Reconstructing Soil After Simulated Surface Mining with Minimal Traffic*

Abstract

Federal law requires restoration of surface-mined prime farmland to original productivity. Thus, excessive soil compaction by heavy machinery during reconstruction is problematic. Fulton et al. (2002) described a mechanical system capable of reconstructing severely disturbed soil without exposing the soil to any machine traffic. This system was modified to improve productivity and tested by fully excavating and reconstructing approximately 0.6 ha of clay loam subsoil and silt loam topsoil in 2007. The mean deviation from prescribed surface elevation of reconstructed soil was 1.75 cm. The mean soil reconstruction rate was 641.3 m3/hr, equivalent to 0.05 ha/hr constructed 1.2 m deep. Soil cone index was measured in March 2008 and March 2009 and dry bulk density was measured in March 2008, November 2008 and March 2009, with both measurements taken at 5 cm depth increments between 10 and 60 cm. Mean cone index varied from approximately 038 to 0.70 MPa in March 2008 and from 0.70 to 1.20 MPa in March 2009. Mean dry soil bulk density varied from approximately 1.17 to 1.33 Mg/m3 in March 2008, from 1.42 to 1.60 Mg/m3 in March 2009. These results indicate that physical properties consistent with successful row crop production can be achieved with reconstructed soil. A 3-year study to compare corn yield to pre-disturbance measurements for this site was initiated in 2009.