bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variation in Nutrient Content of Loblolly Pine Needles with Season, Age, Soil, and Position on the Crown
Authors: Wells C. G. , Metz L. J. 
Published: July 2010

AbstractThe nutrient content for the 17‐month cycle of loblolly pine (Pinus taeda) needles from the upper, middle, and bottom parts of the crown was determined for the first growth whorl of 1959. Needle weight per fascicle increased until April 1960 and then decreased slowly until abscission. Percentages of N, Ca, and Mg were greater in the needles from the bottom part of the crown, whereas P and K percentages were greater in the upper part of the crown. Percentage of N in the needles increased during winter months after the first growing season. Phosphorus percentage decreased each month for 1 year and then increased slightly. Calcium and Mg percentages in general increased throughout the growth and maturation of the needles with the content approaching a constant value during winter months. The basic influence of the soil on some plots was reflected in a two‐fold difference in Ca and a three‐fold difference in Mg content of the mature needles. It appears that about one‐half of the N, P, and K are translocated from the needles immediately before abscission.The results of this study indicate that needles of the first growth whorl of the season at the top of the crown should be sampled in August and September of the first growing season for P; from December through March for K, Ca, and Mg; and from June through September of the second growing season for N.
The Occurrence and Cause of Iron Oxide Deposits in Tile Drains
Authors: Spencer W. F. , Patrick R. , Ford H. W. 
Published: July 2010

AbstractA red sludge‐like deposit was found in several tile systems in Florida citrus groves. This deposit prevented the tile from functioning properly by blocking the passageway through which water entered the title. The deposit was found to be due primarily to “iron bacteria” which oxidize and precipitate reduced iron in the drainage water. Chemical analyses indicated a large proportion of the material was organic—probably bacterial cell bodies and waste products. The inorganic portion was mainly hydrated iron and aluminum oxides. Bacteriological studies of the material indicated the following genera of bacteria were responsible for the formation of the deposits: Gallionella, Leptrothrix, Thiothrix, Thiobacillus, Crenothrix and Cladothrix. The predominating genera within a tile line varied with location. The deposits occur in both bituminous pipe and clay tile whether installed in sawdust filter or wrapped with fiberglass. The relative amounts of the deposit in tile at various locations were related to the amounts of reduced iron extracted from the soils with an aluminum chloride solution.
Threads of Genesis in the Seventh Approximation
Authors: Cline Arvad J. , Johnson Donal D. 
Published: July 2010

AbstractA common criticism of the newly proposed system of soil classification as presented by the Seventh Approximation is its apparent departure from the genetic aspects present in the older systems. Since so much of the published text is devoted to discussions of morphology, it is easy to understand why this impression is gained at first reading. However, the impression is faulty, and the relationship between the accepted theories of soil genesis and the Seventh Approximation is more specifically drawn than was this relationship in the older systems. The major difference being that in the Seventh Approximation the relationship to genesis is drawn by specific definitions of the kind of morphology representative of a kind or a degree of genesis rather than by direct reference to a genetic process itself or its degree of activity. In nearly every case the choice of morphological character selected to be definitive for a category is based on our understanding of how these characteristics represent a specific kind or degree of genetic process.This constitutes both strength and weakness in the Seventh Approximation. Its strong relationship to genesis imparts a desirable sense of direction to the system. This same strong adherence may lead to faulty criteria or to improper selection of definitive morphological characteristics where our knowledge of genesis is imperfect. This last is inevitable under any conditions, and the advantages strongly outweigh the disadvantages.
Comparative Rates of Decomposition in Soil of Wood and Bark Particles of Several Species of Pines
Authors: Allison F. E. , Murphy R. M. 
Published: July 2010

