Total nitrogen and phosphorus balance sheet in a typic ustochrept soil under intensive cropping and fertilizer use

Abstract

Balance sheets were computed for total nitrogen and phosphorus in plough layer (0–15 cm) of a Typic Ustochrept soil under continuous multiple cropping for seven years (1971–72 to 1977–78) with a fixed rotation of pearl millet (Pennisetum typhoideum L.) wheat (Triticum aestivum L.) (Vigna sinensis Savi.) The treatments considered of soil test-based rates of N, P and K, applied both singly and in combinations together with farm yard manure, sulphur and zinc superimposed over optimum rates (100%) of NPK. Heavy, losses of N (762–899 kg ha−1) occurred in the plots which received high rates of Nviz. 150% of recommended NPK and 100% NPK plus FYM. Application of N alone accelerated N losses whereas addition of P, PK, PKS to N minimised such losses. Enrichment of P (66 to 198 kg ha−1) occurred in all phosphate-treated plots. A marginal net decrease (29–54 kg ha−1) in P levels was observed in control and N alone treatments.