Maize/peanut intercropping alleviates continuous peanut cropping stress via root exudate– and rhizosphere bacteria–mediated mechanisms

Maize/peanut intercropping alleviates yield decline and soil degradation under peanut continuous cropping, yet the mechanistic contributions of maize root exudates (MRE) and maize rhizosphere bacteria (MRM) remain unresolved. Here, we integrated a decade-long field experiment with decoupled pot trials to disentangle their respective roles. Field results showed that intercropping increased peanut yield by 24.36 % and reduced pod rot by 89.00 %, driven by higher soil-available phosphorus (AP) and potassium (AK), and by increased bacterial diversity and network complexity. Decoupled experiments revealed two complementary pathways. MRE operated via a “nutrient–enzyme–driven” mechanism: it increased shoot biomass by 28.01 % and mobilized AP and AK by enhancing amylase and α-glucosidase activities, concomitant with enrichment of Dyella and Actinospica , increased network complexity, and accumulation of phenolic and organic acids (e.g., 2-methylsuccinic acid) that facilitated nutrient activation. Conversely, MRM followed a “structural–physiological optimization” pathway: it increased root biomass and specific root length by 14.12 % and 12.12 %, respectively, while elevating alkali-hydrolyzable nitrogen (AN) and peroxidase activity. MRM reduced rhizosphere bacterial diversity but selectively enriched functional groups (eg., Bradyrhizobium , Burkholderia ), generating a streamlined network. This restructuring was coupled with the co-enrichment of signaling metabolites (eg., N-acetyl- L -glutamine and jasmonoyl- L -isoleucine) and the reduction of autotoxins. Collectively, MRE enhances P and K mobilization through acid-mediated network intensification, whereas MRM improves N-use efficiency through targeted bacterial assembly and root optimization. This study elucidates the microecological basis of intercropping-induced alleviation of continuous cropping stress and provides a framework for employing cereal exudates and synthetic consortia to regulate legume-based systems under continuous cropping. • Maize exudates mobilize P and K via organic acids and bacterial shifts. • Maize rhizobacteria optimize root architecture and N via microbial-exudate interactions. • Mimetic exudates or SynComs can overcome continuous cropping stress.