Soil properties currently limiting crop yields in Swedish agriculture – An analysis of 90 yield survey districts and 10 long-term field experiments

•Among manageable soil properties, soil pH and extractable soil P had the largest impact on Swedish crop yields.•Current recommendations on soil pH and soil P require upward adjustment.•Surprisingly, increasing soil organic matter (SOM) reduced yields, most probably due to lower pH in soils richer in SOM. This study evaluated yield statistics and data from a comprehensive national soil inventory representing 90 yield survey districts and from the Swedish long-term soil fertility experiments. The aim was to identify the most yield-limiting soil properties and best agronomic practices in order to further improve yield. Principal Component Analysis, multi-variate analysis, step-wise regression, and tree partitioning analysis identified the same variables affecting yields in the national and experimental datasets. Crop yields were significantly affected by soil pH, soil organic matter (SOM), plant-available soil phosphorus (P-AL) and mean annual temperature. Contents of plant-available potassium and magnesium in soil had no significant impact on yield, except in potatoes. Soil pH was found to have the greatest potential to affect crop yields, even at values >6.5 (pH(H2O)). Soil organic matter ranging from 3 to 6% in Swedish arable soils had an indirect negative effect on crop yields by lowering soil pH values with higher SOM content. To fully exploit the known benefits of SOM, liming requires more attention. One important finding was that current Swedish agricultural recommendations require updating. High-yielding crops demand more plant-available soil P and a range of 60−100 mg P-AL kg−1 soil is needed for sufficient P supply. A new target value of pH 7 for all crops except potatoes is recommended.