chemical treatments had two roles in cracking patterns (Dc and AW):
physical effect by modification of aggregate size distribution and chemical
effect by removal of Fe/Al oxides and SOC (Table 6). The physical effect
was estimated with the regression models of crack parameters against
the content of clay-sized aggregates (Fig. 7). The physical effect contributed
89.9–92.3% for Dc and 66.1–95.1% for AW in the YPF soil with the
exception of DCB treatment, greater than those in the OPF soil (52.2–
79.6% for Dc and 48.5–89.3% for AW). For the water treatment, no
chemical effect on Dc and AWwas supposed. For the YPF soil, the chemical
effect of DCB treatment on Dc and AWwas negative, so that estimated
Dc and AW calculated from clay-sized aggregate content were several
times larger than the measured ones. Generally, the contribution of
physical effect was higher than that of chemical effect. Physical effect of
H2O2 treatment on Dc (79.6–92.3%) and AW (89.3–95.1%) was higher
than that of oxalate and DCB treatments for the both soils except for
DCB treatment in the YPF soil.