Showing papers in "Soil Science in 1973"
TL;DR: The relationship between ionic strength and electrical conductance (EC) developed by Ponnamperuma et al. as discussed by the authors was corrected for ion-pair formation and extended to more saline aqueous extracts.
Abstract: The relationship between ionic strength and electrical conductance (EC) developed by Ponnamperuma et al. (1966) was corrected for ion-pair formation and extended to more saline aqueous extracts. The linear regression for the ionic strength and the EC of 27 soil extracts and 124 river waters
402 citations
TL;DR: The phenomenon of addition of eolian mineral particles to soils during their genesis modifies the classic concept of soil development from underlying parent materials was investigated in this article, where the authors reported the presence in many soils of dust particles that had been transported relatively short or
Abstract: The phenomenon of addition of eolian mineral particles to soils during their genesis modifies the classic concept of soil development from underlying parent materials. Numerous evidences have been reported of the presence in many soils of dust particles that had been transported relatively short or
338 citations
329 citations
TL;DR: In this paper, a two-constant rate equation was developed which successfully described the rate of phosphate adsorption by hematite and gibbsite conformed to the Freundlich equation.
Abstract: The phosphate adsorption by hematite and gibbsite conformed to the Freundlich equation. The rate of phosphate adsorption was rapid initially and decreased with prolonged reaction time. A two-constant rate equation was developed which successfully described the rate of phosphate adsorption. T
218 citations
TL;DR: In this article, the general properties of flux-concentration relation [F(θ) are established for various phenomena: one-dimensional sorption and infiltration with constant concentration conditions and one dimensional sorption (for the linear soil only) with constant and variable flux and variable concentration conditions.
Abstract: The flux-concentration relation [F(θ)] expresses in reduced form the dependence of flux density on moisture content during various unsteady flow phenomena in unsaturated soils. In this first paper of a series, the general properties of F(θ) are established for various phenomena: one-dimensional sorption and infiltration with constant concentration conditions and one-dimensional sorption (for the ‘linear’ soil only) with constant and variable flux and variable concentration conditions. These studies provide a guide to the properties of F(θ) in more complicated phenomena in one-, two-, and three-dimensional systems. F(θ) is independent of time for some phenomena and it varies only mildly with time for some others; and, for some phenomena, the dependence of F(θ) on the ‘shape’ of the moisture diffusivity function lies within fairly narrow bounds, which are fixed by reference to the extreme cases of the ‘delta-function’ and the ‘linear’ soil. This relative stability of F(θ) makes it a useful aid to the study of methods of solving the unsaturated flow equation. It is employed in later papers in a critique of Parlange's method and in the development of a new quasi-analytical technique. An appendix demonstrates that the approximation of step-function moisture profiles implies a delta-function moisture diffusivity function.
143 citations
TL;DR: In this article, Humic acid is readily available from leonardite, a naturally occurring oxidized form of lignite coal, and it has been found to greatly promote root initiation of Pelargonium hortorum cuttings.
Abstract: Humic acid is readily available from leonardite, a naturally occurring oxidized form of lignite coal. Humic materials have been found to greatly promote root initiation of Pelargonium hortorum cuttings. Sodium humate, humic acid, fulvic acid, and leonardite produced a proliferation of roots at optimum concentrations of 0.05%, 0.05%, 0.05%, and 0.5%, respectively. Pea root tip elongation measurements indicated that the humic materials possess auxin activity.
136 citations
136 citations
TL;DR: In this paper, onion roots infected with the endomycorrhizal fungi Endogone mosseae and E. fasciculata had high levels of radioactivity when 32P-labeled phosphate was incorporated in soil 27 mm from the root surface.
Abstract: Segments of onion roots infected with the endomycorrhizal fungi Endogone mosseae and E. fasciculata had high levels of radioactivity when 32P-labeled phosphate was incorporated in soil 27 mm from the root surface. Autoradiography indicated diffusion of 7.5 mm or less from the point of applic
123 citations
TL;DR: Particulate opaline silica accounted for 0.01 to 3.79 percent of the dry weight of leaves from 36 deciduous angiosperm tree and shrub species as discussed by the authors.
