Soil organic matter content after eleven years of no-till and plough

The organic matter content of the soil was analyzed on a medium textured slightly humic soil at the Inforama Rütti in Zollikofen which had been cultivated either with no-till or plough over eleven years. In several soil layers down to 40 cm the organic matter content as well as bulk density were analyzed. Due to differences in the soil density, the organic matter content was expressed as a proportion of the mineral soil material content rather than soil volume. After eleven experimental years no significant difference in the organic matter content of the two soils was found. However, there were considerable differences in the depth profile of the organic matter content of the two treatments. With no-till considerably higher contents were usually found in the top 10 cm layer, as compared to the plough treatment. This was compensated by mostly higher contents in lower layers (20 to 40 cm) of the plough tilled soil. Due to the more stable soil structure and the better water infiltration the no-till system can be considered an effective erosion prevention measure. As considerable quantities of organic matter are lost through run-off of the top soil layer a change to the no-till system in regions with high erosion risk (17 % of the tilled area in Switzerland) could lead to an increase of the organic matter content in the top soil layer. Furthermore, the no-till system could also contribute to a reduction of CO2 emissions thanks to savings in fuel and mineral N-fertilizers.