bluuebunny/crossref_metadata_2025_split huggingface dataset:
Site Index Comparisons for Several Forest Species in the Southern Appalachians
Authors: Doolittle Warren T. 
Published: July 2010

AbstractThis paper gives methods and results of a study of relationships of site indices of 10 tree species common in the Southern Appalachians. These species are: scarlet oak, black oak, northern red oak, chestnut oak, white oak, white pine, shortleaf pine, pitch pine, Virginia pine, and yellow‐poplar. Site indices of the 10 species were correlated by regression methods so that when the site index of 1 species is known for a given piece of land, it is possible to determine, by use of equations or a chart, the site index for 1 or all of the other 9 species. Results of a special field test showed that the standard error of estimate for predicting site index of scarlet oak from other species was ±5.36 feet by using equations and ±5.28 feet by using the chart. White pine had the highest site index on all lands or sites except on the best, where yellow‐poplar was superior. Of all species, the chart shows that yellow‐poplar is the most responsive to site change; it has the highest site index on the best sites and the lowest site index on the poorest sites.
Nature of the Reactions of Monocalcium Phosphate Monohydrate in Soils: I. The Solution That Reacts with the Soil
Authors: Lindsay W. L. , Stephenson H. F. 
Published: July 2010

AbstractThe dissolution of monocalcium phosphate monohydrate (MCP) in water was followed over a 17‐day period; and the resulting solution was compared with solubility isotherms of the system CaO‐P2O5‐H2O at 25°C. Shaking excess MCP with water at room temperature resulted in rapid dissolution during the first few minutes. Within an hour and continuing for more than 24 hours, the solution was in metastable equilibrium with newly formed dicalcium phosphate (DCP) dihydrate and undissolved MCP. The composition of the solution later changed as anhydrous DCP slowly precipitated and the first‐formed DCP dihydrate dissolved. The final solution was in equilibrium with anhydrous DCP and undissolved MCP.Band placement of MCP in soil was found to initiate a series of reactions. The solution phase from the reaction zone was sampled by means of filter papers separating several 5‐mm. layers of Hartsells fine sandy loam. Reduced water vapor pressure at the fertilizer band caused water to move inward from the surrounding soil. This transport of moisture resulted from both liquid and vapor movement. A wetted zone formed in the immediate vicinity of the band. The solution sampled at the fertilizer band approximated very closely the composition of the metastable triple‐point solution (MTPS) in which P is 3.98M, Ca 1.44M, and pH 1.48. This highly concentrated solution moved slowly away from the fertilizer band into the partially dried soil, dissolving Fe, Al, Mn, and other constituents from the soil. In this complex chemical matrix many different phosphate compounds of Fe, Al, Ca, and Mn are expected to precipitate as the solution reacts with more soil and pH rises gradually to that of the surrounding soil. Water continued to move into the fertilizer zone even after MCP had dissolved. This caused dilution of the first‐formed solution and enabled it to move farther into the surrounding soil.
Adsorption of N‐Butane by Kaolinite and Montmorillonite: Phase Changes in the Monolayer Region
Authors: Jurinak J. J. , Volman D. H. 
Published: July 2010

AbstractThe adsorption of n‐butane by Ca‐kaolinite and Ca‐montmorillonite, using high vacuum technique, was studied to determine the nature of the differences that occur during the adsorption of nonpolar molecules by clay minerals. The adsorption is described in terms of a 2‐dimensional mobile film with the spreading pressure, ϕ, calculated by the integrated Gibbs equation. At surface coverages of < 4%, the adsorbed films on both surfaces can be described as an ideal 2‐dimensional gas, i.e., ϕA = kT, where A is the molecule area, k is Boltzman's constant, and T is the absolute temperature. Throughout the monolayer region, adsorption of n‐butane could be described as either a perfect or imperfect gaseous film. The ϕA — ϕ curves show that a transition from a liquid expanded to a liquid intermediate phase occurs in the imperfect gas region of both clay systems. The differences noted in the nature of the phase changes on both surfaces coupled with the isosteric heats of adsorption is explained on the basis that kaolinite is essentially nonporous and has a homogeneous surface, whereas the presence of capillary pores dominates the adsorption of n‐butane by montmorillonite.
Digestion of Clay‐Protein, Lignin‐Protein, and Silica‐Protein Complexes by Enzymes and Bacteria
Authors: Estermann Eva F. , Peterson G. H. , McLaben A. D. 
Published: July 2010

