bluuebunny/crossref_metadata_2025_split huggingface dataset:
Response of Phaseolus vulgaris L. to Molybdenum Under Acid Conditions
Authors: Franco A. A. , Munns D. N. 
Published: July 2010

AbstractCommon beans (Phaseolus vulgaris L.) have been found not to respond to molybdenum (Mo) when grown on deficient soils that were also very acid (< pH 5.2).Greenhouse and growth chamber experiments in soil and solution culture were done to (i) test whether soil acidity prevents Mo response in bean by interferring with Mo uptake or translocation to nodules; (ii) establish relationships between Mo concentrations in nodules and in other plant parts; and (iii) assess cultivar differences in Mo uptake.In the six cultivars studied, plant Mo concentrations were little influenced by pH in the range 4.8 to 5.8. In more detailed experiments with the cultivar Venezuela 350, neither pH (4.8 to 6.3) nor temperature (21 to 31°C) affected Mo concentration or distribution over a wide range of Mo supply in soil and solution culture.Nodule Mo concentration varied less than shoot Mo in response to varied external supply. It correlated with Mo in stems better than in leaves or roots. Root Mo related closely to external Mo. Leaves appeared to act as sinks for Mo disposal at high Mo levels.One bean cultivar accumulated more Mo in stem and seed than five other cultivars. It was also noted that Mo was 10 times higher in seeds produced at Davis, Calif., (on an Entisol) than at Goiana, Brazil (on an Oxisol). These data confirm that genetic and environmental controls on seed Mo can be manipulated to help control Mo deficiency.
Soil Carbon, Nitrogen, and Bulk Density Comparisons in Two Cropland Tillage Systems after 25 Years and in Virgin Grassland
Authors: Bauer Armand , Black A. L. 
Published: July 2010

AbstractStubble mulching is advocated as a desirable soil management practice, but no data are available for the northern Great Plains showing the effect of its long‐term use on soil properties. Neither have any comparisons been made of organic carbon (C) levels in cropland and virgin grassland in this region since 1947.Four farm field sites, each of moderately coarse‐, medium‐, and fine‐textured soils under conventional tillage, stubble mulch tillage, and virgin grassland (never cultivated) were sampled at 0 to 7.6, 7.6 to 15.2, 15.2 to 30.5, and 30.5 to 45.7 cm to measure organic C, total nitrogen (N), and bulk density.Average organic C and total N to a depth of 45.7 cm, % by weight, were significantly higher under stubble mulch than conventional tillage management. Organic C concentration in moderately coarse‐ and fine‐textured soils was 44 and 13% higher, respectively, under stubble mulch than conventional management, but it did not differ between the two management systems in medium‐textured soils.The percentage loss of C and N from the 0‐ to 7.6‐ and 7.6‐ to 15.2‐cm soil zones due to cropping as compared to virgin grassland was no greater than the percentage loss found in 1947 at field stations after nearly 40 years of cropping. In another comparison considering only medium‐textured soils on farm fields, percentage loss of organic C after about 70 years of cropping, using 1979 virgin grasslands as a reference, was no greater than loss after about 40 years of cropping, using 1950 virgin grasslands. Continued cultivation of dryland soils, especially with stuhble mulching, has maintained organic C and total N at higher levels than was projected from earlier research.Cropland bulk densities to 30.5 cm ranged from 7 to 20% higher than on grassland but did not differ between conventional and stubble mulch tillage management.
Agricultural Erosion Indicated by 137Cs Redistribution: II. Estimates of Erosion Rates
Authors: Brown R. B. , Kling G. F. , Cutshall N. H. 
Published: July 2010

AbstractErosion rates were estimated for 6‐ and 12.9‐ha nested agricultural watersheds in the western Willamette Valley, Oreg., using 137Cs activity levels and two different approaches, termed “volumetric” and “gravimetric.” The volumetric approach involved calculation of the volume and mass of sediment currently residing in depositional zones, based on areal extent of the zone and depth of occurrence of 137Cs in the zone. This sediment was assumed to have come from the uplands (sideslopes plus ridgetops) by erosion during the period of fallout (since 1954). Reasonable ranges of watershed sediment delivery ratios and lengths of record were assumed. It was estimated by this technique that modern erosion rates in the uplands had been between 3 and 14 metric tons ha−1 yr−1.The gravimetric approach involved algebraic manipulation of areal concentrations of 137Cs activities in depositional and upland zones to obtain estimates of erosion loss of 137Cs from the uplands. Estimated 137Cs losses were converted to estimated soil losses, which ranged from 6 to 27 metric tons ha−1yr−1.Considering the imprecision of these markedly different means of estimating soil loss rates, the volumetric and gravimetric estimates agree reasonably well. Together, they provide good evidence that the rate of modern erosion at the study site has been within and very possibly above the range of erosion rates normally thought of as tolerable.
Influence of Intensive Cultivation and Irrigation on Soil Properties in the Jordan Valley, Israel: Recrystallization of Carbonate Minerals
Authors: Magaritz Mordeckai , Amiel Abraham J. 
Published: July 2010

