摘要
团聚体结构和稳定性关系着一系列土壤过程。为探明不同类型地带性土壤团聚体稳定性与孔隙结构变化规律及二者关系,该研究以中国温带与亚热带地区5种地带性土壤(黑土、棕壤、褐土、黄褐土和红壤)为研究对象,结合CT扫描、湿筛法和Le Bissonnais(LB)法,量化孔隙结构,测定各地带性土壤团聚体平均重量直径(Mean Weight Diameter,MWD)。结果表明:团聚体水稳性受到土壤类型和土层深度的综合影响,从大到小依次为黄褐土、褐土、棕壤、黑土和红壤;基于LB法测定的团聚体平均质量直径排序为MWDsw(慢速湿润)>MWDws(预湿润震荡)>MWDfw(快速湿润),即5种团聚体的主要破碎机制是快速湿润引起的消散作用;5种地带性土壤团聚体不同当量直径孔隙度由北至南呈“U”型变化,且这种变化程度随土层深度增加而减弱;团聚体孔隙大小均以30~<75μm孔隙为主,孔隙形状以细长型孔隙为主。细长型孔隙度自北向南呈先下降后上升的趋势,不规则型和规则型孔隙度变化趋势相反;偏最小二乘回归表明,规则型孔隙度、孔隙平均形状因子、75~100μm孔隙度和细长型孔隙度与团聚体水稳性显著相关,细长型孔隙起正向作用;规则型孔隙、细长型孔隙、75~100μm孔隙度和>100μm孔隙度是MWDfw、MWDws、MWDsw的主控因子。研究结果有助于加深土壤团聚体与孔隙特征关系的认识,从而更好地揭示土壤过程作用机制。
Aggregate structure and stability are related to a series of soil processes.However,it is still lacking in the microstructure and aggregate stability for the different types of zonal soil aggregates.In order to explore the changes of aggregate stability and pore structure for the different types of zonal soil aggregates and their relationship,this study aims to explore aggregate stability and its relevance to the pore structure characteristics in the different types of zonal soil.Five types of typical soils(Black,Brown,Cinnamon,Yellow-cinnamon,and Red soil)were selected as the research objects using geogenesis.The soil samples were collected separately from the Hailun(Heilongjiang),Shenyang(Liaoning),Luoyang(Henan),Xiangyang(Hubei),Changsha(Hunan),and Haikou(Hainan),according to the latitudinal direction zonality of soil distribution.The pore structure and MWD of aggregates were quantified using the CT scanning,wet sieving,and Le Bissonnais method..The results indicated that the water stability of aggregates was affected by the soil type and soil depth,and the values from low to high were Yellow-cinnamon soil,Cinnamon soil,Brown soil,Black soil and Red soil.The eluvial horizon in the Red soil was the highest(1.49 mm),and the parent material horizon in Yellow-cinnamon soil was the lowest(0.19 mm).The average mass diameter of the aggregates measured by LB method was ranked as MWDsw(slow wetting)>MWDws(shaking)>MWDfw(fast wetting),indicating that the dissipation and external mechanical failure were the main fragmentation mechanisms of aggregates.The resistance of soil aggregates to dissipation and fragmentation gradually decreased and then increased from north to south.Significant differences were found in the aggregate microstructure of different soil types.The porosity of the five zonal soil aggregates with different equivalent diameters showed a U-shaped variation from north to south,and the degree of variation decreased with the increase of soil depth.The total porosity and pore number were the highest for the Black soil aggregates and the lowest for the Yellow-cinnamon soil aggregates.The pore sizes in most aggregates were observed to be 30-<75μm.However,the pores larger than 100μm were dominated in the Yellow-cinnamon soil,which was connected with the original particle arrangement and the low content of cementing material in the soil.The aggregate pore morphology was dominated by elongated pores with a few regular and irregular pores.The elongated pores decreased first and then increased from north to south.By contrast,an opposite trend was found in the irregular and regular pores.The aggregates stability showed significant positive correlations with the total porosity,total pore numbers,elongated porosity,<30,30-75,75-100,and>100μm porosity,while inversely correlated with the regular and irregular porosity(P<0.01).Partial least squares regression(PLSR)showed that the water stability of aggregates was significantly correlated with the regular porosity,,mean pore shape factor,75-100μm porosity,and elongated porosity.The regular porosity,elongated porosity,75-100μm porosity and>100μm porosity were proved to be the main controlling factors of MWDfw,MWDws and MWDsw.These results will help to deepen the understanding of the relationship between soil aggregates and pore characteristics,and better reveal the mechanism of soil processes.
作者
彭珏
陈家赢
王军光
蔡崇法
Peng Jue;Chen Jiaying;Wang Junguang;Cai Chongfa(Key Laboratory of Arable Land Conservation Middle and Lower Reaches of Yangtze River of the Ministry of Agriculture,Soil and Water Conservation Research Centre,Huazhong Agricultural University,Wuhan 430070,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2022年第18期113-121,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家重点研发计划项目(2021YFD1500703)
国家自然科学基金(42177317)。
关键词
团聚体
土壤
孔隙
稳定性
结构
地带性
aggregates
soils
pores
stability
structure
zonality
作者简介
彭珏,博士生,研究方向为土壤侵蚀机理。Email:pengj12345@mail.hzau.edu.cn;通信作者:王军光,博士,副教授,研究方向为土壤侵蚀机理。Email:jgwang@mail.hzau.edu.cn。
