EFFECT OF BIOPOWER APPLICATION ON WEED GROWTH AND YIELD OF RICE

ABSTRACT Biopower is a commercial rice biofertilizer comprised of various associative nitrogen fixers. In this present study, a field trial was carried out to assess the effects of Biopower application on the growth of some rice weeds and yield of rice (Oryza sativa). Four common rice weeds namely Cyperus rotundus, Echinochloa colonum, Marsilea minuta, Paspalum paspaloides, and mixed weeds were sown in 1:1 weed crop ratio in soil amended with i) ½ dose of N (nitrogen) + recommended doses of PK (phosphorus, potassium) fertilizers, ii) recommended doses of NPK fertilizers, and iii) farmyard manure (FYM) + ¼NPK fertilizers, with and without Biopower application. Biopower application variably reduced weed biomass in different soil amendment systems. The effect of Biopower on weed biomass was most pronounced in NPK, followed by FYM amendment, resulting in up to 50% and 36% reduction in weed biomass, respectively. Biopower application enhanced shoot N content of rice in all the treatments. The effect of Biopower application on shoot N content was most pronounced in ½N-PK and least in NPK applied plots. The four weeds planted with rice reduced rice grain yield by 12-75% in different soil amendments. Biopower application enhanced grain yield in rice, in weed free control, and in different weeds infested plots by 38-90% in ½N-PK, 6-13% in NPK and 12-150% in FYM applied plots. The present study has come to the conclusion that adverse effect of weeds on grain yield of rice can be managed by the application of Biopower in combination with either ½N-PK or FYM amendment.