alfalfa (Medicago sativa) proved to be much more effective in water removal from the claypan and deep subsoil than bluegrass (Ppoa pratensis). Disregarding expansion in the surface layer due to freezing, the greatest shrinking‐swelling effects were in the claypan. About one‐fourth of the magnitude of soil water change in the claypan of Mexico silt loam was manifested as a change in soil layer chiekness.
Molybdenum Deficiency Symptoms in Cotton
Authors: Kallinis Thomas L. , Vretta‐Kouskoleka Helen
Published: July 2010

Molybdenum deficiency symptoms were developed in first generation cotton (Gossypium hirsutum, var. Coker) growing in purified nutrient solutions. The first symptoms appeared when the plants were 7 weeks old. The young leaves became chlorotic between the veins, while the old leaves became greasy and swollen between the veins. Cupping of their margins occurred either upward or downward. Addition of Mo in the nutrient solution of the deficient plants corrected all deficiency symptoms and allowed the plants to develop normally again. The Mo content of the leaves exchibiting advanced deficiency symptoms was 1.14 ppm, of leaves exchibiting incipient deficiency symptoms was 1.88 ppm, and of healthy leaves was 2.37 ppm.
Phosphorus and Zinc Interactions in Flax
Authors: Burleson C. A. , Page N. R.
Published: July 2010

Phosphorus‐Zn interactions in fiber flax, Linum usitatissimum L., were studied in growth chambers by means of a two‐zone root technique and nutrient solutions. Zinc and P were added separately from each other and the other essential elements; therefore, any interactions that occurred between them or with other elements had to take place at root surfaces or within the plant.

Increasing either Zn or P in the substrate increased the concentration and total uptake of the respective element in the roots and tops of the flax plants.

When P was added first, Zn increased total P in the lower and upper roots and decreased total P in the tops. When Zn was added first, P increased total Zn in the lower roots and decreased total Zn in the tops.

The results indicate that P and Zn react together within the roots in a manner that reduces either their mobility or solubility.
Soil Phosphorus in South Dakota: III. Phosphorus Fractions of Some Borolls and Ustolls
Authors: Westin F. C. , Buntley G. J.
Published: July 2010

The data for the phosphorus fractions and carbon and nitrogen for 8 soils classified as Borolls and 8 as Ustolls along a 260‐km transect are compared. The Ustolls generally have, in their upper horizons, appreciably more Fe‐P, and reductant‐P, less Ca‐P, and slightly less Al‐P than the Borolls. Organic P values are a little higher and carbon and nitrogen percentages are slightly lower among the Ustolls.

In general, the ratio of carbon to phosphorus in the organic matter is lower among the Ustolls indicating that there probably is a higher rate of mineralization of organic P taking place in the Ustolls than in the Borolls.

The proportions of the phosphorus fractions in the various horizons of the soils appear to reflect the climatic change occurring along the transect.
The Influence of Crop Management on Runoff, Erosion, and Soil Properties of a Marshall Silty Clay Loam
Authors: Moldenhauer W. C. , Wischmeier W. H. , Parker D. T.
Published: July 2010

A series of field plots at Clarinda, Iowa, were operated from 1932 through 1963 to study effects of crop and soil management on infiltration, erosion, and crop yield. Major treatment changes were made in 1943 and 1953. Before 1953, soil‐erosion rates were high, especially when corn (Zea mays L.) followed several years of corn, and were inversely related to organic carbon content and aggregate stability of the soil.

After the 1953 revision of the study, erosion loss from continuous corn that received annual applications of 179 kg of N per ha (160 lb/acre) were relatively low and were not closely correlated with soil carbon content or with aggregate stability. However, erosion was inversely related to high nitrogen fertility, which, in turn, was accompanied by a trend toward increased soil carbon and high carbohydrate content of the soil. The erosion‐reducing effect of the nitrogen additions were most evident under intense July and August thunderstorms. Soil loss from corn following good meadow was, however, substantially less than from the nitrogen‐treated continuous corn, particularly when erosive rains occurred during the corn seedling stage of the crop year. Crop yield was directly related to N fertility and not to aggregate stability or to organic‐matter content of the soil.
Retention of Boron by Layer Silicates, Sesquioxides, and Soil Materials: I. Layer Silicates
Authors: Sims J. R. , Bingham F. T.
Published: July 2010

The characteristics of boron retention by layer silicates were studied. Boron retention was determined by a procedure developed for use with solution concentrations ranging from zero up to several hundred parts per million B, which consisted of treatment of the adsorbent with B solutions, washing with methanol to remove excess B, and extracting the retained B with 0.01N NaCl (pH 3).

Vermiculite, kaolinite, montmorillonite, and hydrobiotite all exhibited a pH‐dependent affinity for B with maxima in the alkaline range. Access to the interlayer surfaces of the expanding lattice clays was necessary for maximum B retention by these clays. Boron retention by these layer silicates was, in the main, attributed to hydroxy iron and aluminum compounds occurring in the samples as impurities.
Reactions Affecting Cation Exchange Kinetics in Vermiculite
Authors: Klobe W. D. , Gast R. G.
Published: July 2010

Strong retention of cations, commonly referred to as fixation, was studied using Cs and Sr exchange reactions with Montana vermiculite. Fixation was defined as the property of an exchanger to retain cations in a state such that they are not available for rapid isotopic exchange in a well‐stirred system. Efforts were directed toward qualitatively determining some of the conditions under which fixation occurs.

