3.3 Microstructures of soil aggregates
A significant difference was observed in the two-dimensional shape
between the splashed soil aggregates and the undisturbed soil (Figure
2D). The undisturbed soil aggregates primarily consisted of
macroaggregates with clear outlines and boundaries, containing more
macropores and a relatively loose soil structure (Figure 2A). Compared
with the undisturbed soil, the soil structure after raindrop splashing
was more compact, the number of macropores was reduced, the number of
small and medium aggregates was increased, and the phenomenon of
fragmentation was shown. Markedly, after being splashed by rainfall at
the intensity of 217.26 mm h-1, the soil aggregates
were the most broken (Figure 2B-D). The 3D structural differences of
soil aggregates were more obvious than those in 2D (Figure 2 and 3D).
After splashing, the percentage of soil macroaggregates was reduced,
being replaced by an increased number of microaggregates; this result
indicates that the aggregates were obviously broken, and the soil
structure was relatively denser. Table 3 reports that the average
aggregate particle size in splashed soil was significantly smaller than
that of the undisturbed soil (P < 0.05), especially after a
rainfall intensity of 68.61 and 217.26 mm h-1. The
average aggregate particle size decreased by 2.43%, 3.25% and 3.55%
after splashed by three rainfall intensities, respectively. This result
is consistent with the micromorphology of aggregates.