Species and Community Structure of Weeds in Main Winter Wheat Areas of Northern Xinjiang

【Objective】 To determine the weed composition and structure in winter wheat fields of northern Xinjiang in the hope of providing theoretical foundation of regional weed control measures. 【Method】 The weeds of winter wheat fields in Qitai County and Emin County of northern Xinjiang were investigated by the sampling method of inverted “W”-pattern with nine sampling points. 【Result】 The result showed that 60 weed species were present, which belonged to 20 families and 52 genera, mainly including Asteraceae, Leguminosae and Gramineae. The dominant species in wheat fields in northern Xinjiang was Echinochloacrusgalli(L.)Beauv., Chenopodiumglaucum L. and Polygonum convolvuluswere regional common weeds. The weed distribution of three regions was different from each other, there were 47 species of weed in wheat fields in Emin County, 32 and 31 species in southern hill areas and central plain area in Qitai County, separately. Analysis of the diversity showed that Shannon-Wiener index of Emin County was the highest, which was 2.51, and the highest Simpson index was in plain area of Qitai County, which was 0.19, the Pielou indexes of Emin County wheat area were higher than Qitai, which were 0.65. 【Conclusion】 Echinochloacrusgalli(L.)Beauv has effect on winter wheat growth and yield in northern Xinjiang obviously, Chenopodiumglaucum L. and Polygonum convolvulushave have impact on regional wheat areas where the weed happens. Other normal weeds which happen in some wheat fields have less effect on the growth and development of wheat. In the three survey areas, the species richness and species diversity index in Emin County are the highest, while the dominant species of weeds in the central plain area of Qitai County are the most concentrated.