bluuebunny/crossref_metadata_2025_split huggingface dataset:
Specific Surface Determination by Duo‐Interlayer and Mono‐Interlayer Glycerol Sorption for Vermiculite and Montmorillonite Analysis
Authors: Mehra O. P. , Jackson M. L. 
Published: July 2010

AbstractIn a new method for specific surface determination, montmorillonite is made to sorb exactly two interlayers of glycerol (a true monolayer on each planar surface) at 35° C. in a vacuum of < 1 mm. of Hg. Vermiculite sorbs only one interlayer under these conditions. Both montmorillonite and vermiculite sorb only a mono‐interlayer of glycerol at 110° C. in a previous method. The two analytical methods thus give the amount of glycerol corresponding to the second interlayer in montmorillonite, and this makes possible quantitative analytical determination of montmorillonite and of vermiculite.To illustrate, Wyoming montmorillonite sorbs 21.1% glycerol at 110° C., and 41.6% at 35° C. in vacuum, which gives an analysis of 98% montmorillonite, whereas Colorado vermiculite sorbs the same amount of glycerol under both these conditions, equivalent to only a monointerlayer. The presence of fine amorphous material in montmorillonitic fine clays is revealed by a higher specific surface than obtained with 100% montmorillonite. Dissolution of the allophane from Black Cotton soil (India) resulted in a specific surface analysis of 94% montmorillonite (5 to 10% kaolinite is present). Ladybrook fine clay fraction (Queensland, Australia) showed 90% montmorillonite and 10% of mono‐interlayer expanding mineral.
Release of Fixed Potassium as a Diffusion Controlled Process
Authors: Mortland M. M. , Ellis Boyd 
Published: July 2010

AbstractRate of release of fixed K from vermiculite with 0.1N NaCl was studied to attempt to characterize the ratelimiting process. Of the processes considered, film diffusion satisfied most criteria as rate limiting. The activation energy of the release of K by 0.1N NaCl in the system studied was about 3,550 cal./mole, a value of the order frequently obtained for diffusion processes.
Effect of Nutritional Stress on Plant Composition: I. The Interaction of Added Nitrogen with Varying Sulfur Supply
Authors: Rendig V. V. , McComb E. A. 
Published: July 2010

AbstractGreenhouse and laboratory experiments with alfalfa as the test plant were designed to test the hypothesis that minimum levels of certain plant metabolites may occur at an intermediate stage of nutritional stress. This possibility in the case of S was indicated by results which had been obtained for amide and free amino N in alfalfa hay and appeared to be at variance with reports in the literature that accumulation of these N fractions are symptoms of S deficiency.Several levels of S both with and without applied N were used. Because of the sensitivity of Rhizobia activity to pH, CaCO3 was added to keep the reaction of the medium in a favorable range at the varying nutritional levels. Plants were obtained by rooting cuttings from a single clone and were grown in both soil and liquid cultures. Physiological age at time of harvest was identified by flower development.Since physiological studies indicate the importance of carbohydrate/nitrogen ratios, reducing and total sugars were determined as well as several N fractions. The implication of the findings in terms of nutritional stress effects are discussed.
Report on Flame Photometric Determination of Exchangeable Mangesium in Soils
Authors: Attoe O. J. 
Published: July 2010

AbstractTwelve soil samples, varying from about 40 to 1600 ppm. of exchangeable Mg, were analyzed for this constituent by collaborators at 13 state and federal laboratories. Twelve laboratories used the Beckman flame photometer and one laboratory the standard AOAC method. All laboratories followed the same extraction procedure, and at 7 of these the determinations were made by two operators. An analysis of variance revealed there were highly significant differences in the results obtained between laboratories and between operators within laboratories. However, in terms of the accuracy usually obtained for Mg by other methods, there was fairly good agreement between laboratories and between the flame photometric and AOAC methods.
Influence of Certain Soil Fumigation Treatments on the Response of Tobacco to Ammonium and Nitrate Forms of Nitrogen
Authors: McCants C. B. , Skogley E. O. , Woltz W. G. 
Published: July 2010

