Cropping system partially offsets tillage-related degradation of soil organic carbon and aggregate properties in a 30-yr rainfed agroecosystem

• Tillage intensity increased soil organic C losses and risks of wind water erosion. Occluded POM was more management-sensitive in smaller than larger sized aggregates. Maximizing plant inputs via cropping system type partially mitigated negative tillage effects. Soil disturbance from N management limited mitigating effects system. increases the susceptibility agricultural soils to erosion carbon losses, but could be through other practices such as crop rotation. Here, we evaluated 30-year impacts on surface bulk density, nutrient availability, dry aggregate size distribution, water-stable aggregation. This study established 1980 eastern Nebraska USA, included six treatments varying (no-till, ridge till, disk subsoil rip, chisel plow, moldboard plow) four rotation (continuous soybean [ Glycine max (L.) Merr.]; soybean-corn Zea mays L.]; corn-soybean, continuous corn) a randomized block design with replicates. Surface were sampled 2011 properties assessed, including occluded particulate matter (oPOM) micro/macroaggregates (0.053–0.5 mm) mega-aggregates (>2.0 mm). Because significant treatment differences converted an equivalent mass (ESM) basis accurately assess After 30 years, only main for most measured properties. (SOC) stocks (ESM ∼0−30 cm depth) decreased intensity, higher when corn Dry distributions shifted towards classes whenever As result, mean weight diameter (mm) followed similar trend. also increasing intensity. In near-surface (0–7.5 cm), highly-erodible oPOM highest no-till sensitive (56–69% loss) mega-aggregate (5–35% loss). Even soils, concentrations under compared rotated systems likely due greater frequency fertility management-related disturbances (i.e. fertilizer injection annually vs every two years). These results suggest that maximize can mitigate long-term tillage, method application) limit effect