In this study

the vertical distributed soils from Wutai Mountain were used as the object

and the subalpine meadow soil (A)

mountain meadow soil (B)

brown soil (C)

leached cinnamon soil (D) and calcareous cinnamon soil (E) were collected from high to low according to the vertical distribution. The distribution characteristics of Ca—SOC and Fe(Al)—SOC in soils and all level water-stable aggregates (＞2 mm

2～0.25 mm

0.25～0.053 mm and ＜0.053 mm) were analyzed. The results showed that: from A to E

the content of Ca—SOC in soils didn’t change significantly

while the content of Fe(Al)—SOC increased firstly and then decreased. With the decrease of aggregates′ particle size

the change trend of Ca—SOC and Fe(Al)—SOC′s content in A was opposite (the former increased firstly and then decreased

the latter decreased firstly and then increased)

and decreased first and then increased in B. Also

the change trend of Ca—SOC and Fe(Al)—SOC′s content in D was opposite to that of B

which was increased firstly and then decreased. In addition

the Ca—SOC and Fe(Al)—SOC′s content in C decreased gradually

while increased gradually in E. The correlation analysis showed that the soils and ＞2 mm aggregates had a significant positive correlation between Fe(Al)—SOC and TOC

the correlation coefficient were rsoil=0.898 (P＜0.05) and r＞2 mm=0.978 (P＜0.01). The content of Fe(Al)—SOC in soils and all level aggregates was significantly higher than that of Ca—SOC

and the contents of Ca—SOC and Fe(Al)—SOC in 2～0.25 mm and 0.25～0.053 mm aggregates were significantly positive correlated. Therefore

in Wutai mountain soil

the bonding ability of Fe—Al bond and the stability of Fe—Al complex were higher than Ca—SOC

besides

the content and distribution ratio of Fe(Al)—SOC in soil and all level aggregates were significantly higher than that of Ca—SOC.