Modern silvoarable agroforestry systems have diverse environmental benefits, and are listed as an efficient measure to increase soil organic carbon (SOC) stocks. However, detailed information of these systems on SOC accumulation, soil organisms and nutrient availability under the local conditions in Switzerland is scarce. In this study we determined these properties in a 13-years old silvoarable agroforestry system in Sursee (Canton of Lucerne). Soil samples were collected on the tree strip and at three different distances on the arable strip using a transect-sampling design (0-0.8m soil depth, 32 soil cores in total). We estimated a mean annual SOC accumulation rate of 0.20 ± 0.08 Mg ha-1 yr-1 in this system, mostly by increases in SOC within the tree strip. These values are low compared to the few existing estimates reported in our pedoclimatic zone. We further discuss the plant availability of nitrogen and phosphorus, their storage in soil microorganisms and the enzyme activities involved in C-, N- and P-cycling.