Abstract

Field experiments were conducted at TNAU, Coimbatore during Nov. '95 to Sept. '96 to study the effect of two sources (green manure and urea) as basal N in combination with different times of urea splits on yield attributes of rice. The conjunctive use of green manure, on equal N basis as basal, was equally effective but did not have any yield advantage over the urea N. Split application of urea at active tillering was vital, when the basal N was applied as GLM. but not for urea N basal. Nitrogen to a medium duration rice variety may be applied in five splits. First top dressing after the basal (AT stage) is vary if basal N is given through green manure without starter N. But, when fertiliser N is applied as basal, an optimum dose of 20 kg N at active tillering is sufficient to maintain the tiller production. Higher N (40 kg) at AT stage increases the biomass production through unproductive tillers and that ultimately leads to poor HI. On the other hand, low N status critically reduces the tillering too. An additional dose of 20 kg a week after AT was found to be beneficial to improve the panicle efficiency and ultimately the grain yield. irrespective of basal N sources. Split application of N at heading stage seems so delicate. Increasing the rate of N more than 20 kg i.e., 30 or 40 kg N/ha resulted in poor grain yield by increased sterility.

Keywords: Green leaf manuring, Nitrogen, Urea N, Heading N, Basal N, equal N basis