bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Crop Residue, Soil Temperature, and Sulfur on the Growth of Winter Wheat
Authors: Stewart B. A. , Whitfield C. J.
Published: July 2010

The interrelations of wheat straw, fertility levels, and three soil temperatures on the growth and nutrient status of winter wheat were investigated. When only N and P were added, the decomposition of straw incorporated with the soil immobilized a portion of the available S and caused a reduction in yield. When S was added with the N and P, the incorporation of straw had no effect on yield.

Ratios of total N to total S and protein N to protein S were determined on the wheat tissue. Indications are that a total N/S ratio of these elements can be used as a very good criterion in assessing the S status of plants. A total N/total‐S ratio of about 17:1 or less suggests that S is not limiting, while a greater ratio points out that S is limiting the formation of protein. The N‐S relation in soil organic matter is also discussed in relation to its abilities and limitations in supplying S for plant growth.
Contribution of Adsorbed Cations to Diffusion in Clay‐Water Systems
Authors: van Schaik J. C. , Kemper W. D. , Olsen S. R.
Published: July 2010

Self‐diffusion of sodium and calcium ions was measured in bentonites containing various amounts of water and the respective chlorides. The contribution of mobile exchangeable cations to diffusion was calculated from the data by subtracting measured rates of free electrolyte diffusion from the total rate of self‐diffusion measured in these systems. Mobile exchangeable cations accounted for from 3 to over 500 times as much diffusive movement as was accounted for by free electrolyte cations in these systems. The fractions of the exchangeable cations that were in the diffuse layer were estimated from the contribution of exchangeable ions to diffusion, the fluidity of water near clay particles and the calculated concentration distributions of the adsorbed cations. Approximately 70% of exchangeable sodium ions were mobile. Approximately 25% of exchangeable calcium ions were mobile.
Ureolysis, Immobilization, and Nitrification in Black Spruce (Picea mariana Mill.) Humus
Authors: Roberge M. R. , Knowles R.
Published: July 2010

The transformations of urea in black spruce humus from an untreated plot and from a plot fertilized with 400 lb urea‐N/acre 2 years before sampling were studied using incubation tests. Urea‐N (3,500 ppm) added in the laboratory disappeared within 2 days. During the first 3 days, exchangeable ammonium‐N equivalent to about 82% of the added urea‐N appeared and the pH increased by 1.5 units, but no nitrates were formed. Thereafter, and up to 42 days, there was a very small immobilization of the ammonium‐N and a decrease in pH of approximately 0.5 unit. Nitrification occurred only after 28 days, and then only in the field‐treated humus when urea was again added in the laboratory. The addition of (NH4)2CO3‐N (3,500 ppm) had very similar effects except that a slightly greater rise in pH was accompained by somewhat more immobilization of the ammonium‐N than occurred following the addition of urea.

It is concluded that ureolysis was very rapid; that, in spite of the high C/N ratio, immobilization was small; and that, in most treatments, nitrification was negligible, and therefore leaching of nitrates following the fertilization of acid forest soils with 400 lb urea‐N/acre is not likely to be a problem.
Effect of Nitrogenous and Potassic Salts with Phosphates on the Yield and Phosphorus, Nitrogen, Potassium, and Manganese Contents of Oats (Avena sativa L.)
Authors: Hamilton Herman A.
Published: July 2010

On a neutral Grey Wooded soil receiving identical rates of N, P, and K from different sources, there were significant differences (at the 5% level) in oat grain yields as well as straw yields. The choice of salts used influenced differently the yields of straw and those of grain. Whereas maximum grain yields were realized with monocalcium phosphate monohydrate (MCP) + (NH4)2SO4 + KCl, maximum straw yields were obtained with MCP + (NH4)2SO4 + K2SO4. With diammonium phosphate (DP) as a source of N and P, there were no significant differences in yield of grain or straw with the use of K2SO4 or KCl, however N, P and K uptake by straw was invariably greater with K2SO4 than with KCl. Despite the equivalence of N, P, and K applied, there were considerable differences in the nutrient composition of grain and straw. With the exclusion of the control treatment, N in straw varied from 0.40 to 0.54%, P from 0.021 to 0.046%, K from 3.38 to 3.94%, and Mn from 9.4 to 63.4 ppm. In a comparison of the nitrogenous sources associated with MCP + KCl, Mn uptake was in the order NH4Cl > (NH4)2SO4 > NH4NO2. While the symptoms of Mn deficiency were most pronounced for the control treatment, these symptoms disappeared in all the fertilized treatments excepting MCP + KNO2.
Plant Responses to Oxygen Supply and Physical Resistance in the Root Environment
Authors: Rickman R. W. , Letey J. , Stolzy L. H.
Published: July 2010

Limiting and nonlimiting aeration treatments which were monitored with platinum microelectrodes were applied to soil at two levels of compaction in a greenhouse experiment. Total dry weight of tops and depth of root penetration were used to compare tomato (Lycopersuon esculentum ‘Rutgers’) growth under the various treatments. No difference in top growth was detected between the two levels of compaction when oxygen diffusion rate (ODR) values were nonlimiting in both. Roots penetrated compacted layers in which ODR values were non‐limiting but their rate of extension was slower than in less compacted layers with nonlimiting ODR. Top growth in soils with low ODR values was reduced regardless of compaction. Root extension in the least compacted soil with low ODR values was less than root extension in that soil with high ODR values.
Electrochemical Determination of Diffusion Coefficients in Clay‐Water Systems
Authors: Mokady Raphael S. , Low Philip F.
Published: July 2010

