Differential above‐ and belowground responses of mungbean ( <i>Vigna radiata</i> L.) cultivars with diverse phenology to contrasting soil phosphorus distribution

Abstract Deep placement of phosphorus (P) fertilizer significantly increases crop yield and nutrient uptake in rainfed cropping systems. However, genotypic differences in root system architecture (RSA) play an important role in response to P rates and placement strategies. This study investigated genetic variation in RSA and its effect on exploiting deep P bands in four contrasting, early‐ to late‐maturing mungbean ( Vigna radiata L.) varieties. Four P treatments were control (no additional P), surface (30 mg P mixed in the top 5 cm), sub‐layer (30 mg P mixed at 20‐ to 25‐cm depth), and deep band (30 mg P applied in a band at 20‐cm depth). The randomized complete block design included four replications. RSA was measured in the top and bottom 30 cm of the soil profile. Shallower P placement widened root growth angle by 14%, while deeper placements increased mean root diameter and root volume by 15% and 31%, respectively. Deep banding and sub‐layer treatments advanced flowering and increased pod yield in the early‐maturing variety Berken, without significantly altering root surface area, P uptake, or shoot P concentration. Berken also showed the lowest shoot P concentrations, least P uptake, and greatest internal P use efficiency. Genotypic differences in RSA and root functioning played a major role in response to P placement, with the strongest response observed in the deep P band treatment, despite a lack of root proliferation. These findings provide insights into optimizing P placement and selecting mungbean genotypes for improved productivity in rainfed cropping systems.