The Impact of Poplar Short Rotation Coppice on Topsoil Physical Properties and Related Water Conditions

In Europe, the establishment of short rotation coppice (SRC) systems for biomass production has been expanding in the last decades. Several studies have considered the impacts of SRC on soil properties; many have focused on studying its effect on biochemical properties while only a few have addressed physical and hydraulic properties. This study reports the assessment of soil physical and hydraulic properties on two SRC sites on sandy soils planted with 3-year-old poplar trees and an adjacent conventional agricultural field in Western Slovakia. All sites contain a comparable sandy loam soil texture and both SRC fields differed only in the groundwater accessibility. Water infiltration experiments were conducted in the field with subsequent sampling of the upper topsoil (0–5 cm depth). The samples were further processed in the laboratory to obtain the water retention and hydraulic conductivity functions of the soil covering a wide range of soil pore saturation. These hydraulic functions were fitted by using the bimodal version of Kosugi-Mualem’s hydraulic model to estimate the pore-size distribution (PSD) of the soils. The comparison between the SRC field neighboring the agricultural field and the latter showed similar hydraulic soil properties such as the topsoil water retention. However, macropore content, bulk density (BD) and infiltration capacity differed under SRC particularly in the tree row. Analogously, the two SRC fields showed similar topsoil water contents. Other soil properties differed presenting an increased macropore content and higher BD in the SRC field with distant groundwater connection. Our findings suggest that the SRC management may influence the topsoil properties.