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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

THE EFFICACY OF COVER CROPS FOR POLLINATOR HABITAT PROVISION AND WEED SUPPRESSION IN A SOUTHERN ILLINOIS AGROECOSYSTEM

Bryan, Casey J. 01 May 2019 (has links)
Increases in agricultural intensification over the past century have resulted in significant alterations to the rural landscape across the Midwest. Pollinators are essential to sustain natural and managed ecosystems. They are vital for food production and their declines have been linked, in part, to a rise in intensive agricultural practices. There is a recognized need among numerous stakeholders to build sustainability into the management of agroecosystems to protect both the biotic and abiotic resources of these systems. The use of cover crops is gaining interest among agricultural producers for benefits such as improving water quality and soil health. Cover cropping systems have the potential to provide floral resources to pollinators and suppress problematic driver weeds. The overall objective of this study was to quantify the effects of cover crops on plant and pollinator biodiversity within agricultural systems. This study aimed to characterize the pollinator diversity indicative of the patchwork mosaic forest-agroecosystem of Crab Orchard National Wildlife Refuge; evaluate the roles cover crop treatments play in supporting pollinator diversity and weed suppression benefits in a conventionally managed system; and provide the basis of recommendations for sustainable weed suppression tactics and for enhancing the quality of pollinator habitat within agricultural systems.
152

Statistical Steganalysis of Images

Min Huang (7036661) 13 August 2019 (has links)
<div>Steganalysis is the study of detecting secret information hidden in objects such as images, videos, texts, time series and games via steganography. Among those objects, the image is the most widely used object to hide secret messages. Detection of possible secret information hidden in images has attracted a lot of attention over the past ten years. People may conduct covert communications by exchanging images in which secret messages may be embedded in bits. One of main advantages of steganography over cryptography is that the former makes this communication insensible for human beings. So statistical methods or tools are needed to help distinguish cover images from stego images. <br></div><div><br></div><div>In this thesis, we start with a discussion of image steganography. Different kinds of embedding schemes for hiding secret information in images are investigated. We also propose a hiding scheme using a reference matrix to lower the distortion caused by embedding. As a result, we obtain Peak Signal-to-Noise Ratios (PSNRs) of stego images that are higher than those given by a Sudoku-based embedding scheme. Next, we consider statistical steganalysis of images in two different frameworks. We first study staganalysis in the framework of statistical hypothesis testing. That is, we cast a cover/stego image detection problem as a hypothesis testing problem. For this purpose, we employ different statistical models for cover images and simulate the effects caused by secret information embedding operations on cover images. Then the staganalysis can be characterized by a hypothesis testing problem in terms of the embedding rate. Rao’s score statistic is used to help make a decision. The main advantage of using Rao’s score test for this problem is that it eliminates an assumption used in the previous work where approximated log likelihood ratio (LR) statistics were commonly employed for the hypothesis testing problems.<br></div><div><br></div><div>We also investigate steganalysis using the deep learning framework. Motivated by neural network architectures applied in computer vision and other tasks, we propose a carefully designed a deep convolutional neural network architecture to classify the cover and stego images. We empirically show the proposed neural network outperforms the state-of-the-art ensemble classifier using a rich model, and is also comparable to other convolutional neural network architectures used for steganalysis.<br></div><div><br></div>The image databases used in the thesis are available on websites cited in the thesis. The stego images are generated from the image databases using source code from the website. <a href="http://dde.binghamton.edu/download/">http://dde.binghamton.edu/download/</a>
153

The impact of land cover and land use on the hydrologic response in the Olifants

Ncube, Mthokozisi 23 October 2008 (has links)
Water availability in Southern Africa is highly variable both in time and space, thereby exposing the region to high risks in water availability. This is further compounded by numerous human activities which have significant impact on water resources. The brunt of the risks associated with water scarcity is particularly heaviest on resourceconstrained farmers who depend largely on rain-fed agriculture for subsistence. With continuously increasing demands on the water resources, the need for a better understanding of the hydrological systems becomes crucial as it forms the gateway for providing reliable information for managing water resources. It is also increasingly becoming more important to address land and water linkages because land use decisions are water use decisions. Operational hydrology provides an insight into the effects of man-made changes, the foreseeable hydrological characteristics at a given site, and the long-term prediction of the future hydrological effects of human activities. This provides for a more holistic approach in managing land and water resources as well as the impact of land use on partitioning rainfall into streamflow. This report discusses the application of the SWAT model to the B72E - F quaternary catchments in the Olifants Water Management Area to assess streamflow generation and the effects of human-environment interactions on the hydrology. Results show an expected correlation between land cover and the hydrologic response where an increase in land cover corresponds to a reduction in the streamflow. Range grass shows a higher reduction in the streamflow followed by forestry with arid land giving the highest increase in streamflow. Prediction in the similar neighbouring and ungauged B72A catchment gives a MAR of 68mm. Additionally, a rigorous analysis of the concepts of a local hydrological model, HDAM, is done with respect to rainfall which is the main driver of the model. Modifications of some of the relationships used in the model are suggested with the potential of streamlining the model and making it more applicable in the region.
154

