Abstract:The twelve soil samples used in the experiment were collected from Baiyin Xi, Inner Mongolia, Taibai Mountains, Chengcheng, Yichuan, and Yangling, Shaanxi, representing different ecological systems, such as pasture, forest, meadow and arable lands The air dried soils were hydrolyzed with 6 mol/L HCl for 20h. After the hydrolysates were purified with the column of H type acidic anion exchangeable resin, seventeen amino acids were determined on Beckman 121 MB amino acid analyzer. The results show that t...