Legume Genomics and Genetics 2025, Vol.16, No.3, 108-127 http://cropscipublisher.com/index.php/lgg 123 manure rotation and high-proportion legume forage forage planting to maintain the nutrient balance of farmland and grassland. For example, in organic rice production, the rotation system of one season of rice and one season of astragalus green manure not only meets the nitrogen demand of rice, but also suppresses weeds and pests, achieving stable production. Another example is the planting of alfalfa and clover in organic pastures to replace nitrogen fertilizer application, and the recycling of nitrogen is achieved by returning livestock manure to the fields. Facts have proved that these models based on legume nitrogen fixation can fully achieve productivity comparable to conventional agriculture while significantly reducing environmental load. Ecological agriculture also emphasizes reducing the use of pesticides, and the systemic resistance and soil health improvement effects induced by the legume symbiotic system can precisely reduce the risk of crop diseases and pests. Therefore, in ecological agricultural demonstration areas, we can often see intercropping of leguminous crops and other crops, and the application of symbiotic agents. These measures together build a more stable and low-cost farmland ecosystem. The legume symbiotic system can also be combined with animal husbandry, forestry, etc. to form a comprehensive model. For example, in the "rice field crab farming" model, leguminous forage is planted on the ridge to fix nitrogen, which not only provides feed for field crabs but also fertilizes the soil, realizing a planting and breeding cycle. In the forestry and fruit industry, planting leguminous green manure between orchard rows has been proven to significantly improve soil and reduce pests and diseases, and is an important technology for orchard ecological management (Cheng et al., 2022). When afforestation is carried out on barren hills, leguminous shrubs and mycorrhizal fungi inoculation are often used to increase the survival rate of afforestation seedlings and the speed of soil improvement, which reflects the ecological benefits of combining agriculture and forestry and using fungi to help forestry. It can be foreseen that future ecological agriculture will more systematically integrate leguminous crops, symbiotic microorganisms and multiple industries to form a closed-loop agricultural ecosystem. For example, the circular agricultural model combining "grain-economic-feed-fertilizer": growing leguminous forage (feed) to raise livestock and poultry to produce fertilizer, and then using fertilizer to raise grain and economic crops; then using livestock waste to cultivate microbial agents for leguminous crops to inoculate, and so on, to maximize the potential of each link. Leguminous symbiotic nitrogen fixation provides a biological nitrogen source and soil fertilization link, which is one of the key supporting technologies. Therefore, we should strengthen the research on the role of symbiotic systems under different ecological agricultural models, and integrate them into organic, circular and other models according to local conditions to achieve synergistic efficiency. 7.3 Strategies for promoting regional agricultural sustainability To promote the legume-microorganism symbiosis to serve the green transformation of agriculture on a larger scale, it is necessary to work together from multiple aspects such as policy, promotion, and science and education. First, at the policy level, governments at all levels can introduce incentives to encourage the planting of leguminous green manure and grain-bean rotation. For example, in the pilot program of the crop rotation and fallow system that has been implemented in my country, certain subsidies are given to the planting of green manure and leguminous crops. In the future, subsidies for nitrogen-fixing green manure can be further increased to motivate farmers to add leguminous crops to the staple food rotation. At the same time, a production and marketing guarantee system for leguminous crops should be established, such as developing a soybean revitalization plan to improve the income of soybean farmers and ensure the steady increase in the sown area of leguminous crops. With the expansion of the planting area of leguminous crops such as soybeans, the symbiotic nitrogen fixation effect in the soil will accumulate, the use of chemical fertilizers in the whole society is expected to achieve a turning point decline, and agricultural non-point source pollution will be alleviated. Secondly, in the promotion of agricultural technology, it is necessary to strengthen the training and demonstration of microbial agents and scientific fertilization and weight loss technology. Many farmers do not have enough understanding of the nitrogen fixation potential of leguminous crops, and they are still accustomed to applying excessive nitrogen fertilizers to peanuts and soybeans, resulting in the inhibition of symbiotic nitrogen fixation. The methods of leguminous nitrogen reduction planting should be disseminated to farmers through field schools,
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