bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence of Clay Minerals on the Enzymatic Hydrolysis of Organic Phosphorus Compounds
Authors: Mortland Max M. , Gieseking J. E. 
Published: July 2010

AbstractOrganic phosphorus compounds contain a large portion of the total phosphorus in many soils. The release of phosphate from the organic form is thought to be enzymatic in nature. Since clays compose an active and important part of the soil, a study was made of their effect on the enzymatic hydrolysis of several organic phosphorus compounds.The effect of clays on the enzymatic hydrolysis of fructose‐diphosphate, phytin, glycerophosphate, and lecithin was studied. The enzymes were prepared from bread yeast, wheat bran, bread yeast, and kidney cortex, respectively. The various clays studied included kaolinite, Wyoming bentonite (montmorillonite), Swygert (illite), and Cisne (a clay similar to Putnam). The activity of the enzyme was determined with no clay present, and then in the presence of various amounts and kinds of clays. The enzymatic reactions were performed paying special attention to the control of pH, temperatures, inhibitors, activators, and concentrations. The difference between the activity of the enzyme on the organic phosphorus compound in the presence of a suitable buffer and the activity in the presence of clays was considered a measure of the influence of the clay upon the enzyme activity. All of the clays used in this study exhibited an inhibiting influence upon the enzymatic hydrolysis of the organic phosphorus compounds. The amount of inhibition varied with the kind of clay according to the following series: Wyoming bentonite (montmorillonite) > Cisne (Putnam‐like clay) > Swygert (illite) > kaolinite.The inhibition of phosphatase activity by clays is roughly proportional to the base exchange capacity of the clay. A constant, evaluated for each clay in an empirical equation which describes hydrolysis of the organic compound in the presence of varying quantities of clay, is approximately equal to the ratios of the base exchange capacities of the various clays. The study indicates that the inhibition is due to the effect of the clay on the enzyme and not to adsorption of the organic phosphorus compound by the clay.
The Titanium Content of Hawaiian Soils and Its Significance
Authors: Sherman G. Donald 
Published: July 2010

AbstractA study has been made to determine the titanium oxide content of typical soils of each great soil group occurring in the Hawaiian Islands. The nature of the occurrence of titanium oxide and its relationship to soil formation was investigated.The titanium oxide content of Hawaiian soils ranged from 2.5 to 25.0%. The titanium oxide content is higher in the surface horizon in the soils which are developed under a climate having an alternating wet and dry season. The greatest accumulation was found in the soils belonging to the Humic Ferruginous Latosols, which occur in areas having an alternating wet and dry season but adjacent to the tropical rain forest. Titanium oxide accumulates in tropical soils under the same conditions that iron oxide accumulates. It is easily dehydrated at or near the surface to form concretions, coatings to surfaces of aggregates or soil particles, or as a massive horizon. Titanium oxide, as anatase, rehydrates slower than iron oxide and is more resistant to reduction when the soil internal drainage becomes poorer. Under extreme reducing conditions titanium oxide will be reduced and will be leached from the soil. Under certain conditions of poor drainage the iron and titanium oxides are reduced and removed by leaching, and the aluminum oxide, gibbsite, is resilicated to kaolinite.
Structure and Its Influence on Tilth of Soils
Authors: Klingebiel A. A. , O'Neal A. M. 
Published: July 2010

AbstractThe purpose of this study was to determine some of the changes that have taken place in the structure of several Corn Belt soils and its influence on tilth, permeability, volume weight, and percent of pores drained.Samples of soil were examined in the field to determine the type, class, and grade of structure, direction of natural fracture when lumps were broken, and size and number of visible pores. Six to twelve undisturbed soil core samples 3 inches thick and 3 inches in diameter were taken at random from each plot and depth to determine permeability, volume weight, and percent of pores drained at 60 centimeters tension.Many surface soils that originally were granular or crumb in structure have changed through cultivation and poor management practices to a fine fragmental or massive structure. With these changes in structure the percolation rate decreased from 8.4 inches to 0.2 of an inch per hour, percent of pores drained was reduced from 9.2 to 3.5, and the volume weight increased from 1.1 to 1.31.The surface crust was the least permeable layer in the upper 18 inches of the soils studied.
The Morphology and Genesis of the Gray‐Brown Podzolic and Related Soils of Eastern Canada
Authors: Stobbe P. C. 
Published: July 2010

