The drainage of restored opencast coal sites

Abstract. The soil conditions both before and after restoring opencast sites and their effect on drainage and crop growth are discussed both in general and with specific reference to the site concerned. Both drainage treatments showed a benefit over the undrained control, although no extra benefit was observed from drains at 20-m spacing with mole drains and subsoiling compared to drains at 40-m spacing with mole drains. Subsoiling reduced bulk density and increased surface infiltration rates, but improvements to the soil brought about by subsoiling were short-lived.     

Microbiology of soils at opencast coal sites. II. Population transformations occurring following land restoration and the influence of ryegrass/fertilizer amendments

Data from field work and pot experiments gave insight into transformations occurring in soil microbial populations at opencast coal sites during the first year of land restoration. Total bacterial biomass increased markedly immediately following restoration, while pot experiments revealed that this flush was confined to soil stored below 1 m depth in stockpiles, where anaerobic conditions develop. Fungal and actinomycete propagules declined at the outset of restoration, but rallied during the first year, while the bacterial flush subsided. Fungal hyphae, which accounted for 50% of microbial biomass in surface mound and freshly restored soils, accounted for > 99% one year after restoration. Experiments involving fertilizer and ryegrass amendments showed the biomass of restored soil to be limited by carbon, rather than nitrogen or phosphorus.     

Changes in the microbial community and physico-chemical characteristics of topsoils stockpiled during opencast mining

Abstract. Experiments on the effects of stockpiling soil on an opencast coal mine in Derbyshire showed that there were significant changes in the microbial community. Numbers of aerobic bacteria in stored soils ranged from 0.5 to 12.8 ± 10⁷ colony-forming-units (CFU)g^-1 with the smallest values being in the deepest parts of the oldest stores, whereas an adjacent undisturbed soil contained 6.6 ± 10⁷ CFU g^-1. There was a greater effect on the numbers of fungal spores, which ranged from 0.1 to 6.7 ± 10⁵ CFU g^-1 soil, all less than the 10 ± 10⁵ CFU g^-1 recorded for the undisturbed control soil. The number of fungal spores in the deepest part of the older soil stores was only 1/100 of the number in the undisturbed soil. This was mirrored by the biomass values, as determined by adenosine triphosphate (ATP) assay. Values of ATP ranged from 0.38 to 13.13 nmol g^-1 as compared to 5.8 nmol g^-1 in the undisturbed soil. All three of these microbiological properties decreased in value with both age and depth of storage. Neither anaerobic nor spore-forming bacterial numbers were greatly affected by storage.
The pH values tended toward neutrality in the deeper parts of the soil stores, and there was less organic matter in the older stores.     

Influence of wetlands and coal mining on stream water chemistry

Comparisons of stream water chemistry over a 2 yr period in East Fork, which drains an entirely forested watershed, and Big Run, which drains a forested watershed 8 % of which is occupied by Big Run Bog, indicated that Big Run Bog had no effect on stream water H⁺ or Cl^? concentrations, but with increasing stream discharge the wetland was a source of Ca⁺⁺ Mg⁺⁺, K⁺, Na⁺, NO₃ ^?, and SO₄ ^?, and a sink for Fe^{+ +}. Further comparisons with Tub Run, which drains a forested watershed, 13 and 12% of which is occupied by Tub Run Bog and an abandoned, unreclaimed coal surface mine, respectively, suggested that Tub Run Bog removes H⁺, Ca ++, Mg⁺⁺, Fe⁺⁺, and 50₄ ^? from inputs of acid mine drainage. Wetland areas on the landscape contribute to the regulation of stream water chemistry in ways that are different from upland areas, and wetlands may have considerable applied potential for minimizing the impact of the mine drainage on stream water quality.     

Chemical and biological characteristics of alkaline saline soils from the former Lake Texcoco as affected by artificial drainage

 Soils from the former Lake Texcoco are alkaline saline and were artificially drained and irrigated with sewage effluents since the late 1980s. Undrained soil and soil drained for 1, 5 and 8 years were sampled, characterized and incubated aerobically for 90 days at 22±1  °C while production of CO₂, available P and concentrations of NH₄ ⁺, NO₂ ^– and NO₃ ^– were monitored. Artificial drainage decreased pH_H2O, water holding capacity, organic C, total N, and Na⁺, K⁺, Mg²⁺, B, Cl^– and SO₄ ^2– concentrations, increased inorganic C and Ca²⁺ concentrations more than 5-fold while total P was not affected. Microbial biomass C decreased with increased length of drainage but bacteria, actinomycetes, denitrifiers and cellulose-utilizing bacteria tended to show opposite trends. CO₂ production was less in soils drained ≥5 years compared to undrained soil but more than in soils drained for 1 year. Emission of NH₃ was negligible and concentrations of NH₄ ⁺ remained constant over time in each soil. Nitrification, as witnessed by increases in NO₃ ^– concentrations, occurred in soil drained for 8 years. NO₂ ^– concentrations decreased in soils drained ≤1 year in the first 7 days of the incubation and remained constant thereafter. It was found that artificial drainage of soils from the former Lake Texcoco profoundly affected soil characteristics. Decreases in pH and Na⁺, K⁺, Cl^– and SO₄ ^2– concentrations made conditions more favourable for plant growth, although low concentrations of inorganic N and available P might be limiting factors. Received: 1 December 1999     

