Integrated effect of Azolla in combination with nitrogenous fertilizer on chemical properties of soil and yield of rice grown under SRI

The study was conducted to assess the effect of azolla application in combination with nitrogen fertilizer on yield of rice and chemical properties of soil under system of rice intensification (SRI)at CSKHPKV, Palampur during kharif, in the year 2016. Azolla first produced and then collected. The collected azollawas evaluated for nitrogen (%), nitrogen fixation, carbon and nitrogen ratio (C: N), protein content, phosphorous, potassium, secondary elements (S, Ca and Mg) and micronutrient cations (Fe, Mn, Zn and Cu). Azollawas applied along with graded doses of inorganic N fertilizer. Maximum paddy grain yield of 5.13 t ha^-1 was observed with application of 125 kg N ha^-1 + 8 tonnes of azolla followed by 100 kg N ha^-1 + 8 tonnes of azolla. However, lowest rice grain yield (0.83 t ha^-1) was in control with no application of azolla and fertilizer N. Thehighest straw yield was observed with 125 kg N ha^-1 + 8 tonnes of azolla. The increase in pH (5.57) was also observed with combined application of azollaand fertilizer nitrogen. Organic carbon, CEC as well as available N, Pand K were higher in 125 kg N ha^-1 + 8 t azolla.