AbstractFertilizer mixtures in which the nitrogen was allammonium, all‐nitrate or equal parts ammonium and nitrate were applied in conjunction with the following soil fumigation treatments: not‐fumigated, Dowfume W‐85 (ethylene dibromide), Shell DD (dichloropropene and dichloropropane), and methyl bromide. Data were obtained on the effect of fumigation and N treatments on (1) the relative levels of ammonium and nitrate N in the soil during the growing season, (2) the ammonium and halogen content in the tobacco leaf at certain stages of growth, and (3) the yield and certain properties of the cured tobacco leaf.Methyl bromide and Shell DD reduced nitrification to a greater degree than did Dowfume W‐85. Three weeks after transplanting, the ammonium N and halogen contents in tobacco leaves from the ammonium N treatment were higher than from the nitrate N treatment on soil fumigated with Shell DD or methyl bromide, but no different for the Dowfume W‐85 or not‐fumigated treatments.The yield and quality index of tobacco from the Shell DD and methyl bromide fumigation treatments increased with increasing percentage of the total N applied in the nitrate form. With Dowfume W‐85, the highest yield was from the mixture of ammonium and nitrate N. There were no differences in yield or quality among N treatments on soil not‐fumigated. For all fumigation treatments, the percentage N and percentage nicotine in the cured leaf were higher where ammonium N than where nitrate N was applied.
Some Physical and Chemical Changes in the Soil Brought about by Saturation With Natural Gas
Authors: Adams Russell S. , Ellis Roscoe 
Published: July 2010

AbstractSevere chemical and physical changes may occur in soils saturated with natural gas. Plant growth may be retarded or completely eliminated.A study was made of the profile of four gas‐saturated field sites and the adjacent normal soils. Determinations were made for total carbon, available P, pH, exchange‐able Mn, exchangeable ferric iron, and exchangeable ferrous iron. At two sites pH titration curves were determined. A sharp inflection in the curve at pH 2 was observed with gas‐saturated soils. Substantial increases of total carbon, exchangeable Mn, and exchangeable ferric iron occurred in the gas‐saturated soil. Exchangeable ferrous iron increased moderately. Determinations of soil pH and available P gave varied results, but in general showed increases in the gas‐impregnated soils. Physical determinations at the two most severely affected sites revealed some increase in water retention and total porosity with a corresponding decrease in bulk density in the gassaturated soils. The disturbed Fe‐Mn relationships may be one of the major factors accounting for the frequently observed detrimental influence of gas‐saturated soils on vegetative growth. The change in water retention was not considered injurious to the plants.
Effect of Nitrogen Volatilization on Soil Acidity Changes Due to Applied Nitrogen
Authors: Hiltbold A. E. , Adams Fred 
Published: July 2010

AbstractNitrogen was applied as urea, NH4OH, (NH4)2SO4, (NH4)H2PO4, (NH4)2HPO4, NH4NO3, and NaNO3 to 10‐, 20‐, and 25‐g. samples of soil and incubated under conditions favorable for nitrification. Glucose was added during incubation to supply energy for denitrification. The samples were later analyzed for pH, NH4+, NO2‐, NO3‐, and organic N. The final acidities and extent of nitrification and volatilization varied considerably, even among identically treated samples. Volatilization losses of N ranged from none to the entire amount applied.The acidity resulting from nitrification was calculated for each sample and compared to actual acidity. The difference between calculated and observed acidity was accounted for by equivalent N volatilization. This relationship was obtained with 3 soils regardless of the N source applied and the probable gaseous form of loss.
Field Infiltration Studies With Green Manures and Crop Residues on Irrigated Soils
Authors: Williams W. A. , Doneen L. D. 
Published: July 2010

AbstractThe effects of leguminous and gramineous green manure crops and corn and cotton crop residues on soil structure were compared by measuring water infiltration rates in irrigation furrows. Experiments were performed on alluvial soils of widely varying texture, developed in a Mediter‐ranean‐type climate.Gramineous summer and winter green manures improved infiltration relative to fallow. This benefit was restricted to soils of medium and fine textures. The effectiveness of barley green manure increased as it advanced in maturity. Neither summer nor winter annual legumes influenced infiltration.Corn crop residue and, to a lesser extent, cotton crop residue were effective in improving infiltration. Corn roots alone also made a significant, but lesser, contribution to improved infiltration.
Turbidimeter Technique for Measuring the Stability of Soil Aggregates in a Water‐Glycerol Mixture
Authors: Davison James M. , Evans D. D. 
Published: July 2010

