bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology and Genesis of Some Grayish Claypan Soils in Oklahoma: I. Morphology, Chemical and Physical Measurements
Authors: Culver James R. , Gray Fenton
Published: July 2010

Grayish or grayish‐brown soils with thin silty A horizons over clayey argillic horizons occurring in the Reddish Prairies of Oklahoma are described. Four profiles, two of the established Waurika series and two of the proposed Nardin series were characterized by detail profile descriptions and by physical and chemical analyses. Particle‐size distribution, bulk density, cation exchange capacity, extractable cations, pH, and organic matter were determined by soil horizons. Attempts were made to classify the pedons studied according to the 7th Approximation to ascertain the validity of the proposed Nardin series.

These soils have thin silty A2 horizons with abrupt thick argillic horizons ranging from 42 to 55% clay. Clay, fine silt, organic matter, and carbonates were lost from the A horizons and were accumulated in the Bt horizons. The soils have high base status with Ca and Mg the dominant cations. A secondary maximum of organic matter accumulation occurs in the B2t horizons.
Profile Distribution of Nonexchangeable Mg in the <1µ Clay in Seven Loess‐Derived Soils
Authors: Protz R. , Riecken F. F.
Published: July 2010

The nonexchangeable Mg content of the <1µ clay in seven loess‐derived soils representing a wide range of soil development decreases with depth. A direct relationship exists between the nonexchangeable Mg content of the <1µ clay and exchangeable Mg/g of <2µ clay. An inverse relationship is present between nonexchangeable Mg in the <1µ clay and exchangeable H/g of <2µ clay. The montmorillonite/kaolinite ratio increases sharply with depth to 50 cm, below which the ratio remains constant. It is concluded that Mg has not been built into the clay fraction during soil profile development.
Reactions between Fulvic Acid, a Soil Humic Compound and Inorganic Soil Constituents
Authors: Schnitzer M.
Published: July 2010

The order of stabilities at pH 5.0 of complexes formed between a water‐soluble Podzol fulvic acid and nine divalent metal ions was Cu > Pb > Fe > Ni > Mn > Co > Ca > Zn > Mg. Log K (stability constant) values ranged from 8.69 for the Cu‐complex to 2.09 for the Mg‐complex and were higher at pH 5.0 than at pH 3.5. The Irving‐Williams series was not followed. Provisional results indicated that log K values for Fe3+‐ and Al3+‐fulvic acid complexes were higher than those for divalent metal‐fulvic acid complexes. Two types of reactions occurred between fulvic acid and metal ions and hydrous oxides: a major one in which both COOH and phenolic OH groups reacted simultaneously, and a minor one involving less acidic COOH groups only. To develop analytical methods for investigating metal‐organic matter complexes occurring in soils, model compounds, containing varying metal to fulvic acid ratios, were prepared. The methods so developed were later used as diagnostic tools for the characterization of metal‐organic matter complexes extracted from natural soils or occurring as distinct horizons in soil profiles.

In contrast to unreacted fulvic acid, metal fulvic acid complexes reacted with phosphate via the metal to form fulvic acidmetal‐phosphate. The interlamellar adsorption of fulvic acid by montmorillonite depended on the pH of the medium, the fulvic acid concentration and the type of cation with which the clay was saturated. Fulvic acid was found to have a positive effect on root initiation, which appeared to be related to its metal complexing ability.
Potassium Supplying Power of Iowa Soils at Their “Minimal” Levels of Exchangeable Potassium
Authors: Tabatabai M. A. , Hanway J. J.
Published: July 2010

The plant removal of native K from seven surface soils and seven subsoils from Iowa was studied at their “minimal” levels of exchangeable K. The “minimal” levels of exchangeable K were directly related to the percentages of <2 μ clay present in the surface soil samples. Plant uptake of nonexchangeable K was a linear function of time of cropping for all the soils and was highly correlated with the “minimal” level of exchangeable K. In the 758‐day cropping period, an average of about 24 times as much K was removed by the plants as was present as exchangeable K in the soils at their “minimal” exchangeable K levels. Long‐term K supplying powers of the soils used were highly correlated with their “minimal” levels of exchangeable K.
Hydrolysis and Sorption Reactions of Orthophosphate, Pyrophosphate, Tripolyphosphate, and Trimetaphosphate Anions Added to an Elliot Soil
Authors: Blanchar R. W. , Hossner L. R.
Published: July 2010

The reactions of trimetaphosphate (TMP), tripolyphosphate (TPP), pyrophosphate (PP), and orthophosphate (OP) with an Elliot soil were studied.

The hydrolysis reaction TMP→TPP→PP + OP→3 OP was studied by equilibrating TMP added to the Elliot soil at a rate of 400 µg. P/g soil and measuring TMP, TPP, PP, and OP at various times. These measurements showed that TMP persisted less than 1 day and TPP less than 8 days. Less than 10% of the PP formed had been hydrolyzed after 16 days.

The sorption of TMP, TPP, PP, and OP in the soil was studied. TMP was not appreciably adsorbed by the Elliot soil. The P adsorption capacities for OP, PP, and TPP calculated from the Langmuir equation were 462, 965, and 706 µg P/g soil, respectively.

A method for extracting and determining TMP, TPP, PP, and OP in soils was developed. The method consisted of two extractions (2% EDTA + 0.1N NH4F pH 4.2 and 2% EDTA + 1N NAOH), followed by an anion exchange resin separation of the P forms. Recovery of added P was 94% using these extractants. The average error for the extraction and separation was 17%.

