Variation characteristics of aggregate composition, SOC in aggregates, Feo in aggregates, and Fec in aggregates in QRS under various anthropogenic land use activitie

QRS represents a pre-Holocene paleosol that developed under warm and humid climatic conditions. A series of QRS pedons, influenced by anthropogenic land use activities, were sampled including sparse forest grassland, grassland, woodland, and cultivated land. According to the principle proposed by Brewer (1976), the Btr2 horizon in the buried QRS, which had the lowest degree of weathering in the profile, was selected as the reference basis. By utilizing the Soil Reconstruction Method and using Ti as the stable element, the gains and losses of aggregates, SOC in aggregates, Feo in aggregates, and Fec in aggregates were calculated for 0–30 cm layer in the QRS under different anthropogenic land use activities compared to the buried one.QRS代表全新世前古土壤，其形成于暖湿气候条件下。本研究采集了一系列受人为土地利用活动影响的QRS土壤单体，采样涵盖疏林草原、草原、林地与耕地四种土地利用类型。依据Brewer（1976）提出的原理，选取埋藏型QRS剖面中风化程度最低的Btr2层作为参照基准。本研究采用土壤重建法（Soil Reconstruction Method），以钛（Ti）作为稳定元素，以埋藏型QRS为对照，计算了不同人为土地利用方式下QRS 0~30 cm土层内团聚体、团聚体有机碳（SOC）、团聚体无定形铁（Feo）以及团聚体游离铁（Fec）的相对得失量。