EFFECT OF WEED-MANAGMENT PRACTICES ON NUTRIENT LOSS AND YIELD OF RICE(ORYZA-SATIVA) IN NAGALAND

In a 2-year study maximum yield of 4.86 and 4.43 tonnes/ha during 1989 and 1990 respectively of rice (Oryza sativa L.) was obtained under th e season-long weed-free treatment. No significant difference in rice y ield, however, was observed between the treatments of season-long weed -free and weed-free up to 60 days after planting. Weed-free condition at early stages of growth was found more important than at later stage for getting higher yields of rice. The maximum reduction of 49.5% in grain yield was found in the unweeded control plots. The maximum numbe r (83.8/m(2)) and dry weight (746 kg/ha) of weed was obtained in the u nweeded control plots. Season-long weed-free condition resulted in hig hest accumulation of N, P and K.