广州市流溪河河岸带土壤反硝化作用的多尺度影响因子  

Effects of multi-scale control factors on spatial heterogeneity of denitrification in riparian soil:a case study in Liu Xi River of Guangzhou city

作　　者：刘庆[1,2,3] 魏建兵[4] 吴志峰[5] 钟世锦[5] 何元庆[2] 吉冬青[2] 

机构地区：[1]中国科学院广州地球化学研究所,广东广州510640 [2]广东省生态环境与土壤研究所,广东广州510650 [3]中国科学院大学,北京1000494 [4]沈阳大学区域污染环境生态修复教育部重点实验室,辽宁沈阳110044 [5]广州大学地理科学学院,广东广州510006

出　　处：《中国环境科学》2015年第10期3069-3077,共9页China Environmental Science

基　　金：国家自然科学基金项目(41171399);国家科技支撑计划项目(2012BAH32B03-5)

摘　　要：以广州市水源地流溪河二级支流的河岸带为研究对象,分析嵌套结构的多尺度因素对河岸带土壤反硝化作用的影响,确定调节河岸带土壤反硝化酶活性的不同尺度控制因素.结果表明:以土壤反硝化酶活性表征的反硝化潜力,其在研究区内的剖面尺度空间变异性显著大于断面尺度和流域景观尺度;反硝化酶活性的空间变异受多尺度因子的作用,其中剖面尺度中土壤有机碳、全氮、硝态氮等因子对其空间分布起主要的直接控制作用,而断面尺度的景观位置、植被密度与流域景观尺度的地形指数、高程及土地利用类型等因子通过影响土壤性质而间接调控反硝化酶的空间分异性;研究区的反硝化酶活性在剖面尺度中表层最高,随着深度增加呈急剧减小的趋势;断面尺度中活性值最高位于河岸区中间的景观位置,因该位置具有良好的景观连接性和较高的植被密度;流域景观尺度中,除受人为扰动严重城市化地区外,河岸带土壤反硝化酶活性沿流域从上游至下游呈不断增加的趋势.Soil denitrification enzyme activity was measured by a hierarchical sampling approach within the riparian zone of the Liu Xi River tributary of Guangzhou city, and explored and identified multi-scale factors that influenced soil denitrification. The results showed that soil denitrification potential—represented by soil denitrification enzyme activity（DEA）—showed more heterogeneity on a profile-scale than on a cross-sectional scale and landscape-scale in riparian zones; multi-scale factors controlled the degree of spatial variation in soil denitrification. The profile-scale factors, including soil TOC（total organic carbon）, TN（total nitrogen） and NO3--N（nitrate nitrogen）, were the major direct regulators of the spatial distribution of DEA. The cross-sectional scale factors, including landscape position and vegetation density, and the landscape-scale factors, including TI, elevation and land-use types, indirectly regulated the distribution of DEA. At the profile scale, the highest DEA occurred on the upper soil, but dramatically declined from the soil surface to the deeper layers. At the cross-sectional scale, the highest DEA was observed at the landscape position, with good landscape connectivity and high-density vegetation within the middle part of the riparian zone. At the watershed scale, DEA showed an increasing trend from upstream to downstream except for the sites in urbanized areas.

关 键 词：反硝化作用 河岸带土壤 多尺度 控制因素 

分 类 号：X522[环境科学与工程—环境工程]