Risk of phosphorus losses in surface runoff from agricultural land in the Baltic Commune of Puck in the light of assessment performed on the basis of DPS indicator

Stefan Pietrzak; Grażyna Pazikowska-Sapota; Grażyna Dembska; Lidia Anita Dzierzbicka-Glowacka; Dominika Juszkowska; Zuzanna Majewska; Marek Urbaniak; Dominika Ostrowska; Agnieszka Cichowska; Katarzyna Galer-Tatarowicz

doi:10.7717/peerj.8396

Risk of phosphorus losses in surface runoff from agricultural land in the Baltic Commune of Puck in the light of assessment performed on the basis of DPS indicator

PeerJ. 2020 Jan 7:8:e8396. doi: 10.7717/peerj.8396. eCollection 2020.

Affiliations

¹ Department of Water Quality, Institute of Technology and Life Sciences in Falenty, Raszyn, Poland.
² Department of Environmental Protection, Maritime Institute, Gdańsk, Poland.
³ Physical Oceanography Department, Eco-hydrodynamics Laboratory, Institute of Oceanology of the Polish Academy of Sciences, Sopot, Poland.

Abstract

Background: In order to counteract the eutrophication of waterways and reservoirs, a basic risk assessment of phosphorus (P) losses in the surface runoff from agricultural land should be included in water management plans. A new method has been developed to assess the risk of P losses by estimating the degree of P saturation (DPS) based on the P concentration of the water extract water-soluble P.

Methods: The risk of P losses in surface runoff from agricultural land in the Puck Commune on the Baltic Sea Coast was assessed with the DPS method. The results were compared to an agronomic interpretation of the soil test P concentration (STP). Research was conducted on mineral and organic soils from 50 and 11 separate agricultural plots with a total area of 133.82 and 37.23 ha, respectively. Phosphorus was extracted from the collected samples using distilled water on all soil samples, acid ammonium lactate on mineral soils, and an extract of 0.5 mol HCl·dm^-3 on organic soils. The organic matter content and pH values were also determined. The results of the P content in the water extracted from the soils were converted into DPS values, which were then classified by appropriate limit intervals.

Results and discussion: There was a high risk of P losses from the soil via surface runoff in 96.7% of the agricultural parcels tested (96% of plots with mineral soils and 100% of plots with organic soils). Simultaneously, a large deficiency of plant-available P was found in soils from 62% of agricultural plots. These data indicate that the assessment of P concentration in soils made on the basis of an environmental soil P test conflicts with the assessment made based on STP and create a cognitive dissonance. The risk level of P losses through surface runoff from the analyzed plots as determined by the DPS indicator is uncertain. This uncertainty is increased as the DPS index is not correlated with other significant factors in P runoff losses, such as the type of crop and area inclination.

Keywords: Agricultural land; Degree of phosphorus saturation; Eutrophication; Surface runoff.

Grants and funding

This work was supported by the National Centre for Research and Development within the BIOSTRATEG III program No. BIOSTRATEG3/343927/3/NCBR/2017. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.