AbstractThe purpose of this investigation was to establish the range in characteristics of the Gray‐brown Podzolic soils of Eastern Canada and to characterize the different kinds of Gray‐brown Podzolic profiles. It was based on a comparative study of the morphological and some chemical characteristics of all the soil series of this group which have been recognized to date in Canada.The Gray‐brown Podzolic soils in Eastern Canada occur only on calcareous materials, and their maturity of development can be correlated with the length of time they have been subjected to weathering. They have mull‐like, neutral to moderately acid, A1 horizons, comparatively thick but only slightly to moderately unsaturated A2 horizons and B2 horizons which contain more clay and sesquioxides than the other horizons of the profile.A number of intergrade Gray‐brown Podzolic types, which possess some characteristics of the other groups in the region, have been characterized. The findings suggest that the cycle of profile development on calcareous materials in this region is from Brown Forest to Gray‐brown Podzolic to Brown Podzolic and Podzol soils.
The Measurement of Oxygen Diffusion in the Soil with a Platinum Microelectrode
Authors: Lemon E. R. , Erickson A. E. 
Published: July 2010

AbstractThe current obtained in the electrolysis of an electro‐reducible material, as oxygen, at the surface of a platinum electrode can be used to calculate the rate of diffusion of that material to the surface. Measurements made in the soil, based on this principle, give promise of furnishing a new, simple, rapid, and inexpensive method of determining the rate of oxygen supply to an undisturbed environment similar to that in the liquid film surrounding an actively respiring plant root. The method compared favorably with other methods for measuring soil aeration in a greenhouse experiment.Evidence presented indicates that factors controlling the diffusion rate in the gaseous phase of the soil extend into the liquid phase as well. The data show greater oxygen diffusion rates with larger aggregates and greater soil porosity. The rates decreased with increasing depth below the soil surface. At the lower porosities moisture film thickness has a greater effect on oxygen supply than at the higher porosities.Growth of tomatoes correlates well with oxygen diffusion measurements made with the microelectrode, and a critical rate is suggested for their growth.
Factors Affecting the Interlayer Expansion of Vermiculite and Montmorillonite with Organic Substances
Authors: Barshad Isaac 
Published: July 2010

AbstractAn evaluation of the factors affecting interlayer expansion of the mica type layered minerals was made by X‐raying various dehydrated forms of montmorillonite and vermiculite while immersed in liquids of varying dipole moments and dielectric constants. The results showed that the extent of interlayer expansion was determined by the size, charge, and total amount of the interlayer cations and by the magnitude of the dipole moment and the dielectric constant of the immersion liquid. The results were explained on the basis of the nature of the electrostatic interlayer attractive forces within the crystal lattice itself and by the laws governing complex formation between charged particles.
Field Measurements for Tests of Soil Drainage Theory
Authors: Kirkham D. , de Zeeuw J. W. 
Published: July 2010

AbstractMeasurements are reported for water table heights, rainfall, permeability, and in some cases, of ditch and drain tile outflow, for tile drains and ditch drains in replicated plots in the recently reclaimed North East Polder, the Netherlands. The spacing of the ditches and tiles is 8, 10, 12, and 16 meters, the nominal depth of tiles 1 meter, of ditches 60 cm. The measurements were made in November and December 1950, when evaporation and transpiration effects were small, and are believed to be the most extensive measurements yet made for testing modern drainage theory under field conditions. An order of magnitude theoretical test of the data appears satisfactory. From an immediately practical view point it was found that tiles, apparently because of their greater depth, kept the water table lower at all times than the ditches. Tiles at 50‐foot (16‐meter) spacing kept the water table ½ foot below the soils surface; tiles at 25‐foot spacing kept the water table 2 feet below the soil surface. For ditches at the same spacings the values were ¼ foot and 1 foot 3 inches.
A Forest Land Capability Classification
Authors: Plair T. B. 
Published: July 2010

