The dry soil was carefully ground to pass a 250 mm sieve
(Andruschkewitsch et al., 2014; Helfrich et al., 2008) to ensure the
complete dispersion of macro-aggregates. The amount of the
remaining material on top of the 250 mm sieve was negligible and
discarded in case of the clayey soil but was collected and mixed in
equivalent parts into each of the