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了解土壤侵蚀与沉积对土壤CO_2通量的影响有助于正确评价侵蚀区域土壤和大气之间CO_2交换过程与机制.本试验于2014和2015年雨季(7~9月)在长武农田生态系统国家野外站进行,利用土壤碳通量测量系统LI-8100(LI-COR,Lincoln,NE,USA)和土壤温度及水分数据采集器(EM50,DECAGON,USA),测定侵蚀和沉积地貌下的土壤CO_2通量、土壤水分和温度,并采集径流泥沙.结果表明:1侵蚀区和沉积区土壤CO_2通量均值依次为1.05μmol·(m~2·s)~(-1)和1.38μmol·(m~2·s)~(-1),沉积区较侵蚀区增幅达31%(P<0.05);沉积区土壤CO_2通量温度敏感性(8.14)是侵蚀区(2.34)3倍以上.2侵蚀区与沉积区土壤水分均值分别为0.21 m~3·m~(-3)和0.25 m~3·m~(-3),沉积区较侵蚀区提高19%(P<0.05).尽管侵蚀区较沉积区土壤温度稍有提高(7%),但差异不显著.3泥沙中有机碳平均含量(7.26 g·kg~(-1))较试验之初(6.83 g·kg~(-1))提高6%.4土壤水分和土壤有机碳(SOC)在侵蚀区和沉积区的重新分布对土壤CO_2通量空间变异有重要影响.
Understanding the influence of soil erosion and sediment on soil CO_2 flux can help to correctly evaluate the CO_2 exchange process and mechanism between soil and atmosphere in the eroded area.This experiment was conducted in the rainy season of 2014 and 2015 (July-September) in Changwu farmland ecosystem National Field Station. Soil under erosion and sedimentary landforms was measured using a soil carbon and carbon flux measurement system LI-8100 (LI-COR, Lincoln, NE, USA) and a soil temperature and moisture data logger (EM50, DECAGON, USA) CO_2 flux, soil moisture and temperature, and collected runoff and sediment.The results showed that the average values of soil CO_2 fluxes in the eroded and sediment areas were 1.05μmol · m ~ 2 · s -1 and 1.38μmol · (m ~ 2 · s) -1, and the deposition area increased by 31% (P <0.05) compared with the erosion area. The temperature sensitivity of soil CO_2 flux in the deposition area (8.14) was more than 3 times that of the erosion area (2.34). The mean values of soil moisture were 0.21 m -3 m -3 and 0.25 m -3 m -3 respectively in the eroded and sedimentary areas, and the sedimentary areas increased by 19% (P <0.05) compared with the eroded areas. Soil temperature in the eroded area was slightly higher than that in the sedimentary area (7%), but the difference was not significant.3 The average content of organic carbon in sediment (7.26 g · kg -1) was significantly higher than that in the initial test (6.83 g · kg -1 -1)) increased by 6% .4 Soil moisture and soil organic carbon (SOC) The redistribution of soil erosion and depositional zones has an important effect on the spatial variability of soil CO2 fluxes.