Ecological restoration of degraded sodic lands through afforestation and cropping

Abstract

Land degradation and their restoration are emerging issues all over the world for the environmental management. In this study, degraded sodic land was rehabilitated through afforestation and cropping for 50years. We assessed physico-chemical (bulk density, water holding capacity, pH, electrical conductivity (EC), organic carbon, nitrogen, phosphorus, exchangeable cations and exchangeable sodium percent [ESP]), biological (microbial biomass-C, N, and P, quotients and counts), and biochemical (dehydrogenase, β-glucosidase, alkaline phosphatase, acidic phosphatase and protease) properties of rehabilitated forest land (R-FL) and rehabilitated crop land (R-CL) in two depths (0–15 and 15–30cm) and three seasons. The changes were compared with degraded sodic land (D-SL), control site. At 0–15cm soil depth in the R-FL and R-CL, compared to D-SL, water holding capacity, organic carbon, total nitrogen, available nitrogen, available phosphorus, exchangeable cations, ESP, microbial counts (bacteria and fungus) and biomass (C, N and P) and enzymatic activities were significantly greater, while bulk density and microbial quotient were significantly lower. Soil pH, EC, Na+, ESP and alkaline phosphatase decreased significantly, while other soil properties increased significantly in both rehabilitated lands (R-FL and R-CL). Afforestation with multiple tree species and long-term cropping system improved the soil fertility status and restored the degraded site to different levels. Furthermore, seasonal variations were land use specific and showed different trends across land use types. The study concluded that afforestation with multiple tree species induced greater changes in soil properties during restoration of degraded sodic lands in comparison to cropping system.