Equations were derived to calculate fixation using isotopic equilibrium values attained with separate aliquots of carrier‐free isotope. Cesium fixation occurred in all size fractions of vermiculite ranging from 40–20 mesh through < 0.2 µ upon addition of 1 symmetry stable CsCl. The amount of 134Cs fixed at this Cs level depended on the sequence of adding separate aliquots of isotope and the corresponding stable salt, and appeared to be caused by lattice collapse.

The amount of Cs fixed increased with increasing additions of CsCl. However, when Cs saturation of the vermiculite exchange capacity exceeded 4.5%, the fraction of sorbed Cs that became fixed was relatively constant. A plot of Cs fixation vs. percent Cs saturation of the exchange capacity indicated that fixation was independent of time over an interval of 4 months.

In contrast to the Cs results, Sr was always readily exchangeable, with no evidence of lattice collapse.
Determination of the Partial Pressure of Ammonia in Soil Air
Authors: Blanchar R. W.
Published: July 2010

A method for determining partial pressures of NH3 from 0.01 to 0.50 mm Hg in soil air was studied. Soil samples which had been treated with various amounts of ammonium hydroxide were placed in 1‐liter polyethylene bottles and allowed to equilibrate. A known volume of air from the bottle was removed by partially compressing the bottle with a press. The air was bubbled through 0.1N HCl and the ammonium content of the acid determined by the Nessler reaction. The partial pressure of NH3 (PNH3) was calculated from the ideal gas law equation.

The method gives a reliable estimate of the partial pressure of NH3 in soil air. It was shown that the PNH3 of a sample placed in the polyethylene bottle could be determined after a 1‐hour equilibration period.

Samples which were sealed in the polyethylene bottles for 48 hours had lower PNH3 and higher PCO2 values than samples placed in the bottles for only 1 hour. Reduced PNH values in bottles which had been sealed for 1 day or more were attributed to pH reduction due to CO2 accumulation.

Germination of corn seeds (Zea mays L.) was damaged when the initial PNH2 value was 0.156 and final values were between 0.077 and 0.104 mm Hg. The germination of corn seeds was not reduced when initial PNH3 values were 0.091 and final values were 0.067 and 0.048 mm Hg.
A Constant—Head Device for Flow Measurement with Limited Volumes of Solution
Authors: Gairon S. , Falkenflug V. , Hillel D.
Published: July 2010

A device is described which automatically maintains a constant liquid level in a floating cell from which liquid can be extracted at will. The device is particularly useful in flow measurements through permeameters when the permeating solution is limited in volume.
Deaired Water Installations for Measuring the Hydraulic Conductivity of Clays
Authors: Yevnin A.
Published: July 2010

Deaired water is commonly used in order to reach and maintain complete saturation during hydraulic conductivity determination of soils. One falling head and one constant head installation are described for the storage of deaired water and for the measurement of head and rate of flow. Methods of operation and calculation are given.
The Applicability of Darcy's Law
Authors: Swartzendruber Dale
Published: July 2010

Deviations from Darcian proportionality between flow velocity v and hydraulic gradient i are considered in terms of a gradient‐dependent hydraulic conductivity K(i) = v/i. Published greater‐than‐proportional data for saturated flow indicate measured variations in K(i) of 2‐ to 4‐fold, with a potentiality for 5‐ to 15‐fold variations inferred from fitted non‐Darcian flow equations. Non‐Darcian effects for two‐dimensional radial flow are also analyzed. The hydraulic head distribution is shifted from the Darcian‐derived logarithmic pattern toward the characteristic linear distribution for one‐dimensional flow, and the amount of the shift is velocity dependent. This implies that the flow net for two‐dimensional non‐Darcian flow would generally change with flow velocity, and that the high‐gradient flow regions would be more permeable than for Darcian flow.

For a particular unsaturated soil, the soil‐water diffusivity D appears to be a gradient‐dependent quantity D(θ,ω), where θ is the soil‐water content, and ω is the water‐content gradient. A maximum 8‐fold variation in D at given low water contents is associated with a 40% discrepancy between experimental water‐absorption rates and those calculated from proportional flow theory. Similarly, a 115% discrepancy is found for the vertically downward rate of infiltration into a mixture of quartz sand and ground silica, but the deviating behavior can be precisely accommodated with a non‐Darcian infiltration equation derived by a simplified analysis. Various implications of non‐proportional effects are discussed and enumerated briefly.
Solubility and Redox Criteria for the Possible Forms of Selenium in Soils
Authors: Geering Harold R. , Cary Earle E. , Jones L. H. P. , Allaway W. H.
Published: July 2010

The solubility of Se in seven soils indicate that Se concentration in solution is governed primarily by a ferric oxide‐selenite‐adsorption complex (Se oxidation state +4). However, under certain conditions Se may also exist in the oxidation states +6, 0, and −2. The proportions of Se in the four oxidation states are treated theoretically as they are affected by the redox potential, soil pH, and ions with which Se combines.
Self‐Diffusion of Phosphorus in Clays and Soils: I. The Effect of Phosphorus Rate
Authors: Phillips R. E. , Place G. A. , Brown D. A.
Published: July 2010

