Fotopedologia, espectroscopia e sistema de informação geográfica na caracterização de solos desenvolvidos do Grupo Barreiras no Amapá

O presente trabalho utilizou ferramentas de sensoriamento remoto e sistema de informação geográfica, aliadas às informações espectrais do solo e quantitativas e qualitativas do relevo, para a caracterização e discriminação das classes de solos desenvolvidos do Grupo Barreiras na região do município de Porto Grande, Amapá. Após o mapeamento semidetalhado de solos, realizou-se a caracterização pontual das amostras dos perfis por meio de espectroscopia de visível e infravermelho (400-2500 nm), e a análise espacial das redes de drenagem e relevo a partir de fotos aéreas e imagens de radar. As informações quantitativas do relevo foram mais eficientes na caracterização e discriminação dos solos estudados do que as qualitