bluuebunny/crossref_metadata_2025_split huggingface dataset:
Release Rate of Potassium and Structural Cations from Micas to Ion Exchangers in Dilute Solutions
Authors: Feigenbaum S. , Edelstein R. , Shainberg I. 
Published: July 2010

AbstractThe rate of release of K and structural cations from three micas (biotite, phlogopite, and muscovite) was measured in two‐particle size ranges (5 – 20µm and 20 – 50µm), in dilute electrolyte solutions (0.001N), and at pH 3.0 and 7.0. The rate of K release from phlogopite and biotite was similar to the rate of release of structural cations under acidic conditions and significantly higher under neutral conditions. These findings indicate that structural decomposition of phlogopite and biotite is dominant in acidic conditions, and that the role of interdiffusion increases in neutral conditions. Decomposition was more sensitive than interdiffusion to particle size.The rate of K‐release from muscovite was about 5 and 15% that from biotite and phlogopite, respectively. The rate of K release from muscovite was higher than the rate of Al release. This indicates that muscovite is the most stable of the three micas and that the decomposition mechanism for K‐release in muscovite was less important.
Application of Phosphorus, Potassium, and Zinc to Corn Grown for Grain or Silage: Early Growth and Yield
Authors: Rehm G. W. , Sorensen R. C. , Wiese R. A. 
Published: July 2010

AbstractConsiderable effort has been devoted to the study of the application of N and S for corn (Zea mays L.) production on irrigated sandy soils in the western Corn Belt. Requirements for P, K, and Zn have not been extensively researched. This study, initiated in 1974 and continued through 1978, was designed to measure the effect of repeated applications of P, K, and Zn to irrigated sandy soil under systems of continuous grain and silage production.Two adjacent series of plots were used. In one series, corn was harvested for grain and the residue was incorporated with a disk. Corn from the adjacent series was harvested for silage each year, thus eliminating the return of any residue to the soil. Twenty‐three treatments were selected from a 53 complete factorial to fit a central composite design with identical treatments used in both series. To measure early growth, whole plant samples were collected when plants were 40–60 cm tall. Silage yields were measured prior to or at physiological maturity. Grain yields were measured in mid‐October.Fertilizer P had the most consistent effect on early plant growth, yield, and crop maturity. The application of fertilizer P had a curvilinear effect on early growth and yield with maximum yield produced by the application of 22–33 kg P/ha. The rate of fertilizer P required to achieve maximum production in any one year was not related to yield level. The effect of P on crop maturity was not consistent with the effect being linear in some years and curvilinear in others. The effect of fertilizer K was inconsistent throughout the study. Application of fertilizer Zn had no effect on corn growth, yield, and crop maturity. There was no significant P × Zn interaction throughout the study.
Ammonia Loss and Associated Reactions of Urea in Calcareous Soils
Authors: Fenn L. B. , Miyamoto S. 
Published: July 2010

AbstractUrea in soil is a mobile compound which can be lost by leaching or ammonia (NH3) volatilization. This research examined the contributions of water additions and chemical reactions in explaining the behavior of applied urea.Urea [CO(NH2)2] initially moves undissociated into the soil with added water. Ammonia losses from surface‐applied urea thus decreased with increasing amounts of applied water. Ammonia losses from urea were minimal if injected into the soil 2.5 cm or more, whereas NH3 losses from (NH4)2SO4 (AS) were still high when placed 7.5‐cm deep. Application of AS produced chemically equivalent amounts of Ca and Mg whereas urea and NH4OH precipitated Ca and Mg. The amount of Ca and Mg precipitated increased with decreasing NH3 losses. Precipitation of divalent cations enhanced adsorption of NH4 on soil cation exchange sites, thereby reducing upward movement of NH4 and subsequent NH3 losses. The presence of Ca from reaction of AS with CaCO3 enhanced upward movement of NH4 and increased NH3 losses.
The Basic Cation Saturation Ratio Concept and Lime and Potassium Recommendations on Delaware's Coastal Plain Soils
Authors: Liebhardt William C. 
Published: July 2010

