Deep Tillage Effects on Compacted Surface‐Mined Land

Abstract

Federal law requires that surface‐mined prime farmland be reclaimed and restored to premining productivity for row crops (Surface Mining Control and Reclamation Act, Public Law 95–87). In Illinois, reclamation must include soil horizon replacement (topsoil and subsoil) to a depth of 120 cm. Poor physical condition is the most limiting factor in reclarmation in Illinois. The effects of five deep tillage implements (80–120‐cm tillage depth) and two standard agricultural chisel plows (20–35‐cm tillage depth) were evaluated for 6 yr. The seven tillage treatments were applied to a scraper‐placed minesoil that had a high soil strength (2.5–3.5 MPa) throughout the reconstructed profile. A nearby tract of undisturbed Cisne silt loam (fine, montmorillonitic, mesic Mollic Albaqualf) was used as a prime farmland comparison. Crop yields for both corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] significantly increased with tillage depth. Average soil strength decreased and net water extraction increased with increasing depth of tillage. The 1.2‐m‐deep tillage treatments significantly reduced average 23‐ to 114‐cm soil strength from 2.8 to 0.93 MPa. Significant correlation occurred between 23‐ to 114‐cm average soil strength and 6‐yr mean corn (−0.97** [significant at P = 0.01]) and 4‐yr mean soybean (−0.92**) yields. Deep tillage successfully restored productivity; however, the depth of tillage necessary was influenced by initial levels of soil strength.

Rowcrop Response to Topsoil Replacement on High Traffic vs Low Traffic Soil Reconstruction Systems

“…The effects of seven tillage treatments (Fig. 19) ranging in depth from 9 to 48 in) were evaluated on a reclaimed mine soil over a 6-year period in southern Illinois (Dunker et al, 1995). The mine soil consisted of 8 in of topsoil replaced over 42 in of scraper-placed rooting media.…”

High clay contents, dense soils, and spatial variability are the principal subsoil constraints to cropping the higher rainfall land in south-eastern Australia

“…Mechanical loosening of subsoils involves deep tillage, also known as deep ripping (Reeves and Touchton 1991;O'Sullivan 1992;Dunker et al 1995;Allen and Musick 2001;Wesley et al 2001) and subsoiling (Sojka et al 1990;Jasa and Dickey 1991;Reeves and Mullins 1995;Raper 2005). Interactions between soil and tine have been researched and known for the last 30 years (Godwin and Spoor 1977;Spoor and Godwin 1978) but the field application of ripping is highly varied and often without sufficient cognisance of the processes governing success.…”

Land degradation and water productivity in agricultural landscapes.

“…A decrease in porosity, with an associated increase in soil bulk density, induces an increase in the mechanical impedance of the soil, thereby limiting root proliferation (Oussible et al, 1992;Dunker et al, 1995). Based on field experiments using upland rice, Hasegawa and Kasubuchi (1993) illustrated the water extraction patterns of plants.…”