Self‐diffusion coefficients of 32P were measured in kaolinite clay, montmorillonite clay, illite clay, Dundee silt loam soil, and Sharkey clay soil. Phosphorus in the form of concentrated superphosphate was added to each clay or soil at the rates of 10, 20, 40, 80, 160, and 320 ppm. The clays and soils were maintained near a neutral pH and at a water content in equilibrium with 173 mbar tension. The water‐soluble, Ca, Fe, Al, occluded Fe, and occluded Al fractions of phosphorus were measured for each clay and soil at each rate of added phosphorus.

The self‐diffusion coefficients and phosphorus rates of each clay and soil were linearly and positively correlated. The diffusion coefficients in kaolinite and montmorillonite clays were approximately 40 times larger than those in illite clay, Dundee silt loam, and Sharkey clay. No general relationship was established between the self‐diffusion coefficients and the various fractions of soil phosphorus when all soils and clays were considered as a group. When each clay or soil was considered individually, there was a highly significant relationship between the diffusion coefficients and water‐soluble phosphorus, aluminum phosphate, or the combination of the two. The amounts of phosphorus found in the various fractions differed greatly between soils. The kaolinite and montmorillonite clays initially contained relatively small quantities of phosphorus while illite clay, Dundee silt loam, and Sharkey clay initially contained relatively large quantities of phosphorus.
Uptake of Fertilizer and Soil Nitrogen by Ryegrass, as Affected by Carbonaceous Residue
Authors: Terman G. L. , Brown M. A.
Published: July 2010

Annual ryegrass (Lolium multiflorum) was grown on limed Hartsells fine sandy loam and Decatur silty clay loam fertilized with 0, 120, 300, 600, and 900 mg of N as 15N‐labeled (NH4)2SO4 per pot (3 kg of soil). Half of the pots also received 15 g of corn (Zea mays) forage residue (1.05% N) mixed with the soil and half received none. Six clippings of forage and roots were harvested after the final clipping.

Total yield of dry forage and uptake of N were linear for all rates of applied N without residue and for the 300‐, 600‐, and 900‐mg rates with applied residue. As estimated by linear regression from total N uptake, apparent recovery by six clippings of ryegrass plus roots, grown without residue, was 78% from Hartsells soil and 76% from Decatur. The corresponding slightly lower recoveries of 75 and 72% of the fertilizer N applied reflect uptake of soil N. Recoveries of fertilizer N were 90% from the Hartsells and 85% from the Decatur soil‐plant systems. As estimated by difference, recoveries of fertilizer N by ryegrass increased, and recoveries from the plant‐soil systems decreased with increase in amount of applied N.

Crop uptake of soil N increased as fertilizer N was depleted from the soils.

Addition of the carbonaceous residue caused apparent immobilization of 141 mg of fertilizer N in Hartsells and 164 mg in Decatur soil. Percentages of fertilizer N immobilized in the soils decreased, but actual amounts increased with increasing amount applied. A portion of the fertilizer N, independent of amount applied, was immobilized in each soil.
Limitations of Quantitative Soil Clay Mineralogy
Authors: McNeal Brian L.
Published: July 2010

Analysis of the effects of varying the parameters assigned to soil mineral species for the purpose of quantitative mineralogical analysis suggests that absolute determination of mineral contents may be precluded by the variations in soil mineral properties which can be reasonably expected to occur. Rejection of those variations that produce unreasonable results for specific groups of soils, however, verifies that estimation of sample mineral contents for these soils is often valid to within ± 5%.
System Dependence of the Water Content‐Pressure Head Relationship
Authors: Watson K. K. , Whisler F. D.
Published: July 2010

The drainage to a water table of a saturated, stratified sand column in which a fine sand overlay a course sand evidenced a relationship between water content and pressure head for the coarse sand which was characteristically different from that obtained during the drainage of a uniform column of the coarse sand. The water content‐pressure head relationship for each system is presented and the system dependence of the relationship discussed. The effect of this system dependence, and the limitation it places on the use of current analytical approaches in predicting pressure head and water content profiles during the drainage of layered soils, is then considered.
A Rapid, Qualitative Method for Determining Movement of Applied Manganese in Soil
Authors: Hossner L. R.
Published: July 2010

A rapid, qualitative method for estimating the rate and distance of Mn movement from fertilizer granules in soil is presented. A filter paper saturated with 5N HNO3 is pressed on the soil surface and soluble soil Mn absorbed by the filter paper is then oxidized to permanganate by NaBiO3.
Adsorption and Desorption of Diquat, Paraquat, Prometone, and 2,4‐D by Charcoal and Exchange Resins
Authors: Weber J. B. , Ward T. M. , Weed S. B.
Published: July 2010

