The farming precision in irrigated rice (Oryza sativa) has not been quite sutdied, unlike other rainfed crops, which have been highly diffused. This reasearch aims to assess the AP tools in systematized and non-systematized areas; it was fulfilled in Cachoeira do Sul, Rio Grande do Sul state, Brazil, 30º02'45" South and 52º53'39" North, throughout the years of 2007/2008 and 2008/2009. It has been evaluated the productivity, the spatial dependence of soil properies, the interconnection between the soil properties and the productivity and the main components for the plots. In order to make the evaluation possible, some samples of georeferenced soil were made; in addition, some soil fertility maps were built through the use of the CR campeiro 7 software; the fertilizer application in variable rates as the the maps productivity construction as well were performed by using a volumetric optical sensor. The outcomes show variability in the irrigated rice productivity. According to the semivariograms from the soil properties, there is a dependence on such properties, except on the organic matter from the systematic plot. No relation between correlation productivity and soil properties was shown, since the multivaried analysis of main components explained itself the variability of productivity in the plots. The outcomes show technical viability when it comes to the use of farming precision tools and systematized and non-systematized cultivation. / Agricultura de precisão em arroz irrigado (Oryza sativa) tem sido pouco estudada, ao contrário de outras culturas de sequeiro que sua tecnologia está amplamente difundida. O estudo foi desenvolvido no município de Cachoeira do Sul, no estado do Rio Grande do Sul, Brasil, coordenadas geográficas Sul de 30º02'45" e longitude de 52º53'39" nos anos agrícolas de 2007/08 e 2008/09. O trabalho teve como objetivo avaliar as ferramentas de AP em áreas sistematizadas e não sistematizadas. Foram avaliadas a produtividade, a dependência espacial dos atributos do solo, as correlações entre os atributos do solo e a produtividade e os componentes principais para os talhões. Para avaliação foram realizadas amostras de solo georeferenciadas, confeccionados mapas de fertilidade utilizando o software CR Campeiro 7®, aplicação de fertilizantes em taxa variável e confecção de mapas de produtividade com o uso de um sensor ótico volumétrico. Os resultados mostraram variabilidade na produtividade de arroz irrigado. De acordo com os semivariogramas dos atributos do solo ocorreu dependência espacial dos atributos, com exceção da matéria orgânica no talhão sistematizado. Não obteve-se correlações da produtividade com os atributos do solo. A análise multivariada de componentes principais explicou a variabilidade da produtividade nos talhões. Os resultados encontrados demonstraram a viabilidade técnica do emprego de ferramentas de agricultura de precisão em arroz irrigado e em cultivos sistematizados e não siste matizados.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Irrigation has the function to adequately supply the water demands of crops so that they express their full productive potential. But there are variations with regard to the relationship soil, plant, atmosphere, infer that in order to determine differences in crop yields, so the use of technology and equipment is essential for good irrigation management. The objective was to evaluate the feasibility of implementing a system with center pivot irrigation in soybean (Glycine max (L.) merrill.) with the aid of irrigameter, and comparing its performance with the tank class A This study was conducted at Grange Boligom Bossoroca in the municipality of RS, in an experimental area of 31.17 ha in the period from january to june 2010. The collection of plants was carried out under control, within each sector, being collected twentyfive plants, always the same, to evaluate their vegetative growth and yield components. Parameters were measured for growth and development, such as leaf area index (LAI) and plant height in fortnightly periods. At harvest were determined yield components like number of plants.m², number of pod.plant-1, number of grain.vagens-1, average grain weignht, dry weight of grain.plant-1, dry weight of stem.plant-1, dry mass of pod.plant-1, total dry weight, harvest index and yield (kg.ha-1).The irrigation management was conducted with irrigation provided by the irrigameter. The irrigation water was applied equally in all sectors, being performed by controlling Irrigameter. Files with the points of the area were viewed through georeferenced ArcGIS version 9.3, which yield maps were generated by interpolation. Average production of different sectors were subjected to ANOVA and Tukey Test at 5% probability. It is concluded that there was a difference of