河岸带不同植被下土壤酶特征及其去污效果

通过测定河岸带常见植被类型下的土壤酶活性,比较其去污效果,分析土壤酶活性与TN、TP、NH4＋-N、COD等农业面源污染物去除率的相关性。结果表明,不同植被类型表层土壤酶活性存在显著差异（P〈0.05）,灌草、草本酶活性较大,乔灌草次之,乔草最小,而不同植被河岸带对农业面源污染物的去除率也表现出基本相同的规律,因此对农业面源污染去除效果最好的河岸带植被类型配置应为灌草或草本（芦苇）;不同植被深层土壤酶活性基本不存在显著差异。由相关性分析可知,TN、NH4＋-N去除率与表层土壤脲酶活性呈显著相关关系,而COD去除率与土壤脲酶的相关性不显著;TP、COD去除率与土壤磷酸酶活性的相关性显著。研究结果为利用土壤酶活性强度作为评价河岸带净化效果的指标提供了理论依据。

Soil Enzyme Characteristics and Its Removal Efficiency of the River Banks with Different Kinds of Vegetation

The riparian zone is the important way for the treatment of the agricultural non-point source pollutants. For the purpose of full un- derstanding and utilization of the riparian zone, it is more and more important to study on the mechanism of the riparian zone for decontami- nation. This paper mainly revealed the influence form the soil enzyme activity of the riparian zone on decontamination. The spatial distribu- tion of the soil enzyme activity in common vegetation types of riparian zone and the removal efficiency of the agricultural non-point source pollutants including TN, TP, NH4＋ -N and COD by the soil enzyme activity were determined. The correlation between soil enzyme activity and sewage purification effect was analyzed in this paper. The results showed that the differences among the surface soil enzyme activity of the different vegetation types were larger （P〈0.05）. The performance of surface enzyme activity was basically the shrub and grass, herbs, shrubs and grass, joe grass. The pollutants purification effect on them also showed essentially the same rule. The vegetation types of riparian zone which worked best in the removal efficiency of the agricultural non-point source pollution were the shrub and the grass, but the differences a- mong the deep soil enzyme activity were not significant. Due to the correlation analysis method, it was also found that the removal efficiency of TN and NH 4＋ -N was significantly correlated with the surface soil urease activity, but the correlation between the COD removal efficiency and soil urease was not significant, the TP and COD removal efficiency were correlated with soil phosphatase activity. There was no significant correlation of all pollutant removal efficiency and the deep soil enzyme activity. This will provide some theory evidences for taking soil enzyme activity strength as the indicators of the purifying effect.