Organic Waste as Fertilizer in Semi-Arid Soils and Restoration in Mine Sites

The use of organic waste such as tannery sludge which has high organic matter, N and P content, as organic fertilizer is suitable for improving soil fertility in semi-arid soils and for remediation of abandoned mine sites. Retention of heavy metals on fractional processes of organic matter cannot be generalized, it depends on the chemical characterization of organic waste and soil. Addition of tannery sludge containing high concentrations of Cr and carbonates to semi-arid soils resulted in an increase in Cr loss in infiltration and runoff after 6 months of incubation followed by simulated rainfall. Under these characteristics, results suggest that tannery sludge represents a potential ha ls amended with organic compost. Chemical characteristics of organic waste such as nitrogen content, humified organic matter, pH, EC, CEC, ESP (interchangeable sodium percent), and SAR (sodium absorption ratio) are important properties to consider in organic matter amendment to semi-arid soils participating on the complexity and leaching of heavy metals and nutrients in the matrix of soil

Soil microbial biomass and organic matter dynamics in metal-contaminated soils

A main aim of this thesis was to compare and evaluate different microbiological methods (total biomass or microbial activity) to detect effects of heavy metals on the functioning of the soil ecosystem. The biomass methods, which included biomass C, biomass ninhydrin-N, biomass N, ATP, substrate induced respiration and the activity methods, which included CO, evolution and arginine ammonification reliably detected effects of heavy metals on the soil microbial ecosystem in metal-contaminated soils from the Woburn Market Garden Experiment which contained, due to past sludge applications, Zn, Cu or Ni at around current European Union (EU) upper limits and Cd at around three times the limit. Most microbiological indices were decreased by up to about 50% in the most metal- contaminated soils and the results were comparatively simple to interpret. Many more problems were encountered when soils from a non-experimental site in Spain, polluted by heavy metals from past mining activity, and now containing heavy metals at up to 27 times current EU limits were examined. Huge variability, caused, for example, by site variations in soil organic C, soil texture, agricultural management and topography, were encountered. While the biomass methods and most measurements of microbial activity (except COj-C evolved) gave some indication of a negative response to increases soil metal concentrations, linked parameters e.g. biomass specific respiration or biomass as a percentage of soil organic C provided much more sensitive indicators of the effects of metals on the soil ecosystem. It was concluded that extrapolation from the field experiment to the natural environment, while difficult, is now a practical proposition

Soil microbial biomass and organic matter dynamics in metal-contaminated soils

A main aim of this thesis was to compare and evaluate different microbiological methods (total biomass or microbial activity) to detect effects of heavy metals on the functioning of the soil ecosystem. The biomass methods, which included biomass C, biomass ninhydrin-N, biomass N, ATP, substrate induced respiration and the activity methods, which included CO, evolution and arginine ammonification reliably detected effects of heavy metals on the soil microbial ecosystem in metal-contaminated soils from the Woburn Market Garden Experiment which contained, due to past sludge applications, Zn, Cu or Ni at around current European Union (EU) upper limits and Cd at around three times the limit. Most microbiological indices were decreased by up to about 50% in the most metal- contaminated soils and the results were comparatively simple to interpret. Many more problems were encountered when soils from a non-experimental site in Spain, polluted by heavy metals from past mining activity, and now containing heavy metals at up to 27 times current EU limits were examined. Huge variability, caused, for example, by site variations in soil organic C, soil texture, agricultural management and topography, were encountered. While the biomass methods and most measurements of microbial activity (except COj-C evolved) gave some indication of a negative response to increases soil metal concentrations, linked parameters e.g. biomass specific respiration or biomass as a percentage of soil organic C provided much more sensitive indicators of the effects of metals on the soil ecosystem. It was concluded that extrapolation from the field experiment to the natural environment, while difficult, is now a practical proposition

Symposium no. 59 Paper no. 642 Presentation: poster 642-1

world. Their beneficial effects can include increases in crop yields, soil organic matter, cation exchange capacity, water-holding capacity and fertility in general. High levels of nitrogen and phosphorus and micronutrients make it an excellent fertilizer. At present, information on the availability of nitrogen and other nutrients from sewage sludge to crops is limited

Conserved metallomics in two insect families evolving separately for a hundred million years

Μetal cofactors are required for enzymatic catalysis and structural stability of many proteins. Physiological metal requirements underpin the evolution of cellular and systemic regulatory mechanisms for metal uptake, storage and excretion. Considering the role of metal biology in animal evolution, this paper asks whether metal content is conserved between different fruit flies. A similar metal homeostasis was previously observed in Drosophilidae flies cultivated on the same larval medium. Each species accumulated in the order of 200 µg iron and zinc and approximately ten-fold less manganese and copper per gram dry weight of the adult insect. In this paper, data on the metal content in fourteen species of Tephritidae, which are major agricultural pests worldwide, are presented. These fruit flies can be polyphagous (e.g., Ceratitis capitata) or strictly monophagous (e.g., Bactrocera oleae) or oligophagous (e.g., Anastrepha grandis) and were maintained in the laboratory on five distinct diets based on olive oil, carrot, wheat bran, zucchini and molasses, respectively. The data indicate that overall metal content and distribution between the Tephritidae and Drosophilidae species was similar. Reduced metal concentration was observed in B. oleae. Feeding the polyphagous C. capitata with the diet of B. oleae resulted in a significant quantitative reduction of all metals. Thus, dietary components affect metal content in some Tephritidae. Nevertheless, although the evidence suggests some fruit fly species evolved preferences in the use or storage of particular metals, no metal concentration varied in order of magnitude between these two families of Diptera that evolved independently for over 100 million years.13 page(s