where y is the percentage of broken aggregates in a given time, tthe
sieving time,aestimates the losses of aggregates during fast wetting,
bis the maximum estimated abrasion loss of aggregates and cis a
time controlling factor equal to 1/3 of the time interval at which approximately 95% of the total loss (a+b) is reached. All determinations were
done in duplicate, obtaining a minimum of 18 destabilization curves per
site (24 in Peñaflor) (3 or 4 treatments × 3 replicates × 2 tests).
In the second step, another sample of 10 g of 1–2 mm aggregates
was gently immersed in ethanol (96%) for 10 min before being sieving
in water for other 10 min. Then, the amount of aggregates that had
resisted the sieving were collected and dried, and its weight corrected
for sand. The percentage of disintegrated aggregates by slaking was
then calculated as the difference between the aggregate loss after
10 min of sieving with and without the ethanol pretreatment.
The OC content of 1–2 mm soil aggregates was determined directly
by dry combustion with a LECO analyser (RC-612 model), without requiring correction for carbonates. For the general characterization of
soils (Table 2), particle size distribution was obtained by laser diffraction analysis (Coulter LS230), OC and CaCO3contents by dry combustion with the LECO analyser, and electrical conductivity (EC) and pH
by standard methods