Microporous distinguished from macroporous

In the context of transport, the presence of macropores plays a particular role. Macropores are large pores, which form at the macroscopic level an obviously distinguished pore system from the soil matrix pore system. Macropores constitute sometimes a separate and/or continuous network in which particle velocities may deviate systematically from those in the soil matrix. As a result, the solutes released in the macropore network will be subjected to a preferential flow as compared to flow in the matrix system and will not completely mix with the total pore water volume at short time intervals. Preferential flow through macropores is considered here as a macroscopic process since concentrations in the macropores cannot easily be determined separately from the concentrations in the micropore system. 

By the term macropores, we distinguish pores larger than 20 nm from the micropores in conventional silica... 

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