Plant uptake of P from soil treated with PP was slightly higher than soil treated with OP.
Infrared Studies of the Mechanism of Adsorption of Urea‐d4, Methylurea‐d3, and 1,1‐Dimethylurea‐d2 by Montmorillonite
Authors: Farmer W. J. , Ahlrichs J. L.
Published: July 2010

Clay‐organic complexes of urea‐d4, methylurea‐d3, and I,I‐dimethylurea‐d2 with montmorillonite were examined by infrared spectroscopy in an effort to add to our understanding of the mechanism of adsorption of the substituted urea herbicides in soils. The complexes were examined in the infrared as dried thin self‐supporting films. Deteration techniques were used to correlate infrared spectra with molecular structure. Urea‐d4 was found to be adsorbed in the interlayer space by montmorillonite through coordination of the carbonyl with the exchange cations. The degree of coordination with the exchangeable cation was least for Ca, intermediate for Ni (II), and largest for Al, representing alkaline earth cation‐clay, transition metal cation‐clay, and acid clay, respectively. Methylurea‐d3 and I,1‐dimethylurea‐d2 reacted with montmorillonite through the carbonyl in a manner similar to urea. The reaction of dimethylurea with montmorillonite was limited by the presence of the methyl groups to the extent that its reaction was the same with Al or Ni as the exchange cation. The amino groups of urea, methylurea, and I,I‐dimethylurea appear relatively inactive as bonding sites.
Separation and Functional Group Analysis of Soil Organic Matter
Authors: Leenheer J. A. , Moe P. G.
Published: July 2010

An investigation was conducted on the Romney silty clay loam and Zanesville silt loam soils to determine an efficient method of separating organic matter from the mineral fraction of the soil with a minimum amount of alteration, and to compare the two soils on the basis of the functional group composition of their organic matter. Soil organic matter was obtained as an organic residue after the sand and silt fractions had been removed from an alkaline soil‐water suspension by sedimentation following dispersion of the soil by ultrasonic vibration, and the remaining suspended clay fraction dissolved by repeated treatments with an HCl‐HF acid mixture. No loss of organic matter was incurred by the physical removal of the sand and silt fractions, but approximately 12% of the Romney organic matter and 37% of the Zanesville organic matter was dissolved by the acid treatments.

Various chemical and instrumental techniques were used to quantitatively analyze this organic matter preparation for the carboxyl, aliphatic hydroxyl, phenolic hydroxyl, and carbonyl functional groups. The Romney organic matter was characterized by its high carboxyl and carbonyl content, whereas the Zanesville organic matter exhibited a high aliphate hydroxyl content. This comparison of functional group composition indicates a greater state of humification (oxidation) for the Romney organic matter than for the Zanesville organic matter. This difference in functional group composition is a major factor affecting the chemical interactions each type of organic matter undergoes in the soil.
Test of Constancy of Self‐Diffusion Coefficients
Authors: Phillips Ronald E.
Published: July 2010

A method is outlined which allows one to determine the constancy of diffusion coefficients measured by the use of Fick's second law subject to two sets of initial and boundary conditions if the spatial distribution of the diffusing ion is known. The constancy of published self‐diffusion coefficients was analyzed for illustrative purposes; they were found to remain essentially constant throughout the diffusion period. The method can be used to calculate constant diffusion coefficients from experimental spatial‐distributions of the diffusing ions. Diffusion coefficients calculated in this manner were compared with the values calculated by other methods; the values are the same, within experimental error, as predicted by theory.
Lindane Diffusion in Soils: I. Theoretical Considerations and Mechanism of Movement
Authors: Ehlers Wilfried , Letey J. , Spencer W. F. , Farmer W. J.
Published: July 2010

Equations are developed to describe the combined vapor and “nonvapor” phase diffusion of a volatile insecticide in soils and compared with the diffusion of lindane in a Gila silt loam in a transient state system. The quantity of diffused lindane appears to increase linearly with increased lindane concentration in the treated soil up to about 20 ppm but deviates from linearity at higher concentrations. The diffusion coefficient of lindane is independent of time until 22 ppm of the initial 80 ppm lindane concentration in the treated soil have diffused into the formerly untreated soil. The diffusion rate then decreases rapidly. The dependency of the diffusion coefficient on concentration and time may be explained by the fact that lindane will reach maximal vapor density in the range of 20 to 30 ppm. After these concentrations are built up in the initially untreated half‐cells by diffusion, vapor diffusion approaches zero and all the diffusion is in the “nonvapor” phase. At a 10% soil water content, 50% of the lindane diffuses in the vapor phase and 50% in the “nonvapor” phase. At near saturation, total diffusion is in the “nonvapor” phase. Lindane diffusion in soils can easily change from “nonvapor” to vapor phase and back to “nonvapor” phase.
Restoring Productivity on Pullman Silty Clay Loam Subsoil under Limited Moisture
Authors: Eck Harold V.
Published: July 2010

Applied fertilizer restored grain sorghum (Sorghum vulgare) yields on 10‐cm cut Pullman silty clay loam to 93% of those obtained on uncut soil. On 20‐, 30‐, and 41‐cm cuts, yields were restored to 87% of those on uncut soil. Soil water storage, water use, and water‐use efficiency data revealed that differences in soil water storage and use were responsible for differences in yield when fertility was not limiting. Topsoil removal decreased and fill increased water‐holding capacity of the soil profile. Topsoil removal decreased water loss from fallowed soil, but fill had little effect.

