Effect of Reclamation Approaches on the Soil Properties and Performance of the Rice-Wheat Cropping System Under Alkali Irrigation
摘要
Soil degradation is a key environmental concern in sodicity–affected agroecosystems due to the application of alkaline irrigation. This study reports the performance of several sodicity reclamation methods adopted to develop a practical solution for the sustainable utilisation of alkali irrigation for agricultural use. Single–time application of elemental S–based formulation (ES), mineral gypsum and annual application of rapid acidulated manure (RAM) were evaluated for three years in a field lysimeter experiment in factorial randomised block design and three replications with high pH (pH1:2 8.7 ± 0.21) soil under rice–wheat cropping system for neutralising the deleterious effect of 3, 6, and 7.5 me L–1 residual sodium carbonate (RSC) in irrigation. Gypsum, ES, and RAM application increased Ca2+soluble and lowered pH and sodium adsorption ratio (SARe), Na+ to (Cl– + SO42–) ratio, (CO32– + HCO3–) to (Cl– + SO42–) ratio, but increased the cation ratio of soil structure stability in soil solution saturation paste extract. The available K, S, fluorescent diacetate hydrolyzing, and alkaline phosphatase activities were greater on amending sodic soil with ES than with gypsum and RAM. The soil organic C, Olsen–P, microbial biomass C and N, and dehydrogenase activity were higher for the soils amended with RAM, gypsum, and ES than the control. Amending soil with ES improved overall system yield (~ 44%) and thereby, increased the net return and B: C ratio of amendment treated soil (ES, RAM and gypsum) than control (P < 0.05). The pHs and SARe were important variables that affected system yield and explained the 57% variability. Elemental S–based amendments can be an effective amendment for neutralizing the alkalinity of irrigation water for improving the rice–wheat yield and soil quality.