Efficacy of biochar as soil amendments for soybean (Glycine max L.) morphology, physiology, and yield regulation under drought

The current research work intends to explore the role of different types of soil biochar amendments for improving physiological, morphological, and yield attributes of soybean under moisture deficit conditions. A pot study under RCBD (randomized complete block design) was conducted for soybean, different types of biochar, i.e., wheat straw biochar (WSB), rice straw biochar (RSB), sugarcane bagasse biochar (SBB), and wood-shaving biochar (WB) under three levels of amendments (0, 10, and 20 MT ha(-1)) to a sandy loam and clay loam soil with three levels of irrigation (optimum moisture irrigation, OMI, i.e., 75% irrigation of field capacity, moisture deficit irrigation, MDI, i.e., 50% irrigation of FC, and severe moisture deficit irrigation, SMDI, i.e., 40% irrigation of field capacity), by examining physio-morphological parameters, leaf nutrients, yield-related parameters, protein content (%), and oil content (%). Under MDI conditions, among all types of biochar utilized in the study, most influential results with soil biochar amendments were recorded in the plants of 10 MT ha(-1) wood shaving biochar with increased percentage of relative water content, improved membrane stability index, enhanced shoot length as well as leaf area along with improved yield attributes as 19% high oil content than control (MDI) in clay loam soil. However, all other biochar types influence soybean growth more positively under MDI, particularly in clay loam soil. But in sandy loam soil, sugarcane bagasse and wood-shaving biochar had more positive influences on soybean. Thus, 10 MT ha(-1) wood shaving (Acacia nilotica) biochar soil amendment can be assessed as an efficient tool to alleviate the effects of water stress under MDI. However, both types of straw biochar due to their soft nature did not influence soybean growth and yield positively in sandy loam soil.