Re-vegetation of cover soils and coal discard material ameliorated with Class F fly ash

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Introduction

Agricultural and industrial activities have greatly accelerated the pace of soil degradation. The mining industry plays a major role in the South African economy, and can often contribute to certain environmental challenges, with respect to soil degradation. Three of the most common factors that characterize degraded substrates are, soil acidification, nutrient depletion and loss of biological activity. Many studies have been conducted to determine what measures can be taken to mitigate these problems, in agricultural lands. However, it has only recently been accepted world wide that there are other alkaline materials that are classified as industrial by-products, which can potentially serve the same purpose as the diminishing lime resources.

Cause and effect of degraded soils / substrates

Many soils are impacted by activities such as intensive agronomic practices or surface mining activities. These soils, or newly created substrates / growth mediums, are often inhospitable to vegetation due to a combination of physical, chemical and microbiological factors. Areas disturbed by mining are highly susceptible to erosion due to a lack of vegetation, steep slopes and the presence of fine, dispersed particles (Limpitlaw et al. 1997).

Soil amelioration

Liming of acidic soils is an ancient agricultural practice to ameliorate soil. Limestone (calcite, dolomite or a combination) is basically the main liming material used to date, with the infrequent use of quicklime, hydrated lime and by-products such as slag and gypsum (for sub-soil amelioration). Current levels of pollution mean that more lime is now required to offset acidification, but extensification is likely to result in a cessation or reduction of liming for economic reasons, while afforestation may result in increased acid deposition and acidification (Goulding and Blake, 1998;Truter, 2002).

Conclusion

Agricultural, municipal and industrial by-products are materials, which are rich sources of nutrients or organic material, and can be beneficially, utilized for crop production, to improve the physical, chemical or microbiological properties of soils or inert substrates. These materials can be co-utilized, or combined, so that the materials are more easily applied to land, or to provide a more complete/balanced nutrition, or enhance soil conditioning, economic, or environmental value of these individual by-products.

READ Spatial assessment of the contribution of subsoil P to crop P nutrition

Acknowledgements
Declaration
Abstract
CHAPTER 1: Literature review on the status quo of degraded soils / substrates as a result of mining activities or intensive agronomic practices, and the rehabilitation of such soils and substrates
Introduction
Cause and effect of degraded soils / substrates
Soil amelioration
Ameliorated soils effect on plant production aspects
Conclusion
References
CHAPTER 2: The utilization of class F fly ash, and co-utilization thereof with sewage sludge, to ameliorate degraded agricultural soils and to improve plant production
Abstract
Introduction
Methods
Statistical analyses
Results and Discussion
Biomass Production
Wheat (Triticum aestivum)
Maize (Zea mays)
Lucerne (Medicago sativa)
Soil chemical analyses
Conclusions
References
CHAPTER 3: The influence of a class F fly ash / sewage sludge mixture and class F fly ash on the physical and biological properties of degraded agricultural soils
Abstract
Introduction
Materials and Methods
Statistical Analyses
Results and Discussion
Soil Physical Analyses
Soil texture analysis
Bulk density
Infiltration rate
Hydraulic conductivity
Root biomass evaluation
Soil Microbiological analyses
Microbial activity
Rhizobium nodulation
Conclusion
References
CHAPTER 4: Reclaiming degraded mine soils and substrates with domestic and industrial by-products by improving soil chemical properties and subsequently enhancing plant growth: A greenhouse study
Abstract
Introduction
Experimental procedures
Statistical Analyses
Results and Discussion
Dry matter production
Root biomass study
Soil Analyses
Mine cover soil
AMD Impacted Soil
Gold mine tailings
Conclusion
References
CHAPTER 5 The beneficiation of degraded mine land using Class F fly ash and sewage sludge to ensure sustainable vegetation
Abstract
Introduction
Materials and Methods
Statistical Analyses
Results and Discussion
Vegetation analyses
Botanical composition
Basal cover
Dry matter production
Soil Analyses
Conclusion
References
CHAPTER 6: Re-vegetation of cover soils and coal discard material ameliorated with Class F fly ash
Abstract
Introduction
Materials and Methods
Statistical Analyses
Results and Discussion
Plant measurements
Soil Analyses
Conclusion
References
CHAPTER 7: Conclusion