Pastes containing different concentrations of MCl (M = Li or Na) were prepared by mixing MCl olutions with M‐montmorillonites. The pastes were used in pairs in which the members differed only in NaCl activity. Initially, a Ag‐AgCl electrode and an M‐sensitive glass electrode were inserted into each paste and the emf between them was measured. Then the members of each pair were brought into contact with Ag‐AgCl electrodes inserted in them. The emf's between the latter electrodes were also measured. From the two kinds of emf measurements the transference numbers of the ions in the different pairs were calculated. These transference numbers, along with the measured electrical conductances of the pastes, were used to calculate the ionic mobilities. Finally, the calculated ionic mobilities and the known ionic concentrations were inserted in the Nernst equation to calculate the diffusion coefficients of the respective salts
Volumetric Calibration of Neutron Moisture Probes
Authors: Douglass James E.
Published: July 2010

A volumetric method of estimating the slope (b coefficient) of a neutron moisture probe calibration curve is discussed. Coefficients obtained for three probes by this method did not differ significantly between soil series or between horizons within a series. Simply dividing the count rate in water by 100 gave a value virtually identical to the b coefficient determined volumetrically for these probes and soils. Agreement was excellent between measured outflow and outflow predicted from neutron measurements made with a volumetrically calibrated moisture probe.
Kinetics of Cesium Sorption by Clay Minerals
Authors: Sawhney B. L.
Published: July 2010

Time course and the processes in the sorption of cesium from dilute solutions by illite, montmorillonite and vermiculite saturated with Ca or K and in the absence of excess saturating cation were investigated.

Cesium sorbed by illite and montmorillonite quickly reached an approximate equilibrium; the Cs sorbed by montmorillonite did not change with time while the Cs sorbed by illite changed only slightly. On the other hand, the Cs sorbed by vermiculite did not reach an equilibrium even after 500 hr. Cesium sorbed by Ca‐vermiculite continued to increase while the Cs sorbed by K‐vermiculite decreased.

Since the sorption of Cs by illite is limited to the external planar surfaces and interlattice edges only, equilibrium is quickly reached. Equilibrium in montmorillonite is attributed to its expanded lattice which makes all exchange sites equally available and permits exchange readily. The increased Cs sorption by Ca‐vermiculite, on the other hand, is attributed to the different sorption rates by different exchange sites: initial fast sorption on external surfaces and edges followed by slow diffusion into the interlayers. The decreased Cs sorption by K‐vermiculite is perhaps associated with the collapse of the partially hydrated vermiculite in suspension to 10A.
Phosphorus Supplying Capacity of Lowland Rice Soils
Authors: DeDatta S. K. , Moomaw J. C. , Racho V. V. , Simsiman G. V.
Published: July 2010

In a greenhouse experiment with rice (Oryza sativa L.) on four lowland soils, Milfor 6(2), an indica variety from the Philippines, was used to test the relative utilization of soil and fertilizer P (P32‐labelled superphosphate) at various N rates. Added P remaining in solution in six soils was also determined using Ca (H2P32O4)2 at various equilibration times.

From 8 to 27% of the total P in the plant was derived from applied P, the amount presumably depending on the availability of soil P under continuous submergence. In general the amount derived was not affected by different levels of N fertilization. The results indicate that, by using the ‘A’ value concept, the rice plant itself gives an indication of the P supplying capacity of some flooded rice soils. Results also show that within 4 days of equilibration the added P remaining in solution was lowest in acid latosolic soils containing kaolin type minerals, moderately high in soils containing mainly montmorillonite, and essentially unaltered in calcareous soil.
Adsorption‐flocculation Reactions of Soil Polysaccharides with Kaolinite
Authors: Saini G. R. , MacLean A. A.
Published: July 2010

The adsorption of a soil polysaccharide by kaolinite saturated with different exchange cations was determined with polysaccharide tagged with C14. Adsorption followed the Langmiur equation. Adsorption increased with exchange cations with the effect of Fe3+ > Al3+ > H+ > Ca2+ > Mg2+ > Na+.

Filtration rates of kaolinite were also increased by saturating with different cations with the effect of Fe3+ > Al3+ > H+ Ca3+, Mg2+ > Na+. In a dispersed system, filtration rates increased with successive additions of polysaccharide and then decreased.

It is suggested that a segment rather than the whole polysaccharide molecule competed with the solvent molecule for surface sites whereby a fraction of the total segments was adsorbed and the remaining segments protruding from he interface were attached to free surface on an adjacent soild particle. With subsequent additions of polysaccharide, it is suggested that conditions were created whereby there was insufficient free surface for bridging or possibly the extended segments interfered physically with one another and prevented bridge formation.
Hydration Status of Adsorbed Cations
Authors: Shainberg I. , Kemper W. D.
Published: July 2010

Energies with which cations adsorb water molecules are calulated and discussed. An amendment to the diffuse layer theory is developed which takes into consideration the hydration energy of the ions, position of the negative charge in the clay, and other steric factors. Calculations using this amended theory predict differences in the adsorption characteristics of Li+, Na,+ and K+ which appear to be in general agreement with experimental observations.

Calculations for the interacting diffuse layer case indicate that the fraction of the adsorbed ions residing in the first molecular layer of water (Stern Layer) is essentially independent of distance between the platelets when this distance is greater than 2.5A. Pushing the platelets closer together results in a arger portion of the adsorbed ions in the Stern Layer.

