Effect of mechanical site preparation on features of the soil in a clear-cut area

In most cases, mechanical site preparation (MSP) is a precondition if high−quality (natural or artificial) regeneration of forests is to be achieved. However, the measures involved here may differ in terms of the level of intervention of the soil environment, at both the surface and deeper down. The choice of MSP methods should be based on climatic conditions, site type and the species whose renewal is sought, while the effect should improve conditions for the emergence and growth of the young generation of trees, with the influence on the soil environment being limited as far as possible. The research sought to compare physical and chemical features of the soils of the microhabitats created in clear−cut areas as a result of MSP using either an LPz double mould−board forest plough (furrow and ridge), an active plough (furrow and ridge) and a forest mill (belt and beyond the belt) as compared with unscarified soil. Investigated physical features included grain size (content of sand, silt and clay), bulk density and actual moisture, while the chemical ones: pHH2O and pHKCl, exchangeable acidity, total content of N and C and the C/N ratio, P2O5 content and base cations Mg2+, Ca2+, K+ and Na+. The most invasive MSP method for the soil environment is the active plough, which leaves the ridge exposed to processes of the decomposition of organic matter (and the highest content of N, C, Mg2+, Ca2+ and K+). Equally, this method may pose the greatest threat of mineral components of the soil being leached, with impoverishment of the habitat ensuing. The forest mill in turn offers the least invasive MSP. Most of the physical and chemical features of soil (other than exchangeable acidity and pHH2O and pHKCl) both in the belt areas and beyond them differed little from the those characterising non−scarified soil. Also the analysed features determined for the furrows ploughed by the active or LPz ploughs or the belt prepared using the forest mill did not differ significantly