Weed Suppression and Plant Interaction in Foxtail Millet and Mung Bean Intercropping System
The intercropping of cereal crops and legumes might increase yield and improve farmland ecological environment, so it is adopted in many regions, especially in organic management fields. However, the knowledge on the interaction among foxtail millet (Setaria italica L.) and mung bean (Vigna radiata L.) intercropping and weeds is relatively limited. The field study was conducted in 2021 and included four planting patterns: (1) treatment F1M1, one row of foxtail millet and one row of mung bean; (2) treatment F2M1, two rows of foxtail millet and one row of mung bean; (3) foxtail millet monoculture and (4) mung bean monoculture. In order to clarify the interaction between weed and crop, their emergence, plant height, biomass and yield were investigated. The results showed that the two intercropping patterns both reduced weed emergence amount, significantly suppressed weed density and biomass compared with its monoculture. In intercropping treatment, the plant height, biomass per plant and yield of foxtail millet were higher than that of monoculture, and the biomass and yield of mung bean was lower than that of monoculture. The total yield of treatment F1M1 and F2M1 was 56.0% and 101.6% higher than that of monocultures. The land equivalent ratio of treatment F1M1 and F2M1 were 3.85 and 5.39, respectively. The aggressivity and competitive ratio of foxtail millet in the intercropping system was higher than that of mung bean and the indices of foxtail millet in treatment F2M1 was higher than F1M1. It meant foxtail millet was the dominant species in the intercropping system and foxtail millet in treatment F2M1 had more advantageous than F1M1. To sum up, the foxtail millet and mung bean intercropping patterns could enhance the weed suppression effects by the crops, and increasing the seedling density of the dominant crop foxtail millet could improve the integrative yield, but this could not substantially alter the weed suppression outcomes of the intercropping system. The data and results of this study are helpful to understand the competitive relationship among crops and weeds in foxtail millet and mung bean intercropping system.