bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Tracer Study of Nitrogen Balance and Residual Nitrogen Availability with 12 Soils
Authors: Legg J. O. , Allison F. E. 
Published: July 2010

AbstractPlantavailability of 15N‐tagged residual N following oats (Avena sativa L.) fertilized with 50, 100, or 200 ppm N was studied under conditions offering maximum exploitation of the tracer N. These conditions were achieved by subsequent uniform additions of nontagged N, as well as other nutrient elements, to promote good plant growth. Total recovery of tracer N in the initial oat crop and two succeeding crops of sudangrass (Sorghum sudanensis), plus that remaining in the soil, averaged 94% for all soils and treatments, but ranged as low as 82% for the low N treatment of the Fargo soil. On most soils the percent total recovery was not influenced greatly by N rates. Tracer N remaining in the soils after cropping ranged from 10 to 36% of the original addition and decreased with increasing N rate.Residual N uptake by the first cutting of sudangrass, as a percentage of the tracer N which was not removed by the previous crop, ranged from 10 to 41% and generally increased with rate. Availability of the residual N to the second cutting of sudangrass dropped to an average of 4.5% of the remaining tracer N, with few significant differences among soils or treatments. Retention and availability of residual N were related to the relative N‐supplying capacities of the soils.
Modified Tube Diameters for the Double‐Tube Apparatus
Authors: Bouwer Herman , Rice R. C. 
Published: July 2010

AbstractExperiences with the double‐tube method indicated that the diameter of the outer tube should be larger than the theoretical minimum because of soil disturbance in the annular space between the inner and the outer tube. Field studies were conducted in Adelanto loam and in river sand using outer tubes of various diameters in combination with an inner tube with a constant diameter. The results indicated that, for an inner‐tube diameter of 12.7 cm, an outer‐tube diameter of 25.4 cm was sufficient to eliminate most of the effects of soil disturbance in the measured value of the hydraulic conductivity. Values of 10.2 cm and 20.3 cm for the diameters of the inner and outer tubes, respectively, also appeared to be satisfactory.
Negative Adsorption by Vermiculite: Salt Exclusion from Interlayer Volumes
Authors: El‐Swaify Samir , Coleman N. T. , Bredell G. , Arca M. 
Published: July 2010

AbstractFor vermiculite immersed in NaCl or CaCl2 solutions, the amount of water that excluded Cl was 0.22 g/g and was not affected appreciably by the electrolyte concentration or the particle size of the mineral. The measured exclusion volume corresponds to the interlayer volume calculated from the c‐axis spacing and an assumed specific surface of 750 m2/g. The results suggest that vermiculite in aqueous solutions should be regarded as having two distinct and clearly separated ionic regions—the interlayer spaces containing exchangeable cations and water but not soluble electrolyte, and the interparticle solution.
Shallow‐Water Impoundment Increases Soil Moisture and Growth of Hardwoods
Authors: Broadfoot W. M. 
Published: July 2010

AbstractSoil moisture during the growing season and radial tree growth were significantly increased by impounding winter and spring rainfall until July 1 on hardwood sites in the Mississippi Delta. In early July, the average moisture per 30 cm of soil amounted to 19.5 cm for the area that had been flooded and 13 cm for the control soil. Even late in the growing season, soil in the impoundment contained about 1 cm more moisture. Timber growth was increased by about 50%. Oxygen in the water was depleted after 15 days of dry weather, but was quickly replenished by rain.
Heats of Immersion Studies on Anion‐Treated Ferric Oxide
Authors: Jurinak J. J. , Burau R. G. 
Published: July 2010

AbstractMicrocalorimetry was used to obtain heats of immersion data for αFe2O3 (hematite) treated with SO4‐2, H2PO4‐1 or MoO4‐2 at pH 4.0. The data were compared with values from a reference OH saturated iron oxide. Using water adsorption data, the net integral heats of adsorption as functions of outgassing temperature (25 to 470C) were calculated. The energies of adhesion were also determined. Anion penetration lowered the surface energy of hematite, as manifested by a lowering of the immersional heats with increasing outgassing temperature. At pH 4.0 the relative bonding strengths of the anions on hematite were concluded to be MoO4‐2 > H2PO4‐1 > SO4‐2 > OH‐1. The heat of immersion values after 25C outgassing indicated limited anion effect as well as a physical interaction of water with αFe2O3. The molybdate ion had the greatest effect on surface energy at all outgassing temperatures.The energy of rehydration (hydroxylation) of the αFe2O3 surface was also calculated from the data.
Nitrogen Effects on Cotton: I. Vegetative and Fruiting Characteristics
Authors: Gardner B. R. , Tucker T. C. 
Published: July 2010