Utilização de índices de vegetação para estimativa da proteção do solo pela cobertura vegetal : uma contribuição para o uso da equação universal das perdas de solo /

Veniziani Junior, José Carlos Toledo. January 2003 (has links)
Orientador: Marcos César Ferreira / Banca: Sergio dos Anjos Ferreira Pinto / Banca: Diana Sarita Hamburger / Resumo: O processo de erosão acelerada se apresenta como um dos maiores problemas ambientais da atualidade, influenciando a produção agrícola, devido às conseqüências no empobrecimento do solo e no abastecimento de água, diminuindo a sua disponibilidade em reservatórios. Este trabalho apresenta uma proposta para avaliação da ambiental das variáveis relacionadas ao desenvolvimento de processos erosivos além da verificação da adequação do uso e ocupação do solo as necessidades especiais da área, tendo como estudo de caso a Bacia do Córrego Santo Antonio, situada no município de Jaú-SP. Propomos como indicador quantitativo da cobertura vegetal, os índices de vegetação (IV) obtidos por meio de imagens de satélite. Na avaliação da suscetibilidade à erosão nos amparamos no modelo da EUPS o qual foi desenvolvido para obtenção de uma classificação das terras da bacia em classes de risco de erosão além da obtenção classes de capacidade de uso relativas a cada unidade pedológica. O estudo relativo a analise da viabilidade da utilização do IV, foi embasado na amostragem de campo a partir da qual se obteve os valores médios de percentual de interceptação das gotas de chuva para determinados tipos de cultivo na região. Avaliamos ser possível o emprego do índice de vegetação em estudos referentes à proteção do solo e acreditamos serem as classes de risco á erosão um importante indicador das necessidades de planejamento ambiental. Verificamos uma mudança no uso do solo da área do ano 2000 para ao ano 2003, o que provocou grandes alterações nos resultados da adequação do uso do solo na bacia do córrego Santo Antonio. / Abstract: The soil loss process arises as one of the major environmental problems nowadays, influencing the agricultural production, due to its consequences on the soil decay and on the water supply, decreasing its availability in the reservoirs. This work presents a proposal for the assessment of the environmental aspect of the variables concerning the development of the soil loss processes besides the verification of the adequacy of the use and occupation of the land regarding the special necessities of the area, portraying as study of case the Santo Antonio watershed, located in the town of Jaú, São Paulo. We propose as the quantitative indicator of the vegetation covering, the vegetation indexes ( VI) obtained through satellite images. On the assessment of the soil loss susceptibility we looked for support on the USLE, which was developed to obtain a classification of the watershed lands in classes of soil loss risk, besides obtaining classes on the capability of use regarding each pedologic unit. The study about the analysis of the viability of the use of the vegetation index was based in the field samples, from which were achieved the average percentage values of rain drops interception for determined kinds of agricultural growing in the region. We assessed that it is possible to proceed the use of the vegetation index in studies concerning the soil protection, and we believe that the classes of risk regarding soil loss are an important indicator towards the necessities of environmental planning. It was verified a certain change on the land use in the area from the year 2000 until the year 2003, what brought huge alterations on the outcome of the land use adequacy in the Santo Antonio watershed. / Mestre
155

Quantificação experimental da alteração no balanço hidríco e erosão em um neossolo quartzarênico devido à substituição de pastagem por cana-de-açúcar / Experimental determination of water balance and soil erosion changes due to pasture substitution by sugarcane