AbstractThe objective of this forest land capability classification is to classify forest land on a basis of permanent physical factors for the purpose of providing an index to the land and crop management requirements and potentials.It is suggested that all forest soils be grouped into four capability classes. The first class would be the highly productive forest soils, having few or limited hazards to soil losses or damage and only minor limitations to use of equipment or application of any management practice. The fourth class would be the noncommercial forest lands. These would be the extremely high‐hazard lands, or those soils very low in production, or those having conditions requiring excessive operating costs, or a combination of these. The second and third classes would include those lands between the first and the fourth classes.The specific site indices (the total average height that has been or will be attained at a given age — ordinarily 50 to 100 years) or the slope groups that would be put in any one capability class could be different for each forest region, subregion, or individual making the classification. Standardization can and should be achieved to the extent of defining the capability classes and subclasses. The following graphic presentation is suggested as a standard.Class A1 — Very well suited to forestry; low hazards, minor limitations and high productive potential.Class B1 — Well suited to forestry; moderate hazards and limitations with high productive potential.Class B2 — Well suited to forestry; moderate productive potential with low hazards and minor limitations in use.Class B3 — Well suited to forestry; moderate productive capacity with moderate hazards and limitations to use.Class C1 — Fairly well suited to forestry. High hazards, severe limitations, and high productive potential.Class C2 — Fairly well suited to forestry. High hazards and severe limitations with moderate productive capacity.Class C3 — Fairly well suited to forestry; low hazards with minor limitations and low productive potential.Class C4 — Fairly well suited to forestry; moderate hazards and moderate limitations with low productive potential.Class C5 — Fairly well suited to forestry. High hazards, severe limitations with low productive potential.Class D — Unsuited to economic productive use for forestry due to excessive hazards and limitations and extremely low productivity.
A Study of the Relationship between Chemically Available Phosphorus and Plant Growth Response on Several Michigan Soils
Authors: Smith F. W. , Cook R. L. 
Published: July 2010

AbstractThe objective of this investigation was to correlate plant growth response with chemically measured available phosphorus in the soil.Eight chemical methods of extracting the available phosphorus in the soil samples were utilized. An attempt was made to correlate growth response of wheat with chemically measured available phosphorus. The principles of Mitscherlich as modified by Bray were employed.In general, the amount of chemically measured phosphorus as extracted by the Spurway active extracting solution was quite low in comparison to that extracted by the other methods, all of which contained some hydrochloric acid. Increasing the time of shaking during extraction or increasing the ratio of extracting solution to soil did not improve the Spurway active test.The use of any of the methods of Bray provided a considerably clearer picture of phosphorus availability because the inclusion of fluoride in the extracting solution enabled the adsorbed phosphorus in the soil to be removed. Apparently this removal was essential in measuring chemically available phosphorus. An extracting ratio of one part of soil to 50 parts of solution was more desirable for adsorbed phosphorus studies than the narrow ratio of one part of soil to 10 parts of solution.The two methods of Spurway were apparently of about the same suitability and as such were poorer than any of the methods advocated by Bray and his associates. The use of either the customary method of Bray for measuring total available phosphorus or adsorbed phosphorus at an extraction ratio of 1:10 gave comparable results. Increasing the extraction ratio of 1:50 did not improve the method of measuring total available phosphorus as evidence by correlation with plant yield response. However, increasing the ratio to 1:50 for the adsorbed phosphorus extraction did result in a notable improvement and also resulted in the best single method employed under the conditions of this investigation.
Mica Leptyls and Wavellite Content of Clay Fraction from Gainesville Loamy Fine Sand of Florida
Authors: Dyal R. S. 
Published: July 2010