The adsorption of diquat, paraquat, prometone, and 2,4‐D by charcoal and cation‐ and anion‐exchange resins and their desorption with water and 1M NaCl solutions has been investigated. Prometone and 2,4‐D were adsorbed by charcoal in much greater amounts than were diquat and paraquat, but all of the compounds were readily desorbed with deionized water following normal Freundlich isotherms. Diquat and paraquat were adsorbed by the cation exchange resins (H and Na forms) and both herbicides were readily desorbed by Na+ ions but not with deionized water. Diquat was preferentially adsorbed over paraquat by the cation‐exchange resins and diquat was also more effective in displacing paraquat from the resins. Prometone was adsorbed in small amounts by the cation resin in the Na form and the anion resin in the Cl form and was readily desorbed with deionized water. Prometone was adsorbed by the cation resin in the H form in amounts which were similar to those for diquat and paraquat. None of the prometone adsorbed by the H‐resin was desorbed by equilibrating with water. Prometone desorbed from the H‐resin with 1M NaCl solutions was identified as hydroxypropazine.
Electromotive Force of Inert Electrodes in Soil Suspensions
Authors: Bohn H. L.
Published: July 2010

Attempts to relate the emf of gold, graphite, and platinum electrodes in soil suspensions to the electrode potentials of redox couples in the soil were unsuccessful. EAu and EC did not respond to aeration of the suspensions or to the presence of sucrose as a reducing agent. EPt responded to these conditions, but did not correspond to the electrode potentials of the Mn2+‐Mn oxide, O2‐H2O, or H+‐H2 couples. It is concluded that EPt is a mixed potential whose major components are the O2‐H2O couple in aerated suspensions or the H+‐H2 couple in anaerobic suspensions, but whose value is not related to the Nernstian distribution of oxidized and reduced species. Although EPt is a qualitative measure of the oxidation‐reduction conditions in the soil, it has no quantitative significance.
Occurrence and Synthesis of Soil Zeolites
Authors: Baldar N. A. , Whittig L. D.
Published: July 2010

Analcime has been identified by X‐ray diffraction analysis in a number of strongly alkaline soils developed from granitic alluvium in the San Joaquin Valley, California. Analcime occurrence is restricted to soils containing Na2CO3 and with pH above 9. The analcime is generally concentrated near the soil surface and is most abundant in fine silt (5 to 2µ) and coarse clay (2 to 0.2µ) fractions. The occurrence and distribution of the analcime support the conclusion that it is of pedogenic origin. Cation exchange data indicate that the analcime Na is slowly replaced by NH4 and that divalent cations Ca and Ba, as compared with K and NH4, replace relatively little of the analcime Na. Analcime was effectively destroyed in a soil by treatment with 0.5 N HCl. The mineral was readily synthesized in the acid‐treated soil and in the acid extract from the soil by titration of the systems to pH 9 and above with NaOH followed by digestion at 95C for 14 days.
Genesis of Layer Silicates in Representative Soils in a Glacial Landscape of Southeastern Wisconsin
Authors: Borchardt G. A. , Hole F. D. , Jackson M. L.
Published: July 2010

Quantitative mineralogical analysis of the clays and silts of two representative soil profiles of a glacial landscape indicated the relative extent of depositional influence as well as the effect of mineral weathering. The more intensely leached upland Lapeer loam of about pH 5 has a clay mineralogical content of 20% mica and 12% kaolinite. Clay in the less leached, neutral Saylesville silt loam occurring on a plain at a lower topographic position contains 40% mica and 6% kaolinite, as does the calcareous till under the Lapeer solum. A direct relationship exists between the pH of the horizon and content of mica in soil clay (r = 0.97) for 13 horizons of these and related soils. Variable total sand contents of the different horizons demonstrated the variable origin of the material from which the horizons developed.

About 20 cm of loess was incorporated into the Lapeer loam. The Lapeer solum and weathered Peorian loess of Illinois are similar with respect to (i) content of about 2% K2O in the clay fractions, and (ii) a coarse silt/fine silt ratio of about 0.7. The dolomitic lacustrine deposits of the C2 and C4 horizons of the Saylesville soil had a vermiculite/mica ratio in the clay of 0.18. These horizons contain no sand and have clay mineral components nearly identical to those of the sandy loam till of the Lapeer, which has a vermiculite/mica ratio of 0.19.
A Genetic Study of Two Soils Developed on Granite in Llano County, Texas
Authors: Goss D. W. , Allen B. L.
Published: July 2010

Studies were made of an excessively drained soil and a somewhat poorly drained soil, tentatively named Click and Bauman, respectively, to determine the effects of topography upon their genesis and resulting mineralogy. Heavy mineral data indicate that the soils have developed from relatively homogeneous parent materials. Clays were fractionated at 0.2µ for X‐ray diffraction, differential thermal (DTA), and cation exchange capacity (CEC) studies. The data indicate that the clay mineralogy of both soils is mixed but that the fine clay of the Bauman soil is dominated by a montmorillonite mineral that increases with depth in the profile. The fine clay fraction of the Click soil apparently contains near equal portions of kaolinite, illite, montmorillonite, and X‐ray amorphous material. Appreciable exchangeable Na is present in the subsoil of the Bauman profile but is essentially absent in the Click soil. Soluble weathering products from the surrounding slopes have moved laterally at the soil‐unweathered granite interface and accumulated in the Bauman soil thereby causing its morphology and clay mineralogy to differ markedly from that in the better drained soil.
Movement of Silt‐Sized Particles in Sand Columns
Authors: Wright W. R. , Foss J. E.
Published: July 2010