irrigation between the irrigameter and tank class "A", showed variation in production across sectors, where the sector in 03 production the greatest quantity to 6713.25 kg ha-1 and the lower sector 05 with 5248.05 kg ha-1. / A irrigação tem a função de suprir adequadamente as demandas hídricas das culturas, para que estas expressem seu máximo potencial produtivo. Porém ocorrem variações no que diz respeito à relação solo, planta, atmosfera, que inferem de maneira a determinar diferenças nas produtividades das culturas, portanto, a utilização de tecnologias e equipamentos é fundamental para um bom manejo da irrigação. O objetivo deste trabalho foi de avaliar a viabilidade de implementação de um sistema com irrigação tipo pivô central na cultura da soja (Glycine max (L.) Merrill.) com o auxílio do irrigâmetro, e comparando o seu desempenho com o tanque classe A . O presente trabalho foi desenvolvido na Granja Boligom situada no município de Bossoroca RS, em uma área experimental de 31,17ha no período de janeiro a junho de 2010. A área experimental foi dividida em sete setores de aproximadamente 4,5 ha. A coleta das plantas foi realizada controladamente, dentro de cada setor, sendo coletadas vinte e cinco plantas, sempre as mesmas, para avaliar o seu desenvolvimento vegetativo e os componentes de produção. Foram medidos os parâmetros de crescimento e desenvolvimento, tais como, índice de área foliar (IAF) e altura de plantas em períodos quinzenais. Na colheita foram determinados os componentes de produção como número de plantas.m², número de vagens.planta-1, número de grãos.vagens-1, peso médio do grão, massa seca dos grãos.planta-1, massa seca do colmo.planta-1, massa seca das vagens.planta-1, massa seca total, índice de colheita e produção (kg.ha-1). O manejo de irrigação foi realizado com turno de rega estipulado pelo irrigâmetro. A lâmina de água foi aplicada igualitariamente em todos os setores, sendo esta realizada através do controle do irrigâmetro. Os arquivos com os pontos da área georreferenciada foram visualizados através de software ArcGIS versão 9.3, onde mapas de produtividade foram gerados por interpolação. As médias de produção dos diferentes setores foram submetidas à análise de variância e pelo teste de Tukey a 5% de probabilidade de erro. Conclui-se que houve diferença de lâminas de irrigação entre o irrigâmetro e tanque classe A , ocorreu variação na produção entre os setores, onde o setor 03 obteve a maior produção com 6713,25 kg.ha-1 e o setor 05 a menor com 5248,05 kg.ha-1.

The growing environmental awareness regarding production and use of renewable fuels has led many of countries to create policies to benefit producers of renewable fuels. Thus, the search for raw materials for production of biofuels, which do not conflict with the global food production and exhibit similar performance to fossil fuels, has generated interest towards crambe, a crop of high oil content, inappropriate for animal consumption and which can be applied in crop rotation without the need for exchange farm machinery. However, studies evaluating the influence of spatial variability of soil chemical and physical properties on grain yield and oil content of crambe are scarce. Thus, this study aimed to evaluate the spatial correlation between physical and chemical properties of an Oxisol under compaction states with grain yield and oil content of crambe, through a cross-correlation estimator based on moving windows and assess adequate sampling density for application of geostatistics. For this, we used geostatistical techniques such as kriging and simulation data and using software R. We concluded that increased bulk density and soil resistance to penetration change the source:sinc relationship of crambe, reflecting in lower yield but with grain production of higher quality; chemical attributes that have higher direct spatial relationship to grain yield of crambe are phosphorus, calcium, magnesium and organic matter; sampling grids constructed with points spaced at large distances are not effective in detecting the spatial variability of chemical attributes and grain yield and oil content of crambe; and that the cross semivariogram based on moving windows detects the structure of spatial correlation between the physical and chemical soil properties, independent of its variability or dispersion, showing superior performance when the data have outliers and do not have normal distribution. / A crescente conscientização ambiental a respeito da produção e uso de combustíveis renováveis tem levado muitos países a criar políticas que beneficiam os produtores destes combustíveis. Assim, a busca por matéria-prima para produção dos biocombustíveis não conflitantes com a produção mundial de alimentos e que apresentem desempenho semelhante aos combustíveis