The various assumptions and estimates involved in the development of the theory and the calculations are discussed.
Micronutrient Cation Complexing in Soil Solution: II. Complexing of Zinc and Copper in Displaced Solution from Calcareous Soils
Authors: Hodgson J. F. , Lindsay W. L. , Trierweiler J. F.
Published: July 2010

Zinc deficiencies are generally more widespread on calcareous soils than are Cu deficiencies. The concentration and the degree of complexing of Zn and Cu were measured in the soil solution of 20 calcareous soils from Colorado. The Zn levels in solution were generally less than 2 ppb with rarely more than 75% of the Zn being complexed. Copper levels generally ranged from 5 to 16 ppb in the soil solution with 98 to 99% of the Cu present as organic complexes. Thus, complexing increased the total Cu concentration in solution by a factor of about 100, whereas it increased the total Zn in solution by a factor of 4 or less. Compared to acid soils studied previously, soluble Zn levels were much lower and complexing of Cu was somewhat higher in calcareous soils.
Effect of Surface‐Applied Wheat Straw on Soil Water Losses by Solar Distillation
Authors: Greb B. W.
Published: July 2010

Soil surface application of 1,120, 2,240, and 3,360 kg/ha of wheat straw (Triticum aestivium L,), equivalent to 30, 60, and 90% soil surface coverage, reduced water losses from a wet soil surface by solar distillation 16, 33, and 49%, respectively, for a 20‐day period compared with no straw. A surface application of 6,720 kg/ha, or 180% soil coverage, reduced soil water loss only slightly more than did the 3,360 kg/ha application. Water losses and effectiveness of straw tended to diminish with time as soil water was depleted. The presence of clear plastic canopy increased daily soil temperature maximums at 2.5‐cm depth by approximately 11.5F. Maximum daily soil temperatures, both with and without plastic, were reduced nearly 3 F/1,120 kg per ha of added straw. The results suggest part of the mechanism by which more soil water is conserved under stubble mulch summer fallow than with clean fallow.
A Technique for Rapid and Precise Positioning of Neutron Depth Probes
Authors: MacGillivray N. A. , Goldberg Irving
Published: July 2010

A device is described which replaces the standard cable clamp used for positioning of neutron depth probes. With the technique developed, positioning is accomplished by suspending he probe from brass stops affixed to the cable.

Several years experience have demonstrated this technique to be entirely satisfactory, resulting in improvement in precision of probe positioning, as well as in a considerable saving of time.
Influence of Soil Conditioners on Infiltration and Water Movement in Soils
Authors: Kijne J. W.
Published: July 2010

The infiltration of water at 2mbar suction into horizontal columns of two soil materials of different textures was studied. The columns had been treated with two soil conditioners, Krilium and poly(vinyl alcohol). The soil‐water diffusivities were calculated from the water content distribution data. Treatment of a clay loam with the soil conditioners caused 1.5‐fold to 3‐fold increases in soil‐water diffusivity over the whole range of volumetric water contents. When expressed as a function of soil water potential, soil‐water diffusivity increased by this treatment more than 10‐fold at the lower soil‐water potentials. The same treatment had far less effect on the soil‐water diffusivity of a loamy sand. For both soils the rate of movement of the wetting front increased as a result of treatment with the soil conditioners.

The calculated mean diffusivity and rate of movement of the wetting front in these soils was greater for n‐heptane than for water. The intrinsic diffusivity and penetrability differed for the two permeants. Changes in viscosity, surface tension, and apparent contact angle did not account fully for this dependence of diffusivity and penetrability on the permeating liquid.
Determination of Clay Surface Acidity by Infrared Spectroscopy
Authors: Harter Robert D. , Ahlrichs James L.
Published: July 2010

A new and simple method for estimating pH at the surface of colloidal particles has been devised. By use of infrared spectroscopy the effect that proximity to a colloidal surface has on an organic acid molecule can be ascertained. An intensity ratio of the carboxylate to carbonyl infrared absorption bands (1,550 to 1,610 cm‐1 and 1,690 to 1,760 cm‐1, respectively) of organic acids can be used as an indicator of hydrogen ion activity in the compound's environment. Benzoic acid seems to be the best choice for this type of study, since it is not adsorbed by the clay surface in the presence of water. The surface of Wyoming bentonite seems to be about 100 times more acid than the solution at a pH of about 7.0. As the pH decreases, there is a decreasing difference between surface and solution pH.
Factors Affecting Urea Hydrolysis and Ammonia Volatilization in Soil
Authors: Overrein L. N. , Moe P. G.
Published: July 2010

Laboratory incubation experiments were conducted to determine the effect of rate and depth of urea application and the rate of soil aeration on rates of urea hydrolysis and ammonia volatilization occurring with soils taken from the surface horizons of Chalmers silt loam and Plainfield sand.

Measurements were also made of the effect of urea hydrolysis on the pH of undisturbed soil in the immediate zone of urea application. The rate of urea hydrolysis was shown to be directly proportional to the rate of urea application when soils were incubated at 28C. Ammonia volatilization rates increased at an exponential rate as rates of urea application were increased. This resulted in a larger proportion of the added urea nitrogen being lost from the soil through ammonia volatilization at the higher rates of urea application. Ammonia volatilization rates were inversely proportional to the depth of urea application and decreased more rapidly with depth in wet soil than in moist soil. The pH of Chalmers soil in the zone of urea application attained a maximum pH of 8.8 with both 224 and 896 kg/ha (200 and 800 lb/acre) applications of urea nitrogen. Soils receiving a heavy surface application of urea maintained a high pH throughout a 4‐week incubation period. Soil aeration rate had no significant effect on rates of urea hydrolysis, but ammonia volatilization rates increased as the gas exchange rate in the soil increased.
Water Consumpton by Phaseolus Vulgaris and Zea Mays as Influenced by Manganese Fertilization
Authors: Kozakiewicz Aleksander , Ellis B. G.
Published: July 2010

