Management of nitrogen and evaluation of water-use efficiency in traditional and improved cropping systems of the southern Telangana region of Andhra Pradesh, India

A collaborative research project among the International Atomic Energy Agency, Acharya N.G. Ranga Agricultural University and the International Crops Research Institute for the Semi-Arid Tropics, was initiated in 1999 with the objective of developing a set of options for improving the nitrogen (N) nutrition of dry-land cropping systems by use of N from biological N2 fixation, fertilizer and organic matter at the Regional Agricultural Research Station, Palem, Mahabubnagar District, Andhra Pradesh. The main experiment consisted of traditional (sorghum-castor) and improved (sorghum/pigeon pea-castor) cropping systems on a two-year rotation cycle with four N-management options. Nitrogen-15-labelled fertilizer and farmyard manure (FYM) were included as sources of N. In spite of low rainfall (390 mm in 1999; and 450 mm in 2000) both sorghum and castor responded to applied N. Intercropped pigeon pea had beneficial effects on the succeeding castor crop. A grain yield advantage of 88 kg ha-1 was obtained with castor following sorghum/pigeon pea compared to that following sole sorghum. In on-farm participatory trials, the yields of sorghum, castor and pigeon pea were substantially higher with improved practice compared to farmers' practice. There was no significant difference between urea alone and urea plus FYM as a source of N to sorghum and castor-based cropping systems. (author)