where Cs is SOC stock (Mg ha−1); Cc is SOC concentration (g kg−1); BD
is bulk density (g cm−1); D is soil layer thickness (cm); and F2mm is the
proportion of N2 mm coarse fraction. In the study area, coarse particles
rarely occur in the loessial soil (Liu et al., 2011). Thus, F2mm was considered
negligible. The ratio of CL to CNL (CL/CNL) was calculated.