In a greenhouse experiment using a Houghton muck soi fertilization with Mn, either with or without liming, increased the efficiency of water utilization by both pea beans (Phaseolus vulgarus) and corn (Zea mays). Where the deficiency was mild (14% increase in dry weight due to use of Mn), the larger Mn treated pea bean plants used less total water in 35 days than did smaller untreated plants.
Salt Displacement of Acid‐Treated Trioctahedral Vermiculites
Authors: Kaddah Malek T. , Coleman N. T.
Published: July 2010

Freshly prepared and 30‐day‐aged samples of HCl‐treated trioctahedral vermiculites from Libby, Montana (L) and northeastern Transvaal, South Africa (S) were leached with 1N or more dilute solutions of NaCl, KCl, CaCl2, or MgCl2. The exchange acidity, exchangeable H3O, Al, and Mg, and the cation‐exchange capacity after acid‐salt treatment were determined.

With both the L and S minerals, the sum of the salt‐displaceable ions after acid treatment corresponded to approximately 90% of the initial CEC. For freshly acidified materials, the exchange acidity (consisting of displaced H3O and Al ions) comprised the bulk of the exchangeable ions. After 30 days of aging in water at room temperature, exchange acidity had decreased by around one‐half, and equivalent amounts of exchangeable Mg had appeared.

The most striking findings concerned: (i) differences between the two minerals with regard to the amounts of H3O and Al displaced by salts, and (ii) differences in displaced H3O and Al depending on the exchanging cation and the concentration of the displacing solution. The exchange acidity from fresh HCl‐treated S vermiculite consisted of about 60% H3O and 40% Al when 1N NaCl, CaCl2, or MgCl2 was the displacing salt. For L vermiculite, titratable acidity displaced by 1N NaCl, CaCl2, or MgCl2 was around three‐fourths Al. For both minerals, exchange acidity measured with 1N or 0.05N KCl, 0.05N NaCl, or 0.02N CaCl2 or MgCl2 was almost entirely H3O.

X‐ray patterns of K‐saturated, acidified samples showed interlayer deposits and reduced collapsibility when the samples were leached with KCl. There were virtually no indications of interlayer material when the samples were leached with 1N CaCl2 before KCl.
Determination of Organic Carbon and Carbonates in Soils
Authors: Anderson J. U. , Harris W.
Published: July 2010

Procedure and apparatus for determining organic and inorganic carbon in soils are described. The digestion acids used differ from those used in common practice in containing no H2SO4.

Sulfate interference was shown to prevent complete digestion of carbonates in a system containing H2SO4.

The procedure described is accurate for carbonates and for organic compounds as difficult to oxidize as benzoic acid. The time required for one determination of organic carbon is 30 min; that for inorganic carbon is 22 min.
A Simple Technique for Preparing and Maintaining Sterile Soils for Plant Studies
Authors: Bartlett R. J. , Zelazny L. W.
Published: July 2010

The proposed method depends upon the antimycotic activity of propylene oxide and the permeability of polyethylene. Inside a warmed pressure cooker, the epoxide diffuses rapidly through a plastic bag, sterilizing the moist soil contained. Release of pressure reverses diffusion. Detoxication is completed under vacuum at 45C. The bag then serves as a chamber for the storage of sterile soil or for the sterile culture of plants.
Thermal Properties of a Pumice Soil
Authors: Cochran P. H. , Boersma L. , Youngberg C. T.
Published: July 2010

Dacite pumice materials deposited by the eruption of Mount Mazama cover a land area for as much as 161 km (100 miles) north and east of Crater Lake, Oregon. Frequent night frosts occur in this region. Thermal properties of the pumice material were investigated to determine their affect on the occurrence of low temperatures in the area and thus gain a better understanding of the factors governing the distribution of lodgepole (Pinus contorta Dougl.) and ponderosa pine (Pinus ponderosa Laws). Thermal conductivities were determined experimentally with a line heat source and calculated theoretically. The theoretical calculations were based on methods which take into account the volume fractions of solid, air, and water of the pumice and the thermal conductivity of each one of these components. The thermal conductivities of dacite pumice were found to be very low, which may account for the frequent occurrence of night frost in this region.
Cation Exchange Capacity Variations with pH in Soil Clays
Authors: de Villiers J. M. , Jackson M. L.
Published: July 2010

Soil clays containing pedogenically chloritized 2:1 layer silicates, after brief contact at 25C with 2% Na2CO3 (pH 11), developed a proportionately large increment of CEC which was retained after thorough washing with neutral salts (KCl, NaCl) to reduce the pH value below 7. A soil clay from Natal, S. Africa showed the largest increase—from 2.4 meq/100 g at pH 5 to 8.0 meq/100 g after alkaline and KCl treatments. This CEC hysteresis or delta value largely disappeared when washing with a NaOAc buffer of pH 5 followed the alkaline treatment. Similar effects were absent from specimen kaolinite, montmorillonite, and vermiculite. The presence of aluminous, pedogenic chlorite was shown, by X‐ray and analytical investigation, to be a common property of the soil clays exhibiting pH dependent CEC. This finding is supported by separate studies on synthetic aluminous chlorite, which showed variable CEC properties essentially identical to those of these soil clays. Release of the initially blocked isomorphous substitutional negative charge by deprotonation of the positive hydroxy alumina in aluminated soils, clays and allophane is the indicated mechanism accounting for pH dependent, hysteretic CEC charge of the mineral portion of soils.
Changes in Exchangeable Potassium Observed on Drying Soils after Treatment with Organic Compounds: II. Reversion
Authors: Scott A. D. , Bates T. E.
Published: July 2010

Undried samples of Marshall subsoil that contained 27 ppm exchangeable (NH4OAc extractable) K were dried to release K and then treated in various ways to maximize K reversion. This was done to determine the possibility of reducing the exchangeable K in dried soil to the level of the undried soil and, thus, of using dry samples with released K to estimate the amount of exchangeable K that was present in the soil before drying.

