摘要
研究土壤侵蚀对有机碳不同组分流失的影响,可为科学评估土壤侵蚀在碳循环中的作用和探明农田有机碳变化机制提供理论依据。该研究以典型黑土区一凸型耕地坡面为研究对象,基于^(137)Cs示踪技术,分析了坡面土壤侵蚀特征及强度分布,定量分析了坡面有机碳组分的变化幅度及侵蚀强度与有机碳组分间的关系。结果表明:研究坡面年均侵蚀速率为3801.71 t/(km^(2)×a),属中度侵蚀,33.33%的采样点为强烈侵蚀,极强烈及剧烈的侵蚀点占比11.11%,主要位于凸型坡中部坡度较陡处,26.67%为沉积点,主要分布在坡脚西侧。自开垦以来坡耕地土壤平均有机碳(Soil Organic Carbon,SOC)含量下降了13.58%,其中矿质有机碳(Mineral-bound Organic Carbon,MOC)和颗粒有机碳(Particulate Organic Carbon,POC)分别下降了7.52%和40.49%;POC中粗颗粒有机碳(Coarse Particulate Organic Carbon,CPOC)下降幅度最大(73.24%),细颗粒有机碳(Fine Particulate Organic Carbon,FPOC)无显著差异。坡面SOC、MOC和FPOC在沉积点均显著大于侵蚀点(P<0.01),沉积点和轻度侵蚀点的SOC及MOC含量显著大于轻度以上侵蚀点(P<0.01),SOC及组分MOC和FPOC均在中度侵蚀下降幅度最大,之后变化轻微。有机碳组分中MOC和FPOC含量随着土壤侵蚀强度的增大呈下降趋势,CPOC与侵蚀强度无显著相关性且沉积点及不同侵蚀强度之间均无显著差异(P>0.05)。结果说明坡耕地中CPOC和MOC减少的驱动机制可能存在差异。
Soil Organic Carbon(SOC)in agriculture is an important part of soil fertility and terrestrial ecosystems,and its variations affect food production and global carbon cycle,while soil erosion is the main cause of SOC migration and loss.However,the change mechanisms of SOC in agricultural fields and the quantitative relationship between soil erosion and these nutrients are still poorly understood.Studying the effects of soil erosion on organic carbon loss in the different components can provide a theoretical basis for scientifically assessing the role of soil erosion in the carbon cycle and exploring the mechanism of organic carbon turnover in the farmland.In the study,soil erosion characteristics and spatial distribution of its intensity on the convex slopes located in typical black soil areas of Northeast China were investigated based on the^(137)Cs tracing technique.The relationship between soil erosion intensity and organic carbon components was quantified.Moreover,the differences in organic carbon fractions between uncultivated and cultivated land was also compared.The results showed that the average annual erosion rate from the slope studied was 3801.71 t/(km^(2)×a),thus the soil erosion intensity was categorised as moderate erosion.Among the all the sampling points,the 33.33%of them belonged to the severe erosion and 11.11%of them was extremely severe,which were mainly located in the middle of the steeply convex slope,and 26.67%of the points was in the deposition area,which were mainly distributed in the west area at the bottom of the slope.Compared to soils from the uncultivated slope,the average SOC content had decreased by 13.58%,of which Mineral Organic Carbon(MOC)and Particulate Organic Carbon(POC)had decreased by 7.52%and 40.49%,respectively,and the Coarse Particulate Organic Carbon(CPOC)had decreased by 73.24%,while the Fine Particulate Organic Carbon(FPOC)was not significantly different.The SOC,MOC,and FPOC at the deposition sites on the slope were significantly higher than those at the sites eroded(P<0.01);SOC and MOC at the deposition sites and the mild erosion sites were significantly higher than those of above-mild erosion sites(P<0.01);the higher decrease of both SOC and components of MOC and FPOC was observed in the sites where the moderate erosion occurred and changed slightly thereafter.The MOC and FPOC in organic carbon fractions decreased with the increasing erosion intensity,but there was no significant correlation between CPOC and the erosion intensity,and no significant difference between deposition sites and different erosion intensities was also observed(P>0.05).The result indicated that the difference of driving mechanisms of CPOC and MOC reduction may exist on the slope cropland.Overall,the severity of soil erosion in some black soil areas in Northeast China has not been greatly improved.The SOC content has reduced considerably as land use types have changed(reclamation),posing a serious threat to the sustainable development of agriculture in the black soil area.Erosion control and soil fertility replenishment may be the key to achieving sustainable development in the region.
作者
何彦星
张风宝
杨明义
He Yanxing;Zhang Fengbao;Yang Mingyi(State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Northwest A&F University,Yangling 712100,China;Institute of Soil and Water Conservation,Chinese Academy of Sciences,Ministry of Water Resources,Yangling 712100,China;CAS Center for Excellence in Quaternary Science and Global Change,Yangling 712100,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2021年第14期60-68,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家重点研发计划项目(2018YFC0507001)
国家自然科学基金项目(41877080)。
关键词
土壤
侵蚀
有机碳
^(137)Cs
黑土
坡耕地
组分
soils
erosion
organic carbon
^(137)Cs
black soil
sloping arable land
fractions
