Phosphorus fixing capacity in major red soil series of Dharmapuri district, Tamil nadu

摘要

Fixation of phosphorus generally implies the conversion of the applied phosphorus, which is water or citrate soluble to a more insoluble form. This insoulble phosphate is either consumed by soil microorganisms or precipitated by soluble cations in the soil solution, or adsorbed by the colloidal complex of the soil. For the present purposes it may be warranted to investigate this important problem since it is so closely connected with the economics of phosphorus nutrition to crop and also may removemisconceptions about it that prevails among farmers, fertilizer manufacturers and other personnel interested on phosphorus nutrition. Therefore the present investigation was carriedout during 1994-95 to determine the quantitative fixation of added phosphorus in major red soil series of Dharmapuri District, Tamil Nadu. Four major red soil series viz. Vannapatti, Hosur, Krishnagiri and Sonnepuaram were chosen for this study. Soils from two loacations representing the above series were collected and processed for chemical analysis. The pH was determined in a 1:2.5 soil water suspension, Particle size distribution was determined as outlined by Piper (1950). The organic carbon was determined following the Walkley and Black method as outlined by Piper (1950). Available P was estimated by the method of Olsen's outlined by Jackson (1973) and the results are furnished in Table 1.