Much of the desired K reversion was attained by simply rewetting the dry soil. The rate and amount of this decrease in exchangeable K was enhanced by heating the rewet soil, but even so, the minimum values attained with rewet samples of air‐dry and oven‐dry soil were 54 and 62 ppm K, respectively. For complete reversion, it was necessary to mix the rewet soil with organic compounds and then oven‐dry the mixture.

A decrease in exchangeable K was attained by drying the rewet soil, provided organic additives were present to prevent a release of K. Thus, the effects observed with various organic additives varied with the degree to which the additives were retained in the sample while the water was removed. Additions of high‐boiling‐point, normal alcohols; rewetting with a minimum of water; and slow drying gave the best results. When 10‐g samples of oven‐dry soil with 210 ppm exchangeable K were rewet with 7 ml of water, mixed with 7 ml of octanol and dried at 110C for 48 hours in a gravity‐draft oven, there was only 30 ppm exchangeable K present. Oven drying did not enhance K reversion when sucrose or glycerol was present.
Density Errors for Soltrol‐Tygon Systems
Authors: King L. G.
Published: July 2010

Several investigators have used Soltrol as a liquid for laboratory studies of flow through porous media. It is shown in this note that Soltrol can react with Tygon and possibly other flexible plastic tubing by dissolving the plasticizers from the tubing walls. This reaction increases the density of the Soltrol by as much as 2 to 4% and may cause significant errors in data being collected.
The Method of Mehta et al. Modified for Determination of Organic Phosphorus in Soils High in Extractable Iron
Authors: Bornemisza E. , Vieira L. S. , Igue K.
Published: July 2010

A modification is proposed for the Mehta et al. organic phosphorus determination for soils high in free iron where a strong interference by the dissolved iron occurs in the colorimetric determination of total and inorganic phosphorus. This interference can be eliminated by passing the extracts through a strong acid cation exchange resin which removes the interfering ions.
Determination of Magnesium in HCl Solutions of HF‐HClO4 Digests of Soil Clays by Atomic Absorption Spectroscopy
Authors: Protz R. , DeKalb E. , Riecken F. F.
Published: July 2010

Interferences to the determination of Mg in HCl solutions of HF‐HClO4 digests of soil clays by atomic absorption spectroscopy were suppressed by 4,000 ppm Sr. Recovery of Mg added to digests ranged from 96 to 106%. Duplicate clay samples of 110 soils were taken from soil suspensions on successive days. The Mg content of these samples ranged from 0.74 to 1.61%. The mean deviation between duplicates was 0.03%, with a range of 0.00 to 0.10%. A rapid method for Mg determination in soil clays by atomic absorption spectroscopy is proposed.
Contributions of Soil Factors to Lime Requirement and Lime Requirement Tests
Authors: Pionke H. B. , Corey R. B. , Schulte E. E.
Published: July 2010

One hundred and twenty‐seven soils were examined for relationships existing between lime requirement and the pH‐dependent sites on organic matter and clay as well as “acidic Al.” The ranking of soil properties as predictors of the CaCO3‐equilibrated lime requirement followed the order: pH‐dependent sites on organic matter > nonexchangeable acidic Al > exchangeable Al ≥ pH‐dependent sites on clay. This relationship is defined by the following equation which accounts for 89.5% of the observed variability of lime requirement as determined by neutralization with CaCO3 to pH 6.0 in N KCl: LR (meq/100g) = 0.47 + 0.97 ΔpH(KCl) × % OM + 0.03 ΔpH(KCl) × % clay + 1.73 exchangeable Al + 0.53 non‐exchangeable acidic Al.

A number of the more commonly used lime requirement tests were evaluated as predictors of the CaCO3‐equilibrated lime requirement. Of these tests, the buffer methods were found to be superior to the ΔpH × % organic matter function and base unsaturation, which in turn were decidedly superior to percent base saturation for predicting soil lime requirement. The Shoemaker, McLean, and Pratt buffer was found to be somewhat better than the Woodruff buffer for measuring lime requirement, apparently because of its greater sensitivity to “acidic Al.”
Transport in Soils: The Balance of Mass
Authors: Raats P. A. C. , Klute A.
Published: July 2010

A treatment of transport in soils, based upon a continuum theory of mixtures, is proposed. Some of the general features of this continuum theory of mixtures and of its application to soils are discussed. A soil is regarded as a mixture of phases, e.g., an unsaturated soil is regarded as a mixture of a solid phase, an aqueous phase, and a gaseous phase. The idea of balance of mass is considered in some detail, in particular in relation to deformable soils. The integral balance of mass for a certain phase over a certain volume is formulated. From the integral balance of mass differential forms are deduced. The balance of mass for water in a deformable soil is derived. It is shown that under special circumstances this balance of mass reduces to special forms that appear in the literature.
A Comparison of Injected Anhydrous Ammonia into Bermudagrass Sod Compared to Topdressed Applications of Urea and Ammonium Nitrate
Authors: Hill W. E. , Tucker B. B.
Published: July 2010

Soil fertility experiments, primarily concerned with the evaluation of anhydrous NH3 as a source of N for bermudagrass, Cynodon dactylon (L.), when applied with the rolling coulter‐type applicator, were conducted on Parsons silt loam and Port sandy loam soils. Two factorial treatment combinations were used. The first consisted of four rates of N applied as (NH2)2CO, NH4NO3 and anhydrous NH3. The second consisted of complete factorial combinations of four rates of N as anhydrous NH3 and three spacings of the NH3 applicator knife.

