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本文通过对青海农田杂草调查，并比较十余年前后两次调查结果，分析研究农田草害情况和杂草种群演替趋势及原因。认为青海农田杂草发生种类没有变化，农田杂草总危害和严重危害率明显下降，但杂草群落种群演替明显。杂草群落中原来占优势的野燕麦（Ａｖｅｎａｆａｔｕａ）、密花香薷（ＥｌｓｈｏｌｔｚｉａｄｅｎｓａＢｅｎｔｈ）、藜（ＣｈｅｎｏｐｏｄｉｕｍａｌｂｕｍＬ．）、野芥菜（Ｂｒａｓｉｃａｊｕｎｃｅａ）、遏兰菜（Ｔｈｌａｓｐｉａｒｖｅｎｓｅ）等杂草发生危害下降。危害指数分别由２６．１８、１５．６８、１８．４４、６．６７和４．４减少至１６．５１、３．２、２．２４和２．４。而原来较次要、抗（耐）药性较强的杂草如苣荬菜（ＳｏｎｃｈｕｓｂｒａｃｈｙｏｔｕｓＤＣ）、猪殃殃（Ｇａｌｉｕｍａｐａｒｉｎｅ（Ｌ）ＶａｒｔｅｎｅｒｕｍＲｃｂｂ）、田旋花（ＣｏｎｖｏｌｖｕｌｕｓａｒｖｅｎｓｉｓＬ．）等的发生危害加重，草害指数分别由１１．８４、７．４、７．０５增加到１４．２１、９．１６、１０．６６。还对农田杂草群落危害及不同生态区草害的演替情况作了分析。农田杂草群落种群演替的主要原因是除草剂的单一品种长期使用和耕作管理不当引起的。作者还就防治对策进行?
In this paper, the investigation of farmland weeds in Qinghai was conducted and the results of two surveys more than ten years ago were compared to analyze the situation of farmland weeds and the trend of weed population succession and the reasons. It is considered that there is no change in the types of farmland weeds in Qinghai, and the total damage and the serious damage rate of weeds in farmland obviously decrease, but the succession of population in weed communities is obvious. The dominant dominant species of weed communities were weeds such as Avenafatua, Elsholtziadensa Benth, Chenopodiumalbum L., Brasica juncea and Thlaspiarvense. The Hazard Index decreased from 26.18, 15.68, 18.44, 6.67 and 4.4 to 16.51, 3.2, 2.24 and 2.4 respectively. However, the weaker and more resistant weeds such as Sonchus brachyotus DC, Galiumaparine (L) Vartenerum Rcbb, Convolvulus arvensis L. and other weeds had more serious harm, Index increased from 11.84,7.4,7.05 to 14.21,9.16,10.66 respectively. The hazard of weed community in farmland and the succession of grassland damage in different ecological zones were also analyzed. The main reason for the population succession of weed community in farmland is the long-term use of single herbicide and the improper tillage management. The author also on prevention and control measures?