土层(cm)

退耕年限(a)

1

2

3

4

5

8

15

24

31

0~10

8.2340^dD

14.34^cC

12.89^cC

21.80^dC

12.22^dC

15.02^dD

9.71^dC

12.67^dC

17.39^cC

10~20

6.6492^cC

12.12^bB

9.94^bB

20.84^cC

9.99^cC

12.75^cC

6.57^cB

7.00^cBC

7.639^bB

20~30

4.7671^bB

5.96^aA

9.39^bB

17.38^bB

6.43^bB

8.76^bB

5.78^bB

4.79^bB

2.067^aA

30~40

2.9459^aA

4.95^aA

6.86^aA

10.06^aA

3.961^aA

5.65^aA

4.64^aA

2.71^aA

1.68^aA