Release of cationic aluminium from acidic soils into drainage water and relationships with land use

The concentration of cationic monomeric aluminium (A1³⁺) was determined in streams draining areas in different land use. Relationships between the concentrations of A1³⁺ and companion ions were examined both for streams and for eluates from soil leached in the laboratory with simulated rainwater that ranged in pH and salt concentration. The concentrations of A1³⁺ were consistently greater in streams draining Sitka spruce woodland than in streams in adjacent catchments draining rough grazing. In no case was the A1³⁺ concentration governed by the solubility product of gibbsite. The concentrations of A1³⁺ were very closely correlated with excess anions (total inorganic anions minus basic cations) both for stream water and for eluates from soil leached with simulated rainwater at a constant pH equal to that of the soil (3.8). Exchangeable A1 was the source of A1³⁺ in leachates from soil in the laboratory and the displacement of exchangeable Al was the dominant process accounting for the levels of A1³⁺ in acidic streams. Hydrogen ions were much more important than basic cations in displacing exchangeable Al from the acidic soil used in the laboratory experiments and probably from soils in the field. The greater excess of inorganic anions in streams from Sitka spruce woodland probably resulted from a greater anion excess in the input water (acid rain) together with a greater NO, production in the soil. All three major anions, CI, SO₄ and NO₃ contributed to the greater anion excess.     

Using computed tomography images to characterize the effects of soil compaction resulting from large machinery on three-dimensional pore characteristics in an opencast coal mine dump

Journal of Soils and Sediments - The use of heavy machinery in mining areas increases during mining and dumping of waste soils, causing severe soil compaction and potentially affecting soil...     

Vegetation and pedogenesis on pyrogenic substrates of former peat soils

The role of vegetation and chemical factors in the development of the primary pedogenesis and evolution of pyrogenic formations resulting from fires on drained peat soils was studied. Over four years after the fire, a shallow (1 cm) humus horizon is formed on the surface of the ashy horizon of the pyrogenic formations. For six years, its thickness increases up to 3–4 cm. The dynamics and productivity of the plant cover on the pyrogenic formations were investigated. The dominant plant species were restricted to certain pyrogenic formations. The formation of stable phytocenoses and chemical transformation of substrates are the factors governing the primary pedogenesis on pyrogenic substrates. Four stages in the evolution of the pyrogenic formations were revealed. At the fourth stage, some features appeared that permit us to recognize the development of soddy soils on the pyrogenic substrates (i.e., soddy pyrogenic-mucky, soddy pyrogenic-sandy soils, etc.).     

辽宁阜新煤矸石山生长季的风况研究

采用野外观测与统计分析相结合的方法,对阜新市孙家湾煤矿矸石山不同坡向的风速变化进行研究.结果表明在整个生长季中,对于排矸年限相同的样地,阳坡的风速均大于阴坡;阳坡样地A的平均风速减弱系数比阴坡样地A低13.67%.风速由大到小的次序为5月＞6月＞7月＞9月＞8月.生长季盛行西南风和南风.     

Examining the relationship between coal mining subsidence and crop failure in plains with a high underground water table

Journal of Soils and Sediments - The underground mining of coal leads to land subsidence and changes agricultural land into a water-logged area. This study aims to examine the relationship between...     

Enzyme activities and microbial biomass in topsoil layer during spontaneous succession in spoil heaps after brown coal mining

