加硒和培养时间对土壤酶活性的影响

Effects of Selenium Addition and Incubation Time on Soil Enzyme Activities

硒是重要的微量元素,土壤酶是土壤生物学性质和土壤肥力的重要指标。试验利用土壤加硒培养试验,研究了不同硒水平和培养时间对土壤过氧化氢酶、脲酶、蛋白酶和淀粉酶活性的影响。结果表明,土壤加硒和培养时间对这几种酶活性有显著影响。土壤加硒50 mg kg-1时,对土壤过氧化氢酶和脲酶活性均具有显著抑制作用,土壤过氧化氢酶活性随培养时间延长而降低,而所有加硒水平下,培养30 d的土壤脲酶活性显著高于10 d和20 d。硒对土壤蛋白酶活性的影响随培养时间而变化,在培养10 d时,加硒水平在10 mg kg-1时,土壤加硒对蛋白酶活性具有促进作用,培养30 d时,土壤加硒则对土壤蛋白酶活性具有抑制作用。同对照相比,淀粉酶对加硒的反应不敏感。由此可见,硒对土壤酶活性的影响随硒水平和酶类型而异,土壤过氧化氢酶和脲酶应该是对硒反应比较敏感的酶类,而淀粉酶属于对硒反应不敏感的酶类。

Selenium is an important trace element and soil enzymes are essential indexes of soil biology and fertility,but the effects of selenium on soil enzyme activity have been rarely reported.In order to understand the interaction of selenium and soil enzymes,an incubation experiment by soil selenium addition was conducted to investigate the effects of selenium on soil enzyme activities.The activities of catalase,urase,protease and amylase on the 10th,20th and 30th day after selenium addition were determined.The results showed that soil selenium addition and the incubation time had significant effects on soil enzyme activities.In high level of soil selenium addition（50 mg kg-1）,the activities of soil catalase and urase were significantly suppressed.The activity of soil catalase decreased with incubation time,but the activity of soil urase was significantly higher on the 30th day than that on 10th or 20th day after selenium addition.The effect of selenium on protease varied with the incubation time.In comparison with the control（no selenium addition）,the activity of soil protease was significantly enhanced at 10 mg kg-1 on the 10th day after selenium addition,but on the 30th day after selenium addition,the activity of soil protease was significantly suppressed.The activity of soil amylase was not significantly influenced by soil selenium addition compared with control.In conclusion,the effects of selenium on soil enzymes＇ activities varied with selenium concentrations and the species of soil enzyme,and the soil catalase and urase were the sensitive enzymes,but the amylase was an insensitive enzyme to selenium in soil.