fósseis despertou interesse pelo crambe, uma cultura de grande teor energético, imprópria para o consumo animal e que pode ser aplicada em rotação de culturas sem a necessidade de troca de maquinário agrícola. No entanto, estudos avaliando a influência da variabilidade espacial de atributos químicos e físicos no rendimento de grãos e no teor de óleo do crambe ainda são escassos. Neste sentido, este trabalho objetivou principalmente avaliar a correlação espacial entre atributos físicos e químicos de um Latossolo sob estados de compactação, com o rendimento de grãos e de óleo do crambe, através de um estimador de correlação cruzada baseado em janelas móveis e avaliar a densidade amostral adequada para aplicação da geoestatística. Para isto, utilizaram-se técnicas de geoestatística como a simulação de dados e krigagem com auxílio do software R. Concluiu-se que o aumento da densidade e da resistência do solo altera a relação fonte:dreno do crambe, repercutindo em menor rendimento de grãos, porém com produção de grãos de maior qualidade; os atributos químicos que apresentam maior relação espacial direta com o rendimento de grãos do crambe são o fósforo, cálcio, magnésio e matéria orgânica; malhas amostrais construídas com pontos espaçados a grandes distâncias não são eficazes na detecção da variabilidade espacial de atributos químicos e do rendimento de grãos e teor de óleo do crambe; e que o semivariograma cruzado baseado em janelas móveis detecta a estrutura de correlação espacial entre os atributos físicos e químicos do solo, independente de sua variabilidade ou dispersão, apresentando desempenho superior quando os dados apresentam outliers e não possuem distribuição normal.

Thesis (MSc. (Soil Science)) -- University of Limpopo, 2015 / There exists a considerable level of spatial variability in soil physical and chemical properties within the research block; and the soils are generally shallow. Of all the measured parameters, electrical conductivity, Bray-1 P, exchangeable potassium, calcium and sodium as well as extractable iron and zinc showed a huge percent of variation across the field. Soil variability maps indicated the degree of variability within the research block. The spatial variability of the characterized parameters was significant across the research block. A correlation study was conducted to investigate the relationship between the measured soil physical and chemical properties. Regular soil analyses should be conducted to avoid failure/delay of experiments. It is recommended that inputs such as irrigation and fertilizer application must be varied based on varying soil conditions across the research block. / VLIR project 6 leaders

Despite the increases in the intensity and frequency of disturbances on coral reefs in the Red Sea over the past decade, patterns of variability in fish communities are still poorly understood. This study aims to contribute to a better understanding of how fish communities vary along multiple spatial scales (10-100’ of kilometers) and to provide a baseline for future comparisons, fundamental to assess responses to climate change and other disturbances. Coral reefs along the Saudi Arabian Red Sea coast were surveyed from 2017 to 2019. The reefs ranged from 28° N to 18 °N and were categorized according their geographical location and grouped within three regions, namely north (24-28.5°N; 12 reefs), central (20.4-22.3°N; 11 reefs), and south (18.5-21.2°N; 30 reefs). The quantification of spatial patterns was conducted based on both taxonomic- and trait-based approaches. Considering the dependence of fish communities on the benthic habitat the relationship between different attributes of the fish assemblages and coral cover was also investigated. A consistent pattern of separation between assemblages of the northern and central region from the ones in the south was observed in nearshore reefs but was not evident for offshore reefs. The southern region supported higher densities, biomass, and species richness than the other two regions. The analysis showed that transect and reef scales contributed to the greatest variation in fish communities, suggesting higher levels of variability within small spatial scales. Several parameters of the fish community (total species, total density, total biomass, total functional entities, functional richness, functional redundancy) were positively correlated to coral cover, particularly in the northern region. Responses were not consistent across the Red Sea basin, suggesting that management plans should be regionally based. This study can be helpful to design management strategies as it provides a current baseline from both taxonomic and trait perspectives for Red Sea reefs that can be used to evaluate future changes due to natural and human-based disturbances.