AbstractA lime‐potassium factorial experiment (four K and seven lime treatments) was established on a Coastal Plain soil in 1970. Wide ranges in soil pH and percent Ca, Mg, and K saturation were obtained. Results indicate that the use of the Basic Cation Saturation Ratio Concept for making fertilizer recommendations should be modified for Delaware's sandy Coastal Plain soils. This concept, used by commercial labs, recommends that the exchange complex contain 75% Ca, 15% Mg, and 2–5% K. Research shows that use of these saturation percentages and the resulting Ca/Mg, Ca/K, and Mg/K ratios is not warranted and may result in reduced yields or increased costs, or both. A liming program which maintains the soil pH between 5.5 and 6.0 is suggested. Soil pH > 6.0 tends to result in Mn deficiency. To maintain a soil pH between 5.5 and 6.0 requires a Ca plus Mg saturation of 65–75% rather than that presently suggested by commercial labs (85–90%). Calcium plus magnesium saturation of this magnitude results in a soil pH of 6.5–6.8 on these sandy soils and a resulting Mn deficiency. Wide ranges or ratios of Ca and Mg have not influenced yield as long as soil pH is in the correct range.A K saturation of 2–5% is suggested by the use of this concept, data indicates that this saturation percentage is sufficient for corn and soybeans on Delaware's sandy Coastal Plain soils.
Soil Variability on Surface‐Mined and Undisturbed Land in Southern Illinois
Authors: Indorante S. J. , Jansen I. J. 
Published: July 2010

AbstractFive different soil units were defined on surface‐mined land to group soils that were constructed by similar mining and reclamation methods and from similar materials. Three soil units were defined on undisturbed landscape using the traditional soil series concepts of soil classification and mapping. The goal in defining and mapping soil units on both surface‐mined land and undisturbed land was to minimize variation of soil properties within soil units.A nested sampling design allowed for testing the lateral variation of selected properties within and among the five units on surface‐mined land and within and among the three units on undisturbed land. The analysis of variance conducted separately for the constructed soil units and the undisturbed units indicate that there are more significant differences among the five constructed soil units than among the three undisturbed soil units.Variability, as measured by the coefficient of variation, within the constructed soil units was similar to that within the soil units on undisturbed land. Pre‐mine overburden characteristics and method of soil construction are useful guides for mapping soils on surface‐mined land.
Backfill Alteration Effects on Pipe Drainage of a Clay Soil
Authors: Taylor G. S. , Hundal S. S. , Fausey N. R. , Schwab G. O. 
Published: July 2010

AbstractA permeable backfill may improve pipe drainage for soils that have a slowly permeable subsoil. Permeable backfills were created directly over drains installed 8 years earlier by replacing soil with gravel and by trenching and refilling. The permeable zone extended from the bottom of the plow layer to the drain. The research was conducted on a poorly drained, cultivated, lakebed clay soil in Ohio. The addition of gravel increased drain flow rates by a factor of 2 to 3 during periods of ponding but had no effect on flow rates under nonponded conditions nor on water table drawdown rates. The ponded flow rates for drains with gravel have not changed after 3 years. During the first year, trenching and refilling had the same effect on drain flow rates as gravel. During the second year, the ponded flow rates declined to only 50 or 60% of those with gravel. The permeable backfill functioned as a hydraulic connector and permitted ponded water to bypass the relatively impermeable subsoil in flowing to the drain. Sediment concentrations in the drain water were unaffected by backfill alterations.
Nitrous Oxide Emissions from a Native Shortgrass Prairie
Authors: Mosier A. R. , Stillwell M. , Parton W. J. , Woodmansee R. G. 
Published: July 2010

AbstractNitrous oxide (N2O) emissions from a native shortgrass prairie averade 2.3‐g N ha−1 day−1 during a summer sampling period. Although N2O emissions from the native grassland were small, they were substantially larger than earlier estimates from uncultivated soils. The losses accounted for about 10% of N inputs from atmospheric deposition and N2‐fixation, which represented a significant N‐loss mechanism that had not been recognized. Nitrous oxide losses from similar sites treated with urea to simulate ungulate urine deposition were about three times greater than from untreated soils, but still amounted to only 0.6% of the added N.
Representative Sampling for Bulk Density in a Vertisol
Authors: Chan K. Y. 
Published: July 2010

AbstractUndisturbed bulk density samples (7.5 cm internal diam and 7.5 cm long) were collected using a Tanner Sampler at different depths down to 50 cm from a Vertisol in Australia. Representative samples were obtained only for the top 20 cm layer. For the deeper layers, the bulk density results followed the one‐dimensional shrinkage relationship, instead of the three‐dimensional one, and therefore suggested nonrepresentative sampling. This was explained in terms of the increasing size of the soil structural units with depth, and hence the core samples from below 20 cm were too small to represent the field soil structures.
Inorganic Phosphorus in Calcareous Rockland Soils of the Bahamas
Authors: Taylor Robert W. , Woods Jonathan 
Published: July 2010

