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Understanding the physical properties as well as the potential for organic material in the Martian near-surface environment can give us a glimpse into the history of the site with regards to water, soil formation processes, as well as the conditions necessary for life. This work is done to support the interpretation of data from the Phoenix Mars Lander as well as other past and future landed missions. The Antarctic Dry Valleys are a hyper-arid cold polar desert that is the most Mars-like place on Earth. Soils from two different soil and climate regimes are analyzed to determine their physical properties such as mineralogy, particle size, shape, color, and specific surface area. These data are used to describe the sample locations in Antarctica and infer properties of Martian soils by comparison to Antarctic sites. I find that the particle size distribution can be used to determine the water history of the site and that the behavior of soluble species in the soil can also be used to trace the movement of water through the soil and could be instructive in understanding how soil organic material is processed by the environment. Continuing with the theme of soil organic matter, we revisit the Viking conclusions with regards to organics on Mars and look at the Phoenix data on the same subject. First, we assume that Mars receives organic material from meteoritic infall. These organics will be processed by chemical oxidants as well as UV light down to 200 nm. Chemical oxidation is predicted to produce molecules such as mellitic acid, which could preserve up to 10% of the original organic mass. Using mellitic acid and other similar organic molecules, we irradiate these molecules with Mars-like ultraviolet light, analyzing the gases that come off as irradiation takes place. We find that organic molecules can survive Mars-like UV conditions as layers of UV-resistant organics build up, shielding the remaining organic material. Additionally, the gas products of irradiation depend on the composition of the original organic molecule, implying that even irradiated molecules will carry some information about the composition of the original molecule. Finally, we take this irradiated organic/soil stimulant mixture and analyze it via pyrolysis, similar to the Viking GC/MS and TEGA instruments that are the only instruments operated on Mars capable of detecting organics. We find that the pyrolysis of mellitic acid (and other similar) molecules primarily produces inorganic fragments but that the reduced carbon fragments released depend on the composition of the original organic. However, the introduction of perchlorate, discovered on Mars by the Phoenix Lander, complicates the issue by creating the conditions for molecular oxidation. The high-oxygen content and high pyrolysis temperatures lead to organic combustion during thermal analysis, meaning that, regardless of the initial composition, most soil organics will be oxidized to CO₂ during the detection process. By assuming that organic material was oxidized to CO₂ in the Phoenix and Viking samples. We show that this assumption gives organic concentrations consistent with meteoritic accumulation rates. This finding reopens the possibility for organic molecules in the near-surface environment at the Viking and Phoenix landing sites.

The thesis characterizes soils of the karst platform around Sf. Elena village established by Czech colonists in Romanian Banat. The emphasis is given to the relationships among soil chemical properties and different land use and relief. In the area, occurrence and distribution of soil types was mapped. The relief was found out to be the dominant factor determining soil chemical properties. It affects also the vegetation and land use. Among the different land use types the statistically significant difference was found mainly in organic carbon content, which is the main determinant of sorption capacity. Less favourable properties were found on arable land, where the low nutrient content was observed, too. It gives evidence of a depletion of the soil by farming.

