摘要
为区分土壤团聚体形成和破碎过程,阐明冻融循环对黑土土壤结构的影响,本文利用稀土氧化物(REOs)示踪技术,通过室内模拟试验,探究不同初始含水量(50%田间持水量(T50)vs.100%田间持水量(T100))和冻融循环次数(0次、3次、6次、12次和20次)对团聚体粒径分布、平均质量直径(MWD)以及团聚体周转过程的影响。结果表明:同一初始含水量下,随着冻融循环次数的增加,MWD、>0.25mm和<0.053mm团聚体含量显著降低,0.25~0.053mm团聚体含量显著增加(P<0.05)。6次冻融循环后,T50处理下的MWD显著高于T100处理(P<0.05),5~2mm和<0.25mm团聚体含量无显著差异。除5~2mm团聚体外,冻融循环处理下,相邻粒级团聚体之间周转更为激烈。在同一冻融循环次数下,5~2 mm团聚体向0.25~0.053 mm团聚体的破碎量在T100处理下显著高于T50处理(P<0.05)。冻融循环促进了>0.25 mm团聚体的破碎和<0.053mm团聚体的团聚,表现为0.25~0.053mm团聚体的累积。冻融循环过程中,MWD与各粒径团聚体相对形成量呈显著正相关,与其相对破碎量呈显著负相关(P<0.05)。随着冻融循环次数的增加,各粒径团聚体周转时间显著增加(P<0.05)。同一冻融循环次数下,>0.25mm团聚体的周转时间高于<0.25mm团聚体,T100处理下的团聚体周转时间显著高于T50处理(P<0.05)。综上所述,冻融循环次数和土壤初始含水量通过影响团聚体形成和破碎过程改变土壤结构的稳定性。本研究结果可为进一步探究冻融循环下黑土土壤结构变化提供理论依据。
【Objective】To elucidate the effects of freeze-thaw cycles and initial water content on soil structural stability,rare earth oxides(REOs)were used as tracers to separate soil aggregates formation and breakdown processes.【Method】REOs-labelled soil was reformed and investigated herein.Two initial water contents(50%field water holding capacity(T50)vs.100%field water holding capacity(T100))and five freeze-thaw cycles(0,3,6,12 and 20 cycles)were involved in the simulation experiments.Soil aggregates distribution,mean weight diameter(MWD),and the aggregate transformation processes were measured accordingly.【Result】The results showed that freeze-thaw cycles significantly reduced MWD,>0.25 mm aggregates and<0.053 mm aggregates proportions,but increased the contents of 0.25~0.053 mm aggregates under the same initial water content.After 6 freeze-thaw cycles,MWD was significantly higher under T50 compared with that under T100(P<0.05),but there were no significant differences between the contents of 5~2 mm and<0.25 mm aggregates.Except for 5~2 mm aggregates,more intensive transformation between neighboring size aggregates was observed during the whole simulation experiments.Under the same freeze-thaw cycles,the transformation proportions from 5~2 mm to 0.25~0.053 mm aggregate were significantly higher under T100 compared with T50 treatment(P<0.05).The freeze-thaw cycles promoted the breakdown of>0.25 mm aggregates and aggregation of<0.053 mm aggregales,thas leading to the accumulation of 0.25~0.053 mm aggregales both under T50 and T100 treatments.Also,MWD was significantly positively correlated with the relative formation of soil aggregates and negatively related with the relative breakdown of soil aggregates(P<0.05).Soil aggregates turnover time remarkably increased with the freeze-thaw cycles(P<0.05).Aggregate turnover time of>0.25 mm aggregates was higher than that of<0.25 mm aggregates.Comparatively,the aggregate turnover time was significantly higher under T100 than that under T50 with the same freeze-thaw cycle(P<0.05).【Conclusion】The freeze-thaw cycles and soil initial water content significantly affect the soil structural stability by laying affects on aggregate formation and breakdown processes.The results will provide a theoretical basis for further exploration of the structural changes in Mollisols under freeze-thaw cycles.
作者
刘雅俊
刘帅
甘磊
张中彬
彭新华
LIU Yajun;LIU Shuai;GAN Lei;ZHANG Zhongbin;PENG Xinhua(Guangxi Collaborative Innovation Center for Water Pollution Control and Safety in Karst Area,Guilin University of Technology,Guilin,Guangxi 541004,China;Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China)
出处
《土壤学报》
CAS
CSCD
北大核心
2024年第4期964-977,共14页
Acta Pedologica Sinica
基金
国家重点研发专项(2021YFD1500801)
国家自然科学基金项目(42207360)
江苏省卓越博士后计划(2022ZB466)
中国博士后科学基金项目(2022M723238)共同资助。
关键词
冻融循环
团聚体周转
黑土
稀土氧化物
团聚体稳定性
Freeze-thaw cycles
Aggregate turnover
Mollisols
Rare earth oxides
Soil aggregate stability
作者简介
刘雅俊(1997-),男,山西忻州人,硕士研究生,研究方向为土壤水分与结构。E-mail:lyj4878@163.com;通讯作者:刘帅,E-mail:sliu@issas.ac.cn;通讯作者:甘磊,allen_gl2006@163.com。