Eco-geomorphic interactions occur across a range of spatial and temporal scales from the level of the entire watershed to an individual geomorphic unit within a stream channel. Predicting the mechanisms, rates and timing of sediment production and storage in the landscape are fundamental problems in the watershed sciences. This is of particular concern given that excess sedimentation is considered a major pollutant to aquatic ecosystems. Rates of sediment delivery to stream networks are characteristically unsteady and non-uniform. Because of this, conventional approaches for predicting sediment yield provide incomplete and often inaccurate information. Terrestrial cosmogenic nuclides (TCNs) provide an estimate of spatially averaged rates of sediment yield from 101 to 104 km2 and temporally integrated from 103 to 105 years. Here, I used TCNs to constrain unsteadiness and non-uniformity of sediment yield within specific catchments of the Columbia River Basin (CRB). This is in combination with GIS analysis optically stimulated luminescence (OSL), Carbon-14 (C14) dating of fluvial deposits, and rapid geomorphic assessments. Results showed an order of magnitude spatial variability in the rates of millennial-scale sediment yield at the scale of the entire CRB. At the broadest scale long-term rates of sediment yield generally are poorly predicted from topographic and environmental parameters. A notable exception is the observed positive correlation between mean annual precipitation and sediment yield. Where functional relationships exist, the nature of those relationships are scale and situation-dependent. In addition to the broadest scale, each smaller watershed (e.g., ~ 10 – 2,000 km2) has a distinct geologic, geomorphic, and disturbance history that sets the template for the modern sediment dynamics and the physical aspects of aquatic habitat. Chapter 2 presents results of broad-scale trends while Chapter 3 is comprised of case studies from smaller watersheds. Finally, Chapter 4 explores the relationship between long-term sediment yield and modern channel form.

No description available.

No description available.

Damages caused by urban pluvial floods are believed to increase due to climate change and urbanization as more citizens are impacted in densely populated cities and extreme rainfalls occur more frequently with higher intensities. To prepare cities for these calamities, urban pluvial flood models are created to provide knowledge about how an extreme rainfall event could inundate the studied city. However, due to the scarcity of observation data from these rainfall events, flood models are seldom calibrated which is necessary to ensure their accuracy.  To improve the feasibility of calibrations an emerging data source was tested, crowdsourced images from citizens. Citizens’ observations have become increasingly available due to the increase of mobile phones and the development of social media enabling citizens to document and upload their observations to the public. Researchers could use these observations as an unconventional data source to calibrate models and reduce the knowledge gap regarding urban floods. The aim of this study was to explore and increase our understanding of how citizen’s observations can be used to calibrate an urban pluvial flood model. A case study about the cloudburst event in Malmö was conducted to study this topic. During that event, more than 100 mm of rain fell over a period of 6 hours in the city and caused 60 million euros of damages.  A total of 297 images depicting the flood caused by the cloudburst event were gathered from social media platforms, newspapers archives, and by inquiring citizens. Images were screened and analysed: water levels were estimated in 66 images and were then used to calibrate a 2D flood model. Furthermore, a sensitivity analysis of the calibrated results was conducted by calculating the RMSE for different subsets and compare it with the RMSE for the full dataset of citizens’ observations. This was done to study how different characteristics, such as timestamp and source as well as sample size and location of the images influences the calibration procedure. After the model was calibrated, the importance of spatial variability in the rainfall input was tested by comparing the flood model output between the spatially varied observed rainfall and a Chicago Design Storm rainfall, which lacks spatial variability.  