Fig. 4From: Biochar and biofertilizer reduced nitrogen input and increased soybean yield in the maize soybean relay strip intercropping systemSoybean nodule number and nodule weight under different organic material and nitrogen levels. Note: Fig. A and B represent soybean nodule numbers in 2019 and 2020, respectively. Fig. C and D represent soybean nodule weight in 2019 and 2020, respectively. The growth stage, nitrogen treatment, fertilizer treatment, and significant signs are described in Fig. 2Back to article page