Published online by Cambridge University Press: 27 March 2009
Four field experiments were conducted over the 1992 and 1993 seasons (southwest monsoon seasons, June–October) in the warm subhumid tropical region on the west coast of the Maharashtra State, India. The objective was to investigate the effect of recycling limited amounts of rice straw (RS) (as a source of K and Si) integrated with the use of prilled urea (PU) and urea briquettes (UB) at 60 kg N/ha on the growth and yield of rainfed transplanted rice (Oryza sativa L.). The management practice, consisting of basal incorporation of RS (2 t/ha) integrated with deep placement of UB (one 2·1-g UB/4 hills) immediately after transplanting using a modified 20 × 20 cm spacing, produced a significantly higher grain yield (average increase of 1·3 t/ha) and straw yield (average increase of 1·1 t/ha) than did the RS practice integrated with two equal split applications of PU at the same N rate and hill spacing. The additional yields were attributed to the increase of total and productive tillers/m2 and panicle weight. The results indicate the potential of the integrated RS–UB management for increasing yields of rainfed transplanted rice in the warm subhumid tropical zone.