Soil nitrogen dynamics following short-term revegetation in the water level fluctuation zone of the Three Gorges Reservoir, China
Soil nitrogen dynamics following short-term revegetation in the water level fluctuation zone of the Three Gorges Reservoir, China
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DOI：
10.1016/j.ecoleng.2011.10.005
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发表时间：
2012
影响因子：
3.8
通讯作者：
Chen Ye;Xiaoli Cheng;Yulong Zhang;Zhixiu Wang;Quanfa Zhang
中科院分区：
文献类型：
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作者：
Chen Ye;Xiaoli Cheng;Yulong Zhang;Zhixiu Wang;Quanfa Zhang
随着三峡工程的竣工，海拔145m至175m水位波动区的原生植被因被淹没而消失，水文情势冬水夏水，与自然水情相反。我们在三峡水库河岸生态系统中进行了野外试验，研究了2008年至2009年期间短期植被恢复和洪水条件下的氮（N）动态。在实验室测定了土壤化学和物理特征、净矿化潜力率（NMPR）、净硝化潜力率（NNPR）和反硝化潜力率（DPR）。这些结果表明，短期植被恢复和洪水后无机氮（NH4+-N和NO3−-N）显着减少，这可能与地表水流、洪水、植物氮吸收和氮转化之间的相互作用有关。植物与洪水结合增加了NMPR和NNPR，并且仅在恢复开始时增加了DPR，然后通过调节土壤有机碳(SOC)浓度和土壤中的C:N比以及降低土壤容重，在洪水后降低了DPR。植被类型通过改变 SOC、土壤氮有效性和碳氮比来影响氮动态。由于 SOC 较高，灌木土壤中的无机 N、NMPR 和 NNPR 高于草本和乔木土壤，而乔木土壤中的 DPR 低于灌木和草本土壤，因为 C:N 比较低且 SOC 较低。这些结果表明，植被恢复和洪水后土壤无机氮下降，河岸带植被恢复可能会改善水质。
With the completion of the Three Gorges project, native vegetation in the water level fluctuation zone between the elevations of 145m to175m disappeared due to the inundation with a hydrological regime with flooding in winter instead of summer, a reversal of the natural one. We conducted a field experiment in the riparian ecosystem in the Three Gorges Reservoir to study nitrogen (N) dynamics under short-term revegetation and flooding during the period from 2008 to 2009. Soil chemical and physical characteristics, net mineralization potential rate (NMPR), net nitrification potential rate (NNPR), and denitrification potential rate (DPR) were determined in the laboratory. These results showed a significant decrease in inorganic N (NH4+-N and NO3−-N) following the short-term revegetation and flooding, which was probably related to the interactions between surface flow, flooding, plant N uptake, and N transformation. Plants in conjunction with flooding increased the NMPR and NNPR, and increased the DPR only at the beginning of the revegetation and then decreased DPR after the flooding by regulating the concentration of soil organic carbon (SOC) and C:N ratios in soil, and decreasing the soil bulk density. Vegetation types affected N dynamics by changing SOC, soil N availability, and C:N ratios. The inorganic N, NMPR, and NNPR were higher in shrub soil than those in herb and tree soils due to higher SOC, whereas the DPR in tree soils was lower compared to shrub and herb soils because of lower C:N ratios together with the lower SOC. These results imply that soil inorganic N declined following the revegetation and flooding, and the revegetation in the riparian zone could potentially improve water quality.