Youlton Millon, Cristian Pablo 24 July 2013 (has links)
A cana-de-açúcar tornou-se a cultura com maior expansão nos últimos anos no estado de São Paulo, tendência que deve continuar, considerando sua importância como matéria prima para a produção de açúcar e etanol. Essa expansão acontece principalmente sobre áreas que eram ocupadas por pastagens. Pelas atividades necessárias para o estabelecimento da cultura de cana-de-açúcar, é esperado um aumento da erosão de solos e uma alteração no balanço hídrico. Com esses antecedentes, objetivou-se quantificar experimentalmente o impacto na erosão dos solos e a modificação do balanço hídrico no primeiro metro de solo, causado pela substituição de pastagem por cana-de-açúcar. Foram construídas parcelas de escoamento (20 x 5 \'M POT.2\') sob pastagem e sob plantio novo de cana-de-açúcar (três repetições cada) em uma fazenda com solo do tipo Neossolo Quartzarênico no município de Itirapina-SP. Foi instalada uma estação meteorológica para medir a precipitação e a umidade do solo a 30, 60 e 90 cm de profundidade, e para coletar os parâmetros necessários para calcular a evapotranspiração pelo método de Penman-Monteith. Calhas foram instaladas ao nível do solo para quantificar a interceptação do dossel de cana-de-açúcar. O balanço hídrico para ambos os cultivos foi determinado em escala diária. Após cada evento de precipitação, foi quantificada a perda de solos e o escoamento superficial Durante o primeiro ano, a perda de solo sob pastagem foi de 0,26 Mg/ha.ano (adicionalmente, 0,32 Mg/ha foram coletados devido à perturbação do solo para implantação do experimento), enquanto cana-de-açúcar produziu 2,58 Mg/ha.ano. No segundo período chuvoso, a perda de solo sob pastagem diminui para 0,04 Mg/ha, e sob cana-de-açúcar registrou 0,47 Mg/ha. Estes resultados indicam que a substituição de pastagem por cana-de-açúcar aumentou a produção de sedimentos durante o primeiro ano em 2,32 Mg/ha; no segundo período, com o uso da cobertura de palha no solo sob cana-de-açúcar, o aumento foi de 0,43 Mg/ha. Depois de quatro meses de crescimento, o dossel da cana-de-açúcar intercepta 40% da precipitação. O escoamento superficial no primeiro ano foi de 56,1 mm, e diminuiu para 11,8 mm no segundo período por efeito da palha na superfície do solo. Nos mesmos períodos, o escoamento superficial na pastagem foi de 40,5 mm e 30,4 mm, respectivamente. Apesar da menor infiltração sob cana-de-açúcar, o solo apresenta maior umidade devido ao gradeamento que aumenta a porosidade, e portanto, a capacidade de armazenamento de água no solo. A percolação sob cana-de açúcar é menor que sob pastagem devido à maior evapotranspiração da cultura. / Sugarcane became the culture with the highest expansion in recent years in the state of São Paulo. This trend will continue considering its importance as raw material for the production of sugar and ethanol. The expansion occurs primarily on areas that are currently occupied by pastures, causing impacts on soil and water. Due to the necessary activities for the establishment of the sugarcane culture, a soil erosion increase and a water balance change are expected. With this background, the objective of this work was to experimentally quantify the change in soil erosion and modification of water balance in the first meter of soil caused by the substitution of pasture by sugarcane. Runoff plots were constructed (20 x 5 \'M POT.2\') under pasture and new sugarcane planting (three replicates each) on a farm with Quartzarenic Neosol (Typic Quartzipsamments) soil in the municipality of Itirapina-SP. A weather station to measure rainfall and soil moisture at 30, 60 and 90 cm depth, and to collect the necessary parameters to calculate the evapotranspiration by Penman-Monteith method was installed. Gutters were installed at ground level to quantify the interception of the sugarcane canopy. After every precipitation event the soil loss and the drainage were quantified, and the daily water balance was determined for both soil uses. During the first year, the pasture had a soil loss of 0.26 Mg/ha.yr (additional 0.32 Mg/ha.yr were collected due to the disturbance of the soil during experiment installation), while sugarcane produced 2.58 Mg/ha.yr. In the second rainy season, the losses under pasture decreased to 0.04 Mg/ha and sugarcane recorded 0.47 Mg/ha. These results indicate that the replacement of pasture by sugarcane increased the sediment production during the first year by 2.32 Mg/ha in the second period, covering the soil under sugarcane with straw, the difference decreased to 0.43 Mg/ha. After four months of growth, the sugarcane canopy intercepts 40% of the precipitation. The runoff in the first year was 56.1 mm, decreasing to 11.8 mm in the second period, due to the presence of straw on the soil surface. In the same periods, runoff under pasture was 40.5 mm and 30.4 mm, respectively. Although there is less infiltration under sugar cane, the soil presents higher moisture due to the porosity increase by grating. The percolation under sugarcane is lower than in pasture due to a higher crop evapotranspiration.
156

