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Artificial soils have been employed within the Biomes of the Eden Project since its construction in 2000. Produced from sand, bark, composted green waste and lignite clay, these soils were designed to have their nutrient concentrations controlled through careful fertiliser applications. However, following variable environmental conditions, management practices and planting, the soils across the site are performing variably with regard to nutrient retention and storage. Experiments were conducted to assess the performances of an artificial soil in terms of nutrient cycling. This was carried out in three phases: Firstly, soils from the Humid Tropics and Outdoor biomes were sampled and examined, using a range of analytical techniques, to determine the nutrient characteristics of the established artificial soils from across the Eden Project site. This demonstrated that many of the nutrient concentrations of the artificial soils were consistent with those reported for naturally formed soils within comparable environments. All soil samples were of sandy loam texture (ISO 14688-1), with the sand-sized fraction representing > 50 % of the particle size composition. Statistical analyses suggested that management practices had a greater impact on the nutrient characteristics of artificial soils than environmental conditions. Secondly, an artificial soil was produced, following the Eden Project protocol, to examine its performance under controlled environmental conditions. This was packed into 4 columns (1 m height by 110 mm diameter), maintained at 15 ˚C and subjected to an irrigation regime for 52 weeks. Following 26 weeks of irrigation, 2 of the 4 columns were fertilised. Leachate was analysed for dissolved constituents as were solid samples of the fresh soil and of soil samples collected from the columns following 52 weeks irrigation. Leachate concentrations for all nutrients, excepting phosphate, were observed to decline over the irrigation period. Leached phosphate concentrations increased from weeks 0 to 2, and then remained relatively constant. Low nitrogen concentrations within the leachate from weeks 2 to 38 were caused by nitrogen immobilisation within the soil, whilst subsequent mineralisation resulted in increased concentrations from Week 38. Analyses of solid phase constituents determined little variation with depth. Fertiliser application demonstrated a significant (p < 0.05) increase in leachate concentrations for some dissolved organic nitrogen and nitrate, phosphate, magnesium and calcium and a decrease in pH. Fertiliser application observations showed less prominent differences for the extracted and solid phase constituents. Thirdly, biochar was applied to the artificial soil at three concentrations (10 %, 5 % and 2 %) plus a control (0 %), to determine whether biochar application may improve nutrient characteristics of artificial soils. The biochar amended soils were packed into mesocosms and maintained at 15 ˚C for 6 weeks. In general, leachate analyses demonstrated a decrease in nutrient losses to leaching with increasing biochar concentration, highlighting the potential for improved nutrient retention within the soils.

A finite element procedure is developed for stress-deformation analysis of three-dimensional solid bodies including geometric and material nonlinearities. The formulation also includes the soil-structure interaction effect by using an interface element. A scheme is formulated to allow consistent definitions of stress, stress and strain rates, and constitutive laws. The analysis adopts the original Newton-Raphson technique coupled with incremental approach. Different elasto-plastic laws based on Von-Mises, Drucker-Prager, critical state, and cap criteria are incorporated in the formulation and computer code, and they can be used depending on the geological material involved. A special cap model is also incorporated to predict the behavior of the artificial soil used in current research. Examples are given to verify the formulation and the finite element code. Examples of the problems of soil-moving tool are also shown to compare to the experimental solutions observed in a prototype soilbin test facility. / Ph. D.

Terrestrial microplastics are increasing in abundance and are an emerging contaminant of concern, particularly in agriculture ecosystems where plastic use and subsequent soil contamination are prevalent. Plastic film mulches make up a significant portion of the plasticulture industry and are directly linked to soil microplastic pollution where negative effects to soil biotic and abiotic functions have been observed. In response to this issue, biodegradable film mulches have been promoted as a sustainable alternative to conventional polyethylene-based mulches. These biodegradable mulches, composed of various bioplastics, are designed to be tilled back into the soil where they are expected to decompose. However, the degradation of biodegradable film mulches has proven to be inconsistent and unpredictable, potentially leading to the persistence of micro-bioplastic (MBP) particles in the soil that may cause adverse effects like those of microplastics from conventional mulches. To evaluate the efficacy of this novel technology as a viable alternative to conventional plastic mulches, this 2-month incubation study examined the effects of MBPs derived from polybutylene adipate terephthalate (PBAT)-based biodegradable mulch on a suite of soil health indicators. Using laboratory-prepared soils, the study assessed how clay mineralogy and organic matter content influence soil-MBP interactions under controlled conditions. Our results suggest there is a significant effect of MBPs on soil moisture and nutrient cycling with a potential negative priming effect, particularly in soils where organic matter is limited. Additionally, clay mineralogy significantly mediated soil-MBP interactions. While MBP presence altered C pools, a qualitative analysis suggests the MBP particles remained largely undegraded by the end of the incubation period. These findings suggest that MBPs have the potential to influence soil properties and functions, underscoring the need for further research to fully understand their environmental implications in field conditions.

Research estimated toxicity of refuse-derived fuel fly ash (RDF-FA) on two earthworms species, Lumbricus terrestris and Eisenia foetida. Specific objectives were to: (1) Compare their 14-day LC50s under light and dark conditions; (2) separate toxicity due to osmotic, pH and physical factors from that of heavy metal contaminants; (3) compare relative differences of artificial soil and commercial soil as exposure media for evaluating toxicity to earthworms. The 14-d LC50s for L. terrestris in dark and light were 57.0 and 48.34 % RDF-FA, and 59.25 and 41.00 % RDF-FA for E. foetida using artificial soil. All of the toxicity resulted from heavy metals within the RDF-FA. Using L. terrestris, the LC50s for artificial soil and commercial soil were 52.30 and 64.34%.

The study was focused on disturbances by wild boar (Sus scrofa) and their impact on vegetation of semi-dry grasslands (Festuco-Brometea) dominated by Brachypodium pinnatum. The research was conducted in military area Hradiště in hilly region of the Doupovské hory. Wild boar rooting activities is main source of disturbances regime in this abandoned, previously agricultural area. The vegetation of artificial small scale soil disturbances was compared to undisturbed control plots and vegetation of natural disturbances by wild boar. Experimental plots were established during the summer 2007. Consequently a vegetation survey of these plots was carried out and soil was mechanically disturbed. Succession on disturbances was annually monitored. The surrounding natural disturbances were also mapped three times a year as a potential source of diaspores and to assess their frequency and effect on the landscape level. The list of species in the 2m, 4m and 16m distance from the experimental plot was also made. Results: Disturbances by wild boar increased species diversity and spatial heterogeneity of semi-dry grasslands. There were some species found on experimental plot, which were present not in the surrounding matrix. Most of them belong to hemicryptophytes and species with long-term persistent diaspores. Presence of...