长期施肥对黑土脲酶活性和动力学特性的影响

Activities and Kinetics of Soil Urease Under Long-term Fertilization

为揭示土壤脲酶活性对长期施肥的响应特征,本文以长期施肥的黑土为供试对象,对土壤脲酶的活性和动力学特性进行研究。结果表明:不同施肥处理和剖面土层变化对土壤脲酶活性变化具有交互作用。与对照相比,有机肥、有机肥配施化肥处理的土壤脲酶活性显著增强,在土壤剖面中,脲酶活性具有随土层加深逐渐递减的趋势。同时,土壤脲酶的酶促反应符合一级反应动力学模型。与不施肥处理相比较,施肥处理的Km值减小,有机肥处理的Vmax和Vmax/Km比值都高于单施化肥处理和对照,长期施用有机肥土壤脲酶催化能力增强。

In order to reveal the response characteristics of soil urease activity under long-term fertilizations,the activities and kinetic characteristics of soil urease were studied in black soil with long-term fertilization.The results showed that different fertilization treatments and changes of soil depth had interactions on soil urease activities.As compared with control,the activity of soil urease increased significantly under organic manure fertilization and its plus with chemical fertilizer treatments,and also the activity of urease decreased with soil depth increasing in soil profile.Meanwhile,the enzymatic reaction of soil urease followed first-order kinetics.Km value decreased under fertilization,while organic manure fertilization increased the values of Vmax and Vmax/Km,which were higher than chemical fertilizer treatment and the control,the catalysis capability of soil urease enhanced under long-term organic manure fertilization.