Effect of azolla inoculation on weed growth in wetland rice.
The effect of azolla on growth of Echinochloa spp. in flooded rice was investigated during the 1981-2 samba season. Azolla pinnata was inoculated at 100-500 g/m2 1 wk after transplanting. A basal dressing of 50 kg P/ha and 50 kg K/ha was applied in 3 splits. Growth of Echinochloa spp. after 40 days decreased by 47% with inoculation of azolla at 100 g/m2 to a 76% reduction at 500 g/m2 compared with uninoculated controls. Grain yields increased from 3.6 t/ha in controls to 6.6 t with azolla inoculation at 500 g/m2.