AbstractThe phosphorus (P) status of cultivated and forest calcareous “rockland” soils of the Bahamas was investigated to acquire information on available P, forms of inorganic P, and P adsorption maxima. Available P was extracted by four methods: Bray P‐1, 0.5M NaHCO3, 0.01M CaCl2, and distilled‐deionized H2O. Soil P was fractionated according to the Chang and Jackson procedure, and Langmuir P adsorption maximum was determined by the method of Olsen and Watanabe for soils.For cultivated soils the order for amount of P removed by the extractants was generally NaHCO3 > Bray > H2O > CaCl2. The pattern for forest soils, having less available P, was NaHCO3 > H2O > CaCl2 > Bray. Phosphorus fractionation data of selected soils indicated that 55.7 to 99.9% of the inorganic P was in the Ca‐P fraction. Correlation analysis between P fractions and available P revealed that all four extraction methods were positively correlated only with the Ca‐P fraction. Most of the adsorption maxima (computed from region I of the isotherms) for cultivated and forest soils were in the upper medium range. The Langmuir P adsorption constant, K1, related to the energy of adsorption, was generally smaller for cultivated soils, suggesting that P, being more loosely bound to these soil surfaces, would be more available to plants. Some fine‐textured forest soils had very high K1 values, ranging from 52 × 104 to 222 × 104 liters/mole. The implication is that these soils will require heavy fertilizer P applications to adequately supply crops with P when cultivated initially.
Particle Size Fractions and Their Use in Studies of Soil Organic Matter: I. The Nature and Distribution of Forms of Carbon, Nitrogen, and Sulfur
Authors: Anderson D. W. , Saggar S. , Bettany J. R. , Stewart J. W. B. 
Published: July 2010

AbstractOrgano‐mineral complexes in various size fractions from the surface horizons of two Chernozemic soils (Typic Argiboroll and Udic Haploboroll) were separated without chemical pretreatment by ultrasonic dispersion in water, followed by sieving and centrifugation. The organic carbon (C), nitrogen (N), and sulfur (S) composition in the size fractions and the degree of polycondensation of humic materials extracted by an alkaline pyrophosphate technique were compared. Fifty‐five to 58% of the organic C was in the clay fraction, with greatest absolute amounts in the coarse clay (2–0.2 µm). Carbon/nitrogen ratios narrowed as particle size decreased. The organic matter separated from the coarse‐clay and fine‐silt fractions (5–2 µm) was dominated by conventional humic acids (HA‐A), which based on their strong adsorption at 280 nm and resistance to acid hydrolysis, were considered strongly aromatic and recalcitrant in soil. In contrast, the organic matter associated with the fine clay (<0.2 µm) was largely fulvic acids (FA‐A, FA‐B) and humic acids (HA‐B) that were less aromatic than conventional humic acids and contained considerable amounts of hydrolyzable N. The fine‐ and coarse‐clay fractions (<2 µm) contained >70% of the total soil S, >80% of the HI‐reducible S, and >64% of the carbohydrate C. In relation to C and N, S was preferentially associated with the fine‐clay fractions. The C/S and N/S ratios decreased substantially from maximum values in the fine‐silt fraction (approximately 120:1 and 10:1, respectively) to minimum values in fine clay (approximately 33:1 and 4.5:1, respectively). The distinct differences between the humus of the coarse clay‐fine silt and the fine‐clay fractions indicate that size fractionation following ultrasonic dispersion in water is a promising method of isolating stable and labile forms of soil organic matter. The data also support earlier hypotheses on the nature of soil S that were based on studies of chemical separation of organic matter from complete soils.
Ammonia Losses from Surface‐Applied Nitrogen Fertilizer as Controlled by Soluble Calcium and Magnesium: General Theory
Authors: Fenn L. B. , Taylor R. M. , Matocha J. E. 
Published: July 2010