In general, yields were equal for all sources and all clippings at lower rates of N application. At the higher rates of N application, anhydrous NH3 produced lower yields in the first clipping and higher yields in succeeding clippings. This lag in response from anhydrous NH3 was attributed to sod burn from escaping ammonia. Reducing the applicator knife spacing tended to increase NH3 retention, decrease the sod burn, and increase the NH3 efficiency at the high rates of N application.
Ketone Adsorption on Montmorillonite
Authors: Parfitt R. L. , Mortland M. M.
Published: July 2010

Ketone adsorption by montmorillonite was found to be greatly influenced by the nature of the exchangeable cation. Mechanisms of bonding included (i) direct ion‐dipole interaction of the carbonyl with the ion in cases where the ion had a low hydration energy or where special treatments were used to dehydrate the ion; (ii) outer sphere coordination to the metal ion by bridging through directly coordinated water molecules; (iii) formation of electrovalent bonds through proton donation by 2,4 pentanedione to the clay saturated with Al or Cu ions to form the acetylacetonates of these ions.
Soil Genesis Study of a Lithologic Discontinuity in Glacial Drift in Western Wisconsin
Authors: Foss J. E. , Rust R. H.
Published: July 2010

A study was made of soils developed in superposed parent materials in St. Croix and Pierce counties, Wisconsin. A typical stratigraphic sequence in this area consists of: (i) post‐Cary loess, (ii) Cary till or mixed zone (14,000 years B.P.), (iii) Rockian till (30,000 years B.P.), and (iv) Paleozoic sedimentary rocks. The Cary drift is thin over much of the uplands in this area; thus, current soil profiles are developed in both the Cary and Rockian drifts. Morphological data indicate the presence of a paleosol on the Rockian till. This was substantiated by various physical, chemical, and mineralogical analyses. Characteristics of the paleosol include the accumulation of clay in the B horizon, translocated iron, and a strongly leached solum. The CaO/ZrO2 and Fe2O3/ZrO2 molar ratios of selected size fractions also indicate a weathering interval between deposition of the Cary and Rockian sediments. Clay‐mineral analyses showed variation in lithology and weathering of the drifts.
Chlorinated Insecticides in Runoff Water as Affected by Crop Rotation
Authors: Epstein E. , Grant W. J.
Published: July 2010

The concentration and amounts of three chlorinated insecticides were lower in runoff from a rotation system of potato (Solanum tuberosum L.), oats (Avena sativa L.), and sod, than under continuous potato cropping. Runoff samples from natural runoff plots were collected following each storm, and the amounts of DDT, endrin, and endosulfan were analyzed with a gas chromatograph.

The amounts of pesticides in runoff were small compared to the amount applied. The concentrations of the insecticides in the runoff (soil‐water suspension) were generally greater than those found in the settled soil (sludge).
Determination of Silica in Citrate‐Bicarbonate‐Dithionite Extracts of Soils
Authors: Weaver R. M. , Syers J. K. , Jackson M. L.
Published: July 2010

A procedure was developed for the determination of Si directly in citrate‐dithionite extracts of soils. The procedure, which provides for noninterference by citrate, dithionite, Fe, and P was developed for measurement of the absorbance of the reduced β‐molybdosilicic acid in the working range of 5 to 25 µg of Si in 50 ml. Interference by unoxidized dithionite was eliminated by bubbling air through the extract. The interference by citrate was prevented by an excess of molybdate; that by Fe and P by tartaric acid addition.

The citrate‐dithionite treatment released, per gram of soil, 3 to 174 mg of Fe2O3, 0.8 to 42 mg of Al2O3, and 0.1 to 3.8 mg Si(OH)4. The water‐soluble silica ranged from 0 to 26 µg of Si(OH)4 per ml of solution before removal of reductantsoluble Fe2O3 and Al2O3; it increased into the range of 5 to 58 after removal. At any given pH of Henry soil (in the pH range of 4 to 7), the water‐soluble silica increased markedly as a result of previous citrate‐bicarbonate‐dithionite extraction. The release of Fe, Al, and Si that occurred with the various soils on reduction indicates a possible mechanism by which these constituents may increase sufficiently to support the well‐known formation of montmorillonite from soluble and alluviated materials moved into positions of slow drainage. These constituents in solution would also favor preservation of any montmorillonite present in soil parent materials.
Desorption of Phosphate from Kaolinite by Citrate and Bicarbonate
Authors: Nagarajah S. , Posner A. M. , Quirk J. P.
Published: July 2010

Phosphate which cannot be desorbed from kaolinite by chloride at the same pH and ionic strength at which adsorption took place is significantly desorbed by citrate and bicarbonate.

In the presence of citrate or bicarbonate, phosphate adsorption by kaolinite is reduced. The extent of reduction depends on the way in which phosphate and citrate or bicarbonate are added to the clay. Maximum reduction in phosphate adsorption occurs when phosphate and citrate or bicarbonate are added together or when phosphate is introduced after citrate or bicarbonate adsorption.