Decomposição de resíduos vegetais de culturas de entressafra em sistema de semeadura direta e efeitos nos atributos químicos de um Latossolo e na produtividade de soja e milho /

Marcelo, Adolfo Valente. January 2011 (has links)
Orientador: José Eduardo Corá / Banca: Rogério Peres Soratto / Banca: Luís Reynaldo Ferraciú Alleoni / Banca: José Carlos Barbosa / Banca: Carlos Eduardo Angeli Furlani / Resumo: Em sistema de semeadura direta, os resíduos das culturas de entressafra são utilizados para protegerem a superfície do solo dos agentes erosivos e promoverem a ciclagem de nutrientes. O objetivo desse trabalho foi avaliar o efeito de sequências de culturas na quantidade, qualidade, decomposição e liberação de nutrientes dos resíduos vegetais de culturas de entressafra, bem como a cobertura do solo proporcionada pelos resíduos, na fertilidade do solo, nas frações particulada e associada aos minerais de C, nas substâncias húmicas do solo e na produtividade de milho e soja cultivados no verão, em região de clima tropical. O experimento foi conduzido em Jaboticabal, SP (48°15'22'' W e 21°18'58'' S), em um Latossolo Vermelho eutrófico. O delineamento experimental foi em faixas, com três repetições. Os tratamentos foram constituídos pela combinação de três sequências de culturas de verão (rotação soja-milho, monocultura de milho e monocultura de soja) com sete culturas de entressafra (milho, sorgo, girassol, crotalária, guandu, nabo forrageiro e milheto). O experimento foi iniciado em 2002 e o presente estudo se refere aos anos agrícolas 2008/2009 e 2009/2010. Avaliaram-se as quantidades de matéria seca e acúmulo de N, P, K, Ca, Mg e S pelas culturas de entressafra, bem como a dinâmica de decomposição e liberação dos nutrientes, por meio da utilização de sacolas de decomposição, com os seguintes períodos de avaliação: 15, 30, 60, 120 e 180 dias. A cobertura do solo foi avaliada após o manejo e ao final de cada ano agrícola. Amostras de solo foram coletadas nas camadas 0-10, 10-20 e 20-30 cm de profundidade em duas ocasiões, antes da semeadura das culturas de entressafra, em março, e de verão, em outubro, nos anos de 2008 e 2009. As amostras de solo foram submetidas às análises químicas para determinação dos teores... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In no-tillage system, the offseason crops residues are expected to maintain the soil covered in order to control soil erosion and to promote the nutrients cycling. The objective of this study was to evaluate the offseason crops dry matter quality and production, soil cover, residues decomposition and nutrient release and their effects on soil fertility, C content of humic substances, particulate and mineral associated organic matter fractions and summer maize and soybean yield. A field experiment has been carried out on a Rhodic Eutrudox at Jaboticabal, SP, Brazil (48°15'22'' W and 21°18'58'' S). A randomized split-block design with three replications was used. The treatments were the combination of three summer crops sequences (soybean-corn rotation, monoculture of corn and monoculture of soybean) with seven offseason crops (maize, grain sorghum, sunflower, sunn hemp, pigeon pea, oilseed radish and pearl millet). The cultivations started in 2002 and this study is related to 2008/2009 and 2009/2010 growing seasons. The offseason crops dry matter production and N, P, K, Ca, Mg and S accumulations were evaluated at management moment. The period of time to measure the residue decomposition and the nutrient release was 15, 30, 60, 120 and 180 days, using litter bags. The soil cover was evaluated after the offseason crops management and at the end of each growing season. The soil was sampled at 0-10, 10-20 and 20-30 cm soil depths in two occasions, before the offseason crops sowing, at March, and before the summer crops sowing, at October, in 2008 and 2009. Total organic C, pH, P, K, Ca, Mg and H+Al were determined in each soil samples. The soil samples obtained on October at 0-10 cm were submitted for physical and chemical organic matter fractionation, for particulate, mineral-associated, humic acid, fulvic acid and humin C content determination. The summer monoculture... (Complete abstract click electronic access below) / Doutor
157