AbstractThe finely‐ground woods and barks of 9 species of pine were allowed to decompose in soils in the presence and absence of additional nitrogen for periods of 63 to 800 days. Carbon dioxide evolution was measured at frequent intervals. The pine species studied were white, shortleaf, loblolly, slash, longleaf, ponderosa, western white, lodgepole, and sugar. An average of 16.2% of the wood carbon was oxidized in 60 days in the absence of extra nitrogen and 16.9% in its presence. The corresponding values for the barks were 8.7 and 8.6. The wood species showed variations in CO2 evolution during the 60‐day period, ranging from 8% for sugar pine to 51% for shortleaf pine. The variations for the barks were between 3.0% for white pine and 23.3% for lodgepole pine. Most of the pine woods decomposed somewhat more rapidly than did the other softwoods previously studied, but not nearly so rapidly as did the hardwoods. The pine barks are oxidized at about the same slow rate as are the other softwood barks.
A Test of the Validity of the Diffusion Equation for Unsaturated Flow of Soil Water
Authors: Rawlins Stephen L. , Gardner Walter H. 
Published: July 2010

AbstractA review of the derivation of the diffusion equation from the potential equation for unsaturated flow of liquids in porous materials reveals that the only additional assumption required is that diffusivity is a unique function of water content. The validity of this assumption is tested by following absorption of water into a horizontal column of soil with a gamma ray densitometer. To ensure that required boundary conditions were met, the soil was evacuated to eliminate entrapped air or air pressure build‐up ahead of the wetting‐front; and water was applied quickly, evenly, and at constant negative head through a plane sintered glass bead plate, pressed against the bare plane end of the column to initiate flow. Diffusivity vs. water content curves constructed from these data reveal that diffusivity is not a function of water content alone.
Estimation of Particle‐Size Effects of Water‐Soluble Phosphate Fertilizer in Various Soils
Authors: Burns G. R. , Bouldin D. R. , Black C. A. , Hill W. L. 
Published: July 2010

AbstractA laboratory method was developed for estimating the relative availabilities to plants of the P applied to soil in fertilizer particles differing in size. The method is based on the concept that the total availability of fertilizer P applied in particles of a given size is equal to the product of (a) the number of particles of that size, and (b) the summation of the availabilities of fertilizer P in the hypothetical small volumes of soil that may be considered to comprise the total volume of soil affected by a single particle. The method was applied experimentally to NaH2PO4·H2O particles of three sizes in each of six soils. In this application, appropriate quantities of a concentrated solution of P32‐tagged NaH2PO4 were used to stimulate the effects of fertilizer particles of different sizes, and particles of anion‐exchange resin were used to provide indexes of availability of fertilizer P in segments of the soil affected by one fertilizer particle. These values were integrated to obtain an index of total availability of fertilizer P. The indexes of total availability obtained from the laboratory data were in qualitative agreement with the relative availabilities of fertilizer P to plants in five of the six soils tested.
Moisture Conservation by Surface or Subsurface Barriers and Soil Configuration under Semiarid Conditions
Authors: Willis W. O. , Haas H. J. , Robins J. S. 
Published: July 2010

AbstractConservation of moisture under field conditions using black, polyethylene film and soil ridging was studied during a 2‐year period. Corn, in 42‐inch rows, was used as an indicator crop. Results show a minor surface ridge, 90% film‐covered, to be effective in conserving moisture and increasing yield and water use efficiency. Results also indicate that ridges without covering may conserve moisture. Subsurface barriers were not effective in moisture conservation or in increasing yields under the conditions studied. Good performance of the covered surface ridges is attributed to increased soil temperature in the spring, better utilization of light rains and suppression of evaporation losses. Supplementary laboratory studies of covered surface ridges substantiated the reasons given for improved moisture conservation.
Nutrition Research: Some Problems of the Total Tree Approach
Authors: Madgwick Herbert A. I. 
Published: July 2010

AbstractTotal tree analysis can yield an inventory of nutrients within a stand and, indirectly, a measure of nutrient uptake. The latter may be obtained more accurately by a combination of methods. Stand weight is best estimated by relating tree size to weight from large, intermediate, and small trees. Accurate estimation of nutrient concentrations requires sampling from additional size classes. Attempts to sample average trees yield biased estimates. The number of sample trees required per stand varies with stand characteristics. Five trees per plot gave average prediction errors between 7 and 23% for different parts of red pine trees. To be commensurate with the field work required, laboratory techniques should be of high quality and include analysis for a wide range of elements. Although too cumbersome for a diagnostic tool and, probably, too damaging for use in most permanent sample plots this technique can yield much basic information on stand nutrition and related problems.
Effect of Anions on the Sodium‐Calcium Exchange in Soils
Authors: Babcock K. L. , Schulz R. K. 
Published: July 2010