It was concluded that images from citizens can be used to calibrate an urban pluvial flood model, but the procedure is time-consuming. However, it was also evident that images directly inquired from citizens reduced the time needed as their local knowledge could be integrated. The calibration procedure was also sensitive to the quality of the observations, especially when the images were photographed in relation to the rainfall event. Even though the study had limitations it demonstrates new possibilities to calibrate urban pluvial flood models. / Konsekvenserna av översvämningar från skyfall i städer, så kallade pluviala översvämningar, förväntas öka på grund av urbanisering och klimatförändringar. Det är för att fler påverkas av översvämningar i tätbyggda städer samt att skyfall förväntas öka, både i intensitet och frekvens. Med hjälp av skyfallsmodeller kan dock förståelsen för hur extrema regn översvämmar städer öka. Med denna kunskap kan åtgärder för att minimera konsekvenserna implementeras, såsom blågrön infrastruktur. Däremot finns det en brist av observationsdata från pluviala översvämningar och vilket medför att dessa modeller ytterst sällan kalibreras. Kalibrering är viktig för att säkerställa tillförlitliga modeller.  För att öka möjligheten att kalibrera dessa modeller undersöktes hur observationer från medborgare kan implementeras. Dessa observationer är en relativ oprövad metod men har blivit alltmer tillgängliga tack vare allt bättre mobiltelefonkameror och utvecklingen av sociala medier, vilket gör det enkelt för medborgare att dokumentera och ladda upp sina observationer till allmänheten. Syftet med denna studie är därför att öka förståelsen för hur bilder från medborgare kan användas för att möjliggöra kalibreringen av översvämningsmodeller. En fallstudie över ett skyfall i Malmö 2014 används för att utvärdera denna metod. Under detta skyfall regnade det mer än 100 mm vilket orsakade skador för cirka 600 miljoner kronor.  Totalt samlades 297 bilder som föreställde översvämningen som orsakades av skyfallet. Bilderna samlades ifrån sociala media, tidningsbildarkiv och genom att fråga medborgare efter bilder. Vattennivåerna uppskattades i 66 bilder och de användes sedan för att kalibrera en 2D- skyfallsmodell. Utöver kalibreringen genomfördes en känslighetsanalys av de kalibrerade resultaten genom att jämföra medelfelet för olika subgrupper av bilderna mot medelfelet för alla bilder. Detta gjordes för att studera hur olika egenskaper, såsom när bilden togs och deras ursprung samt bildernas urvalsstorlek och placering påverkar kalibreringsprocessen. Efter att modellen kalibrerats testades också betydelsen av spatial variation i nederbörden genom att jämföra de simulerade vattennivåerna mellan den spatialt varierade historiska regnet och ett syntetiskt CDS-regn som saknar variation.  Utifrån det drogs slutsatsen att bilder från medborgare kan användas för att kalibrera en skyfallsmodell, men metoden är tidskrävande. Dock var det tydligt att bilder som direkt efterfrågades från medborgarna minskade arbetsbördan då deras lokalkännedom kunde inkluderas. Kalibreringen var också känslig för observationerna datakvalitet, särskilt när bilderna fotograferades i förhållande till regnet. Även om studien hade begränsningar visar den att det finns stora möjligheter att kalibrera skyfallsmodeller med observationer från medborgare.

Résumé : Les barrages induisent un impact potentiellement important sur l'environnement et la société par la modification des écosystèmes, le déplacement des populations en amont et surtout par la présence d'un risque imposé aux populations situées à l'aval. Même si les ruptures de ces ouvrages ont une probabilité d'occurrence faible, la cause principale des accidents, à côté des submersions par des crues imprévues, a toujours été la rupture des fondations (ICOLD 1993) suite à des problèmes d'érosion, ou d'insuffisance de résistance au cisaillement le long des discontinuités rocheuses, des joints de levées ou de l'interface barrage-fondation. La fréquence de ruptures par défaut de résistance au cisaillement des discontinuités des fondations des barrages en béton est estimée à 21 % (ICOLD 1995). Les fondations rocheuses présentent souvent une variabilité verticale et horizontale des propriétés de résistance au cisaillement des discontinuités. Une variabilité verticale peut être matérialisée par une moyenne de la propriété de résistance qui varie en profondeur et dont la prise en compte réduit la variance de cette propriété de résistance. Aussi, la rupture des fondations rocheuses par défaut de résistance au cisaillement des discontinuités est un mécanisme qui mobilise les propriétés ponctuelles de résistance au cisaillement présentes sur cette discontinuité. La résistance au cisaillement mobilisée le long de cette discontinuité présente parfois une variance moins élevée que celle de la résistance ponctuelle au cisaillement (échelle de laboratoire). Ces phénomènes de variabilité spatiale ne sont pas pris en compte dans la justification du comportement en cisaillement des fondations ni dans les travaux de recherches publiées