Plastic columns containing fine or medium sand, and capped with fine or medium silt, were leached with distilled water. Both coarse and fine silt moved readily through the medium sand; however, only the fine silt moved appreciably through the fine sand. Deposition of the fine silt in bands was also observed in the fine sand columns.
In Situ Measurement of Soil and Plant Leaf Water Potential
Authors: Rawlins S. L. , Gardner W. R. , Dalton F. N.
Published: July 2010

For a pepper plant (Capsicum frutescens L.) growing in a greenhouse, soil water potential was measured with tensiometers and a thermocouple psychrometer, plant water potential was inferred from a calibrated beta gauge, and transpiration was measured by weighing the soil‐plant system. Water moved through the transpiration stream in the direction of the gradient of the water potential. Regardless of the distribution of water in the soil, transpiration was unaffected by soil water content until it dropped to a value corresponding to −6 to −8 bars water potential. Below this water content, transpiration decreased linearly with soil water content to a soil water potential of −37 bars. At this time the plant water potential was below −50 bars and the transpiration rate was near zero. After irrigation the plant regained full turgor.
Adsorption of Phosphorus by Lake Sediment
Authors: Harter Robert D.
Published: July 2010

The sediment of an eutrophic lake is capable of adsorbing a large amount of phosphorus from the water. To study the sorption mechanism, between 0 and 2.2 mg P was added to 0.1‐g sediment samples (1:50 sediment‐solution ratio). After equilibrium had been established, P remaining in solution was determined, and adsorbed P was extracted with 0.5N NH4F and 0.1N NaOH. Whereas all P adsorbed into the NaOH‐extractable fraction appeared to occur as an iron phosphate, NH4F apparently extracted P bonded by two different mechanisms. When less than about 0.1 mg P was added, NH4F extracted a tightly bonded form of P, probably occurring as an aluminum phosphate. When more than 0.1 mg P was added, additional P in a more loosely bonded form was adsorbed into the NH4F‐extractable fraction. The loosely bonded P appeared to be independent of Al content of the sediment, and could be removed by successive water extraction. The capability of the sediment to adsorb considerable loosely bonded P means that large influxes of P into the lake may be held temporarily and subsequently released to growing plants and algae.
Urease Activity in a Black Spruce Humus Sterilized by Gamma Radiation
Authors: Roberge M. R. , Knowles R.
Published: July 2010

The activity of urease was studied in a black spruce (Picea mariana (Mill.) BSP.) surface organic horizon from Baie‐Comeau, Quebec. Samples were sterilized by 60Co radiation, incubated with urea for 8 hours at 20C and analyzed for ammonia. Urease activity decreased with an increase in humus decomposition. Field fertilization with 450 kg urea‐N/ha 2 years prior to humus sampling increased the urease activity by 40%. Laboratory preincubation of field‐fertilized and unfertilized humus with 3,500 ppm of urea‐N resulted in increased urease activity of 90%. Enzyme assays performed with 21,000 and 63,000 ppm of urea‐N gave similar relative activities to those performed with 3,500 ppm. Some mineralization of N occurred during and following irradiation in the absence of any added substrate. A direct relationship was found between enzyme activity and total and ureolytic numbers of microorganisms.
Distribution of Chlorinated Insecticides in Cultivated Soil
Authors: Nash R. G. , Woolson E. A.
Published: July 2010

The 1966 distribution of nine chlorinated insecticides in a 38 cm profile was determined in a Congaree sandy loam soil which had received accumulations of 73 or 146 kg/ha as frequently repeated foliar applications during the 1951, 1952, and 1953 growing seasons. Residues of aldrin (pure and technical—determined as dieldrin because only trace amounts of aldrin were detected), dieldrin, isodrin + endrin, endrin, heptachlor + heptachlor epoxide, chlordane, BHC, toxaphene, and Dilan were found throughout the profile. BHC and isodrin were more uniformly distributed throughout the profile than aldrin, dieldrin, Dilan, toxaphene, and chlordane. Between 85 to 90% of the latter insecticides were concentrated in the upper 23 cm, which probably corresponds to the cultivated layer. Residues were greatest in the 7.6 to 23 cm depths and least below the 23 cm depth. The relative mobility of the insecticides was: BHC ≥ isodrin > heptachlor > endrin > toxaphene ≥ dieldrin ≥ aldrin ≥ Dilan ≥ chlordane.
Uptake of Native Potassium by Plants from Natural Soil Aggregates of Different Sizes
Authors: Tabatabai M. A. , Hanway J. J.
Published: July 2010

The uptake of the native K by ryegrass (Lolium multiflorum) from undried soil aggregates > 9, 5–9, 3–5, 2–3, and 1–2 mm in diameter was studied in 14 soil samples. Yields of K and percentage K in the plants were highly correlated with the exchangeable K in the undried soils, irrespective of aggregate size. Early in the cropping period, plant yields were slightly higher, and slightly more K was taken up by the plants from the smaller aggregates than from the larger aggregates.
Nomographic Calculation of Linear Extensibility in Soils Containing Coarse Fragments
Authors: Holmgren George G. S.
Published: July 2010

