除草剂阿特拉津对土壤脲酶活性的影响

研究了阿特拉津对4种典型施肥处理的土壤脲酶活力的影响。结果表明，处理初期，低浓度阿特拉津对土壤脲酶有一定刺激作用，高浓度处理在整个试验过程中对脲酶有明显抑制作用，阿特拉津对不同肥力土壤中脲酶的影响有明显差异，对照土壤和NPK肥土壤中脲酶活力较低，脲酶受抑制明显，抑制率分别高达30．35％和28．89％；NPK+秸秆和NPK+有机肥土壤的脲酶活力高，脲酶抑制率低，最高抑制率分别为21．35％和16．86％，不同肥力土壤在整个处理过程中，脲酶抑制率均为先逐渐增大到最大值，然后又逐渐降低；高肥力土壤脲酶抑制率最大值出现的时间比低肥力土壤迟，表明高肥力土壤对阿特拉津有较强的耐受能力。

Effect of atrazine on urease activity in soils with different fertility

Four soils with different fertility were treated with different concentrations of atrazine. The results showed that the urease activity was stimulated in the soils treated with low concentration of atrazine at the first day,while inhibited after treated with high concentration of atrazine during the whole period of the experiment. There was a significant difference in urease activity in soils with different fertility after treated with high concentration atrazine. The urease activity in CK and in NPK was significantly inhibited,the inhibition rate reached 30.35% and 28.89%,respectively,but in NPK+S and NPK+M,the inhibition rate was only 21.35% and 16.86%,respectively. The maximum inhibition rate appeared later in soils with high than with low fertility,showing that soils with high fertility could endure the effect of atrazine.