Nitrogen Uptake and Available Nitrogen Content in Soil as Influenced by Green Manures and Nitrogen Levels

A Study on influence of green manure and nitrogen levels (0, 20, 40, 60 and 80 kg N ha^-1) on nitrogen uptake and available nitrogen content in soil was undertaken at the Agricultural College Farm, Raichur on deep black clay soil during late Kharif season of 2002-03. The result showed that, incorporation of green leaf manure to castor recorded significantly higher nitrogen uptake (72.35 kg ha^-1) over the sole castor without green manuring and castor with in situ green manuring. The available nitrogen content in the soil after harvest of castor was significantly higher in the in situ green manuring treatment (274.30 kg ha^-1) over the sole castor (204.01 kg ha^-1) and castor with green leaf manuring (237.94 kg ha^-1). Among the nitrogen levels, application of 80 kg N ha^-1 recorded significantly higher nitrogen uptake (77.66 kg ha^-1) and available nitrogen content in soil (262.28 kg ha^-1) after harvest of the castor, while N uptake by castor with the application of 60 kg N ha^-1 (74.45 kg ha^-1) was found at par with that of 80 kg N ha^-1.