Debris flows can be considered the most significant geological hazard in areas of high relief in Scotland having impacted upon slope foot infrastructure several times in recent years. The potency of this geohazard is anticipated to increase over the coming decades due to a climatologically enforced upturn in debris flow frequency. In thisresearch material and topographic controls on debris flow activity are investigated using a combination of field and laboratory based analysis of debris flows at six study sites across upland Scotland. Centrifuge modelling is also used to simulate theinitiation of debris flows in soils with varying particle size distributions.Spatial densities of debris flow measured in the field indicate that hillslopes underlain by sandstone and granitic bedrocks, which tend to be mantled by coarser sand rich soils, have a greater frequency of flows than those underlain by schist andextrusive lava bedrocks. Higher debris flow densities on slopes underlain by sandstone and granite lithologies are facilitated by high permeability in overlying regolith matrixes allowing more rapid increase in pore water pressures duringrainstorms although this is likely to be further influenced by packing and organic content. Centrifuge modelling of hillslope debris flows also demonstrate that sandier soils are generally geotechnically more susceptible to slope failure.The susceptibility of a hillslope to debris flow is strongly influenced by slope geometry and morphology. Hillslopes with persistently steep slopes and a high incidence of concavities, gullies and couloirs are topographically more predisposed todebris flow activity due to greater shear stresses and morphologically controlled, gravity induced concentrations of hillslope hydrology. The majority of material in channelised debris flows is entrained during the gully propagation stage of the massmovement. Consequently, such events can be considered accumulative channelised debris flows. Longer and steeper gullies with greater sediment capacities are more likely to yield larger flow mass movements. Coupling between open hillslopes andbedrock gullies is shown to be an essential component for conceptualisation of the debris flow geohazard.Due to the role they play in amplifying debris flow magnitude, hazard management should be focussed around bedrock gullies and stream channels. Highesthazard rankings should be assigned to slope foot infrastructure in proximity to gullied stream channels with high sediment capacities and long, steep profiles conducive to large accumulative channelised debris flows. To avoid detrimental aesthetic impact, hazard management should be strongly geared towards utilisation of lower impactexposure reduction techniques and less visually intrusive engineering approaches such as increasing culvert capacity to accommodate debris flows. During realignment or the planning of future transport infrastructure, culverts with capacities significantly exceeding those required for purely hydrodynamic considerations should be placed straight on to stream channels avoiding proximal gully bends.

Biochars are the product of high temperature treatment of carbonaceous materials with little or no oxygen present, termed “pyrolysis”. Biochars derived from the pyrolysis of biomass feedstocks have proven effective amendments on highly weathered tropical soils. However less is known about their impact on temperate soils and associated crop growth. Moreover, there is inadequate knowledge of the impacts of different biochars produced from different feedstocks under differing pyrolysis conditions. Therefore, a study was conducted to evaluate the effectiveness of different biochars as amendments to improve soil conditions for crop growth, with emphasis on soil fertility and crop nutrition impacts. The response of canola-wheat in rotation to five biochars was evaluated in controlled environment and field experiments conducted on Brown and Black Chernozem soils over a two-year period. Treatments were biochar added at 1 and 2 t ha 1 without and with nitrogen (N) and phosphorus (P) fertilizers at 50 or 100 kg N ha 1 and 25 kg P2O5 ha 1. Parameters evaluated were crop biomass and grain yield, N and P uptake, % recovery of applied N and P, residual soil nutrients (NO3 N, and PO4+ P), pH, electrical conductivity (EC), % organic carbon (% OC) and gravimetric soil moisture. Biochar application resulted in significant increases (p<0.05) in canola yield compared to the control for two fast pyrolysis biochars originating from wheat and flax straw added to the Black Chernozem soil in both studies. No significant response was observed for any of the biochars on the Brown Chernozem. Slow pyrolysis biochar derived from willow feedstock appeared less effective did not show any significant response. Occasional depressions in crop yield were observed in both crops with both soils. In these calcareous Chernozems, biochar did not greatly alter the N and P availability, and its effects on soil pH, % OC, EC and moisture content were small and often non-significant. These results suggest that biochar applications at 1 2 t ha 1 to prairie Chernozemic soils will not have large effects on soil properties or plant growth. Higher rates of application will require development of application technology due to the dusty, powdery nature of the biochar material.

