Enriching soybean with two soil macronutrients through boosting root proliferation with Trichoderma viride

Owing to ineffective biological nitrogen (N) fixation, and imbalanced doses of N and potassium (K) fertilization, soybean productivity is declining under intensive cropping practices. This study aimed to find out the effectiveness of Trichoderma viride priming on soybean root growth promotion, and enhancement of soil-N and K uptakes under graded fertilization. Soybean seeds were treated with freshly prepared T. viride BHU-2953 talc. Root lignification, indole acetic acid (IAA) production, and activity of 1-aminocyclopropane-1-carboxylate deaminase (ACCD) were determined to observe root growth-promoting activities. A pot experiment was conducted to evaluate root volume, and soil exploration by roots, i.e., the potential volume of influence (PVI), uptakes of N and K, and different physiological attributes at different growth periods of soybean. Results revealed that biopriming enhanced the root lignification, IAA, and ACCD, assisting more soil volume exploration (PVI) for better N and K acquisitions. Biopriming increased the plant biomasses which ultimately, led to more seed yield than untreated soybeans, receiving even higher N-K doses. The PVI correlated well with root volume (r² = 0.95; P < 0.01), explaining good soil-nutrient foraging by bioprimed soybeans. Hence, we conclude that T. viride priming can enhance the N and K uptakes in soybeans under graded soil fertilization.