Effect of organic and inorganic amendments on amelioration of sodic soil and sustaining rice (Oryza sativa)-wheat (Triticum aestivum) productivity

Management of degradation of sodic lands in arid and semi-arid regions is a global concern. Amelioration of these soils through chemical amendments like gypsum or phosphogypsum is a costly affair for resource poor farmers having sodic lands. Combined use of municipal solid waste (MSW) compost with chemical amendments can provide a realistic solution for ameliorating sodic soils and sustaining crop productivity. A field experiment was conducted during 2015 to 2016 at Shivri, Lucknow on highly sodic soil [pH 9.8, exchangeable sodium percentage (ESP) 78, organic carbon (OC) 1.30 g/kg and gypsum requirement (GR) 15.2 t/ha] to evaluate the influence of organic and inorganic amendments on amelioration of sodic soils and sustaining productivity of rice (Oryza sativa L.)-wheat (Triticum aestivum L.) cropping system. The treatments consisted of T-1 : Gypsum (G) @ 50%GR, T-2: Phosphogypsum 50%GR, T-3: G @25%GR + on-farm MSW compost @10 t/ha, T-4: PG @25%GR+ on-farm MSW compost @10 t/ha, T-5: G @12.5%GR + on-farm MSW compost @10 t/ha+ pressmud (PM) @10 t/ha, T-6: PG @12.5%GR+ on-faun MSW compost @ 10 t/ha+ PM @ 10 t/ha, T-7: G @ 25%GR + industrial processed (IP) MSW compost @10 t/ha and T-8: PG @ 25%GR + IP MSW compost @10 t/ha. The results indicated that, application of reduced dose (25% of GR) of gypsum (T-3) in combination with on-farm MSW compost @10 t/ha reduced about 14% ESP and increased 11% soil bulk density, 54% infiltration rate, 10% soil organic carbon content, and 13% available N over the recommended practice (T-1). Productivity of rice and wheat crops enhanced to the tune of 4 and 12 %, respectively and thus farmers can save about $ 29444.00/ha on account of reducing the quantity of gypsum or phosphogypsum without any significant yield loss and the saved amount can be utilized to bring more area under reclamation. The maximum N content in rice and wheat grain was recorded with treatment T-4.