N was the only added nutrient required to produce highest yields obtained under limited moisture conditions in this study. Inadequately fertilized treatments used less water than adequately fertilized ones, but water‐use efficiency was greater where plant nutrients were adequate.
Hydrologic and Morphologic Implications of Anisotropy and Infiltration in Soil Profile Development
Authors: Zaslavsky Dan , Rogowski A. S.
Published: July 2010

The concept of anisotropy as a possible factor of soil formation is introduced and the hydrologic and morphologic implications of water infiltration are demonstrated. It is concluded that the magnitude and direction of downhill flux of infiltrating water will depend on the degree of anisotropy as well as on the land slope and its changes. This conclusion may explain in part the greater differentiation of horizons on flat lands than on sloping lands, and the gradual thinning out of the B horizon uphill as the slope increases.
Evaporation from a Simulated Soil Shrinkage Crack
Authors: Adams John E. , Ritchie Joe T. , Burnett Earl , Fryrear D. W.
Published: July 2010

A simulated soil shrinkage crack, 46 cm wide and 62 cm deep, was constructed in such a manner that depth could be varied by 15.2‐cm increments and width could be adjusted between 10 and 70 mm by 20‐mm intervals. The walls of the crack were lined with porous ceramic plates connected to a water supply maintained at −5 mb potential. The simulated crack was installed in the floor of a laboratory wind tunnel located in a controlled environment room maintained at 24.0 ± 1.5C air temperature and 43 ± 3% relative humidity. Evaporation from the simulated crack walls (ceramic plates) was determined for all combinations of four crack widths (10, 30, 50, and 70 mm), three crack depths (30, 45, and 60 cm) and five windspeeds (0, 2.2, 4.5, 6.7, and 8.9 m sec‐1).

Total water loss (evaporation) from the walls of the simulated crack increased as any one or all of the three variables (windspeed, crack depth, or crack width) increased. These three variables accounted for 99.1% of the variability in total evaporation from the crack walls. Turbulent air movement within the simulated crack was the major factor affecting the evaporation.

Both straw and gravel mulches reduced evaporation from the crack walls 85 to 90% with no wind and about 60% at 8.9 m sec‐1 windspeed. The results suggest that evaporation from soil shrinkage cracks may be reduced by closer plant or row spacing or by surface residues such as trash and clod mulches.

Total evaporation from a simulated crack 60 cm deep varied from 0.5 cm3 hr‐1 (10 mm wide, 0 m sec‐1 windspeed) to 18 cm3 hr‐1 (70 mm wide, 8.9 m sec‐1 windspeed). In simulated cracks 60 cm deep and 30–70 mm wide, 50–60% of the total evaporation occurred below 15 cm and 30–40% occurred below 30 cm.
Chemical and Biological Weathering in Vermiculite from Transvaal
Authors: Sawhney B. L. , Voigt G. K.
Published: July 2010

Transvaal vermiculite flakes were weathered in solutions of salts or acids as well as in nutrient solutions inoculated with water extracts of soils from hemlock (Tsuga canadensis) and tulip poplar (Liridendron tulipifera) forest stands. Morphological changes were studied with a microscope and the structural changes were determined by X‐ray diffraction analysis, while the changes in chemical composition were estimated by an electron microprobe.

Weathering of flakes proceeded from edges inward and produced a weathered zone parallel to the flake edges. However, the changes produced by salt solutions were different from those by acids and biological agents.

Treatment with salt solution produced the expanded weathered zone with a 14A c‐axis spacing as compared to 10A spacing of the unaltered zone. Electron microprobe analysis revealed that the salt treatment replaced the interlayer K ions by the hydrated cations of the salt. Treatment with acids or biological agents, on the other hand, produced a bleached and fragile weathered border that was amorphous to X‐rays. Electron microprobe analysis showed that the bleached zone was depleted of Fe, Mg, and Al, besides the interlayer K ions; concentration of these cations decreased towards the extremity of the edge. The amorphous nature of the weathered zone is attributed to the loss of the unit cell periodicity resulting from the removal of a portion of the octahedral and tetrahedral cations.
The Effect of Drying on Soil Strength Parameters
Authors: Camp C. R. , Gill W. R.
Published: July 2010

The influence of drying on the magnitudes of soil strength parameters C and ϕ was determined for three cohesive soils. Shear strength measurements were made using a modified laboratory triaxial apparatus for three different soil types on samples prepared in the laboratory. All samples of a given soil type were molded at the same soil water content and to the same bulk density. Samples were dried slowly to soil water contents between the 1/3‐bar soil water suction level and air dryness.

The criterion used to determine shear was either the development of a definite failure plane or an increase in sample diameter of 0.25 mm (0.010 in), whichever occurred first. Volume change of the sample and the applied axial and radial stresses were measured and recorded continuously throughout a test cycle. Mohr's circles were constructed and the parameters C and ϕ were determined for all samples. The parameters C and ϕ both increased with drying for these soils. Additional studies will be necessary to completely describe the soil shear strength‐drying relationship, or to determine the mechanisms of action which prevail.
Weathering of Mica by Fungi
Authors: Weed S. B. , Davey C. B. , Cook M. G.
Published: July 2010

