The reuse potential and fertilizer value of Iron Coated Sand, tested by PCS

23 October 2019 - Published by Charlotte Boeckaert
The recovery potential and fertilizer value of Iron Coated Sand (ICS) granules, saturated with P, was tested in 2018 in a pot trial on 3 plant species by PCS Ornamental Plant Research. ICS was used in a nutrient filter system as filter material for the removal of P from water discharged of a greenhouse where ornamental plants were cultivated.


Half May 2018, PCS potted LavendulaBuxus and Hedera in a standard substrate for nursery crop without fertilizers, these were manually mixed through the substrate, adapted to the need of each species. 3 different fertilization treatments were given for each plant species: treatment 1 was a standard N and P dose; for treatment 2, a standard dose of N was mixed through the substrate but no additional P was given and treatment 3 was a standard N dose without P, but 30% of P-saturated ICS granules were mixed through the substrate.


The plants in the substrate with standard N and standard P resulted in the biggest plants with the highest fresh weight. For Buxus, there were almost no differences in fresh weight between the plants from the substrate with ICS and the substrate without P. For Lavendula and Hedera, the plants from the substrate with ICS were obviously smaller. There was no release of P from the ICS granules in the substrate. For Hedera, also the chlorophyll, flavonoid and anthocyan content was measured. The plants with standard N and P had the highest chlorophyll content indicating a good quality. The plants of the substrate with ICS had the highest flavonoid and anthocyan content indicating (P)-stress.


ICS granules mixed in the potting soil

In 2019, PCS performs a trial on 1 species (Hedera) to test the P-release from Iron Coated Sand (ICS) after mixing the granules with potting soil by adding phosphorus soluble bacteria (PSB) helping to release the P from the ICS granules. 3 types of PSB’s from 2 companies are drenched pot per pot . One type of PSB is tested at 2 doses.