To maximize nutrient removal efficiency of floating wetlands also the timing of plant harvest is crucial. Perennial macrophytes move their nutrients into the roots when senescence starts in autumn. To be most effective, harvest should be in (late) summer. Not only nutrient concentrations in different plant species are important, but also biomass development and thus total nutrient stocks.
This year the islands were harvested during September. Before the islands were installed in spring the initial nutrient concentrations were determined per plant species. When harvesting the nutrient concentrations will be analyzed again to underline which and how much nutrients the plants took up during the season. The results will show which plants will be most efficient to take up nutrients.
Before and after plant harvest in Germany and Lithuania.