Tillage effects on quality of organic and mineral soils under on-farm conditions in Ohio

Assessment of management-induced changes in soil quality is important for sustaining crop yield. The purpose of conducting on-farm field research is to come up with fact-based answers to farming's challenging questions and this type of research targets "real-world" data. However, research information on impacts of tillage on organic (muck) soils is scanty, and underlying processes of management-induced changes in soil characteristics are poorly understood. In addition, data are scarce on impacts of immediate short-term tillage on historically no-tilled mineral soils. Thus, the objectives of this research are to evaluate impacts of (1) long-term conventional tillage (CT) on organic or muck (Mc) soil compared to non-cropped no-till (NT) condition and (2) short-term CT on mineral (CrB) soil, which has been under NT management under corn. All monitored soil properties were significantly affected by soil type. Compared to CrB, Mc had 6.4 and 5 times higher soil organic carbon (SOC) and nitrogen (N) concentrations, respectively for all sampling depths. Long-term tillage had no impact on Mc probably due to its porous nature, weak structure and high organic matter content. In the mineral soil, short-term CT significantly affected bulk density (BD), water-stable aggregates (WSA), and available water capacity (AWC), especially, in the surface (0-10 cm) layer. The BD was reduced by CT for CrB by up to 14 % (NT 1.6 Mg m(-3)), compared to NT. Residue incorporation in the plow layer under CT (similar to 20 cm) may have increased aggregation by up to 19 % (70-83 %) and SOC by up to 15 % (2-2.3 %) in CrB compared with that under NT (total aggregation 70 %, SOC 2 %). The data of this study demonstrate that (1) selected muck soil had significantly improved soil properties (higher WSA, AWC, SOC and N, and lower BD and penetration resistance) than those of the studied mineral soil, (2) long-term tillage did not affect the properties of the native muck soil, and (3) surface layer of the long-term no-tilled mineral soil was significantly affected by introduction of only 1 year of CT management.