AbstractThis is part of a study regarding the effect of intensive cultivation on the soil properties in the Jordan Valley in an area where a decline of crop yield was detected. The high pCO2 values in the cultivated soil (−1.3 Atm) and the large amount of irrigation water applied enhanced the processes occurring in the CaCO3 − HCO3‐ − CO2 system. The largest difference in the amount of dissolution and recrystallization between the cultivated and undisturbed soils was found in the lower part of the profile (horizon BCa and B3). The total amount of CaCO3 leached from the cultivated soil was about 7% of the total carbonate (about 500 metric tons/ha). Most of this loss was from the finer‐grained fraction. An even larger effect was found on the amount of recrystallized carbonate in the soil (about 11% of the total carbonate). A decrease was observed in the bulk density of the upper soil horizons in the cultivated soil relative to the undisturbed soil. The highest bulk density of the cultivated soil was found at a depth of about 1 m compared to the maximum in the 0‐ to 15‐cm depth in undisturbed soil.
Dissolution of Oxides of Manganese and Iron by Root Exudate Components
Authors: Jauregui Mario A. , Reisenauer H. M. 
Published: July 2010

AbstractThe reactions of malic acid, an important constituent of root exudates, with the hydrous oxides of manganese (Mn) and iron (Fe) were studied to further our understanding of the processes controlling the solubility and plant intake of these elements. The reaction of malate with δ‐MnO2 followed either of two pathways depending on the pH‐controlled adsorption of carboxylates on the oxide surface. In acid systems, the first product of the oxidation of malate (oxaloacetate) is adsorbed on δ‐MnO2 surfaces and hydrolyzed to a molecule each of formate and malonate. These products are further oxidized to carbon dioxide (CO2) and water, and 6 mol of Mn2+ are released; the malonate is oxidized via tartronate, formate, and oxalate, and the formate is oxidized directly. Oxaloacetate not adsorbed by the δ‐MnO2 is rapidly decarboxylated to pyruvate, which is subsequently oxidized to acetate and CO2, and only 2 mol of Mn2+ are released. Although favored by acid conditions, adsorption of oxaloacetate by MnO2 is still significant at the pH of calcareous systems; thus, the reduction of MnO2 can proceed via both pathways in agricultural soils.The reduction of Fe(OH)3 by malate was less than that of δ‐MnO2 and was enhanced by acidity and addition to low levels of δ‐MnO2. Higher levels of added δ‐MnO2 diminished soluble Fe due to adsorption and reoxidation of Fe2+ by the δ‐MnO2.
Residual Available Phosphorus in Near‐Neutral and Alkaline Soils: I. Solubility and Capacity Relationships
Authors: Fixen P. E. , Ludwick A. E. 
Published: July 2010

AbstractA continuous cropping greenhouse study of 28 Colorado soils with phosphorus (P) rates of 0 and 30 ppm was conducted. The objective was to investigate the nature and solubility of residual available P in near‐neutral and calcareous soils.Solubility and capacity factor comparisons indicate that octacalcium phosphate was not likely an important residue in 27 of the 28 soils. One of the soils which had a history of heavy barnyard manure applications appeared to be buffered in the vicinity of the octacalcium phosphate isotherm. Tricalcium phosphate or a mineral similar in composition and solubility may have accounted for at least a portion of the fertilizer residues. The plant availability of tricalcium phosphate is apparently quite low since seven of the nine calcareous soils initially plotting on or near this isotherm responded to P fertilization.
Residual Available Phosphorus in Near‐Neutral and Alkaline Soils: II. Persistence and Quantitative Estimation
Authors: Fixen P. E. , Ludwick A. E. 
Published: July 2010

