Allelopathic interference of six alfalfa varieties at different harvesting stages on the germination, seedling and root growth of green foxtail and barnyardgrass

Abstract

In order to evaluate the allelopathic interference of different varieties of alfalfa on notorious weeds, the sensitivity of green foxtail and barnyardgrass to the extracts from the first, second, and three stubbles of six varieties were investigated through plate culture. The germination rate, seedling length, seedling fresh weight, root length, and root fresh weight of weeds were measured in this study to comprehensively elucidate allelopathic effects. The results suggested that: (1) The allelopathy of six alfalfa varieties tested showed obvious interspecific differences, the inhibition of Zhongmu No.3 on weeds was weaker than other cultivars. (2) The inhibitory effect of alfalfa extracts on green foxtail was enhanced with the increase of stubble times, while the differences between three stubble times on barnyardgrass were not clear, especially between the first and second stubbles. (3) Compared with barnyardgrass, green foxtail was generally more susceptible to the extracts. (4) The inhibitory effect of alfalfa extract on root was stronger than seedlings in the same weeds. The study may help to comprehensively reveal the allelopathic effect of different alfalfa varieties in the first three stubbles on green foxtail and barnyardgrass, providing scientific evidence for weed control based on natural plant extracts in the future.