Physical Properties of Constructed and Undisturbed Soils

Abstract

There is a growing impetus to use soil properties to determine if reclamation efforts are adequate to restore productivity. Constructed mine soils were studied 4 and 11 yr after reclamation to determine physical and hydrological properties. Soils constructed using similar methods and with similar vegetation histories were compared to each other and to an equivalent undisturbed soil. Bulk density was greater in the topsoil and subsoil materials of the constructed soils than in the undisturbed A and B soil horizons. Macropore volume (pore radii > 15 µm) was greater in the topsoil and subsoil materials at the 11‐yr site relative to the 4‐yr site but was significantly lower than that in the undisturbed soil. Small pore volume (pore radii from 4.5 to 0.1 µm) in the reclaimed topsoil materials was similar to the undisturbed A horizon soil but was larger in reclaimed subsoil materials than in the undisturbed B horizon. Saturated hydraulic conductivity (Ks) of the reclaimed topsoil was about 25% that of the undisturbed A horizons and the reclaimed subsoil Ks was less than 10% that of the undisturbed B horizon. The reduction in Ks was attributed to the increase in bulk density and disruption of soil structural units and associated interpedal pore spaces during mining and soil construction. No significant differences in Ks were found between constructed minesoils 4 and 11 yr after reclamation. The results of this study show that soil properties may be useful for evaluating reclamation success after soil construction.

Infiltration Rate of a Sandy Loam Soil: Effects of Traffic, Tillage, and Plant Roots

“…Large differences were also measured by Potter et al (1988), who found that the hydraulic conductivity of disturbed soil was 25% in the topsoil and 10% in the subsoil, compared with the undisturbed soil. The relationship between bulk density and infiltration was measured in two experiments as part of this study.…”

Mountaintop Removal Mining and Catchment Hydrology

“…Minesoils [80] are heavily compacted soils with high bulk density and low porosity near the soil surface [72,81,82]. But due to the presence of large rock fragments [83], porosity may increase with depth [80,84]. Excessive surface compaction limits root penetration and growth [78,85] and lowers the available water holding capacity [82,86].…”

Simulation of soil water content on a small reclaimed watershed in northern Alberta using the Root Zone Water Quality Model (RZQWM)

“…However, reconstructed soil profiles do not resemble profiles under normal evolutionary development. Reclaimed soils often have poor soil structure and hydraulic properties compared with undisturbed soils because of soil compaction by machinery used in soil placement and grading (Bussler et al 1984;Potter et al 1988;Bell et al 1994). This lack of well-formed structure affects the degree to which oxygen, water and nutrients flow through the soil.…”

“…This lack of well-formed structure affects the degree to which oxygen, water and nutrients flow through the soil. Therefore the dynamics of soil water may become affected as a result of alteration of soil structure and horizons following reclamation (Potter et al 1988). For example, in Alberta the Syncrude Ltd. standard practice during reclamation is to place overburden material such as tailing sands at the bottom and then add topsoil, which may sometimes contain peat materials (Leskiw and Moskal 1997).…”