Synergy of Inorganic Amendments and Municipal Solid Waste Compost for Restoration of Degraded Sodic Soils and Sustaining Productivity of Rice-Wheat Cropping System

Management of degraded salt affected soils is an overriding challenge to the researchers. Salt toxicity and lack of organic matter and available mineral nutrients are the major causes for poor fertility and low productivity. Amelioration of these soils through inorganic amendments like gypsum or phosphogypsum is a costly affair for resource poor farmers having sodic soils. Synergy of reduced dose of inorganic amendments and municipal solid waste (MSW) compost can offer a sustainable solution for restoration of these degraded sodic soils and sustaining crop productivity. A field experiment with six treatments consisted of T₁: Gypsum (G) @ 50% GR, T₂: Phosphogypsum (PG) @ 50% GR, T₃: G @ 25% GR + MSW compost @10 t ha⁻¹, T₄: PG @ 25% GR + MSW compost @ 10 t ha⁻¹, T₅: G @ 12.5% GR + MSW compost @ 10 t ha⁻¹ + pressmud (PM) @ 10 t ha⁻¹, T₆: PG @ 12.5% GR + MSW compost @ 10 t ha⁻¹ + PM @ 10 t ha¹, was conducted during 2018 to 2020 on highly sodic soil (pH 9.8 ± 0.10, electrical conductivity (EC)147μ Sm⁻¹ ± 12.0, exchangeable sodium percentage (ESP) 78 ± 2.50 and gypsum requirement (GR) 15.2 Mg ha⁻¹) with the objective to evaluate the synergistic effect of inorganic and organic amendments on restoration of degraded sodic soils and sustaining productivity of rice-wheat cropping system. The study revealed that integrated use of gypsum @ 25% GR + MSW compost @ 10 Mg ha⁻¹ (T₃) increased 11% soil bulk density, 54% infiltration rate, 14% exchangeable sodium percentage (ESP), 10% soil organic carbon, and 13% available N over the control. Combined use of inorganic and organic amendments increased by 56.85, 82.90, 78.80 and 101.00% microbial biomass carbon (MBC), microbial biomass N (MBN) microbial biomass phosphorus (MBP), and dehydrogenase activity respectively over control (T₁) after three years of rice-wheat cropping system. Productivity of rice and wheat crops enhanced to the tune of 4 and 12%, respectively with the adoption of integrated use of organic and inorganic amendments over the use of inorganic amendments alone.