Abstract
Azolla pinnata R. Brown was used as a biofertilizer for rice crops in early and late wet seasons of 1985-1986. Azolla as a dual crop with rice increased the grain yield of rice significantly over an uninoculated Azolla conhrol. The effects of gypsum and lime application and Azolla incorporation with gypsum or lime on rice grain yield and yield components were studied. Both gypsum and lime application, separately or together, showed favourable effects on grain yield. Application of gypsum, 60 kg N ha-1 as urea and Azolla inoculation recorded the highest grain yield.