AbstractA technique is described for measuring the aggregate stability of soil with mechanical agitation in a waterglycerol mixture. The technique consists of uniformly mixing a weighted soil sample in a 1000‐ml. test tube containing a known water‐glycerol mixture. After uniformly mixing, the test tube containing the suspension is immediately placed in a turbidimeter and the change in light transmission with time at a specific depth is measured using a recording potentiometer. The tube is removed after a specific time and the contents again mixed uniformly by a standard technique and an additional curve obtained. This process may be repeated as many times as necessary to obtain the breakdown trends of the aggregates with mechanical agitation. The mean weightdiameter of the soil aggregates in each run may then be determined by plotting the logarithm of th potentiometer reading vs. the square of the aggregate diameter (as callculated using Stokes' law) and measuring the area under the curve. The change in mean weight‐diameter is a measure of the breakdown of the aggregates due to mechanical agitation in the water‐glycerol mixture. Results show that the method measures differencers in structure not measured by the usual wet‐sieve method.
Use of Wax Substrates in Root Penetration Studies
Authors: Taylor Howard M. , Gardner Herbert R. 
Published: July 2010

AbstractBasic information on root penetration into pressure pans is essential in soil compaction studies. The ability of plant roots to penetrate compacted zones may determine moisture effectiveness and nutrient availability on these pressure‐pan soils.The use of wax substrates for simulated plastic pans is discussed and evaluated. Physical characteristics of a number of commercially available waxes are presented.In plant growth‐chamber experiments using wax substrates, the ability of plant roots to penetrate depended upon the wax rigidity, the type of plant, and the density of the soil above the substrate.
Evidence for Sodium Fixation in Salt‐Affected Soils
Authors: Babcock K. L. 
Published: July 2010

AbstractEvidence from isotopic dilution studies is presented to show that adsorbed Na in salt‐affected soils may be exchangeable with Na isotopes but nonexchangeable with Ca++ or NH4+ ions. The evidence also shows that a solid form of Na may be present in these soils which disolves in normal extracting solutions but not in water.
The Action of Duramycin on Plant Roots
Authors: Norman A. G. 
Published: July 2010

AbstractThe polypeptide antibiotic, duramycin, has been reported to be antagonistic to certain plant pathogens. Growth of plant roots, however, is repressed by this compound. The duramycin concentration causing 50% reduction in elongation of the primary root of cucumber is 42 µg. per ml. The deleterious effect is mitigated or prevented by simultaneous presentation of calcium or magnesium ions. Depending on concentration, duramycin resembles polymyxin in being bound to plant roots. Roots exposed to excess duramycin lose solutes, both inorganic and organic, and are irreversibly injured. Auxin‐induced water uptake by hypocotyl segments is unaffected by low concentrations of duramycin which does not have antiauxin properties.
Chelating Agent and Plant Nutrient Interactions Affecting the Iron Nutrition of Soybeans
Authors: Tiffin L. O. , Brown J. C. , Holmes R. S. 
Published: July 2010

AbstractStudies were made to evaluate the effect of absorbed chelating agent on the subsequent absorption‐translocation of iron in soybeans. Iron was separated from the chelating agent by using split‐medium and split‐root techniques.Chelating agents did have some effect on the absorption of radioiron from Millville soil and the translocation of foliar‐applied radioiron. These effects were not great enough to correct iron chlorosis. Phosphorus in the nutrient medium or within the plant depressed the uptake and translocation of iron by the plant. This effect of phosphorus on iron could not be offset by use of chelating agents. The primary role of iron chelates in plant nutrition appears to be that of making iron soluble and available to the root for absorption.
Water Movement into Soil from I dealized Vertical Mulch Channels
Authors: Swartzendruber Dale 
Published: July 2010

