Abstract: To probe the optimal green manure mixed cropping modes under condition of chemical fertilizer reduction,the effects of different green manure mixed cropping modes(Astragalus smicus monoculture,AS; Astragalus smicus+Ro-phanus sativus L. mixed cultivation,AR; Astragalus smicus+Lolium perenne L.,AL; Astragalus smicus+Ro-phanus sativus L.+ Lolium perenne L. mixed cultivation,ARL; Winter fallow,CK)and nitrogen reduction application on yield formation characters of early and late rice were studied with Zhongzao 39 and Taiyou 390 as early and late rice materials,respectively. The results showed that:the substitution proportion of green manure to chemical nitrogen in treatments of green manure return to field was 28.98%-39.68% in 2016 and 30.55%-39.47% in 2017 respectively,which in AS treatment was bigger and which in AL treatment was the lowest. The substitution of green manure to basal chemical nitrogen had not clear affect on tillering dynamics,while all treatments of green manure return to field had the better yield-increasing effect,and the difference among different treatments was observed. In 2016,the yield increasing effect of AS treatment on early and late rice was the best (increased by 7.3% and 8.5%,respectively),and the next was AR treatment (increased by 6.0% and 7.1%,respectively),while in 2017 the yield increasing effect of AR treatment on early and late rice was the best(increased by 7.2% and 5.5%,respectively),and the next was AS treatment(increased by 5.5% and 4.7%,respectively).The substitution of green manure to basal chemical nitrogen was advantageous to heighten the leaf area index and leaf SPAD value at filling stage and dry matter accumulation,and then improve the effective panicles and seed setting rate,while the effect was different among different treatments,and AS and AR treatment performed well in common.So,the substitution of green manure to basal chemical nitrogen fertilizer was advantageous to heighten yield of double cropping rice,and astragalus smicus monoculture and astragalus smicus+Ro-phanus sativus L. mixed cultivation performed well.

Key words: Green manure, Nitrogen fertilizer reduction, Double cropping rice, Yield formation

CLC Number: 

• S143.1