AbstractAmmonia volatilization from soils after surface application of urea or inorganic N was reduced by Ca and Mg nitrates or chlorides. Sulfates were only slightly effective. Suppression of NH3 loss was a result of two chemical reactions: (i) precipitation of CO3 by Ca, thus preventing permanent (NH4)2CO3·H2O (AC) formation, and (ii) Ca depression of soil pH by depression of the dissociation of the CaCO3‐Ca(OH)2 buffer system. Soil pH values as low as 6.5 were recorded in calcareous soil and 3.9 and 4.5 in the acid soils after addition of Ca. Soil pH values in the presence of Ca reached approximate neutrality in 24 hours even in acid soils. Soil pH without Ca but with AC increased to > 9.0 in every soil. Addition of AC plus Ca reduced the pH of calcareous soil to 5.3 and raised it to 5.7 in acid soils. Calcium carbonate precipitation eventually occurred in acid soils, preventing high NH3 losses. Evidently, CaCO3 precipitated on the surface of acid soils after the pH reached a certain critical value and, as expected, the pH was maintained near that of the pure CaCO3 system.
Leaf‐Cutter Ant (Atta cephalotes) Influence on the Morphology of Andepts in Costa Rica
Authors: Alvarado Alfredo , Berish Cory W. , Peralta Francisco 
Published: July 2010

AbstractTwenty‐seven soil profiles distributed within a 2.5‐ha site were described as Typic Dystrandepts of the Colorado soil series. Leaf‐cutter ant influence was noted in 85% of the pedons. The influence on each profile was estimated, and out of all profiles, 37% had low, 26% medium, and 22% high disturbance. The surface area covered by leaf‐cutter mounds was 38.9% of the study area; only 1% of the aboveground disturbed area was active, however. Leaf‐cutter ants transport material from the AB and B horizons to the soil surface, producing a new A1 horizon and, in addition, some subsoil chambers are filled with plant material. It is proposed to use a subindex (i) to denote insect influence as an agent on the formation of a subsoil horizon (ABi, B2i) and also, for the overburden (Ai).
Subsurface Horizon Blending: An Alternative Strategy to B Horizon Replacement for the Construction of Post‐Mine Soils
Authors: McSweeney K. , Jansen I. J. , Dancer W. S. 
Published: July 2010

AbstractThis study was initiated to evaluate various combinations of substratum and B horizon materials, as subsurface rooting media. Materials were collected from each solum and substratum horizon to a depth of about 6 m at two surface mine sites. One of the sites was in southern Illinois and had an infertile Darmstadt (Albic Natraqualf) surface soil with a strongly acid (pH 5.2) and natric subsoil. The other was in west central Illinois and had a Sable (Typic Haplaquoll) surface soil which supports high yielding grain crops with proper management.The experiment was conducted in a greenhouse using large plant containers. The test crop, soybean, was germinated in A horizon material, or in a blend of materials containing A horizon, placed over the given surface rooting medium. This procedure was employed in order to simulate field conditions where seeds germinate in topsoil and root into the underlying material. Performance of the test crop was best where A horizon was segregated and replaced over a blend of the next 3 m of material for treatments made from the Darmstadt materials from southern Illinois. It was poorest where A horizon material was replaced over material from the Darmstadt B2 horizon. The other treatments were intermediate in performance between the A/Top 3 m and the A/B2 (subsoil). A similar trend was found with the Sable materials from west central Illinois, but the difference between the best performing treatment, A/Top 3 m, and the poorest, A/B2 (subsoil), was not as marked.
Granule Size and Composition of Superphosphate Containing Added Copper and Zinc
Authors: Gilkes R. J. , Sadleir S. B. 
Published: July 2010

AbstractThis study determined the distribution and forms of P, S, Ca, Cu, and Zn in Cu‐Zn superphosphate in order to determine whether uniform application of nutrients to soils is promoted by use of such fertilizers. Concentrations of insoluble and water‐soluble Cu, Zn, Ca, P, S, and citrate‐soluble P in various sized fractions of commercial Cu‐Zn superphosphates were almost uniform, apart from a relative concentration of insoluble Cu in the finest‐sized fraction. Most of each constituent was present in 1‐ to 4‐mm granules as a consequence of the preponderance of this size granule in the fertilizers. Individual granules were chemically analyzed and showed little variation in S, Ca, and P concentrations, whereas much wider variations occurred in Cu and Zn concentrations. These variations probably are not of agronomic significance.
X‐Ray Diffraction Line Profile Analysis Vs. Phosphorus Sorption by 11 Puerto Rican Soils
Authors: Jones R. C. 
Published: July 2010