Changes in the activity of extracellular enzymes (cellobiohydrolase, β-glucosidase, β-xylosidase, chitinase, arylsulfatase and phosphatases) and the changes in microbial community and abiotic properties in the topsoil layer, as well as soil abiotic properties during primary succession were investigated in a brown coal mine deposit area near Sokolov, Czech Republic. The study considered the chronosequence of 4 post-mining plots, 4-, 12-, 21- and 45-year old. The 4-year old site had no vegetation cover. Herbs and grasses (mainly Calamagrostis epigeios) were present on the 12-year old plot, shrubs (Salix caprea) occurred on the 21-year old plot and tree cover (Betula spp. and Populus tremuloides) developed on the 45-year old plot. Soil pH gradually decreased with site age, while the content of P, K, C and N peaked in the 21-year old site, being significantly lower in the 45-year old site and much lower in the 4- and 12-year old sites. Phosphatase activities were strongly affected by seasonality while the activities of all the other enzymes measured were more influenced by the effects of succession age and soil layer than by seasonality. Succession age was also the most important factor affecting the total and bacterial PLFA contents, followed by the effects of soil layer and season while for the fungal biomass content-related properties (ergosterol, fungal PLFA and the fungal/bacterial PLFA ratio), season was the most important. Activities of individual enzymes in the topsoil (0–5 cm depth) were significantly affected by both site age and season. Cellobiohydrolase and β-xylosidase were more affected by site age while chitinase and phosphatases were more affected by season. Enzyme activity increased with succession age. Comparison of the effect of site and season on enzyme activity showed that season played a principal role in the enzyme activity of the entire 0–5 cm component of topsoil, as well the soil layers when evaluated separately.     

Effects of afforestation on ammonification and nitrification rates in former agricultural soils

Abstract. The effects of afforestation on potential nitrification, nitrification and ammonification rates were studied at an experimental site in NE Scotland 4½ years after afforestation of former arable land. The site had been planted with three tree species (Sitka spruce, sycamore and hybrid larch) at three different planting densities, with half the plots treated with inorganic NPK fertilizer. Laboratory measurements of potential nitrification, nitrification and ammonification rates, measured using a perfusion system, were compared between the unforested control and combinations of the various treatments. Differences in soil pH and soil moisture content were also investigated.
Potential nitrification rates measured in plantation soils were significantly lower than in the unplanted control soil. Nitrification and ammonification rates were also consistently lower, although these differences were only significant in a few of the treatments. Soils planted with a normal tree density had a tendency to show higher nitrification rates compared to soils planted with a high tree density.
The results suggest that afforestation of former agricultural soils may cause changes in important parts of the soil N cycle soon after planting. At this early stage in the life of the plantation this appears to be unrelated to changes in soil pH or moisture content, even though soils beneath the trees are drier. The apparent change may be the result of differences in the soil microbial community associated with the type of organic matter substrate present in the unplanted and planted soils.     

Degradation of ‘reclaimed’ lands previously disturbed by coal mining in Wales: Causes and remedies

Large tracts of land, officially described as ‘reclaimed’ from former mineral workings, are in poor condition. Problems include gullying, soil erosion, soil compaction, accelerated run-off and poor vegetation cover. Some of these problems are caused by low quality and inappropriate engineering. Some are due to poor land husbandry. There is a need for a national system of quality control inspection for land reclamation sites and provision for training in the special problems of managing reclaimed lands. However, many further problems result from natural soil-forming processes, notably the accelerated breakdown of newly exposed minestones. This chokes the soils with fine particles, decreasing permeability and increasing bulk density. Current research directed to correcting this problem uses trees to build new self-sustaining soils from the ground up and to promote the development of a large and active community of soil organisms. It is hoped that the polysaccharide secretions of these organisms will bind the newly created clays into stable soil aggregates.     

Spatial variability and sampling of cyanide polluted soil on former galvanic factory premises

Former galvanic factory premises are often heavily contaminated with cyanide, requiring redevelopment of the soil. In this study attention is focused on one particular site in the Netherlands. In an area of 0.8 ha 344 observations were taken at different depths in the upper 3 m of soil. Three different procedures based on spatial variability studies are compared to calculate the extent of polluted soil as well as the uncertainties associated with it on the basis of this number of observations. As it turns out, a more evenly distributed data configuration results in a reduction of the extent of soil to be redeveloped when the decision procedure involved is based on the probability of exceeding a critical concentration level. Hence a small but structural reduction of the associated costs was achieved.     

Laboratory mesocosm studies of Fe,Al, Mn,Ca, and Mg dynamics in wetlands exposed to synthetic acid coal mine drainage

