The Innovation Team of Fertilizer and Fertilization Technology at the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS), has discovered that coupling green manure incorporation with optimal water management achieve a triple-win for paddy soil quality, rice productivity and environmental benefits. 

Their related findings have been published in the international journal Agriculture, Ecosystems & Environment under the title "Green manuring combined with optimal water management achieves a triple-win for paddy soil quality, rice productivity, and environmental benefits".

In the winter fallow season in southern rice-growing regions, planting and incorporating green manure can replace some chemical fertilizers, increase rice yields, significantly enhance carbon sequestration, and alleviate soil degradation caused by intensive farming practices. However, the continuous flooded conditions in rice fields promote methane (CH₄) emissions, leading to an increase in the carbon footprint. Various water management measures such as mid-season drainage or alternate wetting and drying are considered effective in reducing CH₄ emissions. However, these measures may exacerbate nutrient loss from rice fields, affecting rice yields, and also lead to increased nitrous oxide (N₂O) emissions, thus compromising environmental benefits. Additionally, frequent rainfall during the rice-growing season reduces the mitigation potential of mid-term water management, while delayed flooding after green manure incorporation may be an efficient measure to reduce nutrient loss, increase rice yields, and enhance environmental benefits.

The research found that compared to winter fallow practices, planting and incorporating Chinese milk vetch significantly increased the total biomass and nitrogen fertilizer partial productivity of rice. It also increased the total nutrient and available nutrient content in the soil, with soil quality indices under different water treatments increasing by 64.6% to 185.6%. Delaying flooding by 10 days after green manure incorporation significantly increased the net ecosystem carbon balance by 65.0% compared to green manure dry tillage, demonstrating a stronger carbon sequestration capacity. The optimized water management after green manure incorporation compared to winter fallow and immediate flooding after green manure incorporation treatments increased net ecological economic benefits by 4.7%-7.3% and 5.8%-8.5%, respectively. The reduction in carbon footprint costs was a key factor leading to the increased net ecological economic benefits under water management. Overall, the delayed flooding by 10 days after green manure incorporation improved soil quality, crop productivity, and environmental benefits.

Professor Zhou Guopeng from Anhui Agricultural University and doctoral student Ma Zhengbo from the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, are the co-first authors of this paper. Researcher Wu Ji from the Soil and Fertilizer Research Institute of Anhui Academy of Agricultural Sciences and Researcher Cao Weidong from the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, are the corresponding authors. The research was supported by the National Key Laboratory for Efficient Utilization of Arid and Semi-arid Farmland in Northern China, the National Key Research and Development Program of the Fourteenth Five-Year Plan (2021YFD1700200), the National Natural Science Foundation of China (32202609, 32072678), the National Green Manure Industry Technology System (CARS-22), and the Basic Research Fund of Central Public Welfare Research Institutions (CAAS-ZDRW202417).

【Citation】: Zhou, G., Ma, Z., Han, S., Chang, D., Sun, J., Liu, H., ... & Cao, W., 2025. Green manuring combined with optimal water management achieves a triple-win for paddy soil quality, rice productivity, and environmental benefits. Agriculture, Ecosystems & Environment, 383, 109507.

Original Link: https://doi.org/10.1016/j.agee.2025.109507