AbstractA series of N fertilization experiments was conducted over three growing seasons, at three elevations, utilizing two varieties of ‘Acala’ cotton (Gossypium hirsutum) on two soil types. The treatments consisted of various rates and timing of N fertilizer applications. Data indicated that N deficiency at early growth stages limited development of vegetative branches, internode elongation, and fruiting, particularly in “one‐peak” flowering areas. Cotton plants can compensate by increased fruiting in longer seasons or “two‐peak” flowering areas when adequate N is available during late season following earlier N deficiency. The effect of N applications on fruiting and yield was dependent on the intial N fertility of the soil and the yield possibility. When N was limited, yield and fruiting were increased by N applications. Petiole analyses were used to show the relationship between N nutrition and yield and fruiting.
Nitrogen Effects on Cotton: II. Soil and Petiole Analyses
Authors: Gardner B. R. , Tucker T. C. 
Published: July 2010

AbstractEvidence is presented to show the validity of soil and petiole analyses as diagnostic tools in planning N fertilizer programs. A highly significant correlation was found between the initial soil nitrate level and yield of seed cotton (Gossy pium hirsutum) without additional N when the soil was sampled as outlined. The level of nitrate N in leaf petioles was found to be a good indicator of the N nutrition of the cotton plant. The N needs of cotton can be determined throughout the growing season by utilizing soil and petiole analyses.
Partially Acidulated Rock Phosphate as a Source of Phosphorus to Plants: III. Uptake by Corn from Soils of Different Calcium Status
Authors: McLean E. O. , Balam B. S. 
Published: July 2010

AbstractRock phosphate was treated with H3PO4 to give 5, 10, 50, and 100% acidulations relative to triple superphosphate. The resulting materials were applied to three Ohio soils brought to different calcium levels. The P uptake and the percentage recovery of added P by corn plants (Zea mays L.) were determined. The soils 1/3‐3/4 Ca saturated generally resulted in better yields, P uptake, and P fertilizer recovery than other Ca saturations. Acidulations beyond 10% in soils less than 1/3 Ca saturated and beyond 50% in soils 1/3‐3/4 Ca saturated were generally not significantly beneficial to P uptake or percentage recovery of added P. Comparison of fertilizers with similar amounts of soluble phosphate but different amounts of insoluble (unreacted) rock phosphate indicated that on the average 1.3 to 1.5 times as much of the added “available” phosphorus was recovered where more insoluble P was present. This was attributed to the reaction of the soil‐formed H3PO4 with unreacted rock phosphate so that less phosphate was fixed by solubilized Al and Fe compounds.
An Instrument for in Situ Measurements of Soil Moisture Flow and Suction
Authors: Cary J. W. 
Published: July 2010

AbstractA soil moisture flux transducer was built and tested in the laboratory under steady‐state conditions in a column of Portneuf silt loam soil. Initial data indicate that the instrument may be developed into a useful field research tool. Its principal advantage is that measurements of moisture flow may be made without any prior information concerning the unsaturated hydraulic conductivity of the soil. Rather, one needs to know only a soil moisture convergence factor which is dependent on the state of the soil and the design of the transducer. While this convergence factor is dependent upon the soil moisture content, the dependence appears to be nearly an order of magnitude less than the dependence of hydraulic conductivity on soil moisture content. It may prove possible to develop the unit for installation in the field to provide continuous measurements of the unsaturated soil moisture flow in the tensiometer range with errors no greater than those arising from the natural heterogeneity of the soil.
A Comparison between Two Methods of Determining the Thermal Diffusivity of a Moist Soil
Authors: Hadas A. 
Published: July 2010

