Quantity–intensity of potassium in rice growing soils of ayacut canal area of A.P

Abstract

Quantity-Intensity relationships of potassium were worked out for rice growing soils of canal ayacut of Kurnool district, Andhra Pradesh. The quantity-intensity relationships of the studied soils showed that the ARK and ± ∆K values increased with increasing concentrations of added K, the concentration of labile K (KL) ranges from 0.10 to 2.50 C mol (p+) kg-1. The AReK the intensity factor showed the range of 0.30 to 5.50 (ML-1) ½ x 10-3 with a mean of 1.42 (ML-1) ½ x 10-3. The PBCK values were in range of 0.125 to 0.833 C mol (p+) kg-1/ (ML-1) ½ x 10-3 with an average value of 0.37 C mol (p+) kg-1/ (ML-1) ½ x 10-3. Higher AReK values were found in red soils than black and mixed red whereas the buffering capacity was in the order of Black > Mixed red > Red. Since K supplying power of soils belonging to Kurnool district, as indicated by PBCK values, was found to be low, the soils of the district require judicious and frequent application of potassic fertilizers for better crop production. Among eight extractants tried, PBCK showed positive correlation with 1 N HNO3 and 1 N NH4OAc (pH 7.0).