AbstractA continuous cropping greenhouse study of 28 Colorado soils with phosphorus (P) rates of 0 and 30 ppm was conducted. The objectives were to (i) evaluate the persistence of residual available P in near‐neutral and calcareous soils and (ii) to predict its quantity. Residual available P was defined as the amount of P removed fron soil by plant uptake until the NaHCO3‐P level dropped to 10 ppm.A residual effect of the fertilizer treatment persisted beyond six greenhouse crops for nearly one‐half of the 28 soils. Recovery of applied fertilizer ranged from 47 to 119% and averaged 74%. The following equation was developed to predict the quantity of residual available P in soils: Residual P, mg/2 kg soil = −17.02 + 2.062 (NaHCO3‐P, ppm) + 0.058 (NaHCO3‐P × clay, %) − 0.187 (lime, % × clay). R2 = 0.90; 55 soil treatment combinations.
Corn Root Development in Constructed Soils on Surface‐mined Land in Western Illinois
Authors: Fehrenbacher D. J. , Jansen I. J. , Fehrenbacher J. B. 
Published: July 2010

AbstractThe effect of B horizon replacement on corn root development in the reclamation of surface‐mined land was studied in a highly productive soil area of western Illinois. Two constructed soils, one with 55 cm of A horizon over 77 cm of replaced B horizon, and the other with 55 cm of A horizon replaced directly over graded dragline spoil, and a third, representative, undisturbed soil, Clarksdale silt loam, were studied. Placement of B horizon material was done without allowing any scraper traffic on the plots, a more careful procedure than would be possible over the entire post‐mine surface under current technology. Corn roots were sampled in 1979 directly under one plant using a 10‐ by 30‐ by 183‐cm soil root monolith. Corn was the first crop planted on the constructed soils following reclamation.The A horizons were similar on all soils. In the replaced B many soil peds were intact and the bulk density was 1.5 g/cm3 throughout, similar to the undisturbed B of Clarksdale. The bulk density of the graded spoil was 1.7 g/cm3 at 54 cm and increased to 1.9 g/cm3 at 102 cm. Depth of root penetration was 163 cm in Clarksdale, 120 cm in A/B, and 74 cm in A/spoil. Root length densities were significantly greater in replaced B than in graded spoil. Below 113 cm, root length densities were significantly greater in Clarksdale than in replaced B.The data suggest that Clarksdale B horizon material, when placed with minimal compaction, is a more favorable rooting medium than the newly placed dragline spoil. Corn yields in 1979, the first year after reclamation, did not substantiate this. However, in 1980 corn yields were significantly higher (1,800 kg/ha higher) on A/B than on A/spoil. Corn yields on undisturbed Clarksdale were about 10% greater than on A over B in 1980.
Chemical and Morphological Soil Characteristics in a New England Drainage‐toposequence
Authors: Veneman P. L. M. , Bodine S. M. 
Published: July 2010

AbstractChemical, physical, and morphological properties of soils in a representative drainage‐toposequence in central Massachusetts were determined. The soils reflect the acid character of the glacial till derived from granitic materials by the low cation exchange capacity (CEC) and base saturation values, although some effect of past liming is evident. Within a depth of 70 cm most catena members are underlain by a hardpan. This appears to be mainly of geogenetic origin but also exhibits pedogenetic influences in the occurrence of free grain and channel argillans in the upper 25 cm of the pan, especially in well‐ and moderately well‐drained profiles. Depth to the hardpan varies between 45 and 120 cm and in general is somewhat less in soils on the steeper slopes than those on the more level areas.The slowly permeable pan severely restricts vertical drainage of excess soil water and causes increased lateral flow. This results in wetter soil conditions downslope as is evident from the presence of mottling in B horizons. The hardpan is characterized by low chroma ped interiors and bright, high chroma ped ferrans indicative of prolonged wet, but unsaturated, soil conditions. The somewhat poorly and poorly drained catena members have B horizons with relatively low chroma matrix colors and high chroma channel neoferrans which reflect a generally wet soil environment with relatively short, drier periods.Dithionite‐citrate and sodium pyrophosphate‐extractable iron and aluminum contents were determined in B horizons of selected profiles along the catena to evaluate the performance of present U.S. soil taxonomic criteria for spodic horizons since the well‐ and moderately well‐drained soils were classified as Brown Podzolic soils until the 1975 revision. Current chemical criteria effectively exclude these soils from spodic horizon qualification.
Deficit, High‐frequency Sprinkler Irrigation of Wheat
Authors: Miller D. E. , Hang An N. 
Published: July 2010