AbstractTwo types of solutions of the heat flow equation were discussed and proposed recently as methods for evaluating the thermal diffusivity of soils. The first one is the harmonic solution for a sine heat wave while the second uses the Laplace transform for solving the heat flow equation. This work was carried out in order to compare the thermal diffusivity values obtained by using these two solutions. Experimental data were analyzed for dry soil as well as for wet soil having 4.5, 7.8, and 14.5% water on dry weight basis.The thermal treatments were: three types of heat waves, a sine wave, half square and a full square wave, all having an amplitude of 6C and periods of 8 and 16 min.For dry soil the sine wave solution yielded lower values than the Laplace solution did. For the wet soil the same trend was observed for the short period while for the longer period a cross‐over, namely, higher values were obtained using the sine wave solution than those obtained by the Laplace solution.These differences are discussed in the light of the experimental conditions and moisture transfer during the heating period.
Mineralization of Organic Phosphorus in Soils as Affected by Addition of Inorganic Phosphorus
Authors: Wier D. R. , Black C. A. 
Published: July 2010

AbstractThe enhancement of mineralization of soil organic P that previous investigators had reported as resulting from incubation of soils with added inorganic P was not found in laboratory experiments. Previously reported recoveries of more than 100% of inorganic P added to certain alkaline soils before incubation, which also might be a consequence of enhanced mineralization of soil organic P, could not be reproduced except where the P was added in an acidified solution. Presumably an acidified solution was used by mistake in the previous work.
Dissolution and Availability to Plants of Rock Phosphates of Igneous and Sedimentary Origins
Authors: Höweler R. H. , Woodruff C. M. 
Published: July 2010

AbstractThree studies were conducted to test the P supplying power of Missouri apatite of igneous origin relative to that of Florida and Arkansas rock phosphates of sedimentary origins. The analyses of the materials showed that Missouri apatite contained as much as 15.4% P, while Florida and Arkansas rock phosphates contained 14.5% and 9.6% P. Arkansas phosphate contained almost 20% CaCO3, Flordia had 9% CaCO3, most of which was incorporated in the apatite structure, and Missouri apatite had only 5.6% CaCO3 as an impurity.The absence of carbonate from the Missouri apatite crystal resulted in a very strong crystalline structure. Incremental dissolution by dilute HCl as well as a greenhouse study with corn and soybeans revealed that this igneous apatite released its P very slowly. The rock phosphates of sedimentary origin with their small degree of crystallinity were decomposed more easily. Florida rock phosphate was most effective in supplying the plant with P while the low P as well as the high lime contents of Arkansas rock reduced the effectiveness of this material as a P fertilizer.
Inorganic Phosphorus Fractions and Their Relationship to Residual Value of Large Applications of Phosphorus on High Phosphorus Fixing Soils
Authors: Shelton J. E. , Coleman N. T. 
Published: July 2010

AbstractLarge applications of P to a high P fixing soil were rapidly converted into Al and Fe‐P. Over an 8 year period a decrease in Al‐P with an increase in Fe‐P occurred. Reductant soluble Fe‐P occurred 3 and 5 years following P applications at 1,371 kg/ha (1224 lb/acre) and 685 kg/ha (612 lb/acre).Soil test P was highly correlated with Al‐P. Regression analysis indicates that increasing rates of P application, or increasing Al‐P level, up to the reported P adsorption maximum, resulted in greater efficiency in increasing the soil test P. At a 1.371 kg/ha rate of application, which was above the reported 719 kg/ha (642 lb/acre) adsorption maximum, the efficiency was greater than at 343 kg/ha (306 lb/acre) rate of application but slightly less than at 685 kg/ha application rate.A method of investigating long‐term field equilibrium conditions in a relatively short period, by boiling, was investigated and resulted in equilibrium conditions requiring several years under field conditions. It is suggested that this method when coupled with other data may be used as a means of estimating P applications which would result in sufficient available P for maximum yields over an extended period.
Rubidium‐Sodium Exchange on Kaolinite and Bentonite
Authors: Kunishi H. M. , Heald W. R. 
Published: July 2010

AbstractExperimental data on the exchange between Rb and Na on kaolinite and bentonite clays were examined in terms of the exchange equation of Heald et al. The results could be interpreted in terms of a single selectivity factor, describing the relative tendencies of the two ions to form ion pairs with the charge on the clay surface when it was assumed that the amount of each ion present in the form of ion pairs was a constant fraction of the total amount of that ion present.
Soil Properties Influencing Differential Ca to Sr Adsorption
Authors: Khasawneh F. E. , Juo A. S. R. , Barber S. A. 
Published: July 2010

