Soil Biochemical Responses To Extensive Grazing in Xerothermic Grasslands: Implications for Soil Health and Biodiversity

Abstract The aim of the study was to assess the effect of grazing native sheep breeds on soil condition. Methods: The study was conducted on soils of xerothermic grasslands in eastern Poland, within four Natura 2000 sites: Ostoja Nadbużańska PLH140011, Zachodniowołyńska Dolina Bugu PLH060035, Stawska Góra PLH060018 and Kąty PLH060010. Soil samples were collected over three years, twice annually: before and after grazing. The intensity of biochemical N transformations was determined based on the activity of nitrogen cycle enzymes, i.e. urease (UrA) and proteases (PrA), as well as N resources (total N, ammonium N and nitrate N) in soils under conditions of extensive sheep grazing. Results: In the soils of all studied habitats, a beneficial effect of extensive sheep grazing on the activity of soil enzymes, the content of total N and mineral forms of N was found. A noticeable improvement in the soil’s biochemical condition was observed in the habitat, which had been subjected to continuous sheep grazing since 2008. The soil of the grazed site was characterized by two times higher PrA and four times higher UrA than the soil of wastelands. Still, long-term studies are needed to investigate better enzyme activity changes and N content fluctuations.