狗尾草是北方人工草地苜蓿初播田中普遍发生的一年生禾本科杂草。由于当年播种的苜蓿幼苗生长十分缓慢,极易受到该类杂草的危害,使当年苜蓿品质和产草量下降,越冬率降低,同时也直接影响到第二、三年产草量。对于人工草地杂草防除问题,人们一直奉行着“除草、除小、除了”的防除原则。然而多年的防除杂草的实践证明:沿用这一原则,不仅没有根除杂草,反而带来一系列的生态问题。随着生态经济学的兴起和发展,人们对杂草的认识不断深 Setaria viridis is an annual gramineous weed that commonly occurs in the field of alfalfa in the northern artificial grassland. Because of the very slow growth of alfalfa seedlings planted that year, vulnerable to the hazards of such weeds, so that year alfalfa quality and yield decreased, overwintering rate decreased, but also directly affect the second and third year of grass production. For artificial grass weed control, people have been pursuing the “weeding, except small, except” principle of prevention and control. However, many years of practice of controlling weeds have proved that following this principle, not only weeds have not been eradicated, but a series of ecological problems have been brought about. With the rise and development of ecological economics, people’s understanding of weeds continues to deepen