Border-rows Effect of Rape (Brassica napus L.) Intercropping with Milk Vetch (Astragalus sinicus L.)

Border-rows effect is an important research content of intercropping system. Milk vetch-rape intercropping is one of the typical intercropping patterns in southern China. However, research on the border-rows effect is very little, which has affected the application and popularization of the milk vetch-rape intercropping system. In this study, two field experiments were conducted from 2018 to 2020. The effects of monoculture, intercropping and different border-rows on agronomic traits and yield of rape were studied. The results showed that milk vetch had a significant effect on the first border-row of rape. The first border-row of rape diameter of root and secondary effective branch number is significantly higher than second and third border-row, and the rape yield per plant in the first border-row of intercropping milk vetch was 135%, 328%, 257% and 147% higher than that in the second, third, fourth and fifth border-rows respectively. The intercropping with milk vetch enhanced the number of pods per plant in first border-row by increasing the agronomic traits of rape, such as plant height, stem diameter, primary effective branch number and secondary effective branch number. In conclusion, intercropping milk vetch significantly improved the agronomic traits of the first and second border-rows rape, increased the yield of rape. So it is recommended that milk vetch intercropping with two rows rape, which has important guiding significance for the application and promotion of milk vetch-rape intercropping in the future.