Die Bodenkultur - Journal for Land Management, Food and Environment


Influence of site properties on pedogenesis and structural stability of arable soils in the Alps


Arable soils occur in the Alps at heights above sea level from less than 200 to more than 1500 m and span a wide range of site conditions. Therefore, the influence of site conditions on pedogenesis uniform soil use can be quantified. The scarcity of erosion features in spite of slope angles well above 20° indicates a pronounced structural stability. Pedogenetic properties and structural stability were studied for 44 soils on a transact from Germany to Italy. Clay content in the topsoil increased with annual precipitation and mean temperature. In contrast, organic matter content decreased with increasing temperature. Even under similar climatic conditions, topsoils from the Alpshave less clay and more organic matter than non-alpine soils. This difference in clay content was attributed to a shorter time of soil development. Larger organic matter content is caused by regular applications of manure in large quantities and by the temporary use as grassland. Pore volume of the aggregates was 60 % greater in alpine than in non-alpine soils due to their higher organic matter content. Aggregate stability against slaking was four times larger in Alpine soils. It increased with increasing organic matter content and decreasing pH. The recommended application of lime to increase structural stability is not supported by the findings. Key-words: Alpine soils, structural stability, aggregate density, soil development, soil use.