水保所知识产出(1956---)知识库

了解土壤侵蚀与沉积对土壤CO2
通量的影响有助于正确评价侵蚀区域土壤和大气之间CO2
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CO2
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CO2
通量均值依次为1. 05 μmol·( m2·s) － 1 和1. 38 μmol·( m2·s) － 1 ，
沉积区较侵蚀区增幅达31%( P ＜ 0. 05) ; 沉积区土壤CO2
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 m3·m － 3 和0. 25 m3·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CO2
通量空间变异有重要影响．

The CO2 flux from soil is an important component of global carbon cycle，and a small variation of soil CO2 flux can
prominently influence atmospheric CO2 concentration and soil organic carbon stock． Soil erosion significantly influences soil CO2
emission． However，the process of soil CO2 flux during soil erosion and soil deposition remains uncertain． At the present study，a
simulated experiment on soil erosion and deposition was conducted at Changwu State Key Agro-Ecological Station，Shaanxi，China．
From July to September in 2014 and 2015，soil CO2 flux was periodically measured using an automated CO2 flux system LI-8100 ( LICOＲ，
Lincoln，NE，USA) and soil temperature and moisture were collected by series data collection system of soil temperature and
soil moisture ( EM50，DECAGON，USA) ． The measurement frequency of soil CO2 flux was once a week during 09: 00 and 11: 00． Soil
temperature and soil moisture of 10 cm topsoil were measured continuously ( at an interval of 30 minutes) during the experiment． At the
same time，runoff and sediment were collected as well in each rain event，and then SOC content in sediment was measured． The results
showed that soil CO2 flux between erosion and deposition sites had a significant difference ( P ＜ 0. 05) ，and soil CO2 flux at deposition
site ［mean value 1. 38 μmol·( m2·s) － 1］was 31% higher than that of soil CO2 flux at deposition site ［1. 05 μmol·( m2·s) － 1 ］，while
temperature sensitivity at deposition site ( Q10
: 8. 14) was 3 times as high as that at erosion site ( 2. 34) ． Soil moisture at deposition
site was 19% higher than that at erosion site ( P ＜ 0. 05) ． Soil temperature was slightly higher at erosion site． The average SOC content
( 7. 26 g·kg － 1 ) increased by 6% in the sediment compared with the initial SOC content ( 6. 83 g·kg － 1 ) ． Soil moisture and SOC
redistribution across erosion and deposition sites were influencing factors for soil CO2 flux under erosional environment． In conclusion，
soil CO2 flux showed a significant variation at erosion site and deposition site． Changes in soil moisture and SOC contributed much to
the difference in soil CO2 flux across erosion and deposition sites．