绿肥对植烟土壤酶活性及土壤肥力的影响

通过田间试验，研究翻压绿肥对植烟土壤酶活性及土壤肥力的影响。结果表明， 翻压绿肥能够明显提高土壤酶活性和土壤肥力水平，当绿肥翻压量在15000 kg/hm2以上时，尤其在22500~30000 kg/hm2之间时对土壤各项指标的影响更加明显。与对照相比，翻压绿肥的各处理土壤脲酶、 酸性磷酸酶、 蔗糖酶、 过氧化氢酶增幅分别为13.10%2~3.81%、 12.92%~29.38%、 75.35%~234.51%、 29.17%~37.08%； 土壤有机质、 全氮、 碱解氮、 有效磷、 速效钾、 pH、 孔隙度增幅分别为13.01%~70.41%、 6.42%~27.52%、 1.14%~10.99%、 15.97%~34.99%、 10.28%~38.30%、 2.74%~7.05%、 0.19%~2.50%，土壤容重降幅为1.47%~5.15%。简单相关分析表明，脲酶、 酸性磷酸酶、 蔗糖酶、 过氧化氢酶4种酶之间以及4种酶与土壤理化因子之间均有极显著的相关关系，而土壤酶活性之间的相互关系表明，土壤酶在促进土壤有机物质转化中不仅显示其专性特性，同时也存在共性关系； 典型相关分析结果为，第一对典型变量线性函数反映了土壤酶活性和土壤养分因子对土壤综合肥力水平的影响，第二对典型变量线性函数反映了施入绿肥对土壤内部重要的生理生化过程变化的影响； 主成分分析结果显示，第一主成分反映了土壤的综合肥力水平，所有因子均对土壤肥力水平起到了正效应，土壤酶活性能够和土壤理化因子共同评价土壤综合肥力水平。以上结果说明，翻压绿肥后土壤生物过程活跃，有利于土壤有机物质的转化和烤烟正常生长所需的营养供应。

Effects of green manure in corporation on soil enzyme activitiesand fertility in tobacco-planting soils

Field experiments were conducted to study the effects of returning green manure on the relationship between enzyme activities and fertility in tobacco-planting soils. The results show that the returning green manure could obviously increase the soil enzyme activities and soil nutrients. In comparison with the control, the treatments which the returning green manure amounts are more than 15000 kg/ha, especially between 22500 and 30000 kg/ha, the effects on soil enzyme activities and nutrients are more obviously. In comparison with the control, the activities of soil urease, acid phosphatase（ACP）, invertase and catalase are increased by 13.10%-23.81%, 12.92%-29.38%, 75.35%-234.51% and 29.17%-37.08% respectively. Soil organic matter, total N, akalytic N, available P, available K, pH, and porosity are increased by 13.01%-70.41%, 6.42%-27.52%, 1.14%-10.99%, 15.97%-34.99%, 10.28%-38.30%, 2.74%-7.05%, 0.19%-2.50% respectively. Soil bulk density is decreased by 147%-515%. The results of correlation analysis reveal that there are significant positive correlations between soil edaphic physicochemical factors and activities of soil urease, acid phosphatase, invertase and catalase. The linear function of the first pair of canonical variables reveals that soil enzyme activities and soil fertility factors are indicators of soil comprehensive fertility, and the linear function of the second pair of canonical variables reveals that the effects of green manure application on the changes of some physiological and biochemical processes of tobacco planting soils. The results of principal components analysis show that the first principal component is the composite indicator of reflecting soil fertility level, all the factors have actively influence on soil fertility. Four soil enzymes are in the first principal component, and more closely correlate with soil fertility, so soil fertility could be objectively evaluated by soil enzyme activities and edaphic physicochemical factors, and using soil enzyme activities and edaphic physicochemical factors to characterize the soil fertility is feasible. The above results reveal burying green manure could promote the activity of soil organism, it is in favor of the turnover of organic matter in the soil and provision of nutrition to meet the needs of tobacco’s normal growth.