Journal ArticleDOI
Evaluation of soil phosphate buffering indices
TLDR
In this article, seven buffering indices were evaluated by determining the additional variance accounted for when each index was added to a regression of plant phosphorus uptake on labile soil phosphate, and three of the most effective and consistent indices were a simple index of the maximum buffer capacity, determined from the Langmuir isotherm over a standard range of equilibrium solution concentrations, the slope of the natural solution concentration, and the amount of adsorption at a standard equilibrium concentration of 0.3 pg phosphorus/ml.Abstract:
Seven phosphate buffering indices were evaluated by determining the additional variance accounted for when each index was added to a regression of plant phosphorus uptake on labile soil phosphate. The study was done on two groups of soils: one relatively homogeneous group of 24 soils all formed on the same parent material, and a heterogeneous group of 30 soils formed on a variety of parent materials. A separate pot experiment was done on each group, ryegrass being grown on the homogeneous soils and white clover on the heterogeneous soils. Only two indices did not account for a large and significant increase in variance in phosphate uptake. The extra variance accounted for was much greater in the heterogeneous group than in the homogeneous group, although the total variance accounted for by both variables was greater in the homogeneous group. The much smaller volume of soil used in the ryegrass experiment may explain the smaller buffering effect in the homogeneous soils. The three most effective and consistent indices were a simple index of the maximum buffer capacity, determined from the Langmuir isotherm over a standard range of equilibrium solution concentrations, the slope of the isotherm at the natural solution concentration, and the amount of adsorption at a standard equilibrium concentration of 0.3 pg phosphorus/ml.read more
Citations
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Book ChapterDOI
Chemistry of Phosphorus Transformations in Soil
S. K. Sanyal,S. K. De Datta +1 more
TL;DR: In this article, the authors discuss the role of phosphorus in vital life processes, such as photosynthesis in plants and energy transformations in all forms of life, and how it plays a significant role in sustaining and building up soil fertility, particularly under intensive systems of agriculture.
Journal ArticleDOI
Le phosphore assimilable des sols : sa représentation par un modèle fonctionnel à plusieurs compartiments
TL;DR: The model applied to various soil samples taken from 2 long-term field ex- periments showed that repeated fertilization or exhaustive cropping can modify all the pools, showing 2 kinds of phosphate buffering capacity (PBC) for soils.
Journal ArticleDOI
A comparison of the Langmuir, Freundlich and Temkin equations to describe phosphate adsorption properties of soils
TL;DR: In this article, four adsorption equations were fitted to phosphate isotherm data for 38 soils from northern New South Wales, and the two-surface Langmuir equation provided the best fit to the data.
Journal ArticleDOI
Phosphorus Sorption and Desorption Properties of the Spodic Horizon from Selected Florida Spodosols
R.R. Villapando,Donald A. Graetz +1 more
TL;DR: In this article, the conditions under which P can be retained in or released from the spodic horizon of Florida Spodosols have not been adequately investigated, and the P sorption and desorption properties of the horizon were evaluated.
Journal ArticleDOI
Relationships between phosphate sorption and iron oxides in Alfisols from a river terrace sequence of Mediterranean Spain
F. Peña,José Torrent +1 more
TL;DR: In this article, a line profile analysis of the X-ray diffractograms was used to predict sorption of crystalline Fe-oxides (goethite and hematite) in a sequence of terraces of the River Guadalquivir in southern Spain.
References
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Journal ArticleDOI
A phosphate sorption index for soils
B. W. Bache,E. G. Williams +1 more
TL;DR: In this paper, the slope of a plot of the sorption, x, against the logarithm of the equilibrium solution phosphate concentration, log c, measured at c= 10−4M, proved a suitable reference index to characterize the phosphate sorbing properties of the soils.
Journal ArticleDOI
A Method to Determine a Phosphorus Adsorption Maximum of Soils as Measured by the Langmuir Isotherm
TL;DR: In this paper, the adsorption maximum claculated from the Langmuir isotherm was closely correlated with the surface area of soils as measured by ethylene glycol retention.
Journal ArticleDOI
Phosphate sorption by soils as a measure of the phosphate requirement for pasture growth
PG Ozanne,TC Shaw +1 more
TL;DR: Development of a laboratory method for predicting the phosphate requirements of pasture plants, in pounds phosphorus per acre, is described and a good correlation between phosphate sorbed and phosphate required was found.
Journal ArticleDOI
A langmuir two-surface equation as a model for phosphate adsorption by soils
TL;DR: In this paper, the Langmuir equation was used for describing P adsorption from solutions < 103 M P, if it was assumed that adorption occurs on two types of surfaces of contrasting bonding energies.