AbstractA mathematical solution in elliptic integrals is obtained for the flow in a system of channels in water‐saturated, uniform soil, assuming a very highly permeable stratum to exist at finite depth. If water enters the soil through the original soil surface as well as the channel surfaces, the increase in flow due to the channels is generally small. However, if the original soil surface is sealed, the channels are relatively effective in restoring the flow to that which occurs in the absence of the channels and surface sealing. From the analysis there emerges the simple depthspacing formula, d0 = 0.28 S, which is presented as a tentative design criterion for the placement of vertical mulch channels.Analysis is also made for soil anisotropy in which the horizontal permeability exceeds the vertical permeability. In all cases this increases the flow contributions of the channels.
Elimination of Interference by Phosphorus and Other Elements in the Flame Photometric Determination of Calcium and Magnesium in Plant Tissue
Authors: Wells C. G. , Corey R. B. 
Published: July 2010

AbstractA rapid, accurate flame photometric method was devised for determination of Ca and Mg in plant tissue. Interferences by P and any Fe and Al that might be present were eliminated by addition of FeCl3 to the acid plant ash extract and precipitation of P, Fe and Al by neutralizing to pH 5.6 with NH4OH. A positive interference by K was corrected by addition of 500 ppm. K to all solutions. NH4OAc was added to prevent clogging of the burner capillary by the NH4Cl solution. Results obtained with the new method agreed well with those obtained with AOAC methods.
Extraction of Soil Organic Matter With Anhydrous Formic Acid
Authors: Parsons J. W. , Tinsley J. 
Published: July 2010

AbstractFormic acid, being a polar compound, has proved a good solvent for polysaccharides and in the anhydrous condition it exhibits neither oxidizing nor hydrolytic properties. Shaking soil with cold anhydrous formic acid dissolved an appreciable quantity of organic matter but extracted considerably less than did two consecutive ½‐hour boiling periods under reflux. Addition of inorganic cations to the extractant increased its efficiency. Recovery of the dissolved material was attained by precipitation with diisopropyl ether containing 1% CH3COCl which held inorganic cations in solution. Repeated precipitation from formic acid solution yielded a material low in ash with a good physical texture. The N extracted from a wide range of soils varied from 27 to 43% of the total N while for composts the value was as high as 87%. The yield of organic material represented from 27 to 39% of the total organic matter for the soils and 80% for the compost.
Fertilizer Studies in the Cauca Valley of Colombia
Authors: Lawton K. , Patino E. 
Published: July 2010

AbstractNine field fertilizer experiments involving six major crops were conducted over an 18‐month period in the Cauca Valley of Colombia. The area of moderate fertility selected for study was a farm located on a slightly sloping outwash adjacent to the Andes mountains. In addition to different crops, other variables under investigation included kind and rate of application of fertilizers, plant population, and irrigation.With two similar experiments on corn conducted at the same time on different soil areas, marked yield response to phosphorus fertilizer was obtained at one location, whereas at the second, neither nitrogen nor phosphorus were beneficial. A third experiment dealing with fertilizer, irrigation, and plant population showed that supplemental water and adjustment of stand were more important than fertilizer requirements in determining corn yields.Yields of field beans in one trial were significantly increased by use of nitrogen fertilizer, but only small benefits were obtained from phosphorus. For soybeans, direct application of fertilizer was only of moderate value in improving yields of grain.With sugar cane, one experiment indicated both phosphorus and potassium were needed for high cane production. Nitrogen fertilizer applied to newly planted Pangolagrass was highly effective in increasing forage yield, while response to phosphorus was negligible.
Characteristics of the Multiple Yellowish‐Red Bands Common to Certain Soils in the Southeastern United States
Authors: Robinson Glenn H. , Rich C. I. 
Published: July 2010

