Co-inoculation of biochar and arbuscular mycorrhizae for growth promotion and nutrient fortification in soybean under drought conditions.

Drought is significant abiotic stress that affects the development and yield of many crops. The present study is to investigate the effect of arbuscular mycorrhizal fungi (AMF) and biochar on root morphological traits, growth, and physiological traits in soybean under water stress. Impact of AMF and biochar on development and root morphological traits in soybean and AMF spores number and the soil enzymes' activities were studied under drought conditions. After 40 days, plant growth parameters were measured. Drought stress negatively affected soybean growth, root parameters, physiological traits, microbial biomass, and soil enzyme activities. Biochar and AMF individually increase significantly plant growth (plant height, root dry weight, and nodule number), root parameters such as root diameter, root surface area, total root length, root volume, and projected area, total chlorophyll content, and nitrogen content in soybean over to control in water stress. In drought conditions, dual applications of AMF and biochar significantly enhanced shoot and root growth parameters, total chlorophyll, and nitrogen contents in soybean than control. Combined with biochar and AMF positively affects AMF spores number, microbial biomass, and soil enzyme activities in water stress conditions. In drought stress, dual applications of biochar and AMF increase microbial biomass by 28.3%, AMF spores number by 52.0%, alkaline phosphomonoesterase by 45.9%, dehydrogenase by 46.5%, and fluorescein diacetate by 52.2%, activities. The combined application of biochar and AMF enhance growth, root parameters in soybean and soil enzyme activities, and water stress tolerance. Dual applications with biochar and AMF benefit soybean cultivation under water stress conditions.