Effect of leguminous green manures on alleviating continuous cropping obstacles in muskmelon cultivation

Continuous cropping obstacles in greenhouse muskmelon cultivation pose a significant threat to sustainable production. While leguminous green manures are known to mitigate soil degradation in other crops, their efficacy and micro-ecological mechanisms in muskmelon systems remain unexplored. Here, we demonstrate for the first time that winter planting of two leguminous green manures, common vetch (Vicia sativa L.) and smooth vetch (Vicia villosa Roth var. glabresens Koch), during fallow periods alleviates continuous cropping obstacles by reshaping soil micro-ecology. Field trials revealed that both green manures significantly increased muskmelon yield (13.71% and 10.68%, respectively), elevated soil pH and organic matter, and reduced salinity (EC by 51.1% and total salt by 35.7%). High-throughput sequencing uncovered enriched microbial diversity, with beneficial taxa (Pirellula, Gemmata, Myceliophthora, Talaromyces) positively correlated with yield, while suppressing pathogenic fungi (Fusarium). Redundancy analysis highlighted soil pH and organic matter as key drivers of beneficial microbial recruitment, whereas salinity promoted harmful taxa. This study establishes a green manure-driven micro-ecological remediation framework, providing a cost-effective strategy for sustainable muskmelon cultivation in southern China.