Field experiments were conducted during Kharif 2007 and 2008 in sandy clay loam soil to study the effect of organic sources and urea on N transformation and yield of rice. The treatments consisted of addition of different organics viz., composted coir pith (CCP), green manures (GM), sugarcane trash compost ( STC), vermicompost (VC), poultry manure (PM) and FYM applied at 100% RDN and combination of above organics @50% N and urea@50%N besides 100% RDN as urea and control. The results revealed that addition of organics or mineral N or both significantly improved rice yields over control in both years. The highest grain yield (5067, 5050 kg ha-1) and straw yield (6490, 6398 kg ha-1) was noticed with vermicompost (50% N) + urea (50% N) which was on par with poultry manure (50%N) + urea (50%N) but superior to rest of the treatments. Rice yield was more with 100% Urea N compared to 100% RDN as organics alone. The best treatment caused 34.2% increase in grain yield over control, 1.36% over 100% urea N. Integrated use of organics and urea recorded higher concentration of ammonium and nitrate nitrogen compared to their individual addition. The N forms were more under vermicompost amended soil followed by green manure and poultry manure. The mineral N was higher at initial stages and decreased with crop growth.
Prof. Dr. Bilal BİLGİN