Sustainability of rice (Oryza satha)-wheat (Triticum aestivum) sequential cropping through introduction of legume crops and green-manure crop in the system

Abstract

A study was undertaken by replacing one of the cereal crops rice (Oryzn sarivn L.) or Xvheat (Trilicun~ nestivu~ii L. emend. Fiori & Paol.) by a grain legume crop or to introduce summer green- manure crop (Sesbarzin) in the sequence. Over 5 years period wheat yield was higher by 0.71 tonneha after pigeonpea [Cnjmlus cnjnr~ (L.) Millsp.] compared with that after rice. The fertilizer dose to rice after lentil (Lens culinaris Medikus) or wheat after pigeonpea should remain the same as in lice-wheat sequence. The overall productivity of the system in terms of wheat equivalent &as highest in pigeonpea-wheat sequence corhpared with rice-lentil or rice-wheat sequence. Introducing Sesbnnin green-manure in rice-wheat sequence increased its productivity by 1.08 tonneslha. Any reduction in fertilizer even with green-manunng brought reduction in system productivity. Inhoductio~~ of legume in the system increased soil organic carbon and available soil phosphorus. Thus replacement of rice with pigeonpea for some time or introduction of Sesbnrzin green-lilanuring may inhance the sustainability of rice-wheat system.