Soil Spatial Scaling: Modelling variability of soil properties across scales using legacy data

Understanding how soil variability changes with spatial scale is critical to our ability to understand and model soil processes at scales relevant to decision makers. This thesis uses legacy data to address the ongoing challenge of understanding soil spatial variability in a number of complementary ways. We use a range of information: precision agriculture studies; compiled point datasets; and remotely observed raster datasets. We use classical geostatistics, but introduce a new framework for comparing variability of spatial properties across scales. My thesis considers soil spatial variability from a number of geostatistical angles. We find the following: • Field scale variograms show differing variance across several magnitudes. Further work is required to ensure consistency between survey design, experimental methodology and statistical methodology if these results are to become useful for comparison. • Declustering is a useful tool to deal with the patchy design of legacy data. It is not a replacement for an evenly distributed dataset, but it does allow the use of legacy data which would otherwise have limited utility. • A framework which allows ‘roughness’ to be expressed as a continuous variable appears to fit the data better than the mono-fractal or multi-fractal framework generally associated with multi–scale modelling of soil spatial variability. • Soil appears to have a similar degree of stochasticity to short range topographic variability, and a higher degree of stochasticity at short ranges (less than 10km and 100km) than vegetation and Radiometrics respectively. • At longer ranges of variability (i.e. around 100km) only rainfall and height above sea level show distinctly different stochasticity. • Global variograms show strong isotropy, unlike the variograms for the Australian continent

Use of an Active Canopy Sensor Mounted on an Unmanned Aerial Vehicle to Monitor the Growth and Nitrogen Status of Winter Wheat

Using remote sensing to rapidly acquire large-area crop growth information (e.g., shoot biomass, nitrogen status) is an urgent demand for modern crop production; unmanned aerial vehicle (UAV) acts as an effective monitoring platform. In order to improve the practicability and efficiency of UAV based monitoring technique, four field experiments involving different nitrogen (N) rates (0–360 kg N ha−1 ) and seven winter wheat (Triticum aestivum L.) varieties were conducted at different eco-sites (Sihong, Rugao, and Xinghua) during 2015–2019. A multispectral active canopy sensor (RapidSCAN CS-45; Holland Scientific Inc., Lincoln, NE, USA) mounted on a multirotor UAV platform was used to collect the canopy spectral reflectance data of winter wheat at key growth stages, three growth parameters (leaf area index (LAI), leaf dry matter (LDM), plant dry matter (PDM)) and three N indicators (leaf N accumulation (LNA), plant N accumulation (PNA) and N nutrition index (NNI)) were measured synchronously. The quantitative linear relationships between spectral data and six growth indices were systematically analyzed. For monitoring growth and N nutrition status at Feekes stages 6.0–10.0, 10.3–11.1 or entire growth stages, red edge ratio vegetation index (RERVI), red edge chlorophyll index (CIRE) and difference vegetation index (DVI) performed the best among the red edge band-based and red-based vegetation indices, respectively. Across all growth stages, DVI was highly correlated with LAI (R2 = 0.78), LDM (R2 = 0.61), PDM (R2 = 0.63), LNA (R2 = 0.65) and PNA (R2 = 0.73), whereas the relationships between RERVI (R2 = 0.62), CIRE (R2 = 0.62) and NNI had high coefficients of determination. The developed models performed better in monitoring growth indices and N status at Feekes stages 10.3–11.1 than Feekes stages 6.0–10.0. To sum it up, the UAV-mounted active sensor system is able to rapidly monitor the growth and N nutrition status of winter wheat and can be deployed for UAV-based remote-sensing of crops

An integrated analysis of facies control on deformation bands in mixed aeolian-fluvial sandstone reservoirs