Submitted by PRISCILA ROBERTA VOLANTE null (privolante@yahoo.com.br) on 2016-12-15T15:51:40Z No. of bitstreams: 1 TESE_Priscila_Roberta_Volante.pdf: 856811 bytes, checksum: d2f614518c8c7da20ea5be7c9aebc8a2 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-12-19T16:34:39Z (GMT) No. of bitstreams: 1 volante_pr_dr_jabo.pdf: 856811 bytes, checksum: d2f614518c8c7da20ea5be7c9aebc8a2 (MD5) / Made available in DSpace on 2016-12-19T16:34:39Z (GMT). No. of bitstreams: 1 volante_pr_dr_jabo.pdf: 856811 bytes, checksum: d2f614518c8c7da20ea5be7c9aebc8a2 (MD5) Previous issue date: 2016-11-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A cinza de bagaço de cana-de-açúcar, gerada pela queima do bagaço da cana-de-açúcar para produção de energia elétrica no setor sucroenergético, vem sendo aplicada ao solo sem critério técnico/científico. Desta forma, o objetivo do presente trabalho foi avaliar o efeito da aplicação de cinza de bagaço de cana-de-açúcar, quando incorporada ao solo ou quando aplicada em superfície, nos atributos físicos e químicos de um Argissolo Vermelho, no crescimento das laranjeiras, na produção de frutas e na qualidade do suco, dois, três e quatro anos após a aplicação do resíduo no solo. O delineamento experimental utilizado foi o de blocos ao acaso, com cinco tratamentos e cinco repetições. As doses de cinza foram 0, 5, 10, 20 e 40 t ha-1 (base seca). Concluiu-se que a cinza de bagaço de cana-de-açúcar, até a dose de 40 t ha-1, pode ser distribuída em solos agrícolas, sendo esta, portanto, uma alternativa para o emprego deste resíduo, sem que o solo seja degradado física e quimicamente, e sem causar prejuízos ao desenvolvimento das laranjeiras, produção e qualidade do suco. / The ash generated by burning the sugarcane bagasse for electricity production on the sugar and ethanol industry, is being applied to the soil without technical/scientific criteria. Thus, the objective of this study was to evaluate the effect of application of sugarcane bagasse ash on soil physical and chemical attributes and on orange trees growth, and fruit and juice quality. The experimental design was randomized blocks, with five treatments and five replications. The ash doses were 0, 5, 10, 20 and 40 t ha-1 (dry basis). The results showed that application of sugarcane bagasse ash to the soil up to 40 ton ha-1 did not affect soil or plant attributes, being an alternative use of this residue on agricultural soils. / CNPq: 140799/2013-3

Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol) / The Succulent Karoo Biome (SKB) in South Africa is widely reputed to house Earth’s greatest diversity of succulent plants. It is also famous for spectacular displays of annual flowers after good rains. The area experiences winter rainfall which infrequently exceeds 100 mm per annum but certain parts of the SKB can get 250 mm. Irrigated agriculture on a large scale was therefore not a viable option when European farmers began colonizing the land. The land was conquered from the indigenous Khoekhoe herders and San hunter-gatherers, South Africa’s first peoples. The biome underwent extreme transformation in the last 200 years following colonisation which resulted in homogenization of the landscape and extinction of many succulents thus reducing biodiversity.

Conventional agriculture is one of the widely adopted agricultural practices globally with an aim to increase production. This practice effectually increases yields, but with a growing array of environment and health concerns. Organic agriculture is reflected as a "sustainable substitute" for conventional agriculture, this phenomenon was investigated in this study by comparing the patterns of diversity and community structure of soil macrofauna as well as their relations with soil properties in organic and conventional ecosystems. Macrofauna was selected as model organisms for this study because these fauna groups are sensitive to changes in their environment and changes in their community structure offer an integrative assessment of ecosystem effects. Soil macrofauna were sampled using standardised procedures of Tropical Soil Biology and Fertility, in organic, intercropped and conventional wheat agroecosystems. The results show that the studied soil macrofauna groups, with an exception of Hymenoptera termites, are negatively affected by the intensity of conventional management, the organic and the intercropped systems exhibited similarities in species distributions, this was attributed to the cultural management practices applied to these systems where livestock manures and mulches, as well as practices such as no-till, are incorporated into the soil. Results obtained from the soil characterisation and analysis revealed that the dissimilarities in agroecosystem management have a significant influence on soil physicochemical properties, which consequently influences the distribution of the macrofauna assemblages. Stable isotopes did not reveal any significant differences between the systems, however macrofauna taxa, plant and soil samples from the organic systems were rich in natural abundance stable isotopes signatures, this aspect needs further investigation through extensive sampling under long term experiments, to observe clear differences. The general results of this study show that organic farming as an agricultural management strategy is the most stable system that positively supports the diversity in the soil macrofauna community and soil physicochemical properties as compared to the conventional system. Macrofauna diversity and functioning in the soil are affected by conventional agriculture, this may have negative implications for nutrient cycling and soil health in ecosystems cultivated under conventional monoculture, tillage and chemical intensifications. Continual research would be imperative to discover how the soil macrofauna contributes to ecosystem function and how they affect the soil ecosystem itself. / College of Agriculture and Environmental Sciences

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