豆科牧草对4种农田常见杂草和水稻化感作用的研究

采用室内生测试验评价了白三叶、紫花苜蓿和毛苕子等3种豆科牧草新鲜茎叶的水浸提液对狗牙根、稗草、马唐和牛筋草等4种农田常见杂草种子萌发和幼苗生长的化感作用。利用盆栽试验研究3种豆科牧草的茎叶按不同比例与土混匀后对水稻秧苗生长的影响。结果表明：供体豆科牧草茎叶的水浸提液对狗牙根、稗草、马唐和牛筋草等的萌发率和幼苗生长均有不同程度的抑制作用,且随着水浸提液质量浓度的增加其抑制作用增强。浸提液质量浓度为0.1 g.mL-1时,毛苕子对稗草种子萌发的抑制作用强于其它3种,抑制率达50.8%;毛苕子对牛筋草幼苗根的抑制作用最强,抑制率达59.9%;白三叶对稗草幼苗茎的抑制率达54.3%。同时将豆科牧草的m（新鲜茎叶）-m（土）为1%和2%时,对水稻的苗高和地上部分的生物量有促进作用,3%时则抑制了水稻的生长。研究表明：施用适量的豆科牧草可以促进水稻生长,同时可有效控制稻田杂草。

Allelopathic effect of forage legumes on four common cropland weeds and rice

The allelopathic potentials of water leachates of three legume forages Trifolium repens,Medicago sativa and Vicia villosa on the seed germination and seedling growth of four common cropland weeds including Cynodon dactylon,Echinochloa crusgalli,Digitaria sanguinalis and Eleusine indica were evaluated in laboratory.The water leachates of the shoots of the three legume forages displayed significantly inhibitory effects on the germination and seedling growth of the tested plants,and the inhibitory effects increased with the concentrations of the water leachates.The water leachates of V.villosa at 0.1 g·mL-1 inhibited the seed germination of E.crusgalli by 50.8%,and the root growth of E.indica by 59.9%.The water leachates of T.repens inhibited the shoot grwoth of E.crusgalli by 54.3%.Incorporation of 1% and 2% fresh shoots of the three legume forages into the soils in pots increased the shoot growth and biomass of rice,but 3% incorporation inhibited the rice growth.These results indicate that appropriate application of legume forages in paddy field not only stimulate rice growth but also control the weeds.