AbstractSamples of Yolo fine sandy loam were leached with two series of solutions of solutions containing Na and Ca in which the composition varied. In each series the composition of the solutions in the corresponding solutions was the same except that in one series the anion was chloride and in the other it was sulfate. After leaching the samples to equilibrium, the exchangeable sodium was higher for the sulfate series than for the chloride series. This may be attributed to the effect of the different activity coefficients of the salts used. The results have significance for efforts to evaluate water quality.
Role of Biological Oxidation and Organic Matter Solubilization in the Subsidence of Rifle Peat
Authors: Hayes M. H. B. , Mortensen J. L. 
Published: July 2010

AbstractNatural profile columns of Rifle peat were obtained by driving asphalt coated steel cylinders into the soil. The columns were incubated in the laboratory for a 102‐day preamendment period. Carbon‐14 labelled rye tissue was then mixed with the upper 6 inches of the soil profile and the columns were incubated for an additional 107 days. Irrigation water was applied and CO2 evolution and organic matter in the drainage water were determined throughout the incubation period.The pattern of CO2 evolution and carbon balance relationships were considerably different from that obtained when small samples of disturbed, air‐dried peat were incubated with plant tissue. There was no evidence of “priming action” due to the addition of tissue, but considerable amounts of organic matter were lost in the drainage water. The addition of plant tissue reduced the rate of biological oxidation of Rifle peat. Tile systems should be placed below a horizon which adsorbs water‐soluble organic matter if loss of organic matter in drainage water is to be controlled.
Corn Response to Time and Rate of Phosphorus Applications
Authors: Seatz Lloyd F. , Sterges Athan J. 
Published: July 2010

AbstractA greenhouse experiment was conducted to study the effects of rate and time of P applications on the growth and P uptake of corn. Different initial rates of P were applied and supplementary P was applied to make all treatments equal to the highest initial rate of 105 pounds P per acre. These supplementary applications were made to one set of each initial treatment at weekly intervals for 7 weeks after planting.In most cases the yield was lower if the supplementary P was not applied within 4 weeks after planting. The higher the initial rate of P the longer the supplementary application could be delayed without yield reduction. In most instances the total P uptake was greatest when the supplemental P was applied 5 or more weeks after planting.A critical period no doubt exists in the development of corn before which P must be available if it is to increase plant growth. If P becomes available after this critical period it will be absorbed by the plant and will be reflected in a higher percentage P composition.
The Effectiveness of a Cotton Bur Mulch and a Ridge‐Furrow System in Reclaiming Saline Soils by Rainfall
Authors: Fanning Carl D. , Carter David L. 
Published: July 2010

AbstractA cotton bur mulch facilitated leaching of soluble salts by rainfall. Salt concentration was reduced in the surface 30 inches of soil to a level below that considered detrimental to growth of field crops. The high efficiency of salt removal by rainfall was attributed to flushing of salts from conducting pores when rains occurred combined with diffusion of salts from nonconducting to conducting pores between rains. Exchangeable Na percentage was also reduced to a low level. A ridge‐furrow system facilitated leaching of salts from below the furrows, but less effectively than the mulch system. Salts returned to the leached zones beneath the furrows, whereas no appreciable return was evident under the mulch. Either practice may prove useful in management of saline soils of the study area and similar locations.
Effect of Fertilizers on the Conductivity of Saturated Soil Extracts
Authors: Chapin J. S. , Fisher F. L. , Caldwell A. G. 
Published: July 2010

