Synergizing Microbial Enriched Municipal Solid Waste Compost and Mineral Gypsum for Optimizing Rice-Wheat Productivity in Sodic Soils

Municipal solid waste management and poor fertility status of sodic soils are two important issues experienced by all developing nations including India. Disposal of municipal solid waste (MSW) being produced in huge amounts is a challenging task for researchers and policy makers. Reclamation of salt affected soils with chemical amendments is a costly affair for resource-poor farmers. Composting of MSW and its enrichment with microbes is one of the options for its recycling and utilization for the reclamation of salt-affected soils. A field experiment was conducted in sodic soil to study the performance of microbial enriched municipal solid waste compost (EMSWC) alone and in combination with a reduced dose of gypsum on growth, yield, nutrient uptake, and grain quality of rice and wheat. The experiment was conducted for three consecutive years from 2018 to 2019 and 2020 to 2021 at ICAR Central Soil Salinity Research Institute, Research farm, Shivri, Lucknow, India, in sodic soil having pH 9.2, electrical conductivity (EC) 1.14 dSm−1, exchangeable sodium percentage (ESP) 48, and organic carbon 0.30%. There were six treatments consisting of control, recommended dose of gypsum (50% GR), and enriched and un-enriched MSW compost with reduced dose of gypsum (25% GR). Based on the results pertaining to plant growth, yield-attributing characters, and yields, the treatment T6 (application of microbial enriched MSW compost @ 10 t ha−1 in conjunction with gypsum @25% GR) performed the best. Grain yield of rice and wheat (5.45 and 3.92 t ha−1) with treatment T6 was 29.45% and 110.75% higher over control (T1) and 29.45% and 110.06% over the recommended dose of gypsum (T2). Maximum nutrient content and N, P, and K uptake in rice-wheat grain and straw was observed with the treatment T6 (MSW compost plus gypsum @ 25 GR). However, the highest Na content and Na: K ratio in plant parts were recorded in treatment T2. The highest positive net return and benefit to cost (B/C) ratio were observed in treatment T6 followed by T5 and the lowest in treatment T1 (control), whereas negative return was calculated in treatment of gypsum alone (T2). This shows that the cost of sodic soil reclamation with application of gypsum was not recovered until the second year of cultivation. The results of this study showed significant impacts in MSW management for regaining the productivity potential of sodic soils.