Use of Azolla as biofertilizer to enhance crop yield in a rice—wheat cropping system under mild climate

Abstract

A field study was conducted to observe the effect of Azolla on rice yield, N uptake and its residual effect on subsequent wheat crop. Azolla developed into a thick mat due to the mild temperature prevailing during the rice season. Azolla was grown as intercrop with rice in field conditions and was used as cover, and also as incorporated treatment alone and in combination with a low dose of urea. As compared to unfertilized control, increase in rice grain yield was 28% for Azolla cover, 53% for Azolla incorporated and 71% for Azolla incorporated +30 kg N/ha treatment. The grain yield of wheat, grown after rice harvest and without any fertilizer application, was significantly higher for Azolla than control and chemical-N treatments. The results of this field study indicated that Azolla can successfully be used for increasing crop yield in a rice-wheat cropping system.