AbstractVarying concentrations of fertilizers were mixed with Yahola fine sandy loam, Norwood silt loam, and Miller clay. Conductivity of the saturation extract was determined using a Wheatstone bridge. There was a marked difference in the conductivity caused by the different fertilizer materials. The fertilizers used are arranged in order of increasing effect (based on weight per unit of soil) on conductivity of the saturation extract: urea, ordinary superphosphate, concentrated superphosphate, phosphoric acid, monoammonium phosphate, diammonium phosphate, potassium sulfate, ammonium nitrate, and potassium chloride. Urea was unique in that the conductivity of the saturated extract increased with time of incubation.
Movement of Molybdenum in the Soil and its Effect on Availability to the Plant
Authors: Lavy T. L. , Barber S. A. 
Published: July 2010

AbstractThe processes involved in Mo availability to corn and soybeans growing in soil were investigated. Both mass‐flow and diffusion were involved. Mass‐flow caused Mo to accumulate at or in the root when the saturation extract contained more than 4 ppb. Mo. Diffusion patterns were usually obtained by autoradiographic procedures when the content was below 4 ppb. The saturation extracts of the soils investigated ranged from 2.2 to 8.1 ppb. Mo. The content of labile Mo in the soil varied from 41 to 211 ppb. of soil. The values of Dp/b for Mo varied from 0.5 to 8.4 × 10‐7cm.2 sec.‐1 and were much larger than for phosphorus.
Acidulation of Phosphate Rock in Soil
Authors: Terman G. L. , Moreno E. C. , Osborn Glen 
Published: July 2010

AbstractSulfur, H2SO4, H‐resin, and 20% superphosphate were compared as acidulants for phosphate rock (PR) as the source of P for corn grown on Hartsells fine sandy loam (pH 5.2 and 6.3) in greenhouse pot experiments. Effectiveness of granular fertilizers for supplying P to the crops decreased as follows: PR + superphosphate > PR + H‐resin > PR + S > PR alone. An intermediate size of granules of PR + S + soil was more effective than either coarser or finer material. H‐resin added to spots of PR in the soil was much more effective in solubilizing P than equivalent amounts of acid as H2SO4 or S. Acidulating PR in the soil with H‐resin or H2SO4 was considerably less effective for solubilizing PR than acidulation prior to application.
A Pedological Characterization of Five Profiles in Gray Wooded Soils Area of Minnesota
Authors: Harpstead Milo , Rust R. H. 
Published: July 2010

AbstractFive soil profiles from the Gray Wooded soils area of Minnesota were investigated in the field for morphological characteristics and in the laboratory for physical, chemical and mineralogical properties. This Gray Wooded soils area has a cool humid climate, mixed coniferous and deciduous vegetation and the profiles studied were developed in well‐drained glacial till of late Wisconsin age.X‐ray diffraction patterns revealed a wide variety of clay minerals. In most cases Ca2+ was the dominant ion on the exchange complex. The upper portion of the B horizon was the most acid part of the profiles with pH values as low as 4.7. Various types of clay films, found to be well developed in the argillic B horizons, were investigated in thin‐sections. The degradation of peds in the A and B horizon was also studied with thin‐sections.A classification of these soils according to the 7th Approximation is suggested.
Evaluation of a Radioactive Tracer Method for Measuring Water Intake of Soils
Authors: Meek B. D. , MacKenzie A. J. , Stockinger K. R. 
Published: July 2010

AbstractA tracer method of measuring water intake by application of radioactive gold in the irrigation water was evaluated. When irrigation water containing a constant known amount of isotope is applied to the soil, the amount of isotope adsorbed is proportional to the amount of water entering the soil. To calculate water intake the amount of isotope adsorbed is determined by measuring the activity of soil samples taken in the field. Two factors, vertical distribution of the tracer in the soil, and magnitude of adsorption on the soil surface from flowing irrigation water, were studied. The radioactive tracer was not measurably lost by adsorption from the tagged water as it flowed over the soil surface. It was adsorbed near the soil surface and sampling to a depth of 6 cm. recovered 95% of the gold in Holtville clay loam. The method was used to determine water intake variability. Samples within a plot had an average coefficient of variability of 9%. This would require 7 samples to determine the mean water intake within 10% at the 1% level.
Chemical and Physical Properties of Soils in a Wet Saline Area in Eastern North Dakota
Authors: Sandoval Fred M. , Benz L. C. , Mickelson R. H. 
Published: July 2010

