Effects of shading on the growth and nutrient accumulation of different varieties of Chinese milk vetch

In order to choose the suitable variety of Chinese milk vetch for the interplant system in the paddy,the pot experiment was carried out to study the effect of shading on the growth and nutrients accumulation of three varieties of Chinese milk vetch which named Yijiang,Xinyang and Zhezi.The results showed that the survival seedlings under shading were more than no-shading,the seedling mortality increased as the shading degree increased.In the early growing stage,the shoot height increased as the shading degree increased,but compound leaves per plant,apparent leaf area and SPAD value decreased as the shading degree increased.As the growth period propelled,the difference among the treatments of the indexes diminished.The shading degree had significant influence on the yield of the three varieties,the yield of Yijiang were higher than other varieties under the no-shading and 40% shading condition,the yield of Zhezi were highest under the 75% shading condition.The content of carbon decreased as the shading degree increased,but the N,P,K contents increased as the shading degree increased.Shading also had influence on the nutrients accumulation of the three varieties,the C,P,K accumulation of Yijiang and the N accumulation of Xinyang were highest under the no-shading condition,the C,P,K accumulation of Zhezi and N accumulation of Yijiang were highest under the 40% shading condition,all the nutrients accumulation of Zhezi were highest under 75% shading condition.In conclusion,Zhezi was suitable interplant in the paddy.