AbstractThe selectivity coefficient, the ratio of Sr to Ca as exchangeable cations divided by the ratio of Sr to Ca in solution, was found to vary from 0.61 to 1.51 on 63 Indiana soils. Soil factors influencing the variation in kc values were studied on selected soils where kc was determined after equilibration of the soil with an 0.1N chloride solution of Ca and Sr having a Ca/Sr molar ratio of approximately 190:1.Organic matter was negatively correlated with the kc value (r = 0.83). Removal of the organic matter with H2O2 on nine soils increased the kc value. The magnitude of the increase was correlated with the percent organic matter in the soil (r = 0.89). The organic fraction of the soil adsorbed Ca preferentially to Sr. The inorganic fraction in most instances adsorbed Sr preferentially.
Yield and Nutrient Removal by Corn (Zea mays L.) for Grain as Influenced by Fertilizer, Plant Population, and Hybrid
Authors: Robertson W. K. , Thompson L. G. , Hammond L. C. 
Published: July 2010

AbstractThe fertilizer requirements of corn (Zea mays L.) on a fine sand with a constant water table depended on the season. In 1 year of 3, yields increased to the highest rate of N‐P‐K (664‐196‐556 kg/ha), however, on the average, requirements were half these quantities. For well‐fertilized corn, the ear yield constituted one‐half the weight of the above ground plant.At the highest yield the N, P, and K concentrations in the ear were 1.5, 0.22, and 0.32%, respectively. The uptake in the fodder of N, P, and K averaged 0.0227, 0.0050, and 0.0185 kg, respectively, per kg of ear corn produced (approximately 1.58, 0.35, and 1.30 lb in the fodder per bushel of grain produced). Of this, 67, 51, and 20%, respectively, were in the ear.Ear corn yields were not consistently affected by plant density (47,840, 68,890, and 95,680 plants/ha). Number of ears increased with stand, but ear weight and quality decreased.Considerable seasonal variations were noted between hybrids. Windy conditions, during and immediately after tasselling, lodged tall varieties more than short varieties.Although the amounts of P and K applied in the fertilizers were well in excess of those removed in the crop, relatively small amounts of these nutrients could be extracted from the soil by 1N NH4OAc (pH 4.8).
A Sandculture Study of Chloride Toxicity to Mature Avocado Trees
Authors: Bingham F. T. , Fenn L. B. , Oertli J. J. 
Published: July 2010

AbstractMature avocado trees (Persea americana) were grown outdoors in large sandcultures under treatments ranging from 0 to 20 meq Cl/liter. All solutions were adequately supplied with essential elements and the solutions were isoosmotic. Chloride injury symptoms include reduced tree growth, transpiration, leaf burn, premature leaf abscession, and possibly reduced fruit production. Criteria for evaluating soil, irrigation water, and leaf analysis are presented.A mechanism for Cl injury is proposed to be the result of excessive accumulation of chlorides in xylem fluids in the leaf, which promotes dehydration and permanent injury to the cells. Rather than being a specific effect, the effect appears to be a special case of osmotic injury.
Sand and Cotton Bur Mulches, Bermudagrass Sod, and Bare Soil Effects on: II. Salt Leaching
Authors: Heilman M. D. , Wiegand C. L. , Gonzalez C. L. 
Published: July 2010

AbstractFour surface cover conditions—sand mulch, cotton bur mulch (Gossypium hirsutum), coastal bermudagrass sod (Cynodon dactylon L.), and bare fallow—were evaluated with and without gypsum for salinity reclamation under natural rainfall conditions in the Lower Rio Grande Valley of Texas. The electrical conductivity of saturated soil extracts (ECe) decreased in the surface 61 cm of all treatments. The sand mulch was the most effective; ECe decreased from 17.6 mmhos/cm initially to 2.8 mmhos/cm the first year of treatment. The ECe changed only from 22.1 mmhos/cm to 15.8 mmhos/cm in 3 years under bermudagrass sod. Salt accumulated below the 61‐cm depth in the bermudagrass plots because of moisture extraction from the saline water table. No benefit was derived from the addition of gypsum. Following termination of the study, ECe remained unchanged after one cropping season of sorghum (Sorghum vulgare). Yields of both grain and forage were a function of reclamation wrought by the treatments. There was a net reduction of salt from the 0‐ to 213‐cm profile for sand and bur treatments, whereas a net increase occurred for the bare fallow and bermudagrass treatments.
Cation‐Exchange Equilibrium Constants of Aluminum‐Saturated Montmorillonite and Vermiculite Clays
Authors: Foscolos A. E. 
Published: July 2010