AbstractA large, imperfectly drained saline soil area in the Red River Valley of North Dakota (glacial Lake Agassiz) was characterized chemically and physically. Two main problem areas were differentiated: one where soils were derived from deep lacustrine sediments of low bulk density with high Mg content frequently, and another, where dense glacial till was close to the surface and was found similar in composition to deep artesian waters having higher contents of Na and B. Dolomite was high in the lakelaid soils with montmorillonite the principal clay mineral. Composition of shallow ground waters was similar to ambient soils. The principal problem is excessive concentrations of soluble salts influenced by shallow water tables. Several chemical and physical interrelationships are explained.
The Effect of pH on Potassium Fixed by an Irreversible Adsorption Process
Authors: Page A. L. , Ganje T. J. 
Published: July 2010

AbstractThe irreversible adsorption of K by soils, vermiculite, and illite under moist conditions was studied over a range of pH 3 to 8. The amounts of K irreversibly adsorbed by the vermiculite and soils that contained biotite‐weathering products were independent of the soil‐ or clay‐solution equilibrium pH as long as the concentration of Al in the systems was kept low. The results were interpreted to indicate that K, which is fixed by irreversible adsorption, is associated only with the permanent charge component of the exchange complex.Acid‐leaching the soils destroyed their capacity to irreversibly adsorb K from KCl solution at pH 3 and markedly reduced their exchange capacities at the same pH. The acid‐leached soils contained relatively large concentrations of base‐titratable Al, which were nonreplaceable with either 1.0N NaCl or 1.0N KCL. Therefore, the results indicate that difficultly replaceable Al on the exchange sites of the acid‐leached soils prevented the adsorption of K on sites which were capable of irreversibly adsorbing it.
A Soil Test for Phosphorus Based Upon Fractionation of Soil Phosphorus: II. Development of the Soil Test
Authors: Al‐Abbas A. H. , Barber S. A. 
Published: July 2010

AbstractThe correlation of soil P fractions with P uptake by millet was used as a basis for developing a soil test. The soil test consists of shaking 1 g. of soil with 20 ml. of solution made up from 17 ml. of 0.3N NaOH and 3 ml. of 0.5N Na2C2O4. The shaking time had little effect on the amount extracted. The soil test works particularly well on soils of pH above 7.
The Effect of Some Chemical Environmental Factors on Cotton Root Behavior
Authors: Rios M. A. , Pearson R. W. 
Published: July 2010

AbstractA vertical split‐root technique is described that permitted the measurement of effects of various ions in the subsurface zone on root development. The surface zone consisted of an adequately limed and fertilized sandy loam soil. Cotton roots failed to develop in the lower zone in the absence of Ca, showing that cotton was unable to translocate Ca downward at a rate that would sustain root growth. Development of cotton roots was not prevented by the absence of P in the rooting medium, showing that the translocation rate of P was adequate to supply these roots from surface soil sources. Concentrations of soluble Al as low as 1 ppm. prevented root growth of cotton seedlings and concentrations of 0.5 ppm. greatly reduced root development and caused severe symptoms of toxicity. Even when roots were severely damaged no effects were observed in the tops. Damage to the subsurface roots by Al was not prevented either by liming and fertilization of the surface soil, or by the presence of adequate Ca in the rooting medium itself. High concentrations of Mn did not affect root growth directly.
Soil Viscoelasticity: Superposition Tests
Authors: Waldron Lawrence J. 
Published: July 2010

AbstractViscoelasticity is a linear deformation theory in which time‐dependence of stress‐strain ratios conforms to the Boltzmann superposition principle. Three types of superposition tests were made on briquets of Yolo silt loam subjected to torsional deformation. The principle was found to be valid when stress, stress duration, and soil water content were kept below certain limits. Deviation from linear behavior as these limits were exceeded first appeared as non‐Newtonian flow rather than as non‐Hookean (instantaneous) elastic response. Where the principle applies, there is a structural stability under deformation which makes viscoelasticity promising for relating mechanical behavior to soil‐water structure.