Growth and nutrient removal of three macrophytes in response to concentrations and ratios of N and P

ABSTRACT

Wastewater from different sources shows great differences in concentrations and ratios of N and P. In order to choose suitable plant species to remove excess N and/or P from polluted waters, it is important to know the performances of these plants under different N and P concentrations. In this study, we investigated the growth and N and P removal rate of three macrophytes, Coix lacryma-jobi, Iris wilsonii, and Arundo donax under six N and P combination treatments. C. lacryma-jobi preferred higher N and P concentrations (16 mg N L⁻¹ and 3.2 mg P L⁻¹), and increasing N supply could increase its P removal rate. I. wilsonii exhibited a growth preference at a combination of moderate N and P concentrations (8 mg N L⁻¹ and 0.8 mg P L⁻¹). A. donax could grow well at all combinations of N and P and had significantly higher relative growth rate and N and P removal rates than the other two species. These results showed A. donax is a promising species to treat various polluted waters and the other two species can be used specifically to treat certain types of wastewater.

KEYWORDS:

• Coix lacryma-jobi
• Iris wilsonii
• Arundo donax
• N and P removal
• biomass
• relative growth rate

Funding

This study was financially supported by the Foundation of Chairman of Guangxi Zhuang Autonomous Region, China (1324105), the National Natural Science Foundation of China (31560089) and the Science and technology program of Guangxi, China (Guike AB16380250, Guikegong 14124004-3-5). Professor Azim Mallik contributed to this paper during his tenure as a Distinguished Foreign Expert at the Guangxi Institute of Botany.