5种除草剂对土壤蔗糖酶和脲酶活性的影响

采用室内培养法,研究了土壤中添加5种除草剂(氟磺胺草醚、甲咪唑烟酸、乳氟禾草灵、扑草净和噻吩磺隆)对土壤蔗糖酶和脲酶活性的影响。结果表明:在0.05、0.5和5 mg/kg的甲咪唑烟酸、乳氟禾草灵、扑草净和噻吩磺隆作用下,在3~40 d内对土壤蔗糖酶活性表现为抑制-激活-恢复效应,其中0.5mg/kg的乳氟禾草灵处理,3 d时土壤蔗糖酶被显著抑制,6、9、25和40 d时被激活;而0.05、0.5和5 mg/kg的氟磺胺草醚处理,前9 d土壤蔗糖酶活性被显著抑制,25和40 d时被激活。在用0.05、0.5和5mg/kg的甲咪唑烟酸、噻吩磺隆和5 mg/kg扑草净处理的3~40 d内,对土壤脲酶活性均表现为抑制-激活-抑制效应;0.05和0.5 mg/kg的扑草净及0.05和5 mg/kg的乳氟禾草灵处理,土壤脲酶在3~40 d内虽然也出现上述变化趋势,但到40 d时已恢复到对照水平;低浓度(0.05和0.5 mg/kg)氟磺胺草醚处理对土壤脲酶表现为抑制-激活效应,而高浓度(5 mg/kg)处理则表现为抑制-激活-抑制作用。

Effects of five herbicides on activities of soil invertase and urease

The aim of this work was to evaluate the effects of five herbicides (including fomesafen, imazapic, lactofen, prometryn and thifensulfuron-methyl) on the activities of soil urease and invertase. The results showed that the invertase in soil samples treated with 0.05, 0.5 and 5 mg/kg soil of imazapic, lactofen, prometryn and thifensulfuron-methyl initially decreased, then increased and finally returned to the normal level in 3-40 d. Application of lactofen with a dose of 0.5 mg/kg tended to decrease invertase at the 3^rd day, while invertase was stimulated at the 6^th, 9^th, 25^th and 40^th days. In addition, in the soil sample treated with fomesafen (0.05, 0.5 and 5 mg/kg), the invertase was significantly lower than the control group during the first 9 days, but it was stimulated at the 25^th and 40^th days. However, urease in the soil samples treated with imazapic and thifensulfuron-methyl (0.05, 0.5 and 5 mg/kg) and prometryn (5 mg/kg) initially decreased, then increased and decreased again. And similar effects were observed in the soil samples treated with prometryn (0.05 and 0.5 mg/kg) and lactofen (0.05 and 5 mg/kg). However, urease in these soil samples was similar with the control group at the end of the experiment. In addition, lower concentrations (0.05 and 0.5 mg/kg) of fomesafen could influence the activity of urease in a pattern of inhibition-activation, while higher concentrations (5 mg/kg) showed a pattern of inhibition-activation-inhibition.