大兴安岭南麓农田土壤团聚体稳定性分析

Stability analysis of farmland soil aggregates in the south foot of the Greater Khingan Mountains

以内蒙古自治区大兴安岭南麓阿荣旗全境农田土壤为研究对象,利用机械筛分法测定团聚体组成,并采用经典统计学对其团聚体组成结构进行分析,探索农田耕层土壤团聚体的结构稳定性。结果表明:阿荣旗各乡镇农田土壤团聚体组成存在较大差异,其中以大团聚体为主,粒径≥2 mm的大团聚体占总体的一半以上;粒径≥2 mm和0.25—2 mm的大团聚体之间及粒径0.053—0.25 mm和<0.053 mm的微团聚体之间具有极强的相关关系。各乡镇之间粒径≥2 mm和0.25—2 mm的大团聚体稳定性存在显著差异;各乡镇之间粒径0.053—0.25 mm和<0.053 mm的微团聚体稳定性差异不显著,微团聚体结构相对稳定。相关结果表明:大团聚体容易受到耕地不合理利用、水土流失等外因影响而产生崩解或分解为微团聚体,造成各乡镇间微团聚体差异性较大团聚体显著,直接影响土壤质量。合理利用耕地,保护性耕作才能阻止水土流失,维护土壤团聚体稳定性。

Taking farmland soil in Arong Banner,the southern foot of the Greater Khingan Mountains,Inner Mongolia Autonomous Region,as research object,the composition of aggregates was determined using mechanical screening method,and the composition and structure of aggregates were analyzed using classical statistics to explore the structural stability of farmland topsoil aggregates.The results showed that there were significant differences in the composition of soil aggregates in farmland of various villages and towns in Arong Banner,with large aggregates predominating,and large aggregates with particle sizes≥2 mm accounted for more than half of the total.There was a strong correlation between large aggregates with particle sizes≥2 mm and 0.25—2 mm,and between microaggregates with particle sizes 0.053—0.25 mm and<0.053 mm.There were significant differences in the stability of large aggregates with particle sizes≥2 mm and 0.25—2 mm among villages and towns;There was no significant difference in the stability of microaggregates with particle sizes of 0.053—0.25 mm and<0.053 mm among villages and towns,and the structure of microaggregates was relatively stable.The relevant results showed that macroaggregates were prone to disintegration or decomposition into resulting in significant differences in microaggregates among villages and towns,which directly affected soil quality.Rational use of cultivated land and conservation tillage could prevent soil erosion and maintain the stability of soil aggregates.