Indicadores fisiológicos e produtividade de morangueiros cultivados sob mulchings e arranjos espaciais em cultivo a campo / Physiological indicators and productivity of strawberry plants grown under mulchings and spatial arrangements in cultivation field

Santin, Anderson 28 February 2014 (has links)
Made available in DSpace on 2017-07-10T17:36:53Z (GMT). No. of bitstreams: 1 2014_Diss_Anderson_Santin.pdf: 2075563 bytes, checksum: c35b4b0d2b620adb609fb0e13986da25 (MD5) Previous issue date: 2014-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The use of cover crops and planting density is directly related to productivity of strawberry plants grown in the field. Given to above, the aim of the present work was to evaluate the productive characteristics and levels of photosynthetic pigments of two cultivars of strawberry on types of mulchings, and numbers of rows per bed planting in the open system The experiments were carried out between May and December/2012 at the Experimental Farm "Prof. Dr. Antônio Carlos dos Santos Pessoa belonging to Unioeste, Campus of Marechal Cândido Rondon, PR. The first experiment was conducted in a randomized block design, factorial 2x4 (Two cultivars, being 'Camarosa' and 'Camino Real' x 4 types of mulchings, being black low-density polyethylene, silver low-density polyethylene, non woven tissue and no mulching) containing three replications. The second experiment was conducted in randomized complete blocks, 2x4 factorial (two cultivars being Camarosa and 'Camino Real' x 4 arrangements of plants per plot, with 1, 2, 3, 4 rows per plot), containing four replication. It was evaluated as pigment, the chlorophylls a and b, chlorophyll a+b and a/b ratio, average number of fruits plant-1, productivity (ton ha-1) or average mass plant-1, average fruit weight-1, soluble solids (Brix), total acidity, pH and soluble solids/total acidity. The mulchings of silver low-density polyethylene and non woven tissue presented lower productivity, not being recommended for the cultivation of strawberry cultivars Camarosa and Camino Real. From among the mulchings used in the present work, black low-density polyethylene was what gave better results, being recommended its use for cvs. Camarosa and 'Camino Real'. The spatial arrangement of plants with two and three rows were presented better results in productivity in the cultivation of the strawberry field / A utilização de cobertura de solo e densidade de plantio estão diretamente relacionadas a produtividade de morangueiros em cultivo a campo. Diante do exposto, objetivou-se com o presente trabalho avaliar as características produtivas e teores de pigmentos fotossintéticos de duas cultivares de morangueiro, sobre tipos de mulchings, e números de linhas por canteiro em sistema de plantio a céu aberto. Os experimentos foram realizados entre maio e dezembro/2012, na Fazenda Experimental Prof. Dr. Antônio Carlos dos Santos Pessoa , pertencente a Unioeste, Campus Marechal Cândido Rondon, PR. O primeiro experimento foi realizado no delineamento de blocos ao acaso, esquema fatorial 2x4 (duas cultivares, sendo Camarosa e Camino Real x 4 tipos de mulchings, sendo polietileno de baixa densidade preto, polietileno de baixa densidade prata, tecido não tecido e ausência de mulching), contendo três repetições. O segundo experimento foi realizado em delineamento de blocos ao acaso, esquema fatorial 2x4 (duas cultivares, sendo Camarosa e Camino Real x 4 arranjos de plantas no canteiro, sendo 1, 2, 3, 4 linhas por canteiro), contendo quatro repetições. Avaliaram-se como teores de pigmentos, as clorofilas a e b, clorofila a+b e relação a/b, número médio de frutos planta-1, produtividade (ton ha-1), massa média fruto-1, sólidos solúveis (°Brix), acidez total, pH e relação sólidos solúveis/acidez total. A Camarosa apresentou maior produtividade que a Camino Real . O TNT não é recomendado como mulching, pois não resistiu ao período de cultivo, e não se mostrou eficaz no controle de plantas daninhas. No PEBD preto obtiveram-se melhores resultados no cultivo de Camarosa e Camino Real . A Camarosa apresentou maior produtividade média e maior número de frutos por planta que a Camino Real . A Camino Real apresentou frutos maiores e de melhor qualidade. O cultivo com duas e três linhas por canteiro apresentaram melhores resultados para MMP e NMFP, podendo empregar três linhas a fim de otimizar a área de plantio, ou duas linhas quando se busca facilitar colheita e tratos culturais
158

