IS FLUORIDE DIFFUSION IN SOIL CRITICAL FOR ITS UPTAKE BY PLANTS?

Abstract

The diffusive mobility of fluoride (F), a species of high biological and environmental significance, has been investigated as a function of soil water content (θ), soil texture, temperature, and incubation time. The F diffusion coefficients were computed by determining the F concentration profile in horizontally incubated and homogenized soil columns, under varied experimental conditions including initial F concentration, bulk density, moisture content, incubation time, and temperature. The present research report is an attempt to explore the implications of F ion diffusion in deciding the water solubility and, thus, the plant availability of the diffusing ion in soil. The study indicates that the role of F diffusion in soil in deciding the extent of its uptake by plants is minimal at low values, but may become critical just after irrigation, rain, or flood. Besides soil temperature, soil texture and incubation time also significantly alter the diffusive mobility of F in soil.

ACKNOWLEDGMENTS

We thank Prof. P.S. Satsangi, Director, Dayalbagh Educational Institute for moral support and encouragement and the Head, Department of Chemistry, D.E.I., for making research facilities available in the department. We are also grateful to Dr. Ravindra Kumar and Dr. S.P. Singh, Department of Mathematics, D.E.I. for their assistance in mathematical computations. This research was financed by the DST, Ministry of Science and Technology, New Delhi.