Biochar Amendments Changed Soil Properties and Improved Cereal Crop Growth Under Salt Stress

Salt stress is a serious problem in agriculture especially in arid and semi-arid regions. This study aimed to determine the responses of soil properties and wheat plants to salt stress (SS) under biochar amendments. The experiment was conducted in pots under controlled conditions. Each pot had a 3 kg soil capacity and was sown with seven grains of Durum wheat (Var. Vitron). After 30 days of sowing, the plants were exposed to three SS levels based on NaCl concentrations (SS0 = 0 g L−1, SS1 = 4 g L−1 and S3 = 9 g L−1), under the application of three biochar doses (B0 = 0 g kg−1, B1 = 5 g kg−1 and B2 = 15 g kg−1). For different soil parameters and plant traits, Tukey post-hoc tests (HSD) were applied to carry out multiple comparisons of means among biochar doses, SS levels and their combinations. The statistical significance threshold was set to p < 0.05. Salt stress slightly reduced soil pH and NO3‒ while causing an increase in soil moisture, electrical conductivity, organic carbon and total CaCO3. The use of biochar improved all measured soil parameters. Plants under SS gained height and leaf surface area (LSA), however SS produced a decrease in areal biomass, relative water content (RWC) and total chlorophyll. Biochar amendments were effective in increasing plant height, LSA, RWC and total chlorophyll. The two biochar doses applied in this study had almost similar effects on the measured soil parameters with a slight superiority of B1 dose for soil moisture, pH and NO3‒. However, the improvement of wheat plant traits was directly associated with the increase in biochar doses. Our findings indicated that the application of biochar as a soil amendment in agricultural lands irrigated with saline water helps to improve wheat crop growth and soil quality in arid and semi-arid regions. Long-term studies on biochar amendments can help to better understand the response of saline soils and crops to environmental stressors such as drought, heat and salinity.