Influence of organic and in organic sources of nitrogen on grain yield, nutrient uptake and agronomic efficiency in rice

Field experiments were conducted at Annamalai University, Experimental Farm, Annamalainagar, during 2007 and 2008 to identify and evaluate different organic manures on productivity enhancement, nutrient uptake and agronomic efficiency and apparent nitrogen recovery in low land rice. The experiment comprised of eight treatments which includes control, recommend dose of nitrogen alone and in combination with graded dose of nitrogen along with various organic manures namely green manure, vermicompost and pressmud compost. These were laid out in randomized block design and replicated thrice. Rice cultivar CO 43 was used as test variety. Both the experiment conducted during samba season (August to January). The results revealed that crop raised with vermicompost registered higher grain, straw yield and harvest index. The vermicompost along with 100% RDN treatments had significant influence on the nutrient uptake. However, higher Agronomic efficiency (AE) and Apparent nitrogen recovery (ANR) was registered under vermicompost along with 75% RDN receive plots. From the above experimental results, it could be concluded that with application of vermicompost @ 5.0 tha-1 along with 100% RDN not only resulted in higher yields but also superior in respect of nutrient uptake under rice cultivation.