SLU long-term field experiments: Soil organic matter in a cereal only cropping system (R3-0020), crop and soil data...

The R3-0020 agricultural long-term field experiments investigate the effect of nitrogen addition levels and straw removal on crop yield and soil properties. The field experiments are located at the Swedish University of Agricultural Sciences (SLU) four field research stations: Lönnstorp (Lund), Lanna (Skara), Säby (Uppsala) and Röbäcksdalen (Umeå). The field site in Säby has been maintained since 1970 and the three other sites since 1980. The experiments consist of a cereal only crop rotation, a crop residue treatment (straw removed or incorporated to the soil) and four nitrogen fertilization levels (0, 50, 100 and 150 kg N ha^-1 yr^-1). Aboveground crop biomass has been collected annually since the beginning of the experiments (Fig. 1), while topsoil samples were collected 2-8 times in the first 10-20 years and every four year since the 90 s (Fig. 2). We report crop yields and nutrient content for grain and straw, as well as carbon and macronutrient content for soils. The data presented here provides a useful time series for investigating the impacts of cereal-only crop rotation, straw removal and nitrogen fertilization levels on soil organic carbon and yield.