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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item Water erosion in oxisols under coffee cultivation(Sociedade Brasileira de Ciência do Solo, 2018) Mendes Júnior, Henrique; Tavares, André Silva; Santos, Walbert Júnior Reis dos; Silva, Marx Leandro Naves; Santos, Breno Régis; Mincato, Ronaldo LuizWater erosion is one of the main environmental impacts of land use. When soil and water losses occur, nutrients essential for the growth and maintenance of plants are removed, with harmful outcomes on the sustainability of agriculture and the environment. In addition, they lead to other deleterious effects, such as sedimentation and eutrophication of water bodies. Estimation of soil losses due to water erosion in sub-basins is essential for prediction of soil degradation, especially in areas of semi-intensive cultivation, such as coffee fields. Thus, the aim of this study was to estimate soil losses in relation to the limit of soil loss tolerance in Oxisols (Latossolos Vermelhos Distróficos) under coffee cultivation. This study was conducted from March 2015 to January 2017 in the Córrego da Laje Hydrographic Sub-basin in the municipality of Alfenas in the southern region of Minas Gerais, southeastern Brazil. Soil losses due to water erosion were estimated from the revised universal soil loss equation and compared to soil loss tolerance. Morphological, physical, and chemical properties of the soil were used, as well as geoprocessing techniques, remote-sensing images, and data from the literature. The results show potential soil losses from 0.01 to 18.77 Mg ha -1 yr -1 , with an average of 1.52 Mg ha -1 yr -1 . The soil loss tolerance ranged from 5.19 to 5.90 Mg ha -1 yr -1 , with 7.35 % of the area having larger losses. Areas with steeper slopes and no sustainable practices have soil losses above the tolerance level and are thus a priority for adoption of measures to mitigate erosive effects. The revised universal soil loss equation enabled water erosion modeling and identification of areas with the highest rates of potential soil loss in watersheds.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.