目前稻田施药次数多,用药量较大,多采用毒土撒施和泼浇等施药法。因许多化学农药都具有脂溶性高、水溶性小的特性,为能用水稀释,一般加工成可湿性剂,乳剂等,采用喷雾或撒施法,但除少量沾附于稻株外,大部分均落入田水中,或沉于土表。有人估计其流损量可达60—90％以上;也有人进行了定量分析,证明理论上只要8ppm的有效浓度,而实际却用了1000ppm At present, there are many pesticides applied in paddy field, and the dosage is large, so poisonous soil spreading and pouring pouring are often used. Because many chemical pesticides have the characteristics of fat-soluble, water-soluble small, can be diluted with water, generally processed into wettable agents, emulsions, spray or spreading law, but with a small amount of attached to the rice plant, most of them Fall into the fields, or sink in the soil table. Some people estimate that the flow loss can reach more than 60-90%; some people conducted a quantitative analysis to prove that the theoretical concentration of 8ppm as long as the actual use of 1000ppm