Quantificação experimental da alteração no balanço hidríco e erosão em um neossolo quartzarênico devido à substituição de pastagem por cana-de-açúcar / Experimental determination of water balance and soil erosion changes due to pasture substitution by sugarcane

Cristian Pablo Youlton Millon 24 July 2013 (has links)
A cana-de-açúcar tornou-se a cultura com maior expansão nos últimos anos no estado de São Paulo, tendência que deve continuar, considerando sua importância como matéria prima para a produção de açúcar e etanol. Essa expansão acontece principalmente sobre áreas que eram ocupadas por pastagens. Pelas atividades necessárias para o estabelecimento da cultura de cana-de-açúcar, é esperado um aumento da erosão de solos e uma alteração no balanço hídrico. Com esses antecedentes, objetivou-se quantificar experimentalmente o impacto na erosão dos solos e a modificação do balanço hídrico no primeiro metro de solo, causado pela substituição de pastagem por cana-de-açúcar. Foram construídas parcelas de escoamento (20 x 5 \'M POT.2\') sob pastagem e sob plantio novo de cana-de-açúcar (três repetições cada) em uma fazenda com solo do tipo Neossolo Quartzarênico no município de Itirapina-SP. Foi instalada uma estação meteorológica para medir a precipitação e a umidade do solo a 30, 60 e 90 cm de profundidade, e para coletar os parâmetros necessários para calcular a evapotranspiração pelo método de Penman-Monteith. Calhas foram instaladas ao nível do solo para quantificar a interceptação do dossel de cana-de-açúcar. O balanço hídrico para ambos os cultivos foi determinado em escala diária. Após cada evento de precipitação, foi quantificada a perda de solos e o escoamento superficial Durante o primeiro ano, a perda de solo sob pastagem foi de 0,26 Mg/ha.ano (adicionalmente, 0,32 Mg/ha foram coletados devido à perturbação do solo para implantação do experimento), enquanto cana-de-açúcar produziu 2,58 Mg/ha.ano. No segundo período chuvoso, a perda de solo sob pastagem diminui para 0,04 Mg/ha, e sob cana-de-açúcar registrou 0,47 Mg/ha. Estes resultados indicam que a substituição de pastagem por cana-de-açúcar aumentou a produção de sedimentos durante o primeiro ano em 2,32 Mg/ha; no segundo período, com o uso da cobertura de palha no solo sob cana-de-açúcar, o aumento foi de 0,43 Mg/ha. Depois de quatro meses de crescimento, o dossel da cana-de-açúcar intercepta 40% da precipitação. O escoamento superficial no primeiro ano foi de 56,1 mm, e diminuiu para 11,8 mm no segundo período por efeito da palha na superfície do solo. Nos mesmos períodos, o escoamento superficial na pastagem foi de 40,5 mm e 30,4 mm, respectivamente. Apesar da menor infiltração sob cana-de-açúcar, o solo apresenta maior umidade devido ao gradeamento que aumenta a porosidade, e portanto, a capacidade de armazenamento de água no solo. A percolação sob cana-de açúcar é menor que sob pastagem devido à maior evapotranspiração da cultura. / Sugarcane became the culture with the highest expansion in recent years in the state of São Paulo. This trend will continue considering its importance as raw material for the production of sugar and ethanol. The expansion occurs primarily on areas that are currently occupied by pastures, causing impacts on soil and water. Due to the necessary activities for the establishment of the sugarcane culture, a soil erosion increase and a water balance change are expected. With this background, the objective of this work was to experimentally quantify the change in soil erosion and modification of water balance in the first meter of soil caused by the substitution of pasture by sugarcane. Runoff plots were constructed (20 x 5 \'M POT.2\') under pasture and new sugarcane planting (three replicates each) on a farm with Quartzarenic Neosol (Typic Quartzipsamments) soil in the municipality of Itirapina-SP. A weather station to measure rainfall and soil moisture at 30, 60 and 90 cm depth, and to collect the necessary parameters to calculate the evapotranspiration by Penman-Monteith method was installed. Gutters were installed at ground level to quantify the interception of the sugarcane canopy. After every precipitation event the soil loss and the drainage were quantified, and the daily water balance was determined for both soil uses. During the first year, the pasture had a soil loss of 0.26 Mg/ha.yr (additional 0.32 Mg/ha.yr were collected due to the disturbance of the soil during experiment installation), while sugarcane produced 2.58 Mg/ha.yr. In the second rainy season, the losses under pasture decreased to 0.04 Mg/ha and sugarcane recorded 0.47 Mg/ha. These results indicate that the replacement of pasture by sugarcane increased the sediment production during the first year by 2.32 Mg/ha in the second period, covering the soil under sugarcane with straw, the difference decreased to 0.43 Mg/ha. After four months of growth, the sugarcane canopy intercepts 40% of the precipitation. The runoff in the first year was 56.1 mm, decreasing to 11.8 mm in the second period, due to the presence of straw on the soil surface. In the same periods, runoff under pasture was 40.5 mm and 30.4 mm, respectively. Although there is less infiltration under sugar cane, the soil presents higher moisture due to the porosity increase by grating. The percolation under sugarcane is lower than in pasture due to a higher crop evapotranspiration.
159

