Effects of Biochar and Municipal Solid Waste Compost on Soil Physical Quality and Productivity Index Under Sorghum Cultivation Irrigated with Saline Water

Amending soil with different materials is gaining acceptance as an effective and inexpensive technique for reclamation of salt-affected soils. The main idea of this study was to investigate the effects of biochar, compost of municipal solid waste and different water salinities level on soil physical quality (SDexter) and soil productivity index (SPI). The treatments were as followed: Control: Soil without biochar or compost and irrigated with tap water, S1: Soil without biochar or compost and irrigated with saline water (EC = 4.5 dS m−1), S2: Soil without biochar or compost and irrigated with saline water (EC = 9 dS m−1), B: Soil amended with 1.5%w/w biochar and irrigated with tap water, B+S1: Soil amended with 1.5%w/w biochar and irrigated with saline water (EC = 4.5 dS m−1), B+S2: Soil amended with 1.5%w/w biochar and irrigated with saline water (EC = 9 dS m−1), C: Soil amended with 1.5%w/w compost and irrigated with tap water, C+S1: Soil amended with 1.5%w/w compost and irrigated with saline water (EC = 4.5 dS m−1), C+S2: Soil amended with 1.5%w/w compost and irrigated with saline water (EC = 9 dS m−1). Soil water characteristic curve (SWCC), Field capacity (FC), Plant wilting point (PWP), Plant available water (PAW), Dexter's index of soil physical quality (SDexter) and SPI were examined in a greenhouse experiment. The SPI was calculated by integrating the effects of six soil quality indices: plant available water, organic matter (OM), Electrical conductivity (EC), pH, Bulk density (BD) and Root weighting factor (RF) for all treatments were calculated. The results showed that the B treatment had a slightly higher effect on SWCC. The applied B and C treatments caused insignificant increase in PAW relative to the control. In addition, application of biochar or compost to soil significantly increased the SDexter. The application of C treatment had insignificantly higher value of SDexter compared to other treatments. Compared with the control, SPI was significantly higher for the B and C treatments. Overall, the application of biochar/compost minimized the destructive effects of saline irrigation water and improved the quality of the salt-affected fine-textured soil.