Response of fodder cowpea to varying levels of Nitrogen and Phosphorus under rainfed conditions of Rajasthan

An experiment was conducted during kharif season 2010 and 2011, at the Central Sheep and Wool Research Institute, Avikanagar (Rajasthan) to study the effect of nitrogen and phosphorus levels on growth attributes, herbage yield and quality of fodder cowpea [Vigna unguiculata (L.) Walp]. All growth attributes were significantly (P<0.05) higher with 30 kg N/ha over 0, 10 and 20 kg N/ha. Maximum green fodder yield (178.1q/ha), dry matter yield (36.1q/ha) and crude protein content (18.6%) were obtained with the use of 30 kg N/ha. The application of phosphorus up to 60 kg P2 O5/ha increased green fodder and dry matter yield (179.1 and 35.8 q/ha) compared to other levels. The maximum gross income (Rs. 28896/ha), net return (Rs. 17044/ha) and benefit: cost ratio (1.69:1.00) was realized under 30 kgN/ha. Similarly, application of 60 kg P2 O5/ha in cowpea gave the additional gross return (Rs. 8100/ha) and net return (Rs. 1769/ha) compared to no use of phosphorus. Thus fertilizer level of 20 kg N/ha and 40 kg P2 O5/ha in cowpea was found suitable to achieve the higher green fodder production and crude protein content.