These effects are attributed to the fact that mole for mole exchange between phosphate and the other anion does not occur. The reduction in phosphate adsorption results not only from competition but also from a concomitant change in charge.
Manganese Uptake Attributed to Diffusion from Soil
Authors: Halstead E. H. , Barber S. A.
Published: July 2010

An investigation of the rate of self‐diffusion of 54Mn in 6 soils gave apparent diffusion coefficients that varied from 0.33 × 10‐7 to 2.20 × 10‐7 cm2 sec‐1.

Uptake studies with corn seedlings gave a high correlation between Mn uptake and the calculated Mn reaching the root by diffusion. Calculation of the concentration gradient necessary to satisfy the Mn uptake rate by diffusion indicated that the Mn concentration at the root surface was only reduced about 5%.
Relationship of Zinc Uptake by Corn and Sorghum to Soil Zinc Measured by Three Extractants
Authors: Wear John I. , Evans Clyde E.
Published: July 2010

Corn (Zea mays L.) and sorghum (Sorghum vulgare Pers.) plants were grown in a controlled environmental growth chamber in 12 medium‐ to coarse‐textured soils with two levels of Zn for each soil. These levels were the native amount in each soil and with 2.5 ppm added. After 4 weeks plants were harvested and Zn concentration and total Zn uptake were measured. Each soil was extracted with three different solutions: (i) 0.05N HCl plus 0.025N H2SO4, (ii) 0.1N HCl, and (iii) 0.05N EDTA at pH 7.0. Zinc uptake by the plants was correlated with the level of soil Zn determined by each extractant. The highest correlation was obtained for corn and sorghum with extractant (i). Correlation coefficients for corn for extractants (i), (ii), and (iii) were 0.89, 0.82, and 0.62, respectively. Correlation coefficients for sorghum for extractants (i), (ii), and (iii) were 0.70, 0.63, and 0.44, respectively.
Pedogenic and Geomorphic Relationships of Associated Aqualfs, Albolls, and Xerolls in Western Oregon
Authors: Parsons R. B. , Simonson G. H. , Balster C. A.
Published: July 2010

The distribution of Willamette, Woodburn, Amity, Concord, Holcomb, and Dayton soils is related to deposits and geomorphology of the main floor of the Willamette Valley. Claytextured alluvium was the parent material for the formation of Dayton, Concord, and Holcomb B horizons. Amity soils occur on low knolls where clay was not deposited. Willamette, Woodburn, and Holcomb soils have thick Al horizons partly as a product of overbank alluvial deposition along natural levees.

Soil formation has resulted in organic accumulation, base eluviation, iron and manganese segregation into concretions, and argillic horizons. The soils contain one or more discontinuities and have not been derived from the weathering in place of “Willamette Silts” as previously reported. Chemical properties may reflect initial differences in the parent materials as well as subsequent soil development.
Detection of Saturated Interflow in Soils with Piezometers
Authors: Betson R. P. , Marius J. B. , Joyce R. T.
Published: July 2010

Piezometers were used as saturated interflow detection devices in a study of partial watershed contribution to storm runoff. Saturated interflow was detected along the AB‐horizon interface in clay loam soils with shallow A horizons. The results of the study showed that at least under some soil conditions piezometers can be useful in determining the extent of saturated flow within a watershed. The occurrence of this flow will normally be confined to the shallow A‐horizon regions.
Effects of Organic Matter, Flooding Time, and Temperature on the Dissolution of Iron and Manganese from Soil in situ
Authors: Meek B. D. , MacKenzie A. J. , Grass L. B.
Published: July 2010

A field plot study was conducted to determine the effects of added alfalfa, four flooding times, and two temperatures on EH (Oxidation‐reduction potential) and dissolution of iron and manganese from a silty clay soil. With no alfalfa added, flooding caused only a small decrease in EH at either temperature. The addition of alfalfa at the higher temperature resulted in a reduction in EH to −100 millivolts. Flooding time had no significant effect on EH until the third day, when the soils subjected to shorter flooding periods began to dry out. Flooding without organic matter increased the Mn2+ and Fe2+ concentrations in solution to maxima of only 3.7 and 2.1 ppm, respectively; while the combination of flooding, organic matter and high temperature increased the levels to 46 and 30 ppm. Flooding time had no effect on the dissolution of iron and manganese. The results of this study show the importance of temperature and organic matter on dissolution of iron and manganese and the relation between EH and soluble iron and manganese.
Determination of Organochlorine Insecticides in Soils and Waters
Authors: Pionke H. B. , Chesters G.
Published: July 2010

Pertinent references on the determination of organochloride insecticides in soil and water samples are reviewed. The particular methods are chosen because of their applicability to heterogeneous systems which often provide problems due to coextraction of indigenous components. The review is divided into three principal sections, i.e., extraction of organochlorine insecticides from soils and waters, cleanup of soil and water extracts, and analysis of purified soil and water extracts. Criteria used in evaluating extraction procedures were based on methods of equilibrating the insecticide with the soil sample and the control of possible insecticide losses through degradation and volatilization. In the section on cleanup procedures special attention is devoted to chromatographic methods, particularly column and thin‐layer chromatography. A large portion of the methods of final analysis of purified extracts is given over to gas‐liquid chromatographic techniques because of the preponderance of its use for insecticide determination. The gas‐liquid chromatographic methods are discussed on the basis of peak resolution, detection and measurement of the insecticides, and confirmation of their identity. Thin‐layer chromatographic, spectrophotometric, and other methods of determination of organochlorine insecticides in purified extracts are evaluated.
Cation Exchange Selectivity of Some Clay‐Sized Minerals and Soil Materials
Authors: Dolcater D. L. , Lotse E. G. , Syers J. K. , Jackson M. L.
Published: July 2010

