Yield-increasing and fertilizer-saving effects, and development potential of green manure-maize rotation in China

Developing green manure-maize rotation systems is a pivotal strategy for simultaneously securing maize yield, reducing and optimizing chemical fertilizer use, building soil fertility, and protecting farmland ecology. This review synthesizes the yield-increasing and fertilizer-saving effects of green manure–maize rotation systems and their underlying mechanisms, and evaluates the development potential of these systems in China. Results from 20 multi-site long-term experiments conducted during 2008–2024 showed that, relative to conventional nitrogen (N) fertilization, green manure-maize rotations increased grain yield by 7.6%, 3.8%, and 3.9% under 0%, 15%, and 30% reductions in N application, respectively. Even without chemical N fertilizer application, maize yield under green manuring still reached 92.7% of that under conventional fertilization. The mechanisms underlying the yield-increasing and fertilizer-saving effects were elucidated from three perspectives: enhancing maize nutrient acquisition and utilization, improving soil health, and strengthening agroecosystem services. The incorporation of green manure combined with reduced fertilizer application can optimize maize yield components, promote nutrient uptake, and improve fertilizer use efficiency. Long-term green manuring can increase soil C and N pools. Soil organic matter and total N increased by 0.45 and 0.13 g/(kg·a), respectively, under green manure combined with 85% of the conventional N rate. Green manure–maize rotation can reduce net global warming potential, decrease N losses, mitigate wind and water erosion, and enhance the resilience of maize production systems to extreme weather events. The potential area for green manure–maize rotation in China is estimated at 6.22 million hectares, yet the average area in 2022–2024 was only 0.56 million hectares, only accounting for 9.0% of the potential area, indicating substantial potential for expansion. The system is currently distributed in North China and the dryland regions of Southwest and South China. Suitable green manure species, sowing management, and incorporation practices for each region are summarized, and the constraints on green manure development and policy recommendations are discussed. Future priorities include continued technological integration, mechanism-oriented research, and theoretical innovation to underpin large-scale adoption of green manure-maize rotation systems.