Abstract

Field experiments were conducted during 1991-94 at Tamil Nadu Agricultural University, Coimbatore to develop integrated N management practice for lowland transplanted rice. The treatments included placement of urea super granules (USG) at 100 kg N/ha, application of prilled urea (PU) at 100 kg N/ha, application of 75 kg N as PU with azolla or FYM or green manure or azospirillum and application of 50 kg N as PU with the combined use of azospirillum, azolla and green manure. The results of three-years study revealed the superiority of the placement of USG over the other treatments. The next best treatment was the application of PU at 100 kg N/ha. However, application of 75 Kg N as PU combined with either azolla or green manure (Sesbania rostrata) registered comparable yields. Substitution of 25 kg N as chemical fertiliser with either azolla or green manure was clearly seen. Possibility of substitution of chemical N fertilisers even to the extent of 50 per cent by the combined use of 50 kg N as PU with Azospirillum, azolla and Sesbania rostrata green manuring was also observed.

Keywords: Integrated nitrogen management, Lowland rice