Effects of azollaand Urea on Growth parameters and Yield of Rice

Abstract

The present work was carried out aiming to determine the effect of differentlevel of urea along with different methods ofAzollaapplication on Nitrogenand Organic matter content of soil, Chlorophyll content of rice and finally toassess its impact on the yield and yield components of rice. The work wasperformed both in field and pot and conducted in the year 2005. Experimental results showed that growing of four crops of Azolla withincorporation thrice (first before transplanting, second and third aftertransplanting) was found more effective and have grain yield increment upto 47.13% and straw yield up to 40.97%. Three crops of Azollawith twiceincorporation after transplanting plus 20 kg N ha -1 have grain yield andstraw yield increment up to 36.12% and31.04% respectively which wasalmost equal to yield produced by NPK (80:40:30 kg ha -1 ); N in split dose. Increased number of crops ofAzollaand incorporated frequently, was foundhelpful in increasing nitrogen and organic matter content of soil, chlorophyllcontent of rice and finally increase the yield of rice, which could reduce theamount of urea or may even substitute the urea from rice field. The presentstudy also reveled that A. carolinianawas more effective biofertilizer sinceA. carolinianaexhibited higher Heterocyst frequency, lower Doubling time,higher Relative Growth Rate, chlorophyll content and Amino nitrogen thanA. pinnata.