Water and Nitrogen Use by Rice-Wheat on Uitic Haplustalf

In an attempt to increase water and fertilizer nitrogen use efficiencies of ricewheat system most efficient method and schedule of fertilizer N application were identified for lateritic soil (Ultic Haplustalf) based on the recovery of water and N by the crops. In a controlled field investigation, fertilizer N was applied in the form of ammonium sulphate to rainfed rice and calcium ammonium nitrate to irrigated wheat by hand placement at 5 cm soil depth (M1) and broadcasting (M2) in two (S2) and four (S4) equal splits. The recovery of N varied from 34 to 50 per cent for rainfed rice and from 68 to 78 per cent for irrigated wheat. It was 5 to 10 per cent higher under M1S4 than the traditional M2S2. M1S4 also helped increase water use efficiency of the crops by 20 per cent over that under M2S2.