5. Conclusions
The impacts of contents of SOC and Fe/Al oxides and puddling intensity
on soil aggregate distribution and cracking patterns in two different
paddy soils were investigated. For the young paddy soil (YPF soil), the
Fe/Al oxides were key binding agents for microaggregates and claysized
removal was more important than that of SOC removal probably due
to higher change of specific surface area (SSA) with Fe/Al oxide
removal. The YPF soil showed more cracking than the OPF soil
under water treatment, which may result from the difference in
SOC and Feo/Alo. The difference in aggregate size distribution related
to puddling intensity also contributed to the difference of cracking
between the two soils.