Further sample degradation cannot be compared because  performed only two slaking cycles.
The change in the calculated [D.sub.RP] values between the slaking cycles is also determined to assess the potential long-term degradation of the investigated samples.
Fragipan resistance to slaking was visually evaluated at every sampling for four weeks and at the end of the experiment through wet aggregate sieving analysis using the following sieve sizes: 50 mm, 22.4 mm, 15.9 mm, 12.5 mm, 7.9 mm, 6.4 mm, 4.0 mm, and 2.00 mm [39, 40].
The NaF, Na-hexametaphosphate, and ryegrass root treatments were the most effective in causing significant slaking in the fragipan clods (Figure 1).
In this case, the aggregate sizes could influence the slaking, swelling, and dispersion processes, and consequently the way in which these processes affect the soil K.
They found that the effect of aggregate slaking on [K.sub.s] reduction was more pronounced in soils with aggregate sizes of 2-4mm than in those with aggregate sizes <2 mm, suggesting that there is an interaction between aggregate size and aggregate slaking in their combined effects on soil [K.sub.s].
In order to determine the effects of the slaking process on seal formation, Lado et al.
These results suggest that, when the clay soil is wetted at a fast rate, the slaking mechanism played an important role in seal formation, while in the soils with clay content [less than or equal to] 41%, the effect of slaking on seal formation was less important.
Soil slaking is the process of fragmentation that occurs when rapid wetting produces failure of dry, unstable soil aggregates, as a consequence of differential swelling and pressure by entrapped air (Quirk and Panabokke 1962).
(1) wettability is greater in cultivated than in non-cultivated soil aggregates due to slaking;
The reduction in slaking
of surface aggregates as carbon content is increased by a period under grass, for example, is well established.
Two distinct processes, slaking
and dispersion, are involved in structural destabilisation during wetting (Emerson 1977).