Cover Cropping-Mediated Regulation of Phyllosphere Microbial Health and Rice Yield

Although cover crops are integral to sustainable agriculture, their specific impacts on rice (Oryza sativa) disease management and yields remain poorly understood. This 2-year field study (2023–2024) evaluated the effects of winter cover crops [winter fallow, Italian ryegrass (Lolium multiflorum, IR), and smooth vetch (Vicia villosa, VV)] on summer rice phyllosphere microbial assembly and yield. Compared to fallow, transpiration rates under VV and IR increased by 31.6% and 25.3%, while net photosynthetic rates increased by 25.0% and 23.9%, respectively (P < 0.05). Cover crops enriched potentially beneficial taxa (e.g., Pseudomonas and Microbacterium) and reduced the relative abundance of Erwinia, which is a potential pathogen reservoir. Furthermore, VV and IR enhanced the abundance of functional fungal genera (Epicoccum, Sporobolomyces, and Rhodotorula). Compared to fallow, the VV and IR treatments increased the grain yield by 26.77% and 21.26%, respectively. Winter cover cropping with VV and IR is recommended for sustainable, high-yield rice production.