水保所知识产出(1956---)知识库

坡度和降雨是影响土壤侵蚀发生和发展的重要因素，分析二者对土壤CO2
通量变化的影响，有助于深入理解侵蚀条件下土壤和大气CO2
之间交换的机理． 选取黄土高原典型侵蚀性土壤黄绵土，于中国科学院水利部水土保持研究所人工模拟降雨大厅，研究不同坡度( 5°、15° 和
25°) 、降雨强度( 30、60 和90 mm·h － 1 ，即I30、I60、I90
) 及历时( 0． 5、1 和1． 5 h，即H0． 5、H1、H1． 5
) 下土壤CO2
通量变化． 结果表明: 同历时和雨强
下，坡度显著影响土壤CO2
通量变化( p ＜ 0． 001) ，且各坡度下土壤CO2
通量呈现出5° ＞ 15° ＞ 25° 的趋势，但5° 与15°之间差异未达到显著水
平，而25°坡度下土壤CO2
通量较5°、15°下显著下降( 16． 3% ～ 36． 5%，10． 8% ～ 27． 1%) ; 同坡度和历时( H1
) 下，随着雨强的增加，土壤CO2
通
量呈现下降的趋势，相较I30
雨强下，I60、I90
雨强下对应坡度的土壤CO2
通量降低了2． 3% ～ 14． 3%，但差异均未达到显著性水平; 同坡度和雨强
( I90
) 下，随着历时的增加，土壤CO2
通量也表现出降低的趋势，H1、H1． 5
历时下，土壤CO2
通量相较H0． 5
下降1． 7% ～ 20． 9%，历时对土壤CO2
通
量影响达显著性水平( p ＜ 0． 1) ; 土壤CO2
通量的变化与坡面SOC 流失量呈线性负相关关系( Ｒ2 = 0． 69 ～ 0． 77，r = － 0． 83 ～ － 0． 88，p≤0． 1) ．
SOC 的流失是导致坡面土壤CO2
通量降低的重要因素．

Slope and rainfall are the key factors to influence detachment，transport and deposition of soil materials by the erosive forces of raindrops and
runoff． The investigation of soil CO2 flux under slope and rainfall is helpful to understand the CO2 exchange mechanism between soil and atmosphere in the
eroded region． A simulated experiment of rainfall and slope was conducted in State Key Laboratory of Soil Erosion and Dryland Farming on the Loess
Plateau． The treatments consist of three slopes( 5°，15° and 25°) ，three rainfall intensities( 30，60 and 90 mm·h － 1，I30
，I60 and I90
) and three rainfall
durations( 0． 5，1 and 1． 5 h，H0． 5
，H1 and H1． 5
) ． Soil CO2 flux significantly decreased as the slope increased( p ＜ 0． 001) ，but there was no significant
difference between 5° and 15°． Soil CO2 flux with slope 25° was declined significantly compared to 5° and 15°( 16． 3% ～ 36． 5%，10． 8% ～ 27． 1%) ．
For the same slope and rainfall duration( H1
) ，soil CO2 flux decreased with the increase of rainfall intensity． Compared with the I30
，the soil CO2 flux of
I60 and I90 decreased by 2． 3% ～ 14． 3%，but the difference did not reach the significant level． With the increase of rainfall duration，soil CO2 flux also
showed a reduced tendency under the same slope and rainfall intensity( I90
) ． Compared with H0． 5
，the soil CO2 flux of H1 and H1． 5 decreased by 1． 7%
～ 20． 9%，and the rainfall duration had a significant influence on the soil CO2 flux． With the increase of slope，rainfall intensity and rainfall duration，
the loss content of SOC had increased significantly( p ＜ 0． 1) ． There were negative linear correlation between soil CO2 flux and SOC losses( Ｒ2 = 0． 69 ～0． 77，r = － 0． 83 ～ － 0． 88，p ≤0． 1) ． SOC loss contribute significantly to the decline in soil CO2 flux during an erosion event．