Effect of green-manuring on nitrogen management in lowland rice (Oryza sativa)

Abstract

An experiment was conducted at Vyara (Gujaiat) during the rainy (kharij) season of 1988-91 on rice (Oryzn sntiva L.). Variety GR 3 grown after the incorporation of green-manure crops, viz. sunnhemp (Crotafaria juncea L.), clusterbean or guar [Cynmposis tetrngonolobn (L.) Taubert] and cowpea [Vignn unguiculatn (L.) Walp.], with 100.80 and 60% of recommended dose of nitrogen. No green-manuring + 100% recommended N was kept as the control. The highest rice yield (6.1 tonnesf ha) was obtained under sunnhemp + 100% recommended N, while no green-manuring + 100% recommended N recorded the lowest grain yield (4.3 tonnestha). Among the green-manure crops, sunnhemp gave the best results. The treatments of green-manuring + 60% of recommended dose of N were at par with no green-manuring + 100% recommended N, indicating that 40% (32 kg N h 3 inorganic nitrogen could be saved through green-manuring.