大豆连作是东北和内蒙古东部大豆产区常见的种植方式。有关大豆连作对产量、品质及病虫害等的研究报道较多[1,2]。但有关大豆连作对田间杂草群落、密度的影响报道较少,为此我们对其进行了研究。1　研究方法选择有代表性的,不同连作年限(1～5年)的大豆田,采用定点定期系统?.. Continuous cropping with soybeans is a common method of planting soybean in the northeast and eastern Inner Mongolia. There are many reports on the yield, quality, pests and diseases of continuous cropping of soybean [1,2]. However, the impact of continuous cropping of soybean on the density of weed communities in the field is relatively poor, so we conducted a study on it. 1 research methods to select a representative, different years of continuous cropping (1-5 years) soybean field, using fixed-point regular system?