Phytocenoses of grasses of non-floodplain meadows as vegetative filters for minimizing nitrogen pollution of water bodies: potential use

Abstract

This article presents the results of an assessment of the phytoextraction capacity of grass communities in non-floodplain meadows within the design of buffer strips used to minimize nitrogen pollution of aquatic ecosystems. The scientific novelty of this study lies in establishing the phytoextraction capacity of grass communities for nitrogen, as well as their impact on the potential for reducing the critical load of eutrophication. Natural phytocenoses are represented by 312 grass associations growing in five plant formations (meadow heathlands (MH), normal dry meadows (NDM), dry temporarily excessively wet meadows (DTEWM), swampy meadows (SM), and peat meadows (PM)). Biological accumulation of the element in the aboveground phytomass of plant associations varies from 50.3 ± 17.1 kg/ha (DTEWM) to 56.4 ± 23.9 kg/ha (NDM). Meadow heathland grass communities have a minimum nitrogen accumulation level of 5.2 ± 2.5 kg/ha. No significant differences in nitrogen accumulation levels were found among the plant communities (NDM, DTEWM, SM, and PM). Within the NDM and SM plant communities, significant differences in the levels of biological accumulation of the element were found among the grass communities. In the plant formations NDM, DTEWM, SM, PM, the nitrogen accumulation capacity of natural meadow phytocenoses is inferior to the accumulation capacity of white willow by 43.2–49.6 %; in the MH formation – 94.8 %. In two grass associations, the phytoextraction capacity significantly exceeds the accumulating capacity of willow. The four grass associations have comparable accumulation capacity values. Meadow heathland phytocenoses have the lowest specific potential for reducing the critical load for eutrophication (0.012·10⁻²–0.033·10⁻² eq. kg PO₄³⁻/m²). Other plant formations have a more significant specific potential, averaging 0.187·10⁻² eq. kg PO₄³⁻/m², ranging from 0.053·10⁻² to 0.528·10⁻² eq. kg PO₄³⁻/m². The research results may be useful in transforming natural landscapes, as well as implementing design solutions related to the design of artificial landscapes used to improve the quality of natural waters and maximize future ecosystem services.