Effect of nutrient sources and transplanting date on aromatic rice (Oryza sativa) under mid hills of north eastern India

A field experiment was conducted during kharif seasons of 2009 and 2010 to find out the effect of dates of transplanting and nutrient sources on productivity, nutrient uptake and economics of aromatic rice (Oryza sativa L.) in lowland condition. The results showed that 16 July transplanted aromatic rice performed better in terms of yield, yield attributing characters and total uptake of N, P and K with different nutrient management practices. Pooled results indicated that integrated application of 50% recommended dose (RD) of NPK through inorganic + 50% RDNP through FYM and rockphosphate recorded highest average grain yield (4.68 t/ha), which was 118% higher than grain yield under control (2.14 t/ha). Available N, P and K and nitrogen use efficiency were found maximum with the application of 50% RDNPK through inorganic + 50% RDNP through FYM and rockphosphate in 16 July transplanted aromatic rice crop. The soil organic carbon (SOC) was enhanced by 11.8% with the application of 100% RDNP through FYM and rockphosphate compared to initial value. Soil microbial biomass carbon (SMBC) was also found maximum under 100% RDNP through FYM and rockphosphate followed by 50% RDNPK through inorganic + 50% RDNP through FYM and rockphosphate. Average net returns (21,324) was found maximum in 50% RDNPK through inorganic + 50% RDNP through FYM and rockphosphate treatment, whereas benefit: cost ratio (1.94) was the highest with the application of 100% RDNPK through inorganic sources of nutrient.