4种农药在草坪中的消解特征及其2种模型模拟的效果比较

Four pesticides partitioning features in turf grass and comparison between two simulation model

4种农药 (百菌清、甲霜灵、毒死蜱和敌百虫 )施用于草坪后 ,挥发和渗漏损失分别不足 3 %和 1% ,其主要损失途径在草坪的草皮、草根层 (0— 2cm) ,而且呈指数模型衰减 ,衰减最快的是敌百虫 ,最慢的是毒死蜱 .但在土壤中 (2— 10cm土层及以下层 ) ,这些杀虫剂的衰减明显较慢 .2种模型模拟这 4种农药施用草坪后的损失过程表明 :CHAIN2D的效果较PRZM的好 ,尤其是模拟挥发和渗漏损失过程 ,CHAIN2D的模拟结果与观测值有较好的一致性 ,而PRZM模拟的结果 ,渗漏损失比观测的明显过多 ,挥发损失则明显过少 ;2种模型模拟这 4种农药在土壤中的衰减过程 ,效果较不满意 。

Based the observed data, four pesticides (Chlorothalonil, Metalaxyl, Chlorpyrifos and Trichlorfon) were applied to turf grass. The fraction of volatilized and leached was less than 3% and 1% respectively. The major degradation access of pesticides is at the thatch and mat layer (0—2?cm) of soil exponentially. Among the four pesticides the degradation rate of trichlorfon was the highest with the estimated half\|Life of aboutte 0\^5, and of Chlorpyrifos was the lowest. However, at soil layer (2—10?cm and below), the degradation was substantial lower. The simulated results showed that CHAIN2D model is better than PRZM on the pesticides' volatization and leaching. Both models didn't give satisfied results in simulating the pesticides' degradation in soil, particularly, in the initial period after application.