Surface and Subsurface Tillage Effects on Mine Soil Properties and Vegetative Response

Abstract

Core Ideas Mine soil physical properties improve with increased tillage upon reclamation in the Gulf Coastal Plain. Growth of loblolly pine seedlings increases with higher intensity tillage on reclaimed mined land. Aboveground herbaceous cover and biomass increases with tillage on reclaimed mined land. Soil compaction is an important concern for surface mine operations that require heavy equipment for land reclamation. Excessive use of rubber‐tired equipment, such as scraper pans, may cause mine soil compaction and hinder the success of revegetation efforts. However, information is limited on management strategies for ameliorating the potential compacting effects of scraper pans, particularly during site preparation for loblolly pine (Pinus taeda L.) plantations. Three forms of tillage and one control were replicated five times on surface mined land in the west Gulf Coastal Plain: no tillage (NT), disking (D), single‐ripping + disking (R+D), and cross‐ripping + disking (CR+D). Mine soil physical properties were investigated at 0 to 30, 30 to 60, and 60 to 90 cm. Percent cover and aboveground biomass of an herbaceous winter cover crop, and survival and growth of loblolly pine seedlings were assessed after one growing season. Herbaceous species biomass was highest on the R+D and CR+D plots and lowest on the NT control. Pine seedling survival was highest on the tilled plots (>90%) compared to NT (85%). The highest intensity combination tillage treatment (CR+D) was superior in terms of lowering soil bulk density (mean 1.36 Mg m–3) and soil strength (mean 2220 kPa) and increasing pine seedling volume index growth (mean 32 cm3). Surface tillage (D) alone improved herbaceous cover and pine seedling survival, while CR+D provided the most favorable responses in mine soil physical properties and vegetative growth.