太湖流域上游竹林河岸带土壤反硝化酶活性及其影响因素

本研究以太湖流域上游竹林河岸带为对象,采用乙炔抑制法分析了夏季河岸带土壤反硝化酶活性(DEA)及其影响因素,以期为竹林河岸带在减少河流氮污染方面的生态功能评估提供数据支持。结果表明: 河岸带土壤DEA为6.32～23.22 μg N·kg^-1·h^-1,平均值为14.65 μg N·kg^-1·h^-1。河岸带土壤有机碳(SOC)、总氮、硝态氮含量、含水量和碳氮水解酶活性共同影响着DEA的垂直分布,使DEA随土壤深度(0～40 cm)的增加而递减;而DEA在水平方向上(同一土壤深度离水距离不同)的变化主要受SOC含量的影响。太湖流域上游竹林河岸带土壤在夏季可能会由于缺乏相对充足的可溶性有机碳而对DEA产生一定的限制。

Soil denitrifying enzyme activity and its influencing factors in a bamboo forest riparian zone in the upper reaches of the Taihu Lake Basin,China

Soil denitrifying enzyme activity (DEA) was measured by acetylene inhibition technique, along with exploration of factors influencing DEA in a bamboo forest riparian zone in the upper reaches of the Taihu Lake Basin during summer. Our aim was to provide important insights into the assessment of ecological functions of bamboo forest riparian zone on reducing nitrogen pollution in rivers. The results showed that the riparian soil DEA ranged from 6.32 to 23.22 μg N·kg^-1·h^-1, with a mean value of 14.65 μg N·kg^-1·h^-1. The vertical distribution (0-40 cm soil profile) of DEA was affected by several factors, such as soil organic carbon (SOC), total nitrogen (TN), nitrate nitrogen (NO₃^--N), soil water content, and activity of carbon and nitrogen hydrolase, which resulted in decreased DEA with increasing soil depth. The horizontal changes in DEA (at the same soil depth but at different distances from river) was mainly governed by the variation in SOC concentration. In this area, the concentration of soil dissolved organic carbon was relatively low, which might inhibit the soil DEA during summer.