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Harbor and ship channel maintenance dredging by the Maryland Port Administration has historically presented a dredge disposal and utilization challenge due to metals and the potential acidity of their sediments. Post-placement low pH (

Significant areas of prime farmland in the upper Coastal Plain of Virginia have been disturbed by heavy mineral sands (Ti/Zr-bearing ilmenite, rutile, zircon) mining over the past 15 years. Mine soils created by the deposition of tailings and slimes in dewatering pits exhibit physical and chemical properties that limit agricultural use due to abrupt textural changes, heavy compaction from grading and the inherently low pH and available P of the processed subsoils. In 2004, the Carraway-Winn Reclamation Research Farm (CWRRF) was developed with Iluka Resources Inc. in Dinwiddie County to evaluate reconstruction strategies for returning mined land to agricultural production. In 2004, row crop plots were established in a randomized complete block design with 4 replications of 4 treatments: 1) LBS-CT - lime-stabilized biosolids (78 dry Mg ha -1 ) with conventional tillage, 2) LBS-NT - lime-stabilized biosolids (78 dry Mg ha -1 ) with no tillage, 3) TS - 15 cm of topsoil replacement with lime+NPK, and 4) C - control (tailings+lime+NPK). All treatments were deep ripped to 90 cm following grading and limed and fertilized annually to optimal levels. Two additional study sites, managed similarly to the treatment plots, included a compacted (no ripping) area (COMP) and a nearby unmined prime farmland (Orangeburg series) field (UM). Between 2005 and 2008, the plots were managed with a corn-wheat/double crop soybean rotation. In 2009, the plots were managed with cotton and in 2010 with wheat/double crop soybeans. During the initial four year corn-wheat/double crop soybean rotation, the two LBS treatments produced significantly higher yields than the TS or C treatments. No significant differences were observed among treatments for the 2009 cotton yield; however, erratically distributed settlement depressions adversely affected crop growth and harvest and led to high variability within each treatment. Similarly, no significant differences were observed for the 2010 wheat and soybean yields in a low rainfall year. Overall, yields from all four treatments typically exceeded 5-year local county averages, but were 25 to 40% lower than yields from the local prime farmland soil under identical management. Relatively low COMP yields illustrated the need for initial deep ripping and periodic tillage to improve physical conditions of these mine soils.

Crop establishment on saline-source fine textured dredged materials is challenging due to the adverse physical properties of the material (e.g. fine texture and lack of structure) and short-term salinity. Two approaches to improve crop establishment and soil properties on such dredged materials on an upland deposition site in Virginia were tested: (1) a topsoil cap plus fertilizer (approximately 20 cm; TS) and (2) incorporation of 30% sand by volume into the surface plus fertilizer (30%S). Each treatment was compared to a Control where only fertilizer was added based on soil fertility testing. A greenhouse study was initiated prior to the installation of field experimental plots. In the greenhouse study, German millet (Setaria Italica L.) yields and average plant height from highest to lowest were Control > TS > 30%S after three months. Large aggregation (250-8000 μm) was highest on the Control (68-70% total soil) followed by the TS (56%) and 30%S (48%) treatments; however, salinity was also higher on the Control treatment vs. the other two. The field experiment was installed in the spring of 2009 with an additional compost treatment added to the plots in splits. Plots were seeded to German millet in May 2009 and no-till drilled to Triticum aestivum (winter wheat) in October 2009. Weed control and a second application of N fertilizer in the spring of 2010 were impossible due to extremely wet soil conditions; therefore, only total biomass (wheat+weeds) data are presented for 2010. Millet yields (4382 kg ha -1 ) and total biomass (4319 kg ha -1 ) were higher on the 30%S treatments followed by the Control and TS treatments. Large aggregation was higher in the Control (70-80% total soil) than the 30%S (40-60%) and TS (20-30%) treatments in 2009 and 2010. Salinity declined with time across all treatments with suitable levels for crop production attained in the amended plots (30%S and TS). Compost additions stimulated microbial biomass and soil C concentrations, but did not significantly increase crop yields or aggregate formation relative to the non-compost treatment. Overall, yields and soil salinity were significantly improved when 30% sand by volume was incorporated into the dredge sediment, making this a feasible remediation strategy in the short-term, provided it is cost-effective.

