Soil physical properties following conversion of a reclaimed minesoil to bioenergy crop production

Abstract

Land use, soil management and vegetation play important roles in restoration of reclaimed minesoils (RMS). There is a growing interest in converting marginal lands to bioenergy crop production instead of using highly fertile soils, which could jeopardize food security and soil quality. The objective of this study was to assess short-term changes of soil physical and hydrological properties after converting a RMS that was under meadow to miscanthus (Miscanthus giganteus) and corn (Zea mays L.) land-uses in Southeast Ohio. The study site was surface-mined for coal and lime, reclaimed and seeded with cool season grass and legume species mixture in 1986. The site remained under meadow land use until the establishment of this study in 2013. The results showed that bulk density (ρb) of the 0–10 cm soil depth (soil surface) under miscanthus and corn (1.28 and 1.25 Mg m−3) increased on average by 9% following conversion of meadow to miscanthus and corn land-uses, compared to the antecedent meadow (1.16 Mg m−3). There were no significant differences in ρb of soil below 20 cm depth, which was >1.5 Mg m−3. Decrease in soil aggregation was also observed at the soil surface after land-use change. The mean weight diameter (MWD) of water stable aggregates was 2.00 mm under the meadow land use, which was significantly lower under the corn (1.45 mm) and miscanthus (0.96 mm) land uses. Subsequently, water infiltration rate decreased by 50% in the miscanthus and corn land-uses compared to the meadow (0.23 cm min−1). Additionally, plant-available water capacity (P-AWC) also decreased by 28% in the miscanthus and corn land-uses compared to the meadow (2.5 cm) at the top 10 cm depth. The data show significant changes in some sensitive soil physical properties within a short period of one year upon converting from reclaimed meadow to miscanthus and corn land-uses, suggesting that disturbances associated with land use change have negative impact on soil properties and soil quality.