To evaluate the potential for constructed wetlands to treat acid coal mine drainage, six model wetland mesocosms (each 2.4 m × 15 cm) were filled with Sphagnum peat (15 cm deep), planted either with cattails (Typha latifolia) and living Sphagnum, living Sphagnum only, or left as bare peat (2 mesocosms per treatment). The model wetlands were exposed to synthetic acid coal mine drainage (pH 3.5, concentrations of Fe²⁺, Al³⁺, Mn^2*, Ca²⁺, and Mg²⁺ of 78.8, 10.0, 5.2, 12.0, and 4.5 mg L^?1, respectively) at a rate of 90 mL min^?1, 6 hr d^?1, 5 d wk^?1, over a 16 week period. Chemical analysis of peat at periodic intervals indicated that the model wetlands were net sources of Al³⁺, Mn²⁺ Ca²⁺ and Mg²⁺, but net sinks for Fe²⁺. Type of vegetation had no significant effect on Fe²⁺ retention; of the 204 g of Fe²⁺ added to the model wetland systems, 162 g were retained. Formation of Fe oxides accounted for 73 to 86% of the Fee' retention, with exchangeable Fe contributing 0.2 to 1.2%, organically bound Fe contributing 4 to 19%, and residual Fe contributing 7 to 15% of total Fee' retention. Fe retention was greatest at the inflow ends of the model wetlands where Fe retention appeared to reach saturation at a final Fe concentration in the peat of 235 mg g^?1. At the rate of application of the synthetic acid mine drainage, we estimated that the model wetland systems would have reached complete Fe saturation after 157 days. We suggest that the mesocosm approach could be useful in generating site-specific data that can be applied to the formulation of cost-benefit analyses that can compare a proposed wetland treatment system with alternative conventional chemical methods for treating acid mine drainage.     

Lignite mining and its after-effects on the Central German landscape

Lignite mining, which has been pursued in Central Germany for 150 years, has left deep scars on the landscape on an area of over 600 km². The open-cast mines set up to extract lignite, along with the dumps and pits arising during the course of mining activities, have resulted in a completely new landscape, the external appearance and abiotic factors of which differ from the developed, cultivated landscapes outside the mining areas. Dumps and slope faces are reclaimed on the basis of specific approaches, while pits are flooded to create strip mine lakes. Soil and water have developed in conformity with their own natural laws, knowledge of which is indispensable for recultivation. The development of new post-mining landscapes above all chiefly determined by ecological standards.     

Impact of soil stockpiling and mining rehabilitation on earthworm communities

As key ‘ecosystem engineers’, earthworms improve mineralization of organic matter, plant growth, soil quality, and are an important component of many terrestrial food webs. Under appropriate conditions, they are therefore likely to accelerate the restoration of soil ecosystem function after mining.Conserving naturally occurring populations and facilitating their recolonisation appears as the most efficient way to increase earthworms’ overall effect. The impact of mining activities and restoration measures on New Zealand endemic earthworm communities was tested. Earthworm biomass and diversity were compared in four different habitat types.Mining activities, not surprisingly, are shown here to have a detrimental impact on earthworm communities. Soil stockpiling induces anaerobic conditions at and below a depth of 1 m, where earthworms do not survive. The use of stockpiled soil for vegetation replanting therefore leads to low diversity and low abundance of earthworms. An alternative restoration technique consisting in transferring vegetation and soil units (the vegetation direct transfer) was efficient in preserving earthworm populations with earthworm biomass and diversity not significantly different from those observed in undisturbed areas. Based on these results, we recommend vegetation direct transfer (VDT) to be prioritised whenever it is logistically and economically feasible. When VDT is not applicable, low stockpiles should be prioritised as they will comprise a higher proportion of good quality soil (at the surface) and a lower proportion of anaerobic and compacted soil (below 1 m depth at the studied site).     

Effects of parent material and land use on soil erodibility

The objective of the present investigation was to find out the effect of different parent materials and land use on soil erodibility. Four types of parent materials such as andesite, basalt, alluvial, and gypsum, and three land use types such as grass, clover, and maize, all wide spread in Erzurum Province in Turkey, were tested. Aggregate stability and soil erodibility factors were determined. The susceptibility of soils against erosion decreased in the order of parent materials basalt > andesite > alluvial > gypsum. Likewise, the susceptibility of land use can be sorted as follows: grass > clover > maize.     

Influence of former cultivation on the unique Mediterranean steppe of France and consequences for conservation management

In Europe, the actual landscape has been mainly influenced by human activities. Agricultural intensification led to a considerable habitat loss and fragmentation, especially for dry semi-natural grasslands.This current study investigates the impact of former melon and cereal cultivation (cultivation period: 1950-1987) on the semi-natural vegetation of the Crau, representing the last xeric Mediterranean steppe in France.Today, the ex-cultivated melon and cereal fields are characterised by different vegetation compositions, species richness and evenness compared to the undisturbed steppe community. Also the abiotic conditions (N, P, K, pH, soil granule fractions) have been changed by former cultivation practices. The rather transient seed bank of the steppe was depleted during the cultivation periods; ancient weed species and ruderals now determine the seed bank of the ex-cultivated fields.It is concluded that the conservation of the last parts of undisturbed steppe must have absolute priority. A re-development of the original and unique steppe community on formerly cultivated fields may take decades or centuries, if at all.