AbstractThe effect of daily deficit sprinkler irrigation on the yield and quality of wheat (Triticum aestivum L.) was evaluated using the line source technique. Studies were conducted on sandy and loam soils with much different water‐holding characteristics. Irrigation rate variables were initiated at about the time of full cover (pre‐ to early‐boot) when the soils were near the upper limit of available water. Evapotranspiration (ET) rates were estimated from evaporation pan (Ep) data as ET = 0.95 Ep. On the sand, the yield and quality of wheat increased with increased application of water, up to about 100% estimated ET. On the loam soil, daily irrigations which equalled or exceeded 40% estimated ET produced similar yields. On this soil, the total water used, including water depleted from the soil, also varied over a wide range without affecting yields.
Measuring the Hydraulic Conductivity of Soil Horizons with Continuous Macropores
Authors: Bouma J. 
Published: July 2010

AbstractMeasurement of Ksat of soil horizons with continuous macropores is discussed. Different fluxes at grad H = 1 cm cm−1 and zero pressure head ranged from 2,000 to 10 cm day−1 in the B21g (clay) of a Typic Fluvaquent with vertical worm channels and from 20 to 1 cm day−1 in the Clg (compact sandy loam) of a Plaggeptic Haplaquod. Fluxes were obtained using (i) large detached columns (Ksat entire soil), (ii) columns that were attached to the subsoil, and (iii) detached columns with light crusts on top [Ksat of the soil matrix, which is referred to as K(sat)].
Ionic Activity Products and Crystal Forms of Calcium and Magnesium Carbonates Precipitated from Calcium‐Magnesium Bentonites
Authors: Levy Rachel , Whittig L. D. , Tanji K. K. 
Published: July 2010

AbstractA series of laboratory experiments were conducted to study quantities, mineral forms, and solubility of alkaline earth carbonates precipitated from Ca‐Mg‐bentonite systems. The effects of Mg on carbonate precipitation and solubility were assessed in isolation from other carbonate precipitation inhibitors commonly found in soils. Five bentonite systems were preconditioned by saturation with different proportions of exchangeable Ca and Mg. Calcium/magnesium ratios ranged from 99:1 to 8:92. Portions of each system were seeded with calcite, and both seeded and unseeded systems were equilibrated with deionized water or NaHCO3. Equilibrium solution concentrations of Ca, Mg, Na, HCO3, and Cl and also pH served as input data to the WATEQF solution chemistry computer program for calculations of ion strength, ion pairs, ion activities, and carbonate ionic activity products (IAP).The data obtained from the series of experiments clearly demonstrated that solubility characteristics of calcium carbonate in the Ca‐Mg‐bentonite systems were influenced by incongruent properties of freshly precipitated carbonate surfaces. The data further show that Mg inhibited crystallization and increased solubility of calcium carbonate and that high concentrations of Mg in the NaHCO3‐bentonite precipitation medium induced crystallization of Mg calcite. In some systems, Mg was precipitated in forms which were not identified by either x‐ray diffraction analysis or IAP characteristics.
Enzyme Activity and Respiration in Minesoils
Authors: Stroo H. F. , Jencks E. M. 
Published: July 2010

AbstractMicrobial respiration and soil enzyme activity measurements were made in both native soils and in minesoils varying in age and vegetation in order to determine the levels of microbial activity during the initial stages of soil genesis. By all indices, microbial activity was lower on unfertilized minesoils than in native soils. Amylase and phosphatase activities increased with time, as did respiration rate, so that after 20 years, activity levels in the surface 10 cm approached those of native soils. Recovery was related to the accumulation of organic matter and nitrogen (N). Recent minesoils receiving high inputs of lime and fertilizers had the highest activity levels found, resulting in a depletion of organic matter and nitrogen which suggests that a self‐sustaining ecosystem has not yet developed on these sites.Respiration rate, and amylase and phosphatase activities were all significantly correlated with each other. Oxidizable carbon (C) and total and mineralizable nitrogen were the soil factors most closely correlated with respiration rate, while clay content also affected amylase activity. Urease activity was not correlated with any of the other indices or soil factors studied.No evidence for enzyme inhibition in minesoils was found, but phosphatase activities were lower in minesoils, suggesting that P mineralization may be slower on minesoils. Mineralizable N increased rapidly with age on unamended sites, but after 20 years it was only one‐half that found in native soils.The presence of vegetation was critical for the recovery of microbial activity. Black locust (Robinia pseudoacacia) was similar to grasslegume vegetation in its effect on microbial activity and N accumulation. Compaction of the soil during reclamation caused slow organic matter and N accumulation, and thus low microbial activity.
Evaporative Flux from Wheat and Fallow in a Semiarid Climate
Authors: Aase J. K. , Siddoway F. H. 
Published: July 2010