Linear extensibility is a variable being used by the Soil Survey Laboratories to characterize the expansion‐contraction properties of soil. It is calculated from bulk density data and must be corrected for coarse fragments when they are present in the field. A pair of nomographs is presented to facilitate these calculations. The volume percent of fine‐earth fabric (F) is determined from the first nomograph and transposed to the second nomograph where it serves to correct the extensibility as determined on the fine‐earth fabric. The value F may also be used to facilitate conversion of other laboratory data to a field basis where coarse fragments are present.
Some Chemical and Physical Properties of Different‐Sized Natural Aggregates from Iowa Soils
Authors: Tabatabai M. A. , Hanway J. J.
Published: July 2010

This study presents data concerning different chemical and physical properties of various‐sized, undried aggregates from seven surface soils and seven subsoils from Iowa.

There was little or no difference in exchangeable K, extractable P, pH, or the percentages of sand, soilt, or clay in the different‐sized aggregates from any one soil sample. In some soils, organic carbon content tended to increase, and bulk density tended to decrease as the aggregate size decreased. The bulk densities of the aggregates were inversely related to the percentages of organic carbon in the aggregates.
The Influence of Ionic Strength and Ion‐Pair Formation Between Alkaline‐Earth Metals and Sulfate on Na‐Divalent Cation‐Exchange Equilibria
Authors: Rao Talur S. , Page A. L. , Coleman N. T.
Published: July 2010

The Na‐Ca and Na‐Mg ion‐exchange equilibria were studied in two soils and in an ion‐exchange resin by batch equilibration procedures. The apparent equilibria, in terms of concentrations, were different for the anions chloride or sulfate. The differences were reduced but not eliminated by ion activity corrections based on ionic strength. A more satisfactory agreement between the results in chloride and sulfate systems was obtained when allowance was made for solution phase activities and ion‐association of Ca and Mg with SO4 ions.
Mineralization of Nitrogen in Grass Roots
Authors: Power J. F.
Published: July 2010

The mineralization of fertilizer N immobilized in grass roots (Bromus inermus L.) is of major importance in regulating the use of N fertilizers on grassland. Grass roots varying in N content were therefore incubated with soil for 10 weeks at 30C, and the net rate of mineralization was measured. Rate of N mineralization during incubation was controlled to a large extent by the N content of the root material—mineralization of N contained in grass roots followed much the same pattern as for that in any other plant tissue. Incubation of unfertilized grass roots (0.84% N) resulted in net immobilization of mineral N. Incubation of N‐fertilized grass roots (containing 1.44% N) resulted in a net increase in mineral N. For both root materials the changes in mineral N were in proportion to the amount of root material added.
The Influence of Nitrification Suppressants on the Rate of Ammonium Oxidation in Midwestern USA Field Soils
Authors: Sabey Burns R.
Published: July 2010

The effectiveness of 2‐chloro‐6‐(trichloromethyl) pyridine, 2‐amino 4‐chloro 6‐methyl pyrimidine, and a resinous polymer coating in suppressing nitrification in the field was studied. Soil samples treated with (NH4)2SO4 alone and with (NH4)2SO4 plus the above materials, were placed in plastic bags and buried in field plots and allowed to incubate during the fall, winter and spring periods. Determinations for NH4+‐N and NO3‐‐N were made throughout the incubations.

Nitrate‐N accumulation occurred at rates as high as 2.5 ppm/day prior to April 15 in samples treated with (NH4)2SO4 alone. Samples treated with the resinous coated (NH4)2SO4 fertilizer had higher NO3‐‐N accumulation rates (up to 4.1 ppm NO3‐‐N/day), whereas samples treated with (NH4)2SO4 and 2‐chloro‐6‐(trichloromethyl) pyridine or 2‐amino 4‐chloro 6‐methyl pyrimidine had rates of nitrification only as high as 2.3 and 1.6 ppm NO3‐‐N/day, respectively, prior to April 15. Although 2‐amino 4‐chloro 6‐methyl pyrimidine appeared slightly more effective after the end of April than 2‐chloro‐6‐(trichloromethyl) pyridine in suppresing nitrification, there were relatively small differences. Both compounds, added according to recommended rates delayed rapid nitrification for about 1 month.
Effect of Partial Removal of Soil Organic Nitrogen with Sodium Pyrophosphate or Sulfuric Acid Solutions on Subsequent Mineralization of Nitrogen
Authors: Stanford George
Published: July 2010

Studies were conducted with Chester loam and Elliott clay loam soils to determine the relationship between amounts of N extracted by Na‐pyrophosphate solutions and reduction in capacities of the soils to mineralize N under anaerobic conditions. By employing wide variations in concentration and pH of the extractant, number of extractions, temperature, and extraction time, a broad range was achieved in total amounts of N extracted (40‐1,200 ppm). Accompanying reductions in soil N mineralization during 10–11 weeks ranged up to 125–170 ppm, respectively, with the Elliott and Chester soils. A close similarity in susceptibility to mineralization of N extracted from the two soils is indicated, although relative amounts of extractable N differed appreciably.