dans la littérature. L'objectif de la thèse est d'élaborer une démarche d'analyse de la variabilité spatiale de la résistance au cisaillement qui prend en compte cette réduction de la dispersion. Cette démarche a été élaborée dans le contexte de l'état de l'art actuel, avec la combinaison des impératifs suivants : • La démarche est basée sur une méthodologie expérimentale i)-alternative à l'essai de cisaillement direct (coûteux en temps et en argent) pouvant être relativement simple à mettre en œuvre ii)- qui permet de générer des données quantitatives de cisaillement suffisamment abondantes pour analyser la variabilité spatiale de la résistance au cisaillement. • Cette démarche a été mise en œuvre au contexte des outils numériques et des méthodes de justification de la résistance à l'effort tranchant d'une fondation rocheuse de barrage-poids. La méthodologie expérimentale définie dans la thèse a fait l'objet d'une validation par étude comparative avec 35 essais de cisaillement direct sur des joints à différents degrés de rugosité et d’altération, prélevés d'une fondation de barrage-poids en béton. Il a été développé une démarche d'analyse de la variabilité spatiale de la résistance au cisaillement des joints. Cette démarche repose sur l'utilisation des données géo référencées de paramètres de cisaillement caractérisant la même famille de discontinuité le long d'un forage vertical. Afin de valider la pertinence et l’applicabilité de cette démarche, nous l’avons implémentée dans un cas d'étude de fondation rocheuse de barrage. A l'aide d'un code de calcul numérique basé sur la méthode des éléments finis, une étude a permis d'illustrer la pertinence de l'analyse de la variabilité spatiale de la résistance au cisaillement des joints dans une étude de stabilité au glissement des fondations rocheuses de barrage. Les résultats montrent que la prise en compte de la variabilité spatiale des paramètres de cisaillement permet d'augmenter la marge de sécurité mesurée à travers une hausse du coefficient de sécurité et une baisse significative de la probabilité de défaillance. // Abstract : Dams induce a potentially significant impact on the environment and society by changing ecosystems, by populations’ relocation upstream and especially by the presence of an imposed risk on populations located downstream. Although dam failures have a low probability, the main cause of accidents, near submersions by unexpected flood has been foundations failures (ICOLD 1993) due to problems of erosion, or insufficient shear strength along the rock discontinuities or the interface between dam and foundation. Among dam failures, 21% are related to lack of shear strength along the discontinuities of the foundations (ICOLD 1995). It is well known that rock, as soil, is a complex engineering material formed y natural process, which induces vertical and horizontal variability. Plus, the sliding process of a rock foundation discontinuity is a mechanism that mobilizes points shear properties of this discontinuity. The variability of shear properties averaged over the sheared discontinuities is less than that of their point shear properties. This is known as the average effect in spatial variability. These phenomena of spatial variability are not taken into account in the standards of stability analysis of dam foundations sliding or research work published in the literature. The aim of the thesis is to develop an analysis of the spatial variability of shear strength that takes into account the reduction of the variability by scaling up effect. This approach was developed in the context of the current state of the art. An experimental method, which aimed to investigate in a simple way the shear strength of joints, was suggested in the thesis and has been validated by comparative study with more than thirty direct shear tests on joints taken from a foundation of concrete gravity dam. It was developed a process to analyze the spatial variability of the shear strength of the joints using the input parameters of the model of Barton and Choubey (1977). This approach is based on the use of geo -referenced data on these parameters characterizing the family of discontinuity along a vertical borehole. To validate the relevance and applicability of this approach, we have implemented it in a case study of a rock dam foundation. Using finite element software, a study illustrates the relevance of the analysis of the spatial variability of the shear strength of the joints in the assessment of stability against rock dam foundations sliding. The results show that taking into account the spatial variability of shear parameters can increase the margin of safety measured through an increase in the safety factor and a significant decrease in the probability of failure.