Model Depth Fitting curve R2 RMSE MAE P-value
Model I layer(5-20cm) (n=104) \[F=0.226\times e^{0.046T}\times M^{-0.535}\]
0.144
0.882
0.707
<0.001**
Deep layer(80-200cm) (n=156) \[F=0.009\times e^{0.107T}\times M^{-0.709}\]
0.460
0.098
0.073
<0.001**
Model II layer(5-20cm) (n=104) \[F={1.578}^{\frac{T-10}{10}}\times(0.936-1.545M+\frac{0.044}{M})\]
0.132
0.883
0.709
<0.001**
Deep layer(80-200cm) (n=156) \[F={2.914}^{\frac{T-10}{10}}\times(0.143-0.478M+\frac{0.005}{M})\]
0.462
0.094
0.071
<0.001**