DETERMINATION OF THE WATER AND AIR CAPACITY OF 25 SUBSTRATES EMPLOYED FOR THE CULTIVATION OF DIEFFENBACHIA AMOENA AND EUPHORBIA PULCHERRIMA
Two instruments were employed for the physical analysis of the substrates: the first consists of 2 superimposed cylinders containing the substrate; the second is a funnel with a porous septum in which the substrate saturated with water is placed at suctions corresponding to water columns of 10, 50 and 100 cm.
Nine mould components were mixed together at different ratios: sphagnum peat moss, uncomposted bark, composted bark, argex, perlite, polystyrene, leaf mould, sand and hydrogel.
Peat, sand and leaf mould have a higher water buffering capacity than other substrates.
Peat and hydrogel increase water retention capacity of the substrate while components helping drainage (argex, perlite, polystyrene, sand) decrease it, raising porosity.
Composted and uncomposted bark have a middle behaviour; the first one has a higher water retention and a lower air capacity than the second one.