The niche complementarity driven by rhizosphere interactions enhances phosphorus‐use efficiency in maize/alfalfa mixture
Liyang Wang, Baicheng Hou, Deshan Zhang, Yang Lyu, Kai Zhang, Haigang Li, Zed Rengel, Jianbo Shen
Abstract
Abstract Rhizosphere interactions between intercropping maize and alfalfa to increase phosphorus (P) acquisition remain largely unknown. This study aimed to investigate the mechanisms underlying niche complementarity to increase P acquisition in the maize/alfalfa mixture by influencing root/rhizosphere interactions. Maize was grown alone (single maize) or with maize (maize/maize) or alfalfa (maize/alfalfa) with low P (30 mg P kg −1 soil) and high P (150 mg P kg −1 soil) supplies. The target maize had greater shoot biomass and P content when grown with alfalfa than maize. Compared with maize, alfalfa had higher secretion of carboxylates and acid phosphatase, suggesting a stronger capacity to mobilize soil P. Phosphorus deficiency also increased the specific root length and the proportion of thin roots (diameter < 0.2 mm) in alfalfa, and intercropped alfalfa had higher carboxylates secretion than monocropped one, indicating that alfalfa root traits were modified by both soil P supply and the identity of neighbor. Increased soil P availability by alfalfa root exudation and improved rhizosphere environment by thin alfalfa roots promoted shoot growth and P acquisition of maize in the maize/alfalfa mixture. The presence of maize increased the secretion of carboxylates from alfalfa roots, suggesting that the root interactions between maize and alfalfa are crucial for improving P‐use efficiency and productivity in intercropping.