dtwSat: Time-Weighted Dynamic Time Warping for Satellite Image Time Series Analysis in R

Wegner Maus, Victor, Camara, Gilberto, Appel, Marius, Pebesma, Edzer 29 January 2019 (has links) (PDF)
The opening of large archives of satellite data such as LANDSAT, MODIS and the SENTINELs has given researchers unprecedented access to data, allowing them to better quantify and understand local and global land change. The need to analyze such large data sets has led to the development of automated and semi-automated methods for satellite image time series analysis. However, few of the proposed methods for remote sensing time series analysis are available as open source software. In this paper we present the R package dtwSat. This package provides an implementation of the time-weighted dynamic time warping method for land cover mapping using sequence of multi-band satellite images. Methods based on dynamic time warping are flexible to handle irregular sampling and out-of-phase time series, and they have achieved significant results in time series analysis. Package dtwSat is available from the Comprehensive R Archive Network (CRAN) and contributes to making methods for satellite time series analysis available to a larger audience. The package supports the full cycle of land cover classification using image time series, ranging from selecting temporal patterns to visualizing and assessing the results.
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Classification of Urban Forms and Their Relationship with Vegetation Cover in Cache County, Utah

Peaden, Stephen J. 01 December 2019 (has links)
As residential urban development increases in the western United States, few studies have shown how different urban forms influence vegetation cover. The two studies in this thesis examine how to define and measure urban form in order to understand the relationship between urban form characteristics and vegetation cover. In the first study, urban form was defined by using past methods of identifying and measuring urban sprawl. Past studies showed the most essential metrics that define residential urban form are building density, centrality, connectivity, land use mix, and parcel size. This study reviews these metrics and proposes revised unified definitions and measurement methods. It is recommended that consistent definitions and methods be used in further research of urban form. Cache County, Utah was used as a study area to apply these methods as a representative community of the western U.S. Residential parcels were measured for each metric. A K-means cluster analysis assign each parcel to one of 50 groups based on metric measurement similarities. The 10 most widely used groups contained 87% of the residential parcels in Cache County. These groups represented urban forms with distinct identifiable characteristics such as Agricultural residential, urban sprawl, historic plat patterns, and evolved versions each. The second study used the metrics and groups from the first study to check for correlations with vegetation cover. A normalized difference vegetation index ( NDVI) of aerial imagery of Cache County was used to classify land cover into three groups: dense vegetation, light vegetation, and no vegetation. Measurements of vegetation cover were extracted for each parcel and each urban form group. Total vegetation cover ( TVC) and dense vegetation cover (DVC) measured higher in urban areas than in the county as a whole. Agricultural residential groups had among the highest TVC, but had the lowest DVC. Non-agricultural residential groups had the highest DVC as a percentage of TVC with the exception of group 4 “Modern Suburban Sprawl” which had the lowest DVC as a percentage of TVC. Group 7 “Satellite Centers” had the highest TVC while group 3 “Dead End Semi-sprawl” had the lowest TVC. Both groups 3 and 7 had the highest DVC as a percentage of TVC. A correlation analysis revealed that TVC had stronger correlations than DVC with urban form metrics. Building density had the strongest correlation with TVC (r = -0.62, p= 0). Correlations with TVC were also found with Parcel size (r = -0.23, p= <.001) and centrality (r = -0.21, p = <.001). Very weak relationships with TVC w ere found with connectivity and land use mix.

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