HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hira, G. S. Articles by Singh, N. T. Search for Related Content PubMed Articles by Hira, G. S. Articles by Singh, N. T. Agricola Articles by Hira, G. S. Articles by Singh, N. T.

Observed and Predicted Rates of Phosphorus Diffusion in Soils of Varying Bulk Density and Water Content¹

ABSTRACT

The self-diffusion coefficient of phosphorus (D) was measured at bulk densities of 1.25, 1.45, 1.60 and 1.75 g/cm³ and at three levels of soil water content in Choa sandy loam and Haibowal silty clay loam. The tortuosity factor was calculated from the self-diffusion coefficient of ³⁶Cl. Appropriate values of the adsorption isotherm and the tortuosity factor were used to predict P diffusion coefficient in both soils.

The tortuosity factor increased with increase in soil bulk density and increase in water content from 7 to 18% in the Choa soil and 14 to 25% in the Haibowal soil. As bulk density increased from 1.25 to 1.60 g/cm³, the observed diffusion coefficient values averaged over all water contents, increased from 0.05 x 10^–10 to 0.31 x 10^–10 and 2.13 x 10^–10 to 5.07 x 10^–10 cm²/sec in Choa and Haibowal soils, respectively. Further increase in bulk density to 1.75 g/cm³ decreased the diffusion coefficient. At high bulk density changes in water content affected the self-diffusion coefficient of P in both soils to a greater extent than at low bulk density. The phosphate ion-soil particle interaction was minimum at a soil bulk density of 1.60 g/cm³.

¹ Contribution from the Dep. of Soils, Punjab Agric. Univ., Ludhiana, India.

² Formerly Graduate Student and Senior Soil Physicist, respectively.

Received for publication August 23, 1976. Accepted for publication January 25, 1977.