AbstractEquilibrium constants of aluminum‐saturated montmorillonite and vermiculite clay minerals were studied in chloride‐salt solutions at concentrations similar to those occurring in soil. Studies were limited to cations occurring most abundantly in soil solutions, viz., H+, Na+, K+, Mg2+, and Ca2+. The order of relative replacing power in the lyotropic series was found to be: Colony Wyoming montmorillonite (90 meq/100g CEC) H < Na < Mg < Ca < K < Al; Otay California montmorillonite (125 meq/100g CEC) H < Na < Mg < Ca < Al < K; Jeffersite vermiculite (175 meq/100g CEC) Mg < Ca < H < Al < Na.
Pore Gas Composition Under Sewage Spreading
Authors: Thomas R. E. , Schwartz W. A. , Bendixen T. W. 
Published: July 2010

AbstractSeptic tank effluent was applied to sand in laboratory lysimeters. Dosing frequencies of 2/day and 6/day were used to observe relationships between changes in the composition of the pore gas and the clogging of the sand. The rate of clogging in the 2/day unit was less than that in the 6/day unit. This reduced rate of clogging was related to pore‐gas and moisture content changes which occurred in the sewage dosing and drainage cycles. The longer cycle of the 2/day frequency provided more oxygen over a greater percentage of the total elapsed time. In the 6/day lysimeter the rapid soil clogging, which is characteristic for anaerobic conditions, started while the oxygen concentration in the pore gas was greater than 13 percent. Water‐filled pores or water films, occurring as the result of an increase in the moisture content, may have provided anaerobic sites in the presence of the high pore‐gas oxygen. Carbon dioxide inhibition of microbial growth did not cause the rapid phase of clogging. Moisture or oxygen determinations may be suitable guides for prevention of the rapid phase of soil clogging.
Soil Erosion in Relation to Properties of Eastern and Western Washington Forest Soils
Authors: Balci A. N. 
Published: July 2010

AbstractSoil was sampled under Douglas‐fir stands (Pseudotsuga meanziesii) located on similar parent materials in eastern and western Washington. Simulated rainfall applied to soil blocks showed real differences in erodibility of east‐ and west‐side soils. All soil properties tested, except texture, differed significantly between the two locations.Over 70% of the variation in soil erodibility was accounted for by a multiple regression equation using erodibility as the dependent variable and loss on ignition, permanent wilting percent, and percent silt as independent variables. Differences in soil properties were attributed to influences of climate on production of plant litter and ensuing decomposition and incorporation of litter in soil by organisms.
Determination of Equivalent Radii for Half‐Tube and Whole‐Tube Drains in Contact With an Impermeable Barrier
Authors: Warrick A. W. , Kirkham Don 
Published: July 2010

AbstractFor soil‐drainage problems, we prove that a half‐tube of radius a, the diameter of which is coincident with a plane barrier, is equivalent to a whole‐tube drain of a smaller radius, b = 2a/π = 0.6366a, installed with its circumference touching the same plane barrier. The value 0.6366a lies between the limits 0.5a and 1.0a found by Kirkham in 1947. The result is applicable by analogy to all types of potential problems, such as those of electricity and heat conduction. The result is useful for applying theoretical results, found for half tubes, to whole tubes as used in practice.
Reduced Sodium Exchange Capacity in Unsaturated Flow
Authors: Mokady R. S. , Bresler E. 
Published: July 2010

AbstractFlowing water with a reduced degree of saturation seems to reduce the apparent or effective cation‐exchange capacity. The experiment was performed by running water through a layered soil, thus obtaining unsaturated flow conditions. It is suggested that the flow direction induces anisotropy with respect to molecular diffusion. The hydrodynamic dispersion in the flow direction is almost unaffected. At the same time there must be some locations off the main water stream with which there is negligible mixing or molecular exchange by diffusion. One may associate to these isolated locations a prevailing direction normal to the mainstream. In this case, it can be said that the unsaturated flow induces anisotropy on ion transfer by mixing or molecular diffusion.