Abstract: Particulate opaline silica accounted for 0.01 to 3.79 percent of the dry weight of leaves from 36 deciduous angiosperm tree and shrub species. Silicification was noted in all cellular elements of the leaves of some species, and the pattern of silica deposition varied widely between taxa. Mor
123 citations
TL;DR: In this paper, a model of soil development based on energy vectors operative in soils is presented and discussed, which can help in predicting more accurately the effect of man's activity on soils of the world.
Abstract: The importance of having an a priori model to guide our imaginative thoughts and research is desirable in any discipline. This is particularly important in a slowly changing system under continuous development such as soils where the separation of cause and effect is most difficult. A model of soil development based on energy vectors operative in soils is presented and discussed. The model proposed is simple initially but can become as complex as the situation requires. The model proposed is simple initially but can become as complex as the situation requires. The model discussed may enable one to design experiments which have a higher probability of definitive results than do previous models. Also the model seems to allow for easier extrapolation of results. Hopefully the proposed model will help in predicting more accurately the effect of man's activity on soils of the world.
TL;DR: In this article, the relative quantities of phosphorus forms can serve as a measure of soil development, as pH and other ionic concentrations change with soil profile development, forms of soil phosphorus also change.
Abstract: In studies of pedogenetic processes, knowledge of transformations and translocations of soil phosphorus can be a valuable aid. As pH and other ionic concentrations change with soil profile development, forms of soil phosphorus also change. Generally as pH drops with development, relatively soluble forms of phosphorus decrease and occluded forms increase. Consequently, relative quantities of phosphorus forms can serve as a measure of soil development. Though phosphorus is relatively insoluble in soils, considerable translocation of phosphorus does take place over the long time spans involved in soil development. Phosphorus redistribution can serve as a reliable indicator of water movement in soil profiles and landscapes. Furthermore, phosphorus distribution in landscapes can control the distribution of vegetative types and organic matter production which will affect profile characteristics.
TL;DR: In contrast to the polymerization reactions, the binding of chloroanilines is strictly a physicochemical process; microbial activity is involved only in the liberation of the chloroaninilines from the parent herbicides.
Abstract: Herbicide-derived chloroaniline residues are immobilized by physical absorption to both the organic and the inorganic fraction of the soil and, in addition, by chemical binding to the soil organic matter. In contrast to the polymerization reactions, the binding of the chloroanilines is strictly a physicochemical process; microbial activity is involved only in the liberation of the chloroanilines from the parent herbicides. The chemical attachment of chloroanilines to humic substances occurs by at least two mechanisms, in a hydrolyzable (probably anil and anilinoquinone) and in a nonhydrolyzable (probably heterocyclic rings and ether bonds) manner. In the test soil (Nixon sandy loam) these two types of bonds immobilized roughly equal amounts of chloroanilines. Free radicals have little or no role in these reactions. The binding of chloroanilines to the soil organic matter greatly increases the persistence of these herbicide-derived residues in the environment.
TL;DR: Soil and plant analysis for tree culture as discussed by the authors, Soil and Plant Analysis for Tree culture, مرکز فناوری اطلاعات و اشاوρزی
Abstract: Soil and plant analysis for tree culture , Soil and plant analysis for tree culture , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
TL;DR: In this article, the degree to which radioactive Na(Cl-36) would migrate from a shallow point source in permafrost, movement was observed and significantly less movement of the Na-22 ion was observed.
Abstract: Soils of continental Antarctica are forming in one of the most severe terrestrial environments. Continuously low temperatures and the scarcity of water in the liquid state result in the development of desert-type soils. In an earlier experiment to determine the degree to which radioactive Na(Cl-36) would migrate from a shallow point source in permafrost, movement was observed. To confirm this result, a similar experiment involving (Na-22)Cl was conducted. Significantly less movement of the Na-22 ion was observed. Ionic movement in the unfrozen interfacial films at mineral surfaces in frozen ground is held to be important in chemical weathering in Antarctic soils.
TL;DR: Sorghum roots were highly sensitive to soil solution Al present in acid Ultisols and Oxisols Corn roots were moderately sensitive and stargrass roots were tolerant as discussed by the authors.
Abstract: Sorghum roots were highly sensitive to soil solution Al present in acid Ultisols and Oxisols Corn roots were moderately sensitive and stargrass roots were tolerant Representative acid soils from the humid region of Puerto Rico contained less soil solution Al than did several selected from the southeastern United States at the same pH level This confirms the observation that critical soil pH range tends to be lower in soils of Puerto Rico than in those of the southeastern United States Soil solution Al concentration can be calculated satisfactorily from soil pH and EC of the saturated paste extract using an equation developed from the data presented
TL;DR: In this article, the genesis of soils formed from volcanic ash is considered in terms of accumulation of humus and the formation and alteration of clay minerals, including the characteristic amorphous allophane.