Acid hydrolysis of Elliott soil with 6N H2SO4 for 12–16 hours reduced N mineralization capacity of the soil to zero. These findings may have important implications in defining criteria for selecting the concentration of an extractant suitable for use in assessing the N status of soils.
The Distribution of Gold in the Silt Fraction of Some Soil Profiles and its Genetical Significance
Authors: Yassoglou N. J. , Nobeli Catherine
Published: July 2010

The distribution of gold in the silt fraction of 13 soil profiles was studied. The element was determined by neutron activation analysis. Activation analysis can be successfully employed for the determination of gold in soil materials, where it is usually found in extremely small quantities ranging from 3 to 120 parts per billion (ppb).

It was found that silt and clay contain much higher amounts of gold than does sand. Parent materials which have undergone one cycle of soil formation seem to contain gold in the silt in the resistant metallic form. In other cases, the elements is associated with easily weatherable minerals and it is progressively lost from the silt fraction during processes of soil genesis. Gold could be used as an index of soil weathering, either as a resistant or as a removable constituent of the silt, depending on the composition and the origin of the parent material of the soil. It can also be used as an index of the lithological continuity of soil profiles.
Vesicular Pores of Pumice by Mercury Intrusion
Authors: Borchardt G. A. , Theisen A. A. , Harward M. E.
Published: July 2010

The pore size distribution of pumice was measured with a mercury intrusion porosimeter. Effects of particle to particle pores were minimized by use of separates based on size and density. Vesicular pores constituted about 98% of the fine porosity (<120µ diameter) in 1–0.5 mm fractions of pumice. Average diameters of internal pores of pumice were found to be in the range of 3 to 7µ. Distinctive curves were obtained for samples from Mt. Mazama, Glacier Peak, and Newberry Crater.
Solubility of Calcium Carbonate Precipitated in Montmorillonite Suspensions
Authors: Doner H. E. , Pratt P. F.
Published: July 2010

Calcium carbonate precipitated in Ca‐ and Mg‐saturated montmorillonite suspensions was more soluble than calcite added to these suspensions. The CaCO3 precipitated from a clay suspended in Ca(OH)2 had a greater solubility than when the CaCO3 was precipitated by the addition of CaCl2 and NaHCO3. The difference in solubility between the two directions of approach to equilibrium was related to the amount of soluble Mg in the system. When CaCO3 was precipitated from CaCl2 and NaHCO3 in clay suspensions with Mg‐saturation as a variable, its solubility was related to the amount of Mg in solution with apparently no effect of the clay per se.
Interaction of Soil Reaction and Method of Seed Inoculation on Alfalfa
Authors: Baker A. S. , Mortensen W. P. , Dermanis P.
Published: July 2010

Comparisons of alfalfa (Medicago sativa L.) growth and survival were made at three sites in western Washington. The soil at each site was adjusted to different pH levels. Conventional seed inoculation and seed pelleted with limestone flour, skim milk, and peat inoculum using methylcellulose as the adhesive were compared at each reaction level. Optimum soil acidity levels for growth and survival of alfalfa were attained at a 0.01M CaCl2‐pH of 5.9 or higher and an exchange acidity level of 0.03 meq/100 g or lower. Both conditions had to be satisfied. Responses to seed pelleting occurred only where the soil was below the optimum acidity level. When soil moisture was adequate during establishment, maximum yields were attained with seed pelleting below optimum soil acidity levels. When moisture was severely limiting during establishment, maximum yields were not obtained with seed pelleting at less than optimum soil acidity levels. Moreover, soil acidity levels had to be closer to optimum to obtain a significant response to seed pelleting. The response to seed pelleting in the years following establishment was due to improved survival rather than individual plant vigor. A high water table during the winter accentuated the response to seed pelleting.
Moisture Characteristics of Pennsylvania Soils: II. Soil Factors Affecting Mositure Retention Within a Textural Class—Silt Loam
Authors: Petersen G. W. , Cunningham R. L. , Matelski R. P.
Published: July 2010

The relationships of morphology and other selected soil properties to mositure retained after equilibration at ⅓ and 15 atm (approx. 0.34 and 15.5 kg/cm2) tension was investigated within silt loams. This laboratory study was restricted to an individual textural class in an effort to hold texture relatively constant while scrutinizing the influence of other soil properties upon the soil moisture regime.

Available moisture, which is assumed as the difference between moisture retained at ⅓ and 15 atm tension, was generally highest in the A, less in the B, and lowest in the C horizon. This moisture retention however, was more a reflection of coarse fragment content than of such horizon developmental features as clay accumulation, gleying, structural development, or fragipan characteristics. There was no significant difference between the moisture retention of cultivated and noncultivated horizons nor between the moisture supplying abilities of gleyed and nongleyed horizons. Nonfragic horizons retained almost twice as much available moisture as fragic horizons.