AbstractAs a contribution to an understanding of the stability of organic matter in soil, and to knowledge of microbial activity at solid‐liquid interfaces generally, the relative influence of clay‐protein and lignin‐protein complex formation in retarding protein mineralization by enzymes and bacteria is evaluated. We have found that monolayers of lysozyme adsorbed on kaolinite and bentonite can be digested by chymotrypsin, mixed soil cultures, and pure cultures of B. subtilis, B. mycoides, and Pseudomonas sp. In contrast, lignin‐protein complexes are extremely resistant to attack. Montmorillonite‐protein monolayer formation retards the rate of enzymatic proteolysis; however, most of the protein can be hydrolyzed under optimum conditions in one day with a resultant decrease in X‐ray diffraction (001) spacings. For equal clay surface areas, a mixture of soil infusion organisms or pure cultures of soil organisms hydrolyze protein freshly adsorbed on montmorillonite or kaolinite at rates nearly equal to that of free, i.e., nonadsorbed, protein, all being compared in aqueous suspension. A decrease in X‐ray (001) spacing of protein‐montmorillonite complexes is observed following digestion by the organisms. Dried, rewetted montmorillonite‐protein complexes are more resistant to attack by soil organisms than freshly prepared complexes. Complexes of protein with silica gel are somewhat comparable to lignin‐protein complexes in being resistant to digestion by Pseudomonas sp.
The Influence of Soil Conditions, Following Tractor Logging, on the Growth of Planted Douglas‐Fir Seedlings
Authors: Youngberg C. T. 
Published: July 2010

AbstractGrowth of planted Douglas‐fir seedlings was investigated on Reddish Brown Latosol soils on two cutover areas in the Cascade Mountains of western Oregon.In April 1955, 2‐0 seedlings were planted on tractor roads, in loose berm material adjacent to the tractor roads, and on undisturbed cutover condition. First‐year survival for all conditions was over 90%. Annual height measurements were made at the end of the 1955 and 1956 growing seasons. Differences in height growth between seedlings on the cutover condition and those on the berm and tractor road conditions were highly significant. Seedling growth differences between berm and tractor road conditions were also statistically significant in several instances. Soil analysis data indicated poor growing conditions on the tractor roads, particularly in regard to aeration, moisture, and N relationships.
Outline of a Generalized Theory of Soil Genesis
Authors: Simonson Roy W. 
Published: July 2010

AbstractProcesses of soil formation have been related to prominent great soil groups by means of names such as podzolization, laterization, and solonization. A change from this point of view seems necessary when soils of the world are considered as a continuum with a number of properties in common. It is therefore proposed that soil genesis be considered as two overlapping steps; viz, the accumulation of parent materials and the differentiation of horizons in the profile. Of these two steps, the second is of more immediate concern to soil scientists.Horizon differentiation is ascribed to additions, removals, transfers, and transformations within the soil system. Examples of important changes that contribute to development of horizons are additions of organic matter, removals of soluble salts and carbonates, transfers of humus and sesquioxides, and transformations of primary minerals into secondary minerals. It is postulated that these kinds of changes, as well as others, proceed simultaneously in all soils. It is further suggested that the balance within the combination of changes governs the ultimate nature of the soil profile. If this point of view is valid, the same kinds of changes occur in horizon differentiation in soils as unlike as Chernozems and Latosols, but the balance among the processes is not the same.
Genesis of Miami Silt Loam
Authors: Thorp James , Cady John G. , Gamble Erling E. 
Published: July 2010