Abstract: The genesis of soils formed from volcanic ash is considered in terms of accumulation of humus and the formation and alteration of clay minerals, including the characteristic amorphous allophane. A chronologic frame of reference has been made possible by the dating of ash layers by means of 14C deter
TL;DR: In this paper, simple and multiple correlation coefficient was run between soil pH, organic matter, available P, exchange K, Ca, Mg and nine other elements in maize tissue sampled from four different soil zones of the Western and Lagos States of Nigeria.
Abstract: Simple and multiple correlation coefficient was run between soil pH, organic matter, available P, exchange K, Ca, Mg and nine other elements in the maize tissue sampled from four different soil zones of the Western and Lagos States of Nigeria. The results indicate that soil organic matter pl
TL;DR: In this article, the authors traced the global transport of aerosolic dust through radioactive debris, biological material, filtration of air, and oxygen isotope abundance measurements in quartz isolated from dust and from soils and sediments identified as having dust origin.
Abstract: Circumglobal transport of aerosolic dust has been traced through radioactive debris, biological material, filtration of air, and oxygen isotope abundance measurements in quartz isolated from dust and from soils and sediments identified as having dust origin. Accretion rates are on the order of a m 1
TL;DR: In this article, evidence for Quaternary environmental changes in southern Africa has been obtained from palynologic, geomorphologic, and pedologic studies, and it appears that in the Vaal and Orange drainage of the interior (26-30°S) colder periods with heavier precipitation alternated with wamer and drier periods, broadly synchronous with glacial and nonglacial trends in high latitudes of the northern hemisphere.
Abstract: Evidence for Quaternary environmental changes in southern Africa has been obtained from palynologic, geomorphologic, and pedologic studies. It appears that in the Vaal and Orange drainage of the interior (26–30°S) colder periods with heavier precipitation alternated with wamer and drier periods, broadly synchronous with glacial and nonglacial trends in high latitudes of the northern hemisphere. By contrast, pedogenesis in the coastal regions (32–34°30′S) corresponded with warmer climates, whereas colder phases were relatively dry.
TL;DR: In this article, the authors presented data on soil profile samples from eleven sites in Nigeria, widely distributed from the high rainfall coastal area of sedimentary parent material to the dry northern area where aeolian deposits from the Sahara Desert have been a major soil-forming factor.
Abstract: This study presents data on soil profile samples from eleven sites in Nigeria, widely distributed from the high rainfall coastal area of sedimentary parent material to the dry northern area where aeolian deposits from the Sahara Desert have been a major soil-forming factor. Weatherable minerals are generally present in the soils formed from crystalline rocks and most of these soils are classified as Alfisols. On the sedimentary rocks and on the ultrabasic crystalline rocks Oxisols have formed. On aeolian parent materials from the Sahara and on the Pleistocene sediments the soils are classified as Inceptosols.
TL;DR: In this paper, the authors present a good example of applying mathematical models to the SOIL-WATER system, using table-form models to describe the movement of chemical molecules through the soil.
Abstract: MODELS DESCRIBING THE MOVEMENT OF CHEMICALS THROUGH SOIL PROVIDE A GOOD EXAMPLE OF APPLYING MODELING TECHNIQUES TO THE SOIL-WATER SYSTEM. SOME OF THE CLASSICAL MACROSCOPIC CONTINUUM THEORIES WHICH HAVE BEEN DEVELOPED ARE PRESENTED HERE IN TABLE FORM. THE EMPHASIS OF MOST STUDIES OF THE MOVEMENT OF CHEMICALS HAS BEEN ON THE INFLUENCE OF STEADY WATER FLOW. RECENTLY APPROXIMATIONS HAVE BEEN MADE TO GIVE BETTER SOLUTIONS FOR NONSTEADY FLOWS. IN PRINCIPLE, FLOW MODELS CAN BE USED TO DESCRIBE THE PROCESSES OF SOIL FORMATION; HOWEVER, THE COMPLEXITY OF SUCH MATHEMATICAL MODELS MAY BE PROHIBITIVE. /AUTHOR/