Efficacy of Lalitpur Rock Phosphate for Finger Millet-Wheat and Barnyard Millet-Wheat Sequences on Acid Soil of Tehri Garhwal

Relative efficacy of Lalitpur rock phosphate (LRP), superphosphate (SSP) and their mixtures in the proportion of 1:1, 1:2, and 2:1 was studied on an acid Inceptisol, Tehri Garhwal of U. P. Himalayas for finger millet-wheat and barnyard millet-wheat sequences, during 1984 and 1985. Mixtures in 2: 1 ratio at 60 kg P₂O₅, recorded highest grain yield of finger millet and barnyard millet indirect effect and of wheat in residual effect. This treatment was also superior to other phosphate sources regarding availability of phosphate, uptake of N and P by crops, availability coefficient ratio (ACR), P use efficiency (PUE) and relative agronomic effectiveness (RAE). RAE of phosphate sources followed the order: LRP + SSP (2: 1) > LRP + SSP (1: 1)> LRP + SSP (1:2)> LRP > SSP.