Moisture retention decreases as coarse fragments increase and therefore moisture retention calculations should be corrected for coarse fragments. Available moisture remained almost constant as organic matter increased within silt loams. Weight percentage contents of kaolinite, illite, vermiculite, montmorillonite, chlorite, and interstratified clays were not significantly correlated with moisture retention. Correlation analyses suggested the 20‐5µ silt as the most important <2 mm size separate controlling available moisture and moisture retained at field capacity.
Standard Free Energies of Exchange for Alkali Metal Cations on Wyoming Bentonite
Authors: Gast R. G.
Published: July 2010

Standard free energies of exchange, Δ Go, were determined for the exchange of Na with Li, K, Rb, and Cs and Li with K between 0.001N chloride solutions and 5% Wyoming bentonite gels at 25C. Values were also determined for Na → Rb, Na → Cs, and Rb → Cs exchanges between 0.0075N chloride solutions and 0.75% Wyoming bentonite suspensions. Application of the additivity rule indicates that the values are accurate to within ±50 to 100 cal mole‐1. Values for the 5% gels range from +48 cal mole‐1 for Na → Li exchange to −1,081 cal mole‐1 for Na → Cs exchange. There is a small but consistent increase in the ΔGo values for the 0.75% suspensions compared to those for the 5% gels. With the possible exception of Li, a linear relationship was found between ΔGo values and Debye‐Huckle parameters for the respective cations indicating that the adsorption of monovalent cations from strong electrolyte solutions is governed by their hydrated radii.
Clay Separation and Identification by a Density Gradient Procedure
Authors: Woolson E. A. , Axley J. H.
Published: July 2010

A method was developed for the separation and partial identification of clays using a heavy liquid density gradient column. The columns consisted of five different layers, theoretically permitting seven different separations in one determination. To aid in separation, the original density of the clay was altered by saturation with H, Ca, K, or Cs. The resulting densities were related to changes in the clay interlayer distance as well as to the equivalent weight of the sorbed cations.

This density gradient method is simple, quick, and requires only basic laboratory equipment. The density values aid clay mineral identification and in some instances may be the only information needed.
Micronutrient Cation Complexes in Soil Solution: III. Characterization of Soil Solution Ligands and their Complexes with Zn2+ and Cu2+
Authors: Geering H. R. , Hodgson J. F.
Published: July 2010

At least three groups of compounds were found to complex Zn2+ and Cu2+ in soil solution from the A horizon of a Williamson silt loam. A nondialyzable fraction of soil solution ligands had a poorly defined acid dissociation, pKa, ranging from 3 to 4.7. The dialyzable fraction had acid dissociation constants of 4.5 and 9.5, which were attributed to aliphatic and amino acids, respectively. The equivalent concentration of the nondialyzable acid fraction was only 1/40 that of the dialyzable fraction, but was more effective in complexing Zn and Cu in the soil solution. The average metal/ligand ratio was equal to unity in complexes of both the dialyzable and nondialyzable fractions with Zn2+ and Cu2+. Estimated, log10 (average formation constants) of the nondialyzable‐metal complexes were calculated on the basis of titratable acidity as 4.3 ± 0.1 and 5.5 ± 0.1 for Zn2+ and Cu2+, respectively.
Instrumental Analysis of Neutron Irradiated Soils
Authors: Kline J. R. , Brar S. S.
Published: July 2010

Soils from a worldwide collection were analyzed by gamma ray spectrometry, after thermal neutron activation, to identify and measure trace elements in soils which can be studied by this technique, and to determine whether gamma ray spectra of soils can be used to identify specimens of soil and trace them to their geographical origin. Samples of 100‐mg size were irradiated for either 5 or 10 min in the Argonne CP‐5 reactor at a thermal neutron flux of 2 × 1013 n/cm2/sec. Gamma‐ray spectrometry of activated samples was delayed until 4 days after irradiation because of high levels of 24Na which obscured the longer‐lived nuclides. Therefore, nuclides with half‐lives shorter than 15 hours were not measured. Long‐lived nuclides, which could be observed after 4 days of delay are 140La, 46Sc, 82Br, 59Fe, 51Cr, 60Co, 152Eu, 154Eu, 153Sm, 181Hf, and 95Zr‐95Nb. Quantitative determinations were easily made by nondestructive methods for La, Sc, Fe, Co, Eu, and Sm. Amounts of Sc were correlated with amounts of Fe, Co, and Eu in soils of highly diverse origin. Similar correlations were not obtained with La. Elemental relationships sometimes resulted in similar gamma ray spectra for soils of dissimilar origin. These spectra, therefore, raised doubts as to whether they could be used without other supporting evidence to identify soil specimens or trace them to their place of origin when the analysis is done with NaI crystals and 400‐channel analyzers.
Stimulation of Soil Respiration by Volatiles from Alfalfa
Authors: Gilbert R. G. , Griebel G. E.
Published: July 2010

Volatile compounds obtained by distillation of a water slurry of alfalfa hay increased the respiration rates of 12 soils three‐ to eight‐fold. The active volatiles are neutral organic compounds that rapidly penetrate the soil and cause an immediate increase in soil respiration. The intensity of the respiration enhancement is directly related to the relative concentration of the volatiles. Low RQ values of soil during exposure indicated the microflora utilized substrates low in oxygen. The optimal temperature for respiration enhancement of treated soil was 36C. The duration and magnitude of the soil respiration response were dependent on the volume of distillate used. The optimal volume maintained the increased respiration rate for 72 hours. Larger volumes reduced the duration of response to 2 hours, suggesting toxicity of the volatiles at higher concentrations.