Total productivity, nitrogen, phosphorus and potassium removal and economics of rice (Oryza sativa)-wheat (Triticum aestivum) cropping system with integrated nitrogen management in rice

A field experiment was conducted during 2000–2001 and 2001–2002 to evaluate the effect of 5 organic sources of nutrients along with 4 levels of N to rice (Oryza sativa L.) and 3 levels of N to wheat (Triticum aestivum L emend. Fiori & Paol.) on the total productivity, nutrient removal and economics of rice-wheat system. Integrated use of Sesbania green-manure along with 180 kg N/ha gave 7.1 tonnes/ha of rice grain and subsequent application of 150 kg N/ha to succeeding wheat crop yielded 6.0 tonnes/ha of wheat grain, thus giving a total production of 13.1 tonnes/ha from rice - wheat sequence. At this production level and fertilizer use, rice removed 136.7, 24.2 and 165.1 kg N, P and K/ha and respective values for wheat were 107.8, 20.0 and 124.7 kg/ha, making a total removal of 578.5 kg nutrients (NPK/ha/annum) from rice-wheat system. The same treatment also gave higher, net return and benefit: cost ratio in the system.