机收稻秸留茬高度对紫云英产量及养分吸收的影响OA

The combined use of Chinese milk vetch(Astragalus sinicus L.)and rice straw is an impor-tant practice for improving soil fertility in paddy fields in southern China.With the increasing adoption of mechanical rice harvesting,variation in rice stubble height may affect yield and nutrient uptake of Chinese milk vetch.A field experiment was conducted to evaluate the effects of different rice stubble heights on yield,nutrient concentration,and nutrient uptake of Chinese milk vetch.The experiment followed a com-pletely randomized design with six treatments:no rice straw returned to the field(CK),rice stubble height of 40 cm(S40),30 cm(S30),20 cm(S20),10 cm(S10),and 0 cm(S0),with the straw evenly distributed on the soil surface.The results showed that rice stubble height significantly affected the yield and nutrient uptake of Chinese milk vetch,with the S40 treatment achieved the highest fresh forage yield.Compared with S40,the CK treatment reduced fresh forage yield by 50.1%,and the ranking of fresh forage yield was S40>S30>S20>S10>S0>CK.Nutrient uptake,including nitrogen,phosphorus,and potassium,showed a pattern similar to that of fresh forage yield.As rice stubble height decreased,nutrient uptake by Chinese milk vetch also declined,with the highest values consistently observed under S40.Principal com-ponent analysis provided a comprehensive ranking of treatment performance as S40(3.46)>S20(0.38)>S30(0.26)>S10(-0.97)>S0(-1.00)>CK(-2.14).Cluster analysis further grouped the treatments into three categories:(Ⅰ)S40,(Ⅱ)S30 and S20,(Ⅲ)CK,S10 and S0.Overall,maintaining a relative high rice stubble height after mechanical harvesting was beneficial for achieving high yield and efficient nutri-ent uptake in Chinese milk vetch.This practice provides a strong material basis for green manure incorpora-tion and offers theoretical support for improving soil fertility and promoting sustainable agricultural develop-ment in red soil regions.