AbstractDaily evaporative flux and accompanying energy balance components were measured for land in summer fallow and in wheat (Triticum aestivum L.) located side by side in a typical strip‐crop farming area. The study was conducted on a Williams loam (fine‐loamy, mixed Typic Argiborolls) 11 km northwest of Sidney, Mont. Two precision‐weighing lysimeters were used, each situated in the middle of two adjacent 180‐ by 180‐m fields. The two fields, including the lysimeters, were alternately cropped and fallowed. ‘Olaf’ spring wheat was grown in 1978 and 1979 and ‘Roughrider’ winter wheat in 1979–1980. The three cropping seasons differed in that 33 cm of rain fell during the 1978 season and about 9 cm fell in each of the 1979 and 1980 seasons. However, because the root‐zone soil profile was near field capacity in the spring of 1979, the yield of about 4,000 kg/ha was comparable to that in 1978. In all 3 years, cropped and noncropped lysimeters lost almost identical amounts of water up to the time that tillering was completed. Thereafter, evapotranspiration from cropped surfaces was much higher than evaporation from noncropped surfaces. The fallowed lysimeter gained 12 cm of water in 1978 and lost 7 and 2.5 cm in 1979 and 1980, respectively. The cropped lysimeter lost 20 cm in 1978, 42 cm in 1979, and 14 cm in 1980. Rates of water use by the wheat were highest during the heading growth stage in 1978 and during flowering in 1979 and 1980. Differences in the growth stage duration among years seemed to have no relationship to degree days. As indicated by both energy balance and daily ratios of evaporative flux (LE) to net radiation (Rn), sensible heat transfer to the crop strongly influenced evapotranspiration, except in 1980 when the crop was stressed most of the season and contributed sensible heat downwind from the cropped area. For a crop to be energy efficient and also have water available for growth, water conservation practices must be followed consistently, and the crop must be protected as much as possible from stress conditions.
Dispersion of Clays on Graphite Supports for X‐Ray Microprobe Analysis
Authors: Berkheiser V. E. , Monsees M. B. 
Published: July 2010

AbstractA method for dispersing clay suspensions on graphite planchets for x‐ray microprobe analysis (XMA) is described. Use of a fluorosurfactant produced separated clay particles, each of which could be analyzed by XMA, in contrast to large aggregates when dried from water. Further improvements in particle flatness and orientation were observed for Ca2+‐saturated Cheto montmorillonite dried at 97% relative humidity.
In‐situ Measurement of Near‐surface Soil Strength by the Fall‐cone Device
Authors: Bradford J. M. , Grossman R. B. 
Published: July 2010

AbstractThis study explored the use of the Swedish fall‐cone device for insitu measurements of shear strength near the surface of soils. A laboratory fall‐cone device was adapted for field use by replacing the original base and lengthening the cone stems. In‐situ strengths were measured on selected soils in southwestern Iowa and southeastern Nebraska. A small increase in water potential resulted in a large decrease in shear strength. A heavier cone gave a lower strength value than a lighter cone. The near‐surface strength of Sharpsburg soils in winter wheat fields was measured throughout the year. The strength immediately after fall planting was 10 to 20 kPa at about −3 kPa water potential. In the spring of 1980, largely because of consolidation from rainfall in the immediate post‐thaw period, the strength was 30 to 50 kPa. In contrast, the spring of 1981 was dry and consolidation did not occur; consequently, there was no increase in strength from that immediately after planting.
Characteristics of Soils in a Stone‐free Surficial Deposit in Central Utah
Authors: Queiroz João , Southard A. R. , Wooldridge G. L. 
Published: July 2010

AbstractParticle‐size distribution, x‐ray diffraction, organic carbon, and calcium carbonate equivalent were measured on selected Calciorthids and Camborthids formed in stone‐free surficial deposits on a structural plain in east‐central Utah. Mylar balloons were tracked with theodolites to determine the circulation of prevailing winds over the mountain slopes and adjacent land forms. Particle‐size distributions (80% silt and very fine sand) and observed wind circulation patterns (strong westerly mesoscale with hydraulic jump) indicate that wind has had a strong influence on the soils and that wind is directly responsible for the complex soil distribution on the land form. Presence of cylindrical soil structure units at depths greater than normal for cicada activity suggests that these features are relict and that these cylindrical soil structure units have been buried. Variable depths over short horizontal distances to K horizons further suggest burial by wind.