莠去津在土壤中的残留动态和淋溶动态

The Residual Dynamics and Leaching Dynamics of Atrazine in Soil

利用 HPL C法对土壤中莠去津的残留动态、淋溶动态进行了研究。结果显示 ,莠去津以有效成分 2 .2 5 kg/ hm2 和 4 .5 0 kg/ hm2 的剂量施用时 ,在土壤中的半衰期分别为 19.1d和 18.1d,即其半衰期与莠去津的施用浓度无关 ,属于典型的一级动力学反应。在 12 0 d的玉米生长期中 ,土壤中莠去津在不断降解代谢的同时 ,逐渐向深层土壤中淋溶 ,多数莠去津持留在表层土壤中。施用莠去津 2 7d后 ,高浓度处理小区莠去津的淋溶深度超过 30 cm,深度为 10～ 15 cm处的土壤在施用后2 7d莠去津的浓度最大。同一土壤深度 ,莠去津在高浓度处理小区的残留量要远高于低浓度处理小区。这些结果显示 ,减小莠去津的用量可以减少莠去津在土壤中的移动 ,表明低剂量施用莠去津是保护地下水免受污染的一种有效措施。

The residual dynamics and leaching dynamics of atrazine in corn field were studied by HPLC. Results showed that the half life in soil for atrazine 40% FL applied alone at the rates of 2.25 kg/hm 2 ( a.i )., 4.50 kg/hm 2 ( a.i ) were 19.1 days and 18.1 days, respectively. Field experiments revealed that disappearance rate of atrazine in soil followed the first order rate law. Over the 120 day growing season of the corn, the degradation and leaching of the residual atrazine in the surface of soil were found. And most of the atrazine applied was kept in the top of the soil. The leaching experiment results showed that the leaching depth was more than 30 cm in feild. The rate of atrazine applicated could influence the leaching behavior of atrazine in soil profile. Initial detection of atrazine was occurred in the depth of 25～30 cm at 27 days after high rate application but no atrazine was found in the lower rate treated soil. As the atrazine application rate was decreased, atrazine eluted through the soil profile over a longer period of time. It suggested that atrazine has low potential to reach the groundwater. The main factors affected the leaching are application rates and the characters of soil.