Integrated nitrogen management in rice (Oryza sativa) wheat (Triticum aestivum) cropping system

Abstract

A field experiment was conducted during 1996 97 and 1997 98 to evaluate the effect of 4 organic sources of nutrients along with 4 levels of N to rice (Oryza sativa L.) and 4 levels of fertilizer N to wheat (Triticum aestivum L. emend. Fiori Paol.) on the productivity and nutrient removal in rice wheat system. Grain yields of rice obtained at 40 kg Ntha with green manuring of Sesbania was similar to that obtained with application of 120 kg Nlha under cowpea [Vigna unguiculata (L.) Walp.] fodder, wheat straw incorporation and the control, indicating a saving of 80 kg Ntha. Application of 120 kg Ntha to wheat grown in Sesbania green manured rice plots yielded about 0.6 tonnetha more wheat grain than that only 2 with 120 kg Ntha. However, integrated use of Sesbania green manure along with 120 kg Ntha gave 6.8 tonneslha of rice grain and subsequent application of 120 kg Nlha to succeeding wheat crop yielded 4.7 tonnestha of wheat grain, thus giving total production of 11.5 tonnestha from rice wheat sequence. At this production level and fertilizer use, rice removed 155.7, 27.7 and 172.4 kg N, P and Wha and respective values for wheat were 126.2, 24.3 and 140.0 kgtha, making a total removal of 646.3 kg nutrients (MPK)/ha/annum from rice wheat system.