Chen Gai, Xu Ming-xiang, Zhang Ya-feng, Wang Chao-hua, Fan Hui-min, Wang Shan-shan
Huan Jing Ke Xue. 2015 Sep;36(9):3383-92.
This study aimed to characterize soil respiration along eroded sloping land at erosion and deposition area under different soil organic carbon(SOC) levels, and linked the relationship between soil respiration and soil temperature, soil moisture, SOC and slope position. Experiments were carried out in the plots of S type slopes include five different soil organic carbon levels in the Loess Hilly Region. The S type slopes were divided into control area at the top of the slope, erosion area at the middle of the slope and deposition area at the toe of the slope. We found that soil temperature had a greater impact on soil respiration in the deposition area, whereas soil moisture had a greater impact on soil respiration in the erosion area compared among control area, erosion area and deposition area. In addition, SOC was the most important factor affecting soil respiration, which can explain soil respiration variation 54. 72%, followed by soil moisture, slope position and soil temperature, which explain soil respiration variation 18. 86% , 16. 13% and 10. 29%, respectively. Soil respiration response to erosion showed obvious on-site and off-site effects along the eroded sloping land. Soil respiration in the erosion area was reduced by 21. 14% compared with control area, and soil respiration in the deposition area was increased by 21. 93% compared with control area. Erosion effect on source and sink of carbon emission was correlated with SOC content of the eroded sloping land. When SOC content was higher than 6. 82 g.kg-1, the slope. erosion tended to be a carbon sequestration process, and when SOC content was lower than 3.03 g.kg-1, the slope erosion tended to be a process of the carbon emission source. The model could reflect the relationship between soil respiration and independent variables of soil organic carbon content, soil temperature and moisture.
本研究旨在表征不同土壤有机碳（SOC）水平下侵蚀沉积区侵蚀坡地的土壤呼吸特征，并将土壤呼吸与土壤温度、土壤湿度、SOC及坡位之间的关系联系起来。实验在黄土丘陵区S型坡地的样地中进行，该样地包括五种不同的土壤有机碳水平。S型坡地分为坡顶对照区、坡中侵蚀区和坡脚沉积区。我们发现，与对照区、侵蚀区和沉积区相比，土壤温度对沉积区土壤呼吸的影响更大，而土壤湿度对侵蚀区土壤呼吸的影响更大。此外，SOC是影响土壤呼吸的最重要因素，可解释土壤呼吸变化的54.72%，其次是土壤湿度、坡位和土壤温度，分别解释土壤呼吸变化的18.86%、16.13%和10.29%。土壤呼吸对侵蚀的响应沿侵蚀坡地呈现出明显的原位和异位效应。侵蚀区的土壤呼吸比对照区降低了21.14%，沉积区的土壤呼吸比对照区增加了21.93%。侵蚀对碳排放源汇的影响与侵蚀坡地的SOC含量相关。当SOC含量高于6.82g·kg-1时，坡面侵蚀倾向于成为一个碳固存过程；当SOC含量低于3.03g·kg-1时，坡面侵蚀倾向于成为一个碳排放源过程。该模型能够反映土壤呼吸与土壤有机碳含量、土壤温度和湿度等自变量之间的关系。
