Yield potential of fine-grain rice (Oryza sativa) under integrated nutrient management

A field investigation was carried out during 1997–98 and 1998–99 to study the effect of organics and integrated nutrient management in fine-grain ‘Ponni’ rice (Oryza sativa L.). Treatments consisted of fully organics, viz. green-manure, green-manure + neem-cake (250 kg/ha) as basal and 30 days after transplanting (DAT), basal + 30 DAT and these treatments in combination with the bio-fertilizer, Azospirillum at 2.0 kg/ha applied at 30 DAT. Integrated nutrient management included green-manure +50 kg N/ha, green-manure + 75 kg N/ha with or without Azospirillum at 2.0 kg/ha applied at 30 DAT. The green-manure +100 kg N/ha and green-manure alone were also compared. Grain yield of 3.4 tonnes/ha was registered under completely organic combination of green-manure at 6.25 tonnes/ha, neem-cake 250 kg/ha as basal and Azospirillum (2.0 kg/ha) at 30 DAT. However, under integrated nutrient management with the combination of green-manure +100 kg N/ha resulted in highest rice yield of 3.9 tonnes/ha.