黑土团聚体有机碳对耕作与水蚀的响应差异  

Different responses of aggregates-associated organic carbon to tillage and water erosion in the black soil region

作　　者：殷爽 李毅然 李露[1] 曹伟[1] 王恩姮[1] YIN Shuang;LI Yiran;LI Lu;CAO Wei;WANG Enheng(School of Forestry,Northeast Forestry University,150040,Harbin,China)

机构地区：[1]东北林业大学林学院,哈尔滨150040

出　　处：《中国水土保持科学》2020年第3期67-73,共7页Science of Soil and Water Conservation

基　　金：国家林业局林业公益性行业科研专项“黑土区坡面侵蚀与土地退化机制”(20140420208);大学生创新训练计划项目“黑土碳氮及其组分对耕作侵蚀与水蚀的响应差异”(201710225161)。

摘　　要：东北黑土区农田土壤有机碳损耗不仅受水蚀影响,同时还受耕作侵蚀的影响,进一步探究2种侵蚀对土壤团聚体有机碳的影响差异,可为探明黑土侵蚀机制、坡耕地水土流失和质量退化提供证据。以东北黑土区未受开垦干扰的天然次生林表层土壤为研究对象,通过模拟不同干扰强度的耕作侵蚀(原位破碎和耕作迁移)与水力侵蚀(雨滴击溅和径流冲刷),研究不同粒径(>2 mm、1~2 mm、0.25~1 mm、0.053~0.25 mm、<0.053 mm)水稳性团聚体有机碳的变化规律。结果表明:随着原位破碎强度的增加,>0.25 mm和<0.25 mm团聚体有机碳质量分数分别表现为增加和降低趋势;随着耕作迁移强度的增加,>0.053 mm和<0.053 mm团聚体有机碳质量分数分别呈现增加和降低趋势;雨滴击溅作用使各粒径团聚体有机碳均呈现增加的趋势,而径流冲刷作用增加>0.25 mm团聚体有机碳质量分数,降低<0.25 mm团聚体有机碳质量分数。仅发现>2 mm、1~2 mm、0.053~0.25 mm团聚体有机碳质量分数变化率与耕作侵蚀强度显著负相关。与水蚀相比,黑土团聚体有机碳对耕作侵蚀的响应更敏感。[Background]Topsoil in the black soil region of Northeast China has become thinner since cultivation,soil degradation has become more and more serious and been causing soil organic matter content to decrease gradually.Soil erosion is the key contribution to soil degradation.The loss of organic carbon in the black soil region of Northeast China has not only been affected by water erosion,but also by tillage erosion.Further exploring the responses of soil organic carbon within different sizes of aggregates to two types of erosion,and determining the predominant type of erosion driving aggregates-associated organic carbon loss in the black soil region could provide evidences for mechanisms of soil erosion and soil loss and soil quality degradation in the black soil region.[Methods]Based on the surface soil of natural secondary forest which has not been undisturbed by reclamation in the northeastern China,the responses of aggregates-associated organic carbon were studied by simulated tillage erosion(in-situ disruption and tillage migration)and water erosion(raindrop splash and runoff scouring)with different interference intensities.The treatment intensities were 5,10,20,30,40 times for in-situ disruption;5,20,30,40 times for tillage migration;40,60,80,100,120 mm/h for raindrop splash;as well as 2,3,4,5,6 L/min for runoff scouring respectively.After simulating,soils from the 0-1 cm surface were collected and incubated for 30 d.Soils after incubation were wet-sieved into>2 mm,1-2 mm,0.25-1 mm,0.053-0.25 mm,<0.053 mm fractions,and then determined the organic carbon content.[Results]After in-situ disruption,soil organic carbon content of>0.25 mm and<0.25 mm aggregates increased and decreased with the increasing interference intensity,respectively.During tillage migration,the organic carbon content of>0.053 mm aggregates increased and<0.053 mm aggregates decreased,respectively.The impact of raindrop splash on organic carbon content of aggregates with different sizes showed a generally increasing trend;however,runoff scour

关 键 词：耕作侵蚀 径流 土壤有机碳 水稳性团聚体 黑土区 

分 类 号：S157.1[农业科学—土壤学]