Physical and biological properties of soils developing from spoil material following surface coal mining in southwest Virginia are poorly understood. Additionally, the effects of various types of soil amendments such as sawdust, topsoil or biosolids on long-term soil development are lacking in the current literature. The objective of this study was to examine water stable aggregation, organic matter (OM) content and microbial biomass in a long-term experiment (27 yr) where various types (control-CON, topsoil-TS, sawdust-SD, and biosolids-B) and rates of soil amendments (biosolids: B-22, B-56, B-112 and B-224 Mg ha -1 ) were applied in 1982. Treatments were replicated four times in a randomized complete block design. Small macroaggregates (250-2000 μm) were higher on the B-224 rate plots compared to other treatments, while there were no differences in large macroaggregates (2000-8000 μm) or microaggregates (53-250 μm) among treatments. Aggregate associated OM, as indicated by carbon (C) and nitrogen (N) concentrations, was highly variable among treatments. Biosolids treatments were clearly higher in total aggregate C and N relative to the CON, TS, and SD treatments; however, these differences were not significant for each aggregate size class due to the variability observed among replicates. There were no significant differences in aggregate C and N among biosolids application rates after 27 years of soil development. However, microbial biomass C was higher in all biosolids treatments compared to the CON, TS, and SD treatments and was slightly higher on the B-56 treatments relative to other biosolids treatments. Despite the large variability in soil development observed in these relatively small research plots, higher rates of biosolids amendments slightly improved macroaggregate structure while application rates between 22 and 56 Mg ha -1 appeared to improve aggregate associated C and N concentrations and soil biological properties.

It is well known that soil microbial communities reestablish following disturbance, but limited research has been done on how long this takes in eastern reclaimed coal mine soils. The objective of this study was to track the development of total microbial biomass in reclaimed mine soils following coal mining in southwestern Virginia. A chronosequence of sites was established based on locally documented shifts in vegetation species with succession (0-2, 5-7, 18-20, and 38-42 yr old) on reclaimed sites with undisturbed adjacent sites used as a reference. The 0-2 yr old sites were covered with annual and perennial grasses and forbs, the 5-7 yr sites by thick stands of Lespedeza cuneata, the 18-20 yr sites predominately with Festuca arundinaceae and patches of deciduous trees, and the 38-42 yr old sites with a mix of planted conifers and native Appalachian hardwoods with a grass understory. Undisturbed sites predominately supported mixed Appalachian hardwoods with a mixed forb/grass understory. Four samples were taken from each site age (3 replicates) at the 0-5 cm depth. Chloroform-fumigation- extraction was used to determine total organic carbon from lysed microbial cells as a proxy for microbial biomass. Microbial biomass carbon (MBC) did not vary significantly among any of the site ages sampled; however, a general trend of increasing MBC from a low level in the more recently reclaimed sites (131-138 g microbial C kg -1 soil) to a higher level of MBC in the 16-20 and 38-42 yr sites (280 and 244 g microbial C kg -1 soil, respectively) was observed. This indicated a recovery of soil microbial communities with time; possibly well within the 5-year vegetation liability release period mandated by the Surface Mining Control and Reclamation Act (SMCRA).

The ultimate goal of mineland reclamation is reestablishment of a productive, functional, and sustainable ecosystem suitable for postmining land use. Evaluation of reclamation success for bond release, however, is limited to examination of the reestablished plant community with emphasis also placed on soil erosion protection and landscape hydrologic function. Most ecosystem components and processes of the reclaimed site are not examined but are crucial to ecosystem function and sustainability. The objective of this paper is to present data from our work on recovery of ecosystem structure (e.g. organisms, soils, mycorrhiza) and function (e.g. biomass production, carbon cycling, nitrogen cycling) on reclaimed surface coal mines in Wyoming. Our studies of chronosequences of reclaimed sites indicate increasing productivity through time in all groups of organisms monitored (plants, bacteria, fungi, nematodes and arthropods) as well as increasing concentrations of soil organic matter, rapid incorporation of organic carbon into soil aggregates, redevelopment of mycorrhizae, and reformation of carbon and nitrogen pools. Although the precise trajectory of the restored ecosystems are very difficult to predict because of changing control variables such as potential biota (invasive species) and climate, our data indicates ecosystem structure and function is recovering on reclaimed surface minelands.