Three trioctahedral micas and one dioctahedral mica (1–5µ size fractions) were used as sources of K+ for seven fungi grown in nutrient solution buffered at pH 6. Vermiculite formed from the mica. The mechanism involved was exchange of solution Na+ for mica K+, with the fungi functioning as K+‐sinks. Reducing the concentration of solution Na+ from 0.054M to 0.017M resulted in decreased rate of utilization of mica K+. Growth of fungi and release of K+ were greater for trioctahedral micas than for the dioctahedral mica and generally followed the K+ ease‐of‐release pattern established using sodium tetraphenylboron and NaCl solutions. The fungi differed in their capacities to promote the mica‐to‐vermiculite transition, and this was probably due mainly to their relative effectiveness as K+‐sinks.
Nutrient Interaction Effects on Sucrose Yield of Sugar Beets (Beta vulgaris) on a Calcareous Soil
Authors: Fuehring H. D. , Hashimi M. A. , Haddad K. S. , Hussieni K. K. , Makhdoom M. U.
Published: July 2010

Thirteen multivariable irrigated field experiments on a calcareous clay soil indicated a high requirement for N, Na, and P for yield levels up to 25.8 mtons of sucrose per ha. Levels of applied Cl, S, Zn, and B needed to be kept low. Partial third‐order regression equations were determined from the central composite, rotatable designs used. Two‐way and three‐way interactions had considerable effect often being considerably more important than the main effects of individual nutrients. Negative interactions of N with S and Zn were reinforced at high Na levels by negative N‐Na‐S and N‐Na‐Zn three‐way interactions. Negative interactions of Na with S, Cl, and Mg, along with the above mentioned three‐way interactions, accounted for most of the positive Na effect. The necessity for high levels of N, P, and Na along with low levels of S and Cl raises the question of what form of Na to apply and how to avoid excess S and Cl. Various interactions affecting the response to Zn, B, K, and Mg require further study.
Neutralizing Soil Acidity under Bermudagrass Sod
Authors: Adams Fred , Pearson R. W.
Published: July 2010

The effectiveness of surface‐applied lime in preventing subsoil acidification from residually acid N sources used on Coastal bermudagrass (Cynodon dactylon L. Pers.) was influenced by (i) soil type, (ii) lime rate, (iii) N source, and (iv) N rate. Lime applied at a rate equivalent to acidity of the N source maintained both pH and exchangeable bases in a loamy sand but not in a clay loam soil. Lime applied at three times the N fertilizer equivalent acidity was more effective in correcting subsoil acidity than were lower rates, and the effect was more pronounced in the coarse‐ than in the fine‐textured soil.

Calcium gluconate was highly effective in increasing subsoil pH and exchangeable base level under Coastal bermudagrass but caused an undesirable fungal bloom. Surface‐applied NaNO3 was effective in correcting subsoil acidity in both a coarse‐ and a fine‐textured soil without accumulation of Na, and the effect was relatively uniform throughout the depth of profile sampled (45 cm). Calcium nitrate was also effective in increasing subsoil pH and exchangeable Ca in medium textured soil to a depth of 45 cm, with less pronounced effects down to 75 cm. Residual basicity of Ca(NO3)2, as measured by increase in exchangeable Ca in the soil profile, ranged from 1.7 to 2.5 kg CaCO3 per kg N, depending upon rate of application.
General Soil Map of the United States
Authors: Douglass J. F. , Austin M. E. , Smith Guy D.
Published: July 2010

This map shows the distribution of the principal kinds of soil in the USA as classified in the system currently used by the soil survey. The map can be used only for comparing soils of large areas. It has 331 units defined mostly as associations of phases of great groups. A brief legend on the front of the map explains the colors that distinguish soil orders, lists the symbols for dominant great groups and special features, and includes an introduction to the nomenclature. A detailed legend on the back of the map is arranged alphabetically by great groups within a suborder of each order. The legend provides general definitions for the orders, suborders, and great groups, present dominant land use for the suborders, and approximate equivalent former names for the great groups. The map, scale 1:7,500,000, size 48 by 71 cm, was compiled on the National Atlas base with an Albers equal area projection. The soil information is current as of December 1967. The base map shows state boundaries, major drainages, principal cities, and state experiment stations. The soil map, in color, is for sale by the U. S. Geological Survey, 1200 S. Eads Street, Arlington, Va. 22202.
Predicting Specific Conductance from Electrolytic Properties and Ion Association in Some Aqueous Solutions
Authors: Tanji K. K.
Published: July 2010

Specific conductances in aqueous solutions of electrolytes up to 0.1N concentration were predicted with an extended form of the Onsager limiting equation and compared with measured values. For completely dissociated chloride solutions the calculations involved ionic conductance, electrophoretic and relaxation effects, and other electrolytic properties. Incompletely dissociated sulfate solutions required additional considerations of ion association of NaSO4‐, CaSO4°, and MgSO4°. Agreement was good between predicted and accepted literature conductance values. This quantitative description of conductance provides a theoretical explanation of why electrical conductivity underestimates analytically determined solute concentrations in waters and soil solutions containing moderate concentrations of SO42‐.
Bicarbonate Accumulation and pH Changes at the Soybean (Glycine max (L.) Merr.) Root‐Soil Interface
Authors: Riley D. , Barber S. A.
Published: July 2010

Investigation of the root‐soil interface environment of soybean roots showed an accumulation of HCO3 and an increase in pH as compared to the original soil. The magnitude of the HCO3 accumulation and pH increases was related to the NO3 level of the soil solution. This effect was attributed to a greater uptake of anions than cations by the plant so that HCO3 release maintained electrical neutrality. The pH increased by as much as one unit and HCO3 accumulation was as great as 35 meq/100 g of dry roots.
Drainage and Nutrient Effects in a Field Lysimeter Study: I. Corn Yield and Soil Conditions
Authors: Lal Rattan , Taylor George S.
Published: July 2010

