Fig. 5From: Biochar and biofertilizer reduced nitrogen input and increased soybean yield in the maize soybean relay strip intercropping systemSoybean nitrogenase activity and nitrogen fixation potential under different organic material and nitrogen levels in 2020. Note: Fig. A and B represent soybean nitrogenase activity, and Fig. C and D represent the soybean nitrogen fixation potential at the R2 and R5 stages, respectively. NA: nitrogenase activity; NFP: nitrogen fixation potential. The growth stage, nitrogen treatment, fertilizer treatment, and significant signs are described in Fig. 1Back to article page