AbstractThis paper reports the occurrence of mica leptyls as the principal constituent and wavellite a minor constituent of the clay fraction from Gainesville loamy fine sand of Florida. The mineralological compositions of clay fraction from seven soils of the lower Gulf Coastal Plain are compared.Methods used for identification are differential thermal analysis, X‐ray diffraction, surface area measurements, chemical analysis, and observation under the electron microscope.Leptyls of mica comprise 60 to 80% of the mineralogical composition of the clay fraction of Gainesville loamy fine sand. Four to 7% of the clay fraction consists of wavellite. Ten to 15% of the clay fraction is kaolinite with some quartz present in the 2‐ to 0.2‐µ fraction. The clay fraction from the seven soils of the lower Gulf Coastal Plain is predominantly kaolin or kaolingibbsite mixtures.
Sawdust Composts: Their Preparation and Effect on Plant Growth
Authors: Davey Charles B. 
Published: July 2010

AbstractGreenhouse studies demonstrated that application of fresh sawdust at the rate of 40 cubic yards per acre strongly depressed the growth of deciduous and coniferous tree seedlings and green manure crops. Treatment of sawdust with anhydrous ammonia, phosphoric acid, and potassium sulfate failed to alleviate completely the adverse influence of sawdust and necessitated additional treatment of stock with nitrogen fertilizers.In order to decrease the C/N ratio, chemically treated sawdust was inoculated with Coprinus ephemerus. This organism proved to be efficient in decomposition of cellulose, and within 3 months converted sawdust into a finely divided dark brown material which resembled a rich mull‐like soil in appearance. The fermentation was invariably accompanied by a volunteer invasion of fungus gnats, Sciaridae spp., and many other microorganisms.Application of composted sawdust to a sandy soil produced marked increase in the growth of both coniferous and deciduous seedlings and medium red clover.
Ammonium Fixation in Soils
Authors: Allison F. E. , Kefauver Margaret , Roller E. M. 
Published: July 2010

AbstractLaboratory experiments are reported which show the extent to which representative soils of the United States are able to fix ammonium, and the effect of various factors on fixation and on the availability of fixed ammonium to nitrifying bacteria. Especial attention is given to the comparative values obtained with KCl and CaCl2 used as the extracting agents.It is shown that subsoils fix much more ammonium than surface soils. Considerable moist fixation may occur in soil if the predominant clay mineral is illite or vermiculite, and these values are increased by drying and heating. Montmorillonitic clays fix little ammonium unless heated.If ammonium‐saturated soils are leached with N KCl, more fixed ammonium is left than if N CaCl2 is used. Since potassium contracts some crystal lattices and calcium expands them, the value in the absence of salts would probably be intermediate.The availability to nitrifying bacteria of fixed ammonium in several soils during a period of 2 months varied between 5 and 24%, being lowest for vermiculite‐containing soils and highest for those containing montmorillonite. Leaching with CaCl2, as compared with KCl, resulted in somewhat higher availabilities of the residual ammonium.Low nitrification values for added ammonium salts were shown to be characteristic of soils that fix ammonium under moist conditions. The percentage nitrification in such soils is markedly increased if fixation is prevented.Ammonium fixation is shown to be a factor of importance in agriculture, especially where ammonium fertilizers are added to the plow sole of nonkaolinitic soils.
Major Kinds of Profiles and Their Relationships in New York
Authors: Cline Marlin G. 
Published: July 2010

AbstractThe Zonal soils of New York are members of the Gray‐Brown Podzolic, Brown Podzolic, and Podzol great soil groups. Each dominates the best‐drained sites of extensive areas, but each is associated locally with a complete catena controlled by groundwater relationships. In addition, Brown Forest soils occupy the best‐drained sites on some highly calcareous materials, and Alluvial soils occur on recent alluvium. Each of these is also associated with a complete catena.
Preliminary Study of Bolivian Soils
Authors: Storie R. Earl 
Published: July 2010