The effects of constant water table (WT) depths, intermittent flooding, two N and two micronutrient (Zn and Cu) levels on corn (Zea mays L.) yields were studied in field lysimeters containing Miami silt loam soil. Constant WT depths were 15 and 30 cm as compared with no WT. Intermittent flooding treatments were 48‐ and 96‐hour periods of weekly flooding for 3 consecutive weeks. All drainage and nutrient treatments had significant and independent effects on corn grain yields. Application of N, Zn and Cu did not offset the detrimental effects of inadequate drainage. Ear leaf concentrations of N and Zn were more significantly correlated with grain yield at lower levels of N and Zn application than at higher ones. Correlation coefficients between grain yield and soil oxygen and between yield and soil carbon dioxide were 0.68 and −0.63, respectively. Soil temperatures at high WT levels were 5 and 6C lower than in well‐drained lysimeters.
Mössbauer Effect in Clay‐Iron Oxide Complexes
Authors: Yassoglou N. J. , Peterson J. B.
Published: July 2010

Clay‐iron oxide complexes were prepared by precipitating iron oxides on kaolinite and bentonite surfaces in acidic suspensions. Mössbauer spectra of these complexes and of a soil clay separate showed measurable absorption of the 14.4 KeV X‐ray of 57mFe. The effect was attributed to 57Fe nuclei precipitated as oxides on the surface of the clay minerals. An increase in the fraction of the gamma rays absorbed without recoil energy loss was observed upon the association of the iron oxide with clay surfaces. The oxalate treatment affected significantly the symmetry of the electrical field around the iron atoms of the complex. The soil clay separate showed resonance absorption both by ferric and ferrous iron. The results show that the chemistry of iron in the soil and of the clay surface may be successfully studied through Mössbauer spectroscopy.
Sulfur Determination in Soil Extracts by an Indirect Atomic Absorption Spectrophotometric Method
Authors: Galindo G. G. , Appelt H. , Schalscha E. B.
Published: July 2010

Soil‐sulfur in Volcanic‐ash derived soils was determined in soil extracts. The sulfur extracted was transformed into sulfate ions and organic matter destroyed by means of a 30% H2O2 solution. Sulfate ions were precipitated with a 15% BaCl2 solution and the precipitate then dissolved in (NH4)2 EDTA, and Barium determined by Atomic Absorption Spectrophotometry. Sulfur recovery was ascertained using an internal standard.
Measuring Unsaturated Soil Moisture Flow With a Meter
Authors: Cary J. W.
Published: July 2010

A meter for measuring unsaturated soil moisture flow was constructed and tested in the laboratory. The meter was made from a single porous plate mounted in a thin brass cylinder. Flow through the meter was calculated from measurements of hydraulic head loss in the porous ceramic plate. The unit was calibrated in silt loam, silty clay, and loamy sand soils under nonisothermal but steady state conditions. It responded to water vapor flow induced by thermal gradients, as well as to liquid flow. Transient tests made in the silt loam soil indicated that it is possible to calibrate the meter under such conditions. Design analysis indicates that increasing the length of the cylinder reduces the sensitivity of the meter's calibration to changes in soil moisture content.
Effect of the Sol‐Gel Transformation in Clay‐Water Systems on Biological Activity: I. Seed Germination and Bacterial Thermogenesis
Authors: Lee K. W. , Davey B. G. , Low P. F.
Published: July 2010

Gels containing 4, 6 and 8% Na‐ or Na/Al‐clay (Na‐clay with hydrous aluminum oxide impurity) were extruded through a 20‐gauge hypodermic needle into petri dishes. Half of the petri dishes were tapped on the laboratory bench to disturb the gels within them. Then all of the gel surfaces were smoothed with a spatula and lettuce (Lactuca sativa L.) seeds were placed on them. It was found that the lettuce seeds germinated faster on the disturbed gels.

In a second experiment, gels containing 4% Na‐ or Na/Al‐clay were mixed with nutrient medium and inoculated with the bacterium Streptococcus faecalis. Then the inoculated gels were extruded through a 20‐gauge hypodermic needle into pairs of calorimetric cells. Before inserting the cells into the Calvert calorimeter, one member of each pair was tapped to disturb the gel within it. It was found that bacterial heat production was greater in the disturbed gels than in the undisturbed ones.

In a third experiment, Na‐ or Na/Al‐clay sols and gels were mixed with nutrient medium, inoculated and, extruded into pairs of calorimetric cells, as before. This time, neither cell was tapped to disturb its contents. But the concentration of clay in one was different from that in the other. It was found that there was a difference in heat production within the cells when one contained a sol and the other a gel. Other work has shown that a disturbance tends to transform a clay gel to a clay sol. Hence, the present experiments indicate that biological activity is different in a clay gel than in a clay sol.
Zinc, Phosphorus, and Lime Interactions With Yield and Zinc Uptake by Phaseolus Vulgaris
Authors: Melton J. R. , Ellis B. G. , Doll E. C.
Published: July 2010