Particulate organic matter (POM) and aggregate recovery following mining disturbances are important for soil biogeochemical properties and ecosystem function. The objective of this study was to track POM accumulation and aggregation in reclaimed soils following coal mining in southwestern Virginia. A chronosequence of sites was selected based on shifts in vegetation communities with succession, typically occurring between 0-2, 5-7, 16-20, and 38-42 years since reclamation. Undisturbed adjacent forested sites were also sampled. The 0-2 yr old sites were covered with grasses and forbs, the 5-7 yr sites by thick stands of Lespedeza cuneata, the 16-20 yr sites predominately with Festuca arundinaceae and patches of deciduous trees (Acer rubrum, Oydendrum arborea, etc.) and the 38-42 yr old sites with a mix of Pinus taeda and deciduous forest with a grass understory. Undisturbed sites predominantly supported mixed Appalachian deciduous forest. Available POM (inter-aggregate) and physically protected (intra-aggregate) forms were determined using a density flotation technique and aggregate size distribution with wet sieving. Inter-aggregate POM did not change across site ages; however, intra-aggregate POM increased significantly between the 5-7 and 16-20 yr old sites and remained unchanged through the 38-42 yr old reclaimed site. Inter-aggregate POM reached levels similar to undisturbed sites, while intra-aggregate POM weights were almost threefold that of undisturbed sites after 16-20 years. By observing just the available POM, we would conclude that reclaimed systems recover to an protected POM, reclaimed system POM storage greatly exceeded undisturbed soil conditions. A positive relationship was observed between small macroaggregates (250-2000 μm) and intra-aggregate POM, suggesting that protection of POM by small macroaggregates in reclaimed systems is extremely important for POM accumulation and subsequently ecosystem function within a period of 20 years. We can also argue the greatest rates of POM accumulation and aggregate formation occur under early succession communities with grasses and forbs rather than under late succession forested communities.

Evaluation of reclamation success on surface mined lands is based primarily on surface topography reconstruction, characteristics of the reestablished plant community, and soil erosion protection. Restoration of ecosystem functions such as nutrient cycling, organic matter decomposition, soil development, and community dynamics are not directly examined but are assumed to be recovering to the degree that the system will be self sustaining and resilient to environmental stress. Obviously, there are important differences and similarities in the goals of ecosystem restoration and mineland reclamation. We have been collecting data on recovery of ecosystem processeses in reclaimed minelands and adjacent undisturbed sites (reference areas) for almost ten years. This paper reports results of our findings on recovery of ecosystem functions on reclaimed surface mined lands and relates characteristics of successfully reclaimed surface mined land to attributes of restored ecosystems.

Evaluation of mine reclamation success is based on examination of aboveground ecosystem components. Recovery of belowground constituents and processes, such as soil structure and nutrient cycling, is crucial to successful reclamation of disturbed lands. Inadequate recovery of belowground ecosystem structure and function during reclamation can lead to future site degradation. Our objective in this study was to test the hypothesis that recovery of plant community properties on reclaimed surface mine land accurately reflect recovery of soil structure, more specifically aggregate size distribution. In this study, above- and belowground constituents were sampled on reclaimed mine sites representing various ages (native rangeland, a 4 month old topsoil stockpile, 14, 26, and 29 year old reclamation) located in northeastern Wyoming. Cool-season grass (native and reclaimed) communities were sampled for aboveground biomass production, cover and species diversity according to Wyoming Department of Environmental Quality standards. Soil samples were analyzed for water stable aggregate size distribution with wet sieving. Soil structure appears to be recovering through time. An increase in macroaggregates (250-2000µm) on a weight basis and a decrease in free microaggregates (53-250 µm) and free silt and clay (

Revegetation of mined lands in North Dakota is challenging because of the poor physiochemical properties of the spoil material as well as the semi- arid climate. Topsoil and subsoil replacement is a successful method used to establish productive and diverse plant communities. Previous studies conducted by Merrill et al. (1998) and Power et al. (1981) determined adequate soil depth for optimal vegetation productivity during six years of study on soil wedges in Zap and Stanton, ND. Re-sampling of these sites in 2003 documented long-term effects of soil depth and other soil characteristics on plant community development. Results of the 2003 study differed from results of past studies. At the Zap, ND Double Soil Wedge (ZSW) in 2003, the highest vegetation production occurred on 40 to 120 cm of total soil depth and the highest species diversity occurred on the alfalfa (Medicago sativa) vegetation plots with 0 to 40 cm of total soil depth. In the previous study, the highest production occurred on 51 to 110 cm of total soil depth. At the Stanton, ND Soil Wedge (SSW) in 2003, the highest production occurred on 65 to 120 cm of total soil depth. In the previous study, the highest production occurred on 92 to 132 cm of total soil depth. Changes through time in soil characteristics at the ZSW and SSW sites were similar. Electrical conductivity (EC) was lower in 2003 compared to 1979 and increased with depth in 2003. pH was higher in 2003 compared to 1979 and also increased with depth in 2003. There was a weak correlation between total soil depth and plant community development after 30 years of establishment compared to a strong correlation observed after six years of vegetation establishment in the previous studies.