AbstractBolivia has great contrasts in topography, climate, vegetation, geology, and soils. There are three broad physiographic regions: I. Altiplano; II. Montanas‐Valles, and III. Llanos, which are divided into 11 soil subregions (as shown on Soil Region Map).The Northern Altiplano (Ia) has prairie‐like soils with many secondary soils varying from recent alluvium to claypan and hardpan soils; the Northern Andes Mountains (Ib) has Alpine Prairie soils; the Southern Altiplano (Ic) has Gray Desert soils, and the Southern Altiplano Mountains has Gray Desert lithosols.The Yungas (IIa), a region of semitropical climate, has yellow and red lateritic soils; the Cochabamba Valley (IIb), where the climate is semiarid, has Noncalcic Brown soils; and the Southern Mountains (IIc) has Noncalcic Brown upland and lithosol soils.The Gran Chaco alluvial plain (IIIa) and the Santa Cruz Plains (IIIc) have large areas of calcareous alluvial soils; the Eastern Llanos or Plains (IIId) has large areas of lateritic and laterite soils; while the Northern Tropical Plains (IIIe) has large areas of alluvial soils of slightly acid reaction.
Capillary Conductivity Values from Moisture Yield and Tension Measurements on Soil Columns
Authors: Richards Sterling J. , Weeks Leslie V. 
Published: July 2010

AbstractWater yield values are given for 35‐cm columns of two soil types, Ramona and Yolo loam. Three to four surface cm of water were withdrawn from the columns in periods of about a week, using 900 cm of water tension. Simultaneous tension values are given for four locations along the column during wetting and drying periods. Some effects of preparing the disturbed soil samples and of length of soil column are indicated.A method is suggested for calculating capillary conductivity by the use of data obtained during transient changes of moisture content and tension in a soil column. Values for Ramona loam are calculated for a tension range of 76 to 627 cm of water. Although the method is not precise, conductivity values are obtained with less complicated equipment and in a shorter time than is possible by the use of previously described methods. Capillary conductivity values seem to vary with tension independent of tension gradients.
Magnesium Deficiency of Some Northeastern Pines
Authors: Stone Earl L. 
Published: July 2010

AbstractMagnesium deficiency of Pinus resinosa, P. strobus and P. banksiana was studied in young forest plantations on light textured soils bordering the western and southwestern margins of the Adirondack province of New York.The most conspicuous symptom of deficiency was a bright yellow discoloration of the tips of the current season's needles, appearing in the fall and affecting the upper part of the tree most strongly. When the deficiency was severe the chlorosis was followed by death of the needle tips or premature loss of foliage. Gross reductions in shoot growth and needle length occurred only under extreme deficiency or when lack of magnesium was accompanied by potassium deficiency.In P. resinosa the appearance of deficiency symptoms was usually associated with magnesium contents less than .16% of the oven dry weight of mature first year foliage; with less than about .13% symptoms were severe. Fertilization with magnesium sulfate at rates of 20 to 50 lbs. Mg/acre eliminated or reduced the symptoms after a lapse of at least a year.Fertilization of deficient trees with magnesium sulfate resulted in increased height growth over a period of at least three years. In two instances this increase was shown to be additive to that due to potassium, without evidence of significant interaction.
Modulus of Rupture as an Index of Crusting of Soil
Authors: Richards L. A. 
Published: July 2010

AbstractApparatus and procedure are described for measuring the modulus of rupture of soil. Briquets approximately 1 × 3.5 × 7 cm. are formed by placing screened dry soil in brass molds, wetting for one hour by subbing and drying at 50°C. The force required to break a briquet when loaded as a horizontal beam is measured and the modulus of rupture, which is the maximum fiber stress, is calculated by the formula s = 3FL/2bd2.At Riverside, Calif., a fine sandy loam under field conditions gave no diminution of stand for beans with s equal to 108 ± 3 millibars, even though surface crusting effects were markedly in evidence. However, with the exchangable‐sodium‐percentage artificially increased to 37, it was found that s increased to 273 ± 6 millibars and no bean seedlings emerged. This failure to obtain a stand was presumably due to the increased mechanical strength of the surface crust caused by the presence of exchangeable sodium.