Abstract

A field experiment was conducted during 1985-86 at Tamil Nadu Agricultural University, Coimbatore with five phosphatic fertilizer sources and three levels to study the residual effect of fertilizers added to the preceeding crops of fingermillet and maize. Aresidual crop of blackgram was raised in a cropping sequence of fingermillet-maize-blackgram and the results indiciated that the availability of soil P increased significantly with all the five sources viz., single superphosphate, rock phosphate, rock phosphate + single superphosphate, rock phosphate + phosphobacterium and Diammonium phosphate. The higher level (90 kg P2 Os/ha) resulted in enhanced availability of phosphorus in all the five sources.

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