我县地处江苏省里下河腹部地区,地势低洼,年降雨量1,021.1毫米,年平均气温14.3℃。耕作制度主要是稻、麦、棉、绿肥轮作制,占面积70％左右,稻、麦和稻、油(菜)连作约30％。主要杂草种类,经鉴定有18科39种,其中主要的恶性杂草有看麦娘、大巢菜,猪殃殃等,局部田块恶性杂草还有萹蓄、荠菜、蓼草、野燕麦等。这些草害已成为三麦生产的大敌。草害对三麦产量影响较大,麦苗期看麦娘发生严重的,要耕翻重种。三麦生长期间人工拔草要化十多个工日。杂草吸收土壤养分比较多,看麦娘密度每平方尺57.7株(单本203.8根)时,土壤含速效氮46.6ppm,速效磷为60ppm;而无杂草的麦田,土壤含速效氮60.2ppm,速效磷为130ppm。看麦娘为害早熟三号大麦后,影响大麦产 My county is located in the belly of the river in the lower reaches of Jiangsu Province, low-lying, annual rainfall of 1,021.1 mm, the annual average temperature of 14.3 ℃. Tillage system is mainly rice, wheat, cotton, green fertilizer rotation system, accounting for about 70% of the area, rice, wheat and rice, oil (vegetables) even make about 30%. The main weed species, identified 18 families and 39 species, of which the main weeds have to see Ophiopogon, large vetch, Galium aparine, local field of malignant weeds are also stored, shepherd’s purse, Polygonum, wild Oats and so on. These grass has become the enemy of the three wheat production. Grass damage has a greater impact on the production of three wheat, wheat seedling stage A serious problem occurs, we must plowing heavy. During the three wheat growing artificial pull more than a dozen working days. The weeds absorbed more nutrients in the soil. When the density of Ophiopogon japonicus was 57.7 plants per square foot (203.8 roots per plant), the available nitrogen was 46.6 ppm and the available phosphorus was 60 ppm. The weedless wheat field contained 60.2 ppm available nitrogen , Available phosphorus 130ppm. See Aman the precarious three barley, the impact of barley production