Investigating The Water Retention Capacity Of Different Growing Substrates

763 Words Oct 31st, 2016 4 Pages
2. Project Objectives
The project objective is to determine the water retention capacity of different growing substrates and whether the substrate has an effect on the quality of runoff, under the climate conditions of Western Australia.
3. Materials and Methods
3.1. Substrate Mixes and Plant
Cynodon dactylon (Couch Grass) was selected as the model plant for the experiment, which was purchased from a local nursery. This is due to its ability to survive on low amounts of water because of its extensive root system (BioNET-EAFRINET 2016). In order to reduce the effects of other growing media on the testing substrate, the Cynodon dactylon (couch) roll was washed with water before planting onto planting pots.
For the present study, substrate preparation was based on an extensive green roof system, which has a shallower layer (6-20cm) of growing medium (IGRA 2014). Therefore, in this case, the depth of substrate was fixed at 14 cm with inorganic and organic composition. The materials used for the preparation of green roof substrate include vermiculite, perlite, sand and organic mulch. Vermiculite is a kind of materials which are aluminium-iron-magnesium-silicates, resembling mica in appearance(Dupré Minerals Ltd. 2016). These materials were brought from the local stores and used in their original form in experiments.
The physical properties of each substrate component were tested and listed in Table 1. Bulk density (at maximum water holding capacity) was measured as per FLL…
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