Recycling of on- and off-farm Plant Biomass in Organic Rice Production at Subtropical Hill Ecosystem of North Eastern Indian Himalayas

摘要

In a two years study (2004-05 & 2005-06) the performance of different types composts prepared from rice (Oryza sativa L) straw, Eupatorium adhenophorum, Lantana camara and grass/weed mixtures were evaluated (applied at the rate of 10 tone/hectare) and compared with the recommended combinations of NPK (80: 60: 40 kg/ha) and farmyard manure (FYM) (10 tone/ha) on productivity of lowland rice under organic production. Two composting procedures were evaluated. One was the Microbial Enriched Compost (MEC), procedure consisting of mixing plant biomass and cow dung in equal proportion (weight basis) followed by addition of microbial inoculants in a slurry of fresh cow dung, virgin soil and well rotten compost mixed in a ratio of 1:1: 0.5 along with appropriate amount of water. The second was Microbial and Nutrient Fortified Compost (MNFC) consisting of MEC, 2.5% rock phosphate (w/w) and 1% neem cake. Bioinoculums such as cellulose decomposers, P-solubilizing microbes and free-living N-fixers were used to improve the quality of the composts. The matured composts had higher NPK contents and lower C/N ratio compared to the fresh dry biomass of the substrates. Significantly higher grain yield was recorded with rice straw MNFC compost followed by the Eupatorium MNFC compost. The nutrient uptake and post harvest soil fertility status were found to be significantly improved due to application of various composts.