中文摘要：

苜蓿为多年生豆科牧草，是一种典型的化感作物，苜蓿体内的化感物质如皂甙等能够有选择地抑制某些杂草。采用生物测定方法．评估了苜蓿叶浸提液对农田中常见的5种杂草的抑制潜力。结果表明：苜蓿叶的抑草效果取决于浸提条件（温度，浓度，时间等）和杂草种类。实验表明，最佳的浸提条件是，浸提液浓度0．45g/ml，浸提时间24h以及浸提温度50℃。各处理条件下，藜的发芽抑制率最高，其次为反枝苋，然后是马唐和狗尾草，苘麻则几乎总是最低的。说明苘麻、马唐和狗尾草比藜和反枝苋的抵抗力或容忍性要好。表4，参16。

英文摘要：

Alfalfa （Medieago sativa） is one of perennial leguminous pastures; also, one of typical allelopathic plants. Its leaves contain abundant allelochemicals such as saponins, which can suppress some weeds selectively. In this study, the inhibitory potential of aqueous extract from alfalfa leaves against of germination of test weeds was assessed by bioassay. The results showed that the degree of weeds suppression was dependent on extract conditions, including extract concentration, incubation temperature and time, and weed species.Among of them, the combination of 0.45g/ml, 24h and 50℃was the best treatment for weed suppression. Under different treatments, the percentage inhibition of germination was arranged in order by Chenopodium albun L. 〉 Amaranthus retroflexus L. 〉 Digitaria sanguinalis L. 〉 Setaria faberii Herrm. 〉 Abufilon theophrasti Medic., which indicated Abutilon theophrasti Medic was more tolerant or resistant than others.