AbstractThe increase in the areas under goethite (110), gibbsite (002), and hematite (104) x‐ray diffraction lines, due solely to small crystallite effects, was plotted against phosphorus sorption for 11 Puerto Rican soils. This increase is shown to be proportional to the total surface area of each phase measured and is therefore referred to as the surface area index. The data showed a very high correlation (R2 = 0.95 for a straight line and R2 = 0.96 for a second‐order polynomial) between the surface area index of goethite and phosphorus sorption. In comparison, the correlation between the surface area index of gibbsite and phosphorus sorption was poor (perhaps because gibbsite was present in low concentrations relative to goethite) but judged to be significant (R2 = 0.56). The correlation between the surface area index of hematite and phosphorus sorption was not significant (R2 = 0.26) as compared to goethite and gibbsite. The sum of the surface area indices of goethite and gibbsite showed a near‐perfect correlation with phosphorus sorption (R2 = 0.98 for a second‐order polynomial). The study demonstrated that, in the case of goethite and to a lesser extent gibbsite, the mean crystallite size is more important than the abundances of the phases for explaining observed phosphorus sorption characteristics of soils.
Variation in Natural N‐15 Abundance of Central Saskatchewan Soils
Authors: Karamanos R. E. , Voroney R. P. , Rennie D. A. 
Published: July 2010

AbstractNatural 15N abundance data from 38 well‐drained cultivated, 11 native pasture, and 9 saline seep soil profiles from Saskatchewan were compiled. The mean δa15N value (per mill 15N excess) for all surface soil samples was 9.4 with a standard deviation of 3.0. Land use was not a factor determining δa 15N values as there was no differences in the δa15N values of surface soil samples from cultivated and native pasture areas; the mean δa15N value for both these types of profiles was 8.6 with a standard deviation of 1.9. However, the mean δa15N value for saline seeps (13.8 ± 3.8) was significantly higher than that of either well‐drained cultivated or pasture soils.Spatial variability does not appear to unduly limit use of natural variations in 15N abundance to study important agronomic processes in Chernozemic soils.
Nitrous Oxide Production by Nondenitrifying Soil Nitrate Reducers
Authors: Smith M. Scott , Zimmerman Karen 
Published: July 2010

AbstractOf 214 soil bacterial isolates able to reduce NO3‐, 209 produced nitrous oxide (N2O), even though only 46 were respiratory denitrifiers (competent to carry out complete reduction of NO3‐ to N gases). Nitrite or NH4+ was the major product of NO3‐ reduction by the nondenitrifying organisms, but typically about 5 to 10% and up to 34% of the NO3‐ reduced by them was released as N2O during a 2‐week incubation. Bacillus and Enterobacter were the most commonly observed genera of nondenitrifying N2O producers. Fermentative NO2‐ reduction and N2O production by a Bacillus sp. and a Citrobacter sp. were characterized in pure culture studies. Dinitrogen (N2) was not produced in detectable quantities by these organisms. When added to autoclaved soil, they accumulated more N2O than two denitrifying pseudomonads, since the latter consume and produce N2O. In tryptic soy broth (TSB), which allows active fermentative growth, NH4+ was apparently the major product of NO3‐ reduction. In nutrient broth (NB), NO2‐ accumulated. Added NH4+ did not inhibit N2O production or apparent reduction to NH4+, indicating that these processes are not assimilatory. The effect of added glucose on N2O production varied with the organism and media composition. Nitrous oxide production from NO2‐ by these organisms was shown to be at least partially a biochemical reaction. The N2O evolved slowly in batch cultures and mostly after apparent growth ceased. This is apparently a novel mechanism of N2O generation which differs significantly from respiratory denitrification.
Measurement of Mycorrhizal Infection in Soybeans
Authors: Bethlenfalvay G. J. , Pacovsky R. S. , Brown M. S. 
Published: July 2010

AbstractInfection of soybean [Glycine max (L.) Merr.] roots by the vesicular‐arbuscular mycorrhizal fungus Glomus fasciculatus (Thaxt. sensu Gerd.) Gerd. and Trappe was assessed throughout the ontogeny of the symbiotic association. Degree of infection was evaluated by a histological method as percent infection and colorimetrically as mg chitin/g mycorrhiza. Correlation of data by the two methods was highly significant (r = 0.99) below 60% infection and not significant (r = 0.62) at higher levels. Assessment of infection by the histological method did not yield significantly different data above 60% infection. Data by the colorimetric method were statistically distinct at all levels of infection. The effects of biological and chemical contaminants on the colorimetric assay were determined. The fungal component of mycorrhizae was compared to purified chitin standards. Use of chitin for standard curves in the absence of degradation products from uninfected root materials significantly (p < 0.05) overstated the degree of infection. Colorimetric determination of fungal infection in mycorrhizae is recommended when high levels of infection are expected.