The effect of harvesting on nutrients accumulaion in aboveground biomass of macrophytes

Koharu Okada, BSc

Master's thesis

Abstract:

Considering fresh water supply issue, application of Constructed wetlands (CW) for waster water treatment is one of effective solution. In Czech Republic, there are several active CW and this study picked one in Zbenice applying for domestic water and storm water. One of significant class of contaminant are nutrients ( nitrogen and phosphorus) and that causes eutrophication of the aquatic environment. This study was focused on nutrient uptake into macrophytes aboveground biomass from discharge and measured amount of aboveground biomass and nutrient standing stock. There are Phalaris arundinacea and Phragmites australis in this CW and harvest of aboveground biomass was conducted on June, July, October and June, September for each macrophytes. The result showed that biomass for P. arundinacea was generally higher in inflow than outflow and biomass, nutrient standing stock of single harvest (1888 gm-2, 3.73 gPm-2 and 33.0 gNm-2) in highest growing period was higher than double harvest. For P. australis there was no regrowth after first harvest and the difference between inflow and outflow was not significant ( p >0.05). Single harvest in September was shown to yield the highest biomass and nutrient accumulation( 3943 gm-2, 6.34 gPm-2 and 62.3 gNm-2). Considering on results, aboveground biomass and nutrients P. arundinacea in a single harvest was higher than in a double harvest. However, newly grown shoots in October after first harvest was contained high concentration of nutrients. And there were significant differences of biomass and nutrient between inflow and outflow for P. arundinacea that were caused by different amount of nutrients load. From these points of view, application of different harvest timing on inflow and outflow can be an effective way to enhance the capability of CW.

Keywords

Macrophytes, wetlands, harvesting, nutrients

Language used: English

Date on which the thesis was submitted / produced: 18. 4. 2018

Thesis defence

• Supervisor: prof. Ing. Jan Vymazal, CSc.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / field:
Engineering Ecology / Nature Conservation