Periódicos
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
Navegar
4 resultados
Resultados da Pesquisa
Item Modis images for agrometeorological monitoring of coffee areas(Editora UFLA, 2013-04) Volpato, Margarete Marin Lordelo; Vieira, Tatiana Grossi Chquiloff; Alves, Helena Maria Ramos; Santos, Walbert Júnior Reis dosAgrometeorological monitoring of coffee lands has conventionally been performed in the field using data from land-based meteorological stations and field surveys to observe crop conditions. More recent studies use satellite images, which assess large areas at lower costs. The Moderate Resolution Imaging Spectroradiometer (MODIS) sensor of the Earth satellite provides free images with high temporal resolution and vegetation specific products, such as the MOD13, which provides the Normalized Difference Vegetation Index (NDVI) processed in advanced. The objective of this study was to evaluate the relation between the NDVI spectral vegetation index and the meteorological and water balance variables of coffee lands of the south of Minas Gerais in order to obtain statistical models of this relationship. The study area is located in the municipality of Três Pontas, Minas Gerais, Brazil. The statistical models obtained demonstrate a significant negative correlation between the NDVI and water deficit. NDVI values under 70% may represent a water deficit in the coffee plants. The models developed in this study could be used in the agrometeorological monitoring of coffee lands in the south of Minas Gerais.Item Imagens do sensor modis para monitoramento agrometeorológico de áreas cafeeiras(Editora UFLA, 2013-04) Volpato, Margarete Marin Lordelo; Vieira, Tatiana Grossi Chquiloff; Alves, Helena Maria Ramos; Santos, Walbert Júnior Reis dosO monitoramento agrometeorológico de áreas cafeeiras tem sido realizado convencionalmente em campo utilizando-se dados de estações meteorológicas terrestres e visitas à lavoura para se observar seu desenvolvimento. Estudos mais recentes utilizam imagens de satélite, que permitem avaliar grandes áreas a custos menores. O sensor Moderate Resolution Imaging Spectroradiometer (MODIS) do satélite Terra oferece gratuitamente imagens com alta resolução temporal e produtos voltados especialmente para vegetação como o MOD13, que fornece o índice de vegetação Normalized Difference Vegetation Index (NDVI) previamente processado. Objetivou-se, no presente estudo, avaliar a relação entre o índice de vegetação espectral NDVI e as variáveis meteorológicas e do balanço hídrico, em áreas cafeeiras do sul de Minas Gerais, visando à obtenção de modelos estatísticos dessa relação. A área de estudo localiza-se no município de Três Pontas, estado de Minas Gerais, Brasil. Os modelos estatísticos desenvolvidos demonstram a correlação significativa negativa entre o NDVI e déficit hídrico. Valores de NDVI menores que 70% podem indicar a deficiência hídrica de cafeeiros. Os modelos desenvolvidos no presente estudo poderão ser usados no monitoramento agrometeorológico de lavouras cafeeiras na região sul de Minas Gerais.Item Geothecnologies in the assessment of land use changes in coffee regions of the state of Minas Gerais in Brazil(Editora UFLA, 2007-07) Vieira, Tatiana Grossi Chquiloff; Alves, Helena Maria Ramos; Bertoldo, Mathilde Aparecida; Souza, Vanessa Cristina Oliveira deCoffee is one of Brazilian most important cash crops due to the incomes generated by exportation. Southern Minas Gerais State represents approximately half of the total national production, although the greatest expansion of the crop has been observed in the western part of the state ( Triângulo Mineiro and Alto Paranaíba regions). As a requirement for future planning, it is important to establish efficient methodologies to map and monitor these lands, with the possibility of an easier periodical updating of the information. In this work geotechnologies were used to evaluate changes, in space and time, of areas occupied by coffee plantations in Minas Gerais. Land use maps of study areas selected in the main producing regions of the state were generated for the years 2000 and 2003 using the GIS SPRING and Landsat images. The results of the quantitative comparison of these maps indicated different behaviours for the regions evaluated. In São Sebastião do Paraíso and Machado, countries (south of Minas Gerais), a decrease of the areas occupied by coffee was observed, whereas in Três Pontas, increased. In Patrocínio, western part of the state, the area occupied by the crop remained unaltered. Remote sensing and GIS were efficient in the evaluation of the spatial-temporal dynamics of coffee lands of Minas Gerais, providing a greater understanding of the different environments and information that can support regional land use planning.Item Crop parameters and spectral response of coffee and spectral response of coffee (Coffea arabica L.) areas within the state of Minas Gerais, Brazil(Editora UFLA, 2006-07) Vieira, Tatiana Grossi Chquiloff; Alves, Helena Maria Ramos; Lacerda, Marilusa Pinto Coelho; Veiga, Ruben Delly; Epiphanio, José Carlos NevesThis work compares coffee plantation (Coffea arabica L.) characteristics to their spectral responses in TM/ Landsat images to obtain identification patterns to be used in mapping and monitoring of coffee crops in the state of Minas Gerais using remote sensing. The fieldwork involved selection of representative areas from the main coffee production regions of the state, with definition of study areas from where the coffee parameters and environmental data were collected. Two pilot-areas representative of the physiographic regions, Alto Paranaíba and Sul de Minas were selected for the study. The field data and TM/Landsat images were treated with the SPRING geographic information system. The reflectance data, as well as the remaining data collected in the field, were organized in a statistical programme for correlation studies. The statistical analysis showed that, among the fourteen variables evaluated, the highest correlation was observed between reflectance measured in the near infrared zone and the percentage of area covered by the plant canopies. This parameter reflects the effects of other crop variables, such as size, diameter, density, vegetative vigour and productivity. Results show that, due to the great variability of the crop and the limitations imposed by TM/Landsat products, the definition of a pattern is unlikely. Nevertheless, for productive adult coffee plants in good vegetative state, the survey and monitoring of the crop can be carried out using TM/Landsat images, particularly in regions like Alto Paranaíba , where the landscape is mostly of gently undulating slopes and the coffee fields are more extensive and homogeneous.