中文摘要：

通过设置在陇中黄土高原的保护性耕作长期定位试验,研究了不同耕作方式下土壤过氧化氢酶、脲酶、碱性磷酸酶和蔗糖酶活性在春小麦不同生育时期和不同土层深度的动态变化。4种耕作方式包括：传统耕作（T）、免耕（NT）、传统耕作秸秆还田（TS）、免耕秸秆覆盖（NTS）。结果表明,NTS可以显著提高耕层0～30cm土壤过氧化氢酶、脲酶、碱性磷酸酶和蔗糖酶活性,春小麦整个生育期分别比T增加了4.02%,8.74%,20.51%和31.45%;而NT和TS对土壤过氧化氢酶和蔗糖酶活性的效应有一定的阶段性。在空间分布上,NT和NTS处理条件下4种土壤酶活性随着土层加深均呈下降趋势;T处理条件下4种土壤酶活性和TS处理条件下土壤脲酶和碱性磷酸酶活性随土层加深呈先增后减趋势,而TS处理条件下土壤过氧化氢酶和蔗糖酶活性随土层加深呈递减趋势。进一步研究发现,不同因子对土壤酶活性的影响效应各异,其中生育时期对脲酶影响最大,耕作方式和覆盖材料对蔗糖酶影响最大,交互作用对过氧化氢酶影响最大。

英文摘要：

Based on field experiments conducted in Dingxi on the western Loess Plateau,the effects of four treatments： conventional tillage（T）,conventional tillage with stubble retention（TS）,no tillage with no stubble retention（NT）,no tillage with stubble retention（NTS） on temporal and spatial disparities of soil enzyme activities during the spring wheat growing season were studied.Soil catalase,urease,alkaline phosphatase and invertase activities under NTS were significantly higher than those under T,being 24.02%,8.74%,20.51% and 31.45% respectively at 0-30 cm depth during spring wheat growing seasons,while the effects of NT and TS on soil enzyme activities were seasonal.There was a decreasing trend of soil enzyme activities with increasing soil depth under NT and NTS treatments.Soil catalase,urease,alkaline phosphatase and invertase activities under T treatment and soil urease and alkaline phosphatase activities under TS treatment increased then decreased with increasing soil depth,while soil catalase and invertase activities under TS treatment decreased.Analysis of variance indicated that the greatest effects of the growing seasons were on soil urease activity,and of tillage and cover on soil invertase activity,while soil catalase activity had the most effect on the interactions of various factors.