农田杂草危害极大。据世界粮农组织的估计,全世界每年因病、虫、草害造成农作物减产损失约204亿美元,其中草害造成的损失约占42％。每年因杂草危害,我国损失粮食约500亿斤;我区损失约9000万斤左右,约占粮食总产的10％。严重的地块减产高达60％以上。因此,调查研究农田杂草的分布规律及有效的防除措施,对农业生产有着重要意义。我校结合教学和生产实习,1982年6月——1983年7月,由教师率领学生,先后对平凉、庄浪、华亭、泾川、灵台、崇信六县农田杂草的分布及为害状况进行了全面普查(调查与访问相结合)。普查面积共2万余亩,取样点5000多个(3亩以下地块取3点,3——5亩地 Farmland weeds are extremely harmful. According to the FAO estimates, the annual loss of crops caused by diseases, pests and weeds in the world is about 20.4 billion U.S. dollars, of which about 42 percent is caused by grasses. Every year because of weed damage, our country lost about 50 billion pounds of grain; my area loss of about 90 million pounds, accounting for about 10% of total grain output. Mass production cuts of up to 60%. Therefore, the investigation of the distribution of farmland weeds and effective control measures for agricultural production is of great significance. Our school combines teaching and production internship, June 1982 - July 1983, led by the teachers of students, successively Pingliang, Zhuanglang, Huating, Jingchuan, Lingtai, Chongxin six county weeds distribution and damage status Conducted a comprehensive survey (a combination of surveys and visits). Census area of ​​a total of more than 2 acres, more than 5000 sampling points (3 acres below the plot to take 3 points, 3 - 5 acres of land