Soil chemical properties as affected by tillage and crop rotation in a long-term field experiment

Long-term field experiments are important for explaining tillage and rotation effects on soil fertility and to develop sustainable nutrient management strategies. An experiment was established in 1996 in Raasdorf (Austria) on chernozem with four tillage treatments (mouldboard ploughing (MP); no-till; deep conservation tillage and shallow conservation tillage) and two crop rotations. Soil samples were taken in November 2003 from 10 cm soil layers down to 40 cm to assess the effects on pH, carbonate content (CaCO3), soil organic carbon (SOC), total nitrogen (Nt), potentially mineralizable N (PMN) and plant-available phosphorus (P) and potassium (K). Soil pH and CaCO3 were not affected by soil tillage. SOC, Nt, PMN, P and K increased in the uppermost soil layer with reduced tillage intensity. SOC, Nt, P and K were more evenly distributed in MP whereas a generally higher decline downwards the soil profile was observed with lower tillage intensity. Lower tillage intensity resulted in a decrease of P and K in 30-40 cm. Rotation affected pH and K distribution in the soil whereas the other parameters were not affected.