中文摘要：

为研究翻耕、旋耕、免耕对作物根系生长影响的机理,以耕层棕壤（0-20cm）和犁底层棕壤（20-40cm）为试验材料,采用盆栽的方法模拟了不同耕作模式及容重,并研究了这些条件对土壤过氧化氢酶、多酚氧化酶、脲酶、磷酸酶、转化酶活性的影响。结果表明：中、下层不同土样及不同容重对土壤酶活性均有显著影响（P〈0.01）。与1.2g/cm3容重相比,容重为1.4g/cm3和1.6g/cm3的土壤分别在不同程度上降低了土壤酶的活性,中、下层容重变化对表层酶活性影响相对较小,但中层受下层容重变化影响较大,容重由1.4g/cm3升到1.6g/cm3时酶活性下降尤为明显。多数情况下,模拟保护性耕作的土壤多酚氧化酶、脲酶、磷酸酶、转化酶活性在对应土层与生育期总比模拟翻耕的高,模拟翻耕土壤处理的中、下层土壤过氧化氢酶活性明显高于保护性耕作处理的酶活性。

英文摘要：

The study was conducted with brown soil（0-20 cm and 20-40 cm） in Shenyang agricultural university experimental station in order to research effecting mechanism of turnover,no-tillage,totary tillage on growth of maize＇s root.With pot experiment,it researched the impacts of different soil bulk density and sample from different soil layers on enzyme activities（polyphenol oxidase,catalase,acid phosphatase,urease,invertase）.The results showed that the influence of different soil layers and different bulk density on soil enzymatic activity were distinct（P0.01）.Enzyme activity decreased when soil bulk density increased（compared to 1.2 g/cm3,activities of enzyme of 1.4 g/cm3 and 1.6 g/cm3 lowered respectively in different degree）,and effect of bulk densities were lower on the surface soil than substrate.In most cases,the conservation tillage soil polyphenol oxidase,urease,phosphatase,invertase activities were higher than turnover soil in corresponding soil layers and growth stage,at the same time,turnover soil catalase activities were significantly higher than no-tillage treatment at middle-stratum soil layers.