Table S1. Selected physicochemical and magnetic properties of studied soils.

General characteristics and physico-chemical properties of the studied soils are presented in Tables S1 and 1. The soils were classified as Aridisols, Vertisols, Inceptisols, Alfisols and Mollisols (Soil Survey Staff, 2014) and Solonchaks, Calcisols, Vertisols, Luvisols, Kastanozems and Cambisols (IUSS Working Group WRB, 2015). Three dominant land uses were selected in the study area including cropland, pasture, and orchard (Table 1). The diagnostic horizons in the studied soil profiles were identified as: calcic horizon (Bk and Ck, for the accumulation of secondary carbonates), gypsic horizon (By, as the accumulation of gypsum), salic horizon (Bz and Cz, for the accumulation of salts more soluble than gypsum), argillic horizon (Bt, for the illuvial accumulation of phyllosilicate clay), and cambic horizon (Bw, as the development of color or structure) (Soil Survey Staff, 2014).本研究供试土壤的基本特征与理化性质详见表S1和表1。供试土壤依据美国农业部土壤调查局（Soil Survey Staff, 2014）的分类体系被划分为干旱土（Aridisols）、变性土（Vertisols）、始成土（Inceptisols）、淋溶土（Alfisols）及软土（Mollisols）；同时依据国际土壤学会世界土壤资源参比基础工作组（IUSS Working Group WRB, 2015）的分类体系被划分为盐土（Solonchaks）、钙积土（Calcisols）、变性土（Vertisols）、淋溶土（Luvisols）、暗栗钙土（Kastanozems）及雏形土（Cambisols）。研究区域选取了三种主导土地利用类型，分别为耕地、牧草地与果园（表1）。供试土壤剖面中的诊断层（diagnostic horizons）被鉴定为：钙积层（calcic horizon，以Bk、Ck标识，对应次生碳酸盐聚集）、石膏层（gypsic horizon，以By标识，对应石膏聚集）、盐积层（salic horizon，以Bz、Cz标识，对应溶解度高于石膏的盐类聚集）、黏化层（argillic horizon，以Bt标识，对应层状硅酸盐黏土的淀积聚集）及雏形层（cambic horizon，以Bw标识，对应颜色或结构发育）（Soil Survey Staff, 2014）。