Long-term effects of crop rotation and different fertilization systems on soil fertility and productivity

The effects of crop rotation and fertilization systems on yield and soil fertility parameters have been investigated in a long-term field trial established in southeast Norway in 1953. The results indicate the small differences between crop rotations and different fertilization systems in yield and soil fertility parameters; the decreasing trend in soil organic carbon (SOC) ( from 3.8 to 3.7%) and increasing trend of N with time ( from 0.32 to 0.36%) and, as a result, the decreasing trend in C/N ratio ( from 12 to 10).