Table 5. Stepwise multiple linear regression of soil organic carbon (SOC) concentrations with selected soil variables at different soil depths.

Soil depth	Independent variables	Coefficient	Explained Variance (%)
0–10 cm	Constant	3.589 **
	Sand	−2.617 **	39.78
	Stones	0.006 **	7.30
	Adjusted R2	0.470
	MSE	0.417
10–20 cm	Constant	0.989 **
	Silt	5.200 **	31.18
	Stones	0.006 **	6.52
	Adjusted R2	0.377
	MSE	0.444
20–30 cm	Constant	0.950 **
	Silt	4.599 **	27.20
	Stones	0.006 **	6.80
	Adjusted R2	0.340
	MSE	0.466
30–40 cm	Constant	1.613 **
	Silt	3.206 **	24.20
	Stones	−0.007 **	10.00
	Adjusted R2	0.342
	MSE	0.477

MSE, mean squared error; R², coefficient of determination; ** Denotes significance of correlation at P<0.01.