2.4. Statistical analysis
Differences in pore characteristics among scans along the soil core
were statistically compared to evaluate depth and management
influences using PROCMIXED(SAS Inst.,1999). Statistical analysis ofdata
was completed according to a completely randomized designwith scans
at different depths within a core as a split-plot. This design was tested
using PROC MIXED with a number of variance–covariance types, and
also compared with AIC statistics between the types. It was found that
these parameters were not significantly different in compound
symmetry (Littell et al., 1998). The PROC GLM procedure in SAS was
used to test differences in depth within and among treatments and to
compare differences among treatments (SAS Inst., 1999). Statistical
differences were declared significant at the α=0.05 level.