Cation exchange selectivity (CES) values for montmorillonite, vermiculite, biotite, muscovite, and micaceous vermiculitic clays from Triangle and Harpster soils were determined by equilibration of each exchanger with a mixed, equinormal solution containing two competing cations. The cation affinity of Na‐saturated materials increased in the order K < Mg < Ca < Sr < Ba for montmorillonite and the soil clays, Mg < K < Ca < Sr < Ba for biotite, Mg < Ca < Sr < K < Ba for muscovite, and K < Ba < Sr < Ca < Mg for vermiculite. Sodium‐saturated micaceous vermiculite gave a K/Ca CES value of 0.2, whereas K‐saturated, dried vermiculite gave a K/Ca CES value of 0.4, indicating that the large number of interlayer wedge sites produced by the structural collapse in K‐saturated and dried vermiculite increased the selectivity for K ions. Potassium‐saturated and dried muscovite having a CEC equal to the similarly treated vermiculite gave a K/Ca CES value of 4.0 compared to 0.4 for the vermiculite, suggesting that layer charge density has a large influence upon K selectivity. The higher CES values for muscovite relative to those for biotite are explained by the smaller ditrigonal holes and the oblique orientation of hydroxyl groups in the muscovite structure.
Canopy Drip: A Source of Mobile Soil Organic Matter for Mobilization of Iron and Aluminum
Authors: Malcolm R. L. , McCracken R. J.
Published: July 2010

Leaf leachates, simulating canopy drip during rainfall, were collected from southern red oak (Quercus falcata var. pagodaefoliz Ell.), live oak (Quercus virginiana Mill.), and longleaf pine (Pinus palustris Mill.), which were the principal tree species growing on soils with spodic horizons on the North Carolina Coastal Plain near Ft. Caswell. The samples of canopy drip were immediately chilled, filtered, and freeze‐dried. From the representative canopy drip sampled it was estimated that approximately 20 kg/ha per year of organic matter could be contributed to the soil from this source. In the laboratory, 139 to 1,480µ moles of Fe or 460 to 1,450µ moles of Al/g of freeze‐dried canopy drip were complexed from nitrate salt solutions depending on the concentration of the leachate solution. This amounts to a possible field mobilization of 0.15–1.53 and 0.22–0.70 kg/ha per year of Fe or Al, respectively.

The active components responsible for Fe and Al mobilization were determined to be polyphenols, reducing sugars, and organic acids. Paper chromatograms and reducing‐sugar analyses indicated that the polyphenol and reducing‐sugar contributions to soil as canopy drip were approximately 1 kg and 4kg/ha per year, respectively. Organic acids were not quantitatively determined. Thus, canopy drip was shown to be an important source of mobile soil organic matter for podzolization and other pedogenic processes.
Morphology and Genesis of Some Grayish Claypan Soils of Oklahoma: II. Mineralogy and Genesis
Authors: Culver James R. , Gray Fenton
Published: July 2010

Mineralogical determinations and the suggested genesis of two proposed Nardin soils described in the first paper of this series are presented. Weathered and unweathered material of the clayey Wellington formation, Permian Redbeds were also studied to create two models showing that the proposed Nardin soils formed in either Permian Redbeds or Post‐Permian sediments. Cation‐exchange capacity, nonexchangeable K, ethylene glycol retention, and clay mineralogy based on X‐ray diffraction and differential thermal analysis were determined for the clay fraction.

The clays are mainly illitic in the surface horizons and interstratified montmorillonite and illite in the argillic horizons. Coarse clays are largely illitic and fine clays, the dominant fraction, are largely montmorillonitic. It is concluded that the proposed Nardin and Waurika soils are developed from similar pedogenic processes from Post‐Permian sediments.
Hydraulic Conductivity Measurements with a Pressure Transducer
Authors: Overman A. R. , Peverly J. H. , Miller R. J.
Published: July 2010

A rapid method for measuring hydraulic conductivities of materials in the range 10‐6 to 10‐10 cm/sec is described. By using a pressure transducer as part of a decreasing head permeameter, the time constant for measurement is reduced. Only small volume transfers of water are required. An example is discussed to illustrate the method.
Hydraulic Conductivity Related to Porosity and Swelling of Soil
Authors: Lagerwerff J. V. , Nakayama F. S. , Frere M. H.
Published: July 2010

The hydraulic conductivity factor in Darcy's equation for viscous flow is analyzed in terms of a modified Kozeny equation. The modifications include a correction for swelling, and the replacement of the cubic exponent of the porosity term by an exponent varying between 0 and 3. The choice depends on the interplay between surface and volume of soil pores, as determined by flocculation‐dispersion conditions. Swelling is calculated from the theory of the diffuse double layer. A theoretical analysis of experimental results on the hydraulic conductivity of two soils for percolants of variable concentration and composition showed that a single value for the electrical potential parameter sufficed to match theoretical with experimental data when the concentration of the percolant ranged from 10 to 100 meq/liter. Taking into account effects of pore size, pore density, effective porosity, and flow matrix on the hydraulic conductivity, the above has been explained in terms of expansive swelling of smaller pores at the expense of larger ones. A number of published studies have been analyzed in the light of the theory proposed. The relevance of the theory with regard to the alleged contrast between grain and pore models of soil has been considered.