Integrated nitrogen management in rainfed rice (Oryza sativa) - linseed (Linum usitatissimum) cropping system

Abstract

Field experiments were conducted for two years (1993-94 to 1994-95) to investigate direct effect of Urea-N itrogen with or without organic materials (paddy straw, farm yard manure and green manure) on productivity of rice and its residual effect on yield of linseed grown after rice under a rainfed low-land vertisol. Application of fertilized green manure as Sesbania rostrata proved to be superior as compared to paddy straw and farm yard manure. Rice yield and nitrogen uptake was significantly higher under combined application of green manure and urea-nitrogen on an equivalent basis. Thus, saving of urea-N upto 50% can be achieved by applying 1.0 t ha'1 (dry weight) Sesbania rostrata in rice. Residual fertility in terms of organic carbon was more under the plots treated with paddy straw during the wet season which reflected in terms of higher grain yield of linseed grown after harvest of wet season rice. Direct application on N to linseed crop during dry season increased the grain yield considerably. The yield increased with the increasing levels of N upto recommended level (40 kg N h a 1). However, N use efficiency decreased with the increasing levels ofN from 0 to 40 kgN ha'1.