Deformation bands are the primary structural element of fault damage zones within porous granular rocks. They are sub-seismic structures that act to modify the petrophysical properties of the host lithology, and as such are an area of focused research to understand their impact on fluid flow in subsurface reservoirs. Deformation bands have been shown to negatively impact fluid flow in reservoirs, with reduced porosity and permeability, and therefore pose a problem for many subsurface energy resources including hydrocarbon exploration and production, groundwater aquifer management, geothermal energies, and carbon sequestration. Deformation bands require a diverse methodological approach in order to fully understand the mechanisms of their formation and their impacts on rock properties. Current understanding of deformation bands has been drawn primarily from field outcrops, subsurface sampling, as well as insights provided by experimental rock mechanics. It is suggested that the formation of these structures and their properties is strongly related to host lithological properties, such as porosity, grain size, sorting and mineralogy, as well as the stress conditions at which they form. Their prevalence within high porosity, coarse-grained lithologies of aeolian origin has shown that grain size and porosity are the primary controls on their formation. However, the prevalence of this facies in the literature presents sampling bias and therefore bias in interpretation of the controls on their formation, with other lithological variables such as grain sorting and bed thickness, relatively understudied. This thesis presents results of an integrated approach to understand the controls on deformation band formation, and the controls on their petrophysical properties. Mixed aeolian-fluvial reservoirs of the United Kingdom, the Triassic Sherwood Sandstone Group and the Devonian Old Red Sandstone Group are host to pervasive deformation band networks associated with faulting, and also offer the unique opportunity to examine the role of extreme lithological variability on their formation. Field sampling of fault damage zones and deformation bands is combined with petrographic and microstructural analysis and complemented with experimental rock mechanics to investigate the link between sedimentary facies and deformation band formation and petrophysical impact. Results of petrographic and microstructural analysis show that the type of deformation band structure formed is function of the porosity and grain size of the host lithology. Grain size distribution analysis reveals fractal grain size relationships which reflect the deformation mechanisms of band formation that is strongly influenced by grain sorting. Deformation bands within aeolian lithofacies display higher porosity and cataclasis than those within fluvial lithofacies, resulting in greater reduction in permeability. This field observation is also supported by triaxial deformation experiments on unconsolidated quartz aggregates in which the porosity, grain size, and mineralogy remain fixed, and sorting is varied. Sorting is found to influence the micromechanics of deformation, and thus the grain textures produced by cataclasis, resulting in greater permeability reduction within well-sorted materials. Measurements of deformation band intensity using two dimensional window sampling also reveal a strong influence of grain sorting on both the intensity of fault damage zones, and the width of deformation bands. Intensity is highest within well-sorted lithologies, where permeability reduction is also highest, however, the average width and width variability of deformation bands is greatest within fluvial facies. It may be proposed that the increased intensity of bands within aeolian facies, may be balanced by the increased width within fluvial facies, and therefore these structures may act to maintain any inherent fluid flow heterogeneity. These observations provide crucial insight into the effects of facies and ultimately lithological properties on deformation bands in mixed aeolian-fluvial reservoirs

Earth resources: A continuing bibliography with indexes (issue 62)

This bibliography lists 544 reports, articles, and other documents introduced into the NASA scientific and technical information system between April 1 and June 30, 1989. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

Sustainable Environmental Solutions

This book collects research activities focused on the development of new processes to replace obsolete practices that are often highly invasive, unsustainable, and socially unacceptable.Taking inspiration from real problems and the need to face real cases of contamination or prevent potentially harmful situations, the development and optimization of ‘smart’ solutions, i.e., sustainable not only from an environmental point of view but also economically, are discussed in order to encourage, as much as possible, their actual implementation

Land Surface Monitoring Based on Satellite Imagery

This book focuses attention on significant novel approaches developed to monitor land surface by exploiting satellite data in the infrared and visible ranges. Unlike in situ measurements, satellite data provide global coverage and higher temporal resolution, with very accurate retrievals of land parameters. This is fundamental in the study of climate change and global warming. The authors offer an overview of different methodologies to retrieve land surface parameters— evapotranspiration, emissivity contrast and water deficit indices, land subsidence, leaf area index, vegetation height, and crop coefficient—all of which play a significant role in the study of land cover, land use, monitoring of vegetation and soil water stress, as well as early warning and detection of forest fires and drought

Celebrating 25 Years of World Wetlands Day

The purpose of this Special Issue is to celebrate 25 years of “World Wetlands Day”. There is no other ecosystem that has its very own Ramsar Convention or such a challenge impacting ecosystem sustainability. Papers for this Special Issue provide an overview of wetland status and function within different regions of the world. The papers in this Special Issue of Land consist of three review papers, ten research articles and one perspective paper. Edward Maltby’s review paper provides us with an overview of the paradigm shift of how we value and assess wetlands over time. Ballut-Dajud et al. provide us with a worldwide perspective on factors affecting wetland loss. Finally, Jan Vymazal provides us with a historical overview of the development of water quality treatment wetlands in Europe and North America. The research papers can be grouped into four groups: 1) use of remote sensing to analyze stability and dynamic factors affecting wetlands; 2) factors affecting the wetlands’ ability to store carbon; 3) assessment of wetlands effect on water quality; and 4) understanding historical use and value of wetlands, farmer’s attitudes about wetland management, and how we can value wetland ecosystem services. Finally, Bryzek et al. remind us that, as wetland researchers and managers, we should minimize damage to wetlands even through field monitoring work