Three levels of Zn (0, 7.5, and 15 pp2m) were added to each of 20 Michigan soils, which varied in pH and texture, and three successive crops of pea beans (Phaseolus vulgaris L.) var. ‘Sanilac,’ were grown in the greenhouse. Lime was applied to 5 of the 20 soils for the second crop and to 13 soils for the third crop. A heavy P application (500 pp2m P) was made on all soils prior to the second crop. The heavy P application generally induced a greater Zn deficiency on soils testing above pH 7.0 which contained free CaCO3. Pea bean growth was reduced by both Zn deficiency (below 20 ppm Zn in tissue) and toxicity (above 50 ppm Zn in tissue). Yields on the acid soils were generally decreased when Zn was applied; however, liming these same soils could induce Zn deficiency.
Cave Features: Information Concerning the Nature and Genesis of Soils
Authors: Fanning D. S.
Published: July 2010

Information about soils may be obtained from speleology, the study of caves. Some caves are shallow enough for roots of surface plants to be present in them. Cave maps and the distribution of stalactites on cave ceilings show that rock structure strongly controls the pattern of water movement through soil‐rock columns. Relatively pure samples of some secondary minerals, formed at temperatures similar to those in the lower parts of overlying soils, may be obtained from caves. Dolomite seldom forms in caves, but calcite and aragonite are common. Impurities, including quartz, clay minerals, and iron oxides, are present in carbonate speleothems. Many speleothems have repeating growth increments (segments, rings). Some of these may be annual. When understood, they may give clues to, and dramatically portray, seasonal changes in the rate of flow and the composition of percolating waters. Studies of percolating waters from undisturbed soil‐rock columns could be made using caves, but it would be difficult to tell what area and volume of soil and rock contributed to the percolate.
Dust Deposition in Relation to Site, Season, and Climatic Variables
Authors: Smith R. M. , Twiss P. C. , Krauss Roland K. , Brown Merle J.
Published: July 2010

Mean monthly dust deposition into standard traps for 14–37 mo at 14 locally nondusty sites east of the Rocky Mountains ranged from 17–459 kg/ha (15–410 lb/acre). Analyses of variance for 13 sites over 27 mo showed significant differences in dust rates, pH, oxidizable matter, and percent clay for sites and for months.

Some late fall and winter months showed significantly lower rates than late spring and summer. The silt plus sand fraction tended to be lower and the percentages of oxidizables were higher for low deposition rates and eastern sites. pH decreased, generally, from west to east. Grass phytoliths were prominent. Illite and kaolinite were dominant over montmorillonite in clay fractions.

Correlation analyses showed positive relations between dust deposition rates and some power of average monthly wind velocity either near the stations or for western Kansas winds. Rainfall parameters tended to correlate positively with dust catch at most stations and at all stations combined, suggesting that considerable sediment is carried down by rainfall. Deposition rates were positively correlated among sites.

Multiple regression equations for predicting monthly dust deposition, using wind, rainfall, and season parameters, seem useful at several locations.
Dermatitis Caused by Sponge Spicules in Soil
Authors: Stone E. L. , Dawson J. E. , de Zeeuw Carl
Published: July 2010

Sharp pointed sponge spicules occur in certain soil types formed from lacustrine mineral or organic sediments, or from weathered limestones. Occasionally the spicules are sufficiently abundant to cause discomfort and skin rashes in persons exposed to soil contact.
Self‐Diffusion of P in Kaolinite Treated With Ca or NH4 Salts and With an Organic Dye
Authors: Peaslee D. E. , Phillips R. E.
Published: July 2010

Self‐diffusion coefficients of P ranged from 2.9 to 16.4 × 10‐8 cm2 sec‐1 in kaolinite clay that received treatments of salts and differing rates of gallein, an organic dye. The presence of 7.75 me/100 g clay of the NO3‐, Cl‐ or SO42‐ salts of Ca or NH4 significantly decreased the diffusion coefficients of phosphorus from those of the untreated clay. Sulfate decreased the coefficients the least; coefficients in the presence of NO3‐ and Cl‐ were similar, but significantly less than in the presence of SO42‐. The self‐diffusion coefficients in the presence of the Ca‐salts were significantly larger than those in the presence of the NH4‐salts. When up to 5.2 m moles of gallein dye per 100 g of clay were added prior to the addition of P, diffusion coefficients increased in a linear manner. The effect of the dye was somewhat less when added after the addition of the P. The increases and decreases in diffusion coefficients induced by the treatments were reflected in changes in water‐soluble P in the treated clay. Phosphorus was added to the kaolinite clay at the rate of 160 ppm for all treatments of salts and dye.
Effect of Manure Application, Aeration, and Soil pH on Soil Nitrogen Transformations and on Certain Soil Test Values
Authors: Olsen R. J. , Hensler R. F. , Attoe O. J.
Published: July 2010

Nitrate production under aerobic conditions was directly related to rate of manure application, period of incubation, and soil pH but was stopped under anaerobic conditions. Average recovery by chemical analysis of N applied as manure to a Plainfield sand at relatively high rates and incubated for 37 weeks was 77% for aerobic conditions and 24% for anaerobic conditions. The addition of manure tended to increase soil pH and the contents of organic N, available P and exchangeable K, Ca, and Mg, particularly at the higher rates. They also increased the field moisture capacity of a Plainfield sand. However, on an acid Ella loamy sand the two highest rates of manure caused a reduction of the values for field moisture capacity, apparently the result of formation of a waxy material that tended to repel water absorption.
The Use of Gas‐Liquid Chromatography for the Determination of Sugars Extracted from Soils by Sulfuric Acid
Authors: Oades J. M. , Kirkman M. A. , Wagner G. H.
Published: July 2010

A quantitative procedure was developed for the determination of soil sugars by gas‐liquid chromatography of the acetate derivatives of the alditols obtained by reduction of the sugars. Myoinositol or quebrachitol was used as an internal standard during the production of alditol acetates and their separation by gas‐liquid chromatography.

