Abstract:

Chinese milk vetch（Astragalus sinicus L.），as an important green manure crop in southern rice-growing regions，exhibits significant variations in yield and soil improvement effects under key agronomic practices such as seeding rate and rhizobium inoculation. Independent field experiments conducted in typical rice-growing areas of Zhejiang Province demonstrated that when the seeding rate was maintained within 1.5-2.5 kg per 667 m2，the fresh grass yield of Chinese milk vetch remained stable above 1 500 kg per 667 m2，with significant （p0.05） enhancements in soil organic matter，total nitrogen，available phosphorus，and available potassium contents. However，increasing the seeding rate to 2.5 kg per 667 m2 provided no additional yield benefits. Rhizobium inoculation significantly promoted plant growth and nutrient accumulation，increasing fresh grass yield by 18.97% and 28.24% for Zhejiang Ningbo Daqiao and Jiangxi Yujiang Daye varieties， respectively，while raising nodule numbers by 42.96% and 47.96%， respectively. The inoculated plants showed significantly improved nitrogen，phosphorus，and potassium contents，further enhancing soil fertility after incorporation. In conclusion，combining a seeding rate of 1.5-2.0 kg per 667 m2 with rhizobium inoculation was recommended for Chinese milk vetchproduction to achieve synergistic improvement in both yield and soil fertility，providing technical support for efficient green manure utilization in southern rice-growing regions.

Key words: Chinese milk vetch（Astragalus sinicus L.）, seeding rate, rhizobium inoculation, yield, improvement of soil fertility