EFFECT OF PLANTING PATTERN AND HERBICIDE ON WEED GROWTH, GRAIN-YIELD AND YIELD ATTRIBUTES OF TRANSPLANTED BUNDED RICE (ORYZA-SATIVA)

A field experiment was conducted during the wet seasons of 1989 and 1990 to study the effect of planting pattern and herbicides on weed growth and yield of transplanted rice (Oryza sativa L). Skip-row planting recorded significantly low weed population (106.6/m2) and dry matter of weeds (551 kg/ha) compared with line and random plantings. Grain yield under skip-row planting was highest (4.74 tonnes/ha) compared With random and line plantings. Among the chemical weed-control treatments, application of butachlor 50 EC @ 1.5 kg ai/ha + 2,4-D Na salt @ 0.8 kg ai/ha significantly reduced the weed population/m2 and dry matter of weeds by 54.23 and 90.07% compared with the weedy control respectively. It also gave high grain yield (5.23 tonnes/ha) and higher additional net return than 2 hand-weedings at 20 and 40 days after transplanting.