Sugars were isolated from soil hydrolysates by neutralization of the acid and precipitation of the sulfate using strontium carbonate. The filtrates were evaporated to dryness and the sugars extracted using methanol.

The release of monosaccharides from soils using H2SO4 was studied and conditions of hydrolysis are recommended which depend on the nature of the soil and the purpose of the investigation.
Weight Loss on Ignition and K Fixation in Clays
Authors: Davis C. E. , Ahmad N. , Jones Robert L.
Published: July 2010

A significant correlation (r2 = 0.65***) was obtained for K‐fixation and loss on ignition in a number of soil clays of contrasting mineralogy and reference clay minerals when samples treated with K were heated hydrothermally (moisture saturated environment) and by dry heat from 100C to 380C. LOI (loss on ignition) values decreased with increase in temperature from 100C to 380C. At 100C, lower LOI values were obtained by hydrothermal treatment compared to dry heat but this was reversed at 200C. At 380C hydrothermal treatment resulted in lower LOI than dry heat for a high montmorillonite soil low in free Fe2O3, but there was little difference in the treatments for a montmorillonite soil high in free Fe2O3 and for soils rich in kaolinite. Loss on ignition was not markedly affected by the treatments for an illitic soil.

For high montmorillonite soils greater K fixation resulted from dry heat treatment at 100C but at higher temperatures, hydrothermal treatment was more effective. At higher temperatures, the dominantly kaolinite clays fixed more K in response to dry heat. Hydrothermal treatment (380C) was only heat treatment that promoted fixation in an illitic soil.
Evaluation of the Intrinsic‐Penetrability and ‐Diffusivity Concepts To Predict Horizontal Infiltration in Porous Media
Authors: Mustafa M. A. , Letey J. , Watson C. L.
Published: July 2010

The equations λ = λi[(γ/η) cos H]½ and D = Di[(γ/η) cos H] have been presented to describe the effect of surface tension, γ, viscosity, η, and solid‐liquid contact angle, H, on penetrability, λ, and diffusivity D, where λi and Di are the intrinsic penetrability and diffusivity, respectively. The equations were tested by studying horizontal liquid‐infiltration at 2 mbars suction of nine organic liquids and 0.01N CaSO4 in glass beads, Pachappa clay loam, and a water‐repellent soil. The equations were found to describe infiltration quite well for all liquids studied in glass beads and Pachappa soil. The equations apply to organic liquids but not to 0.01N CaSO4 in a water‐repellent soil.
Predicted Distribution of Organic Chemicals in Solution and Adsorbed as a Function of Position and Time for Various Chemical and Soil Properties
Authors: Oddson J. K. , Letey J. , Weeks L. V.
Published: July 2010

Equations were developed to describe the mass transfer of organic chemicals through soil and evaluated for various soil conditions. Movement due to diffusion was assumed to be negligible. The model assumed the relationship ∂S/∂t = α(Kc − S) where S is the adsorbed concentration [mass per total volume], c is solution concentration [mass per total volume], t is time, and K and α are constants. The model also considered the effect of applying various amounts of chemical to the soil surface and allowed for a prior adsorbed concentration in the soil ahead of the wetting front. The following are conclusions drawn for the case when the soil is initially free of organic chemical.

K influences the depth of maximum concentration of organic in solution but does not affect the value of that concentration. The organic chemical will move in solution as a wave through the soil. The lower K the more spread out the wave will be. The depth of movement of maximum concentration is equal to the depth of water penetration divided by K.

The concentration of material adsorbed on the soil also moves down as a wave. The position of maximum adsorbed concentration is about the same as for the maximum concentration in solution. Increasing K causes an increase in concentration of adsorbed material.

Application of greater amounts of organic chemicals to the soil surface has the effect of increasing the concentration of organic both in solution and adsorbed but does not influence the depth of movement greatly except at initial time periods.

Increasing the value of α has the effect of making the wave of chemical moving through the soil narrower and increasing the concentration of the organic in solution as it moves through the profile as compared to a lower value of α.
The Effect of Calcium and Its Relation to Several Cations in Soybean Root Growth
Authors: Lund Zane F.
Published: July 2010

Short‐term, split‐root experiments were conducted in a growth chamber with ‘Lee’ soybeans (Glycine max). The upper portion of the root medium was a limed, fertilized sandy loam surface soil; the lower portion was a nutrient solution. Calcium concentration of 0.25 ppm was sufficient to obtain maximum growth rates in a nutrient solution at pH 5.6. More than 2.5 ppm of Ca was required at a solution pH of 4.5, and 5 ppm of Ca was insufficient when the pH was 4.0. High concentrations of Mg [ratios of Ca/(Ca + Mg) of 0.1 or less] also reduced growth. Replacing half of the Mg with K at low ratios of Ca/total cations produced more rapid elongation than the Ca + Mg systems, but had no effect at the higher ratios. Aluminum in the nutrient solution reduced root growth when the ratio of activities of Al to Ca was greater than 0.02.
Measurement of Water Potential and Osmotic Potential in Soil with a Combined Thermocouple Psychrometer and Salinity Sensor
Authors: Ingvalson R. D. , Oster J. D. , Rawlins S. L. , Hoffman G. J.
Published: July 2010

