Composting rice straw using earthworm (Eudrilus eugeniae) or fungal inoculant (Trichoderma viridae) and its utilization in rice (Oryza sativa)groundnut (Arachis hypogaea) cropping system

An experiment was conducted at ICAR Research Complex for North Eastern Hill (NEH) Region, Meghalaya during 2007-09 on composting of paddy straw and its effect on rice (Oryza sativa L.)-groundnut (Arachis hypogaea L.) cropping system. The composting experiment started during first week of February consisted of eight treat- ments (i) Earthworm (Eudrilus eugeniae), (ii) Earthworm + 2.5% lime, (iii) Earthworm + 5.0% lime, (iv) Earthworm + 7.5% lime, (v) Trichoderma viridae, (vi) T. viridae + 2.5% lime, (vii) T. viridae + 5.0% lime, (viii) T. viridae + 7.5% lime. The composting was faster by 67 days and multiplication of earthworm was 22 times higher in the treatment with earthworm + 5.0% lime. Lime application @ 5% of dry weight of composting substrate increased pH of the compost from 6.24 to 7.09 and nitrogen content from 1.69 to 1.91%. The field experiment consisted of 11 treat- ments viz., eight composts produced from composting experiment @ 6 t/ha, farmyard manure (FYM) @ 6 t/ha, recommended dose of fertilizer (80-26.2-33.3 kg N-P-K/ha) and control. There was an increase in soil moisture in 0-15 cm layer by 3.06%, pH from 4.9 to 6.0 and soil organic carbon by 0.39% due to application vermicompost. Application of vermicompost prepared with 5.0% of lime increased the soil microbial biomass by 147% over con- trol and the same was increased by 51% due to application of T. viridae compost prepared with 2.5% lime. The grain and pod yields of upland rice and groundnut increased by 120% and 107% respectively over control due to application of vermicompost prepared with 5.0% lime @ 6.0 t/ha in rice crop.