Comparative study on combined and individual effects of farmyard manure and green-manuring with fertilizer N on growth and yield of rice (Oryza sativa) under submergence-prone situation

A field experiment was conducted during 2003 and 2004 to study the combined and invidual effects of using farmyard manure (FYM), green-manure (dhaincha: Sesbania aculeata L.) along with fertilizer N on rice (Oryza sativa L.) variety ‘Gayatri’ experiencing 10 days’ complete submergence at maximum tillering stage. The crops under both the organics (FYM and green-manuring) thrived better under submergence, due to greater root development, higher critical N level in plant, higher biomass production and less tiller mortality compared with their individual application. Consequently these crops gave significantly higher grain yield (3.03 tonnes/ha). The crops under both the organics ensured higher N uptake (55.50 kg/ha), apparent N recovery (38.32%) and N-use efficiency (29.50 kg grain/kg N applied).