AbstractMultiple bands or strata of soil materials, which are finer textured and browner or redder colored than the material above or below, have been studied. These bands are common in unconsolidated sandy Coastal Plain and glacial deposits. In Virginia, North Carolina, and South Carolina they are found to lie nearly horizontally, are much deeper where the present soil is nearly level than on sloping soil areas, and the soils in which they occur contain “clay balls” and band segments above the continuous bands. Stratification within the bands, charcoal fragments deposited with the sand, and bands showing scour and fill characteristics were observed in the field. In no instance were yellowish‐red bands found to cross bedding planes but rather the redder color follows the texture of the strata.Chemical analyses show that these bands, where continuous, contain more organic matter, and have a slightly lower pH and higher cation‐exchange capacity than the interbands. Percentage free iron in the clay fraction, and clay mineral analyses show no significant differences between the bands and interbands.Attempts to develop clay‐iron oxide strata in the laboratory by leaching unstratified soil materials were unsuccessful. However, some were developed in stratified materials when leached with a complexing or reducing agent. These experiments produced evidence that clay movement in a sandy medium is similar under some conditions to clay movement in a finer textured medium and give support to the conclusion that the bands studied are primarily the result of geologic deposition.Based upon this conclusion, it is proposed that the part of the profile containing such bands be considered as the C horizon of the soil above. The small residual “clay balls” or segments of bands remaining in the B horizon (often a color B) would be considered as fragments of parent material and comparable to partially weathered rock fragments in the lower B of a residual soil.
Non‐Steady‐State Moisture, Temperature, and Soil Air Pressure Approximation With an Electric Simulator
Authors: Hanks R. J. , Bowers S. A. 
Published: July 2010

AbstractAn electric simulator was used to approximate the non‐steady‐state, one‐dimensional solution of several moisture, temperature, and air pressure problems in soil. The simulator consists of a resistance‐capacitance network with accessory units for setting initial conditions and recording or indicating the simulated variable with time and depth. Time and distance can be scaled to convenient magnitudes. Provision for changing the simulated diffusivity with distance and time allows for the approximate solution of several types of moisture problems. An example of absorption, redistribution after absorption, and evaporation from Yolo light clay is given. The absorption solution compares favorably with the mathematical solutions of Klute and Philip.Comparison of mathematical and simulated solution of temperature distribution in a soil with constant diffusivity and temperature varying sinusoidally at the surface shows excellent agreement. The soil temperature (fluctuating with time) between two measured depths is estimated. The solution agrees reasonably with actual field measurements. The solution of the problem of air pressure fluctuation within the soil due to fluctuation at the surface is given where an impermeable layer exists at a specified depth.
Physical and Chemical Properties of Some Peats Used as Soil Amendments
Authors: Dyal R. S. 
Published: July 2010

AbstractMore than half a million tons of peat are sold annually in the United States for soil improvement. The properties of interest to the buyer and seller are discussed and data for these properties given. Dry organic matter of peats as sold are reported as follows: bulk 26.6, bale 66.4, and moisture‐proof packages 37.7 pounds per 100 pounds of peat. The pressure‐plate and pressure‐membrane procedures, as used in soils work, are shown to be satisfactory for measuring moisture‐retention properties of peats.
Utilizing Drought‐Days in Evaluating Irrigation and Fertility Response Studies
Authors: Parks W. L. , Knetsch J. L. 
Published: July 2010

AbstractIt is expected that a crop grown during a year of insufficient moisture will economically require less fertilizer than a similar crop grown with an ample supply of moisture. Likewise, crop response to supplemental irrigation would be greater during a year of low rainfall than during a year of adequate rainfall.The moisture deficiencies may be expressed as “drought‐days” for any specific soil‐crop‐fertility situation. Incorporating “drought‐days” as a production function to characterize the factor‐product relationship as shown in the general equation below permits an evaluation of the effects of drought on yield and on the interactions with other variables such as fertility.Y = b0 + b1N + b2N2 + b3D + b4D2 + b5ND. Where Y = yield, N = pounds of nitrogen per acre and D = drought‐days or drought index.A history of drought conditions for an area may then be used to obtain probabilities of the frequency of occurrence of varying degrees of drought and consequently the effect on yield outcome. This permits the presentation of yield outcome in terms of risks for various inputs rather than as single valued outcomes.Irrigation may be expected to reduce the number of drought‐days encountered in any cropping situation. Expressing crop yields as a function of drought‐days and fertility level permits the evaluation of irrigation on yield and subsequent crop income. Combining this with the probabilities for drought occurrence provides a means for determining the expected irrigation response in an area and attaching probability statements relative to such a response.