A combined thermocouple psychrometer and salinity sensor, which is embedded in a single ceramic body, is described. This design makes possible the measurement of the water and osmotic potentials of soil water at the same location in the soil. Errors produced by spatial variations in soil solution concentration, shown to be large, were eliminated by the instrument's ability to make both measurements on a single sample of soil solution. The instrument was tested in a soil‐plant‐water system, and the data obtained are reported. Desaturation of the ceramic at matric potentials more negative than −2 bars was shown to have a significant effect on conductance of the salinity sensor. Correction for this effect is discussed. Measurements showed that cotton plants extracted more water from the less saline zones in the soil. This had the effect of lowering the water potential to approximately the same value at two depths in the soil profile at the end of a drying cycle.
Transformation of Dibasic Calcium Phosphate Dihydrate and Octacalcium Phosphate in Slightly Acid and Alkaline Soils
Authors: Bell L. C. , Black C. A.
Published: July 2010

Chemical, petrographic, and X‐ray diffraction methods were used to investigate the transformation of CaHPO4·2H2O and Ca8H2(PO4)6·5H2O incubated in slightly acid and alkaline soils for 4, 16, and 44 weeks at 25 and 35C. At 25C, hydrolysis of CaHPO4·2H2O to Ca8H2(PO4)6·5H2O was confirmed after 4 weeks in soils having a pH value higher than about 7.9, and at 44 weeks the new phase was found in soils with pH values higher than 6.9. Transformation of CaHPO4·2H2O to Ca8H2(PO4)6·5H2O increased with increasing pH, temperature, and time of incubation but decreased in the presence of much magnesium. There was no evidence of conversion of added Ca8H2(PO4)6·5H2O to more basic phosphates.
Phosphate Forms in Particle Size Separates of Irish Soils in Relation to Drainage and Parent Materials
Authors: Hanley P. K. , Murphy M. D.
Published: July 2010

Particle‐size separates of sand, silt, and clay from 24 representative Irish soils were analyzed for total, inorganic, and organic P (Mehta & Legg), and for forms of inorganic P (Chang & Jackson). In general, all forms of P were highest in the clay fraction and lowest in the sand. The inorganic P of the clays and silts was mainly iron‐P whereas calcium‐P was the dominant form in the sand fraction.

The influence of parent material on the P content of the separates was examined, and it was found that soils of limestone origin had a higher content of calcium‐P in their separates than did those from the shale‐derived soils. The sands of the shale soils contained more total P than the same fraction in the limestone soils.

Drainage also affected the distribution of P. In general, the clays and silts from the well‐drained soils were higher in total P, but total and organic P and the proportion of organic P to total P was higher in the sands of the poorly‐drained soils than in the sands of the well‐drained soils.

A significant negative correlation (−0.61) was obtained between the percent clay in the soil and the total P content of its clay fraction.
Diffusion of Iron in Montmorillonite as Determined by X‐ray Emission
Authors: Ellis J. H. , Phillips R. E. , Barnhisel R. I.
Published: July 2010

The experimental distribution of Fe2+ and Fe3+ diffusing in thin, water‐saturated montmorillonite clay films (43.5% H2O on oven dry basis) were obtained using a miniature‐probe attachment for an x‐ray emission spectrometer; the montmorillonite clay was initially Ca‐saturated. The ionic concentrations were measured in either 0.5‐ or 1.0‐mm intervals from the origin of the diffusing salt giving detailed, experimental distributions of the diffusing ions. The method is sensitive to slight changes of iron concentration resulting in precise determination of experimental distributions. The method should work equally well for diffusion studies involving other ions with atomic numbers greater than Na.

The diffusion coefficient of Fe3+ increased from 1.6 × 10‐7 cm2sec‐1 at a concentration of 0.1 meq Fe3+ per g clay to 4.35 × 10‐7 cm2sec‐1 at a concentration of 1.6 meq Fe3+ per g clay. Diffusion coefficients of Fe2+ were measured at concentrations up to 0.6 meq per g clay. These values were two to five times larger than for Fe3+.
Lime Requirements of Natal Oxisols Based on Exchangeable Aluminum
Authors: Reeve N. G. , Sumner M. E.
Published: July 2010

The exchangeable Al status of eight Natal Oxisols was found to be a suitable criterion for the measurement of lime requirement defined as the amount of lime necessary for maximum crop production. The principal function of lime in these soils was to eliminate Al toxicity; it had little or no effect on P availability. A “critical value” for exchangeable Al below which trudan (Sorghum sudanense) did not respond to lime application was found. On the average the amount of lime necessary for maximum growth and exchangeable Al control was approximately one‐sixth the amount required to raise the soil pH to 6.5.
Effect of Added Phosphate on the Inorganic Phosphorus Fractions of Soils Derived from Volcanic Ash
Authors: Appelt H. , Schalscha E. B.
Published: July 2010

Changes in native and applied phosphate in volcanic‐ashderived soils of southern Chile were investigated. NH4Cl‐, NH4F‐, NaOH‐, and H2SO4‐extractable P were determined both before and after addition and incubation of these soils with 0, 90, 180, and 270 ppm of P. An anion exchange resin method for extracting P from the soil was also used to study relative P availability.

Initially most of the added P was recovered in the NH4F‐extractable fraction. In the course of time a shift to the NaOH‐extractable fraction occurred. The H2SO4‐extractable fraction did not change with rate of P application or time of equilibration. The anion exchange resin was able initially to extract large amounts of the added P, but the quantities extracted diminished markedly with increased time of incubation. The changes that occurred followed a pattern peculiar to each soil.