AbstractMiami silt loam and other Gray‐Brown Podzolic soils of the United States and Canada are developed from calcareous parent materials of glacial, glacial‐fluvial or loessial origin; a large proportion of these materials were deposited during the Wisconsin stage of glaciation. Study of thin sections with polarized light shows clearly that much of the clay of the B2 horizon has been carried in by water and deposited. Studies of the clay fraction of the soil and parent material indicate that much of the clay was either unaltered or has been transformed from clay originally present, but that some was formed by weathering of primary minerals. Characteristics of the A horizon may be ascribed to the joint effects of leaching, eluviation, and the influence of the broad‐leaved deciduous forest and the associated macro‐ and micro‐fauna. Recent leaching experiments, using “undisturbed” soil columns of Miami silt loam, suggest that B horizons are developed primarily through translocation of suspended fine clay and some humus, especially after the periods of soil drying in late summer and early autumn.
The Genesis of the Red‐Yellow Podzolic Soils
Authors: McCaleb Stanley B. 
Published: July 2010

AbstractMineralogical, chemical, physical, and morphological data are given for 18 profiles of Red‐Yellow Podzolic soils. These soils represent 3 profiles each of 2 sequences, one derived from acid crystalline rocks and the other from sandstones. Six profiles of Reddish Brown Lateritic soils are included for comparison where appropriate.Differences between sequences and within sequences are due either to inherited or to genetic properties, both of which are related to or limited by parent material. All properties studied follow the same kind of distribution with depth. Differences in magnitude reflect inherited differences, whereas the kind of distribution reflects similar genetic differences under uniform environments. Apparent discrepancies in the distribution with depth of clay content, exchange capacity, and associated properties occur as differences in parent materials. Differences in secondary products are also related to differences in parent materials and in turn are related to the observed differences.Suggested mechanisms for the genesis of these soils and their characteristic mottling are presented. The Red‐Yellow Podzolic soils are compared to the Gray‐Brown Podzolic soils in terms of probable genesis.
Relative Water Losses by Evaporation and Transpiration in Field Corn
Authors: Peters D. B. , Russell M. B. 
Published: July 2010

AbstractThe separation of transpiration by corn and evaporation from the soil was experimentally accomplished, in the field, by covering the ground surface with polyethylene plastic. It was found that as much as 50% of total evapotranspiration could be accounted for by evaporation from the soil surface. Transpiration was found to be influenced in a minor way by plant population and soil moisture environment. Corn yields were depressed in only 1 year by elimination of summer rainfall.
Theoretical Aspects of Flow Above the Water Table in Tile Drainage of Shallow Homogeneous Soils
Authors: Bouwer Herman 
Published: July 2010

AbstractHypothetical conductivity‐tension relationships were employed in a study to determine the effect of the thickness of the capillary fringe and the relative conductivity above the capillary fringe on drainage flow. Solutions were obtained with an electrical resistance network using equivalent conductivities.A capillary fringe of 50 cm. increased the drainage coefficients in shallow soil by 24 to 57%, depending on the height of the water table. Smaller increases can be expected with decreasing thickness of the fringe and increasing depth of the impermeable layer. Agreement existed between the results of the network analyses and calculated drainage coefficients, including the effect of the capillary fringe with Hooghoudt's method.The effect of the flow above the capillary fringe on the drainage coefficient appeared to be small so that the flux across the top of the capillary fringe can be assumed to be uniform. Steady‐state drainage coefficients, therefore, can be used to calculate the rate of fall of the water table after cessation of rain when the region near the top of the capillary fringe becomes a source of almost uniform flow because of drainage of pore space.For a certain water‐table position midway between drains, the water table in the vicinity of the drains appeared to be higher with increasing thickness of the capillary fringe. Since hysteresis causes the fringe thickness to be greater for falling water tables than for rising water tables, lower water tables near the drains can be expected with the latter.
Certain Physico‐Chemical Properties of the Pinchen Clay and the Function of Its Free Iron Oxide and Organic Matter
Authors: Kun‐Huang Houng , Tsen‐tuo Chen 
Published: July 2010

AbstractTension‐moisture content relationships of the deferrated soils and control soil indicated that available moisture was reduced from 10.3% to 7.3% as the result of deferration.From the study of vapor adsorption isotherms, the constants of the BET equation were derived. Deferration increased the standard free energy of adsorption of water on the bare surface, ΔF°1, and decreased the specific surface, S, while oxidation decreased both ΔF°1 and S. The deferrated clay was dispersed easier by humic acid, showed less buffering effect against Ba(OH)2, and a decrease in exchange capacity; whereas oxidized clay gave a stronger buffering effect against NaOH. The energy of replacement of Ca by K showed no difference between variously treated clays, indicating binding force of cations at exchange sites was little affected by presence of organic matter or iron oxide.It was concluded that the principal clay minerals and free iron oxide forming fine porous coating might be regarded as the dominant factors affecting moisture and surface characteristics of the Pinchen clay.
Calcium Phosphate Fertilizers: III. The Effect of Surface Area on the Availability Coefficients of the Dicalcium Phosphates
Authors: Bouldin D. R. , Sample E. C. 
Published: July 2010

AbstractSeveral granule sizes (ranging from 20 to 40 mesh to < 325 mesh) of dicalcium phosphate dihydrate (DCPD) and anhydrous dicalcium phosphate (DCPA) were compared in a greenhouse experiment with corn forage grown on Mountview silt loam, pH 6.6. Several comparable screen‐size separates varied with respect to the size of the component crystals. Plant response increased with decreasing granule size.Geometric surface areas of the fertilizers were estimated from the counted number of granules and the size of the granules. Relative rates of solution, which are roughly proportional to geometric surface area, were also measured.The linear correlation coefficients between (a) availability coefficient indexes and geometric surface area were 0.94 and 0.69 for the DCPA and DCPD fertilizers, respectively, and (b) availability coefficient indexes and relative rates of solution were 0.98 and 0.85 for the DCPA and DCPD fertilizers, respectively.The results of these experiments indicate that the availability coefficients of different granule sizes of DCPD and DCPA are primarily dependent upon geometric surface area of the granules and are not much influenced by variations in size of the component crystals in the granule. Per unit of surface area, the availability coefficient of the DCPD is about 2.3 times that of the DCPA.
Extractable Sulfate‐Sulfur in Soils of Florida in Relation to Amount of Clay in the Profile
Authors: Neller J. R. 
Published: July 2010

AbstractSulfate‐S was extracted from the profiles of a number of uncropped soils, using samples obtained in soil surveys. The extractant used was sodium acetate adjusted to pH 4.8 with acetic acid.Little or no sulfate‐S was found in the surface horizons of the soils studied but considerable amounts were present in many of the subsurface layers. These deposits of sulfate‐S were found generally where clay was present in the profile. The amounts of sulfate‐S increase with increase in clay in a highly significant manner and generally at a much greater rate of increase. There appears to be some relation between amounts of sulfate and types of clay.Rainfall on these soils adds about 5 pounds of S annually per acre and much of this sulfate probably leaches down through the sandy surface layers that characterize many of the soils of Florida.
Solubility Criteria for the Existence of Variscite in Soils
Authors: Lindsay W. L. , Peech Michael , Clark J. S. 
Published: July 2010

AbstractThe pKsp value of a highly purified synthetic variscite, Al(OH)2H2PO4, was found to be 30.5 at 25° C. The equilibrium between variscite and its constituent ions in solution was attained only very slowly. The solubility criteria obtained in this study would indicate that the immediate reaction products of applied phosphate in acid soils are much more soluble than variscite but, upon ageing, these intermediate reaction products are slowly transformed into variscite which may coexist with gibbsite as stable solid phases.
Rubidium‐Potassium Relations in the Soil‐Plant System
Authors: Fried Maurice , Hawkes George , Mackie W. Z. 
Published: July 2010

AbstractPotassium and Rb are taken up by plants in a constant ration to that in the substrate, when the substrate is a resin sand mixture. In soils the apparent independent reactions of K and Rb with the soil dominate the supply of these ions to the plant. These reactions tend to mask the competition that is presumed to occur between these ions in the ion uptake process. Increase in the rate of applied Rb was shown to decrease the percent of the added Rb fixed and markedly increase the percent of the added Rb taken up by the plant. High rates of applied K had only a slight effect on Rb uptake. Rubidium did not appear suitable as an “isotope” of K in soil studies.
Soil Temperature and the Early Growth of Corn from Mulched and Unmulched Soil
Authors: van Wijk W. R. , Larson W. E. , Burrows W. C. 
Published: July 2010

AbstractOn corn plots in Iowa, South Carolina, Ohio and Minnesota which were treated with oat straw either plowed under or on the surface and with two levels of N, measurements were made of soil temperature at the 4‐inch depth, and these measurements were correlated with dry matter yields of corn early in the season. The data from Iowa, Minnesota and Ohio support a theory that early season corn growth is decreased by low temperatures caused by a mulch of crop residues. The data from South Carolina, where soil temperatures were considerably higher than in the three other states, showed that the mulch did not appreciably influence the growth rates. The data from all four of the states agreed in a general way with data of Lehenbauer who found that for a range of temperatures from about 50° to 86° F. there is an increase with temperature of seedling growth rate; whereas around 86° to 90° F. there is little influence; and from about 90° to 111° F. there is a decrease. From the soil temperature measurements taken at a 4‐inch depth it was shown how temperatures for other depths could be deduced from a theoretical expression based on heat flow theory. A detailed example of the use of the heat flow theory in studying the mulch problem in practical experimentation is presented.
Differential Thermograms of Selected Organic Acids and Derivatives
Authors: Chesters G. , Allen O. N. , Attoe O. J. 
Published: July 2010

AbstractThirty‐eight organic acids and derivatives were characterized by differential thermal analysis (DTA) employing free access of air. Each thermogram was readily distinguished from the others, inclusive of such closely related acids as fumaric and maleic (cis‐trans isomers), and pyrogallic acid (1:2:3 trihydroxy‐benzene) and phloroglucinol (1:3:5 trihydroxy‐benzene). In general, the peaks were sharp and duplication of the thermograms was highly satisfactory. Although the mechanism involved was not clearly elucidated, the thermograms evidenced fundamental differences in molecular structure.
The Formation of Nitrate from Ammonium Nitrogen in Soils: III Influence of Temperature and Initial Population of Nitrifying Organisms on the Maximum Rate and Delay Period
Authors: Sabey B. R. , Frederick L. R. , Bartholomew W. V. 
Published: July 2010

AbstractA number of soils of varying properties were incubated at several temperatures and rates of inoculation of nitrifying organisms to determine the influence of these factors on nitrification. The time‐nitrification curve generally exhibited a “delay” phase and a “maximum rate” phase followed by a phase in which the rate of nitrification declined as the substrate was exhausted and the end product concentration increased. Each phase must be measured and characterized before difference in nitrification in soils can be fully understood and described.In soils incubated at field capacity, the maximum nitrification rates increased from immeasurably low values to as great as 900 ppm. per week in some soils and the delay periods decreased from about 32 weeks to < 1 day, as temperatures increased from 0 to 25° C. Increase in initial population of nitrifying organisms caused decreases in delay periods but did not appreciably affect the maximum rate above 10° C. The influence of temperature and nitrifying population on delay periods and maximum rates varied greatly among soils indicating that other factors inherent in the soils also affect nitrification.
Chemical and Clay Mineralogical Properties of Certain Memphis Catena Soils of Western Kentucky
Authors: Hutcheson T. B. , Lewis R. J. , Seay W. A. 
Published: July 2010

AbstractChemical and clay mineralogical properties of Memphis, Grenada, Calloway and Henry series were determined and related to degree of internal drainage and genesis. Percent base saturation and other chemical data indicated that the more poorly drained profiles were more severely leached than better drained members. These data, together with the occurrence of larger proportions of expanding lattice 2:1 type minerals to nonexpanding 2:1 types in the more poorly drained profiles, suggest that a high degree of weathering was attained before pan horizon formation occurred.The presence of lower exchangeable Ca/Mg + Na ratios along with lower montmorillonite/vermiculite ratios in B3m horizons than in deeper or shallower horizons suggests that the pans are the result of packing of dispersed clay particles and that vermiculite has formed from montmorillonite or other weathering products in those horizons.
Cholesterol as a Standard in the X‐Ray Diffraction of Clay Minerals
Authors: Kittrick J. A. 
Published: July 2010

AbstractCholesterol was found to be a satisfactory standard with which to align X‐ray diffractometers for work with the relatively long spacings which are the chief diagnostic characteristic of clay minerals. Sensitivity of peak intensity and position to various diffractometer adjustments was determined, and improved results with clay minerals were demonstrated. Alignment of the diffractometer at some relatively short spacing introduces the risk of obtaining a long‐spacing peak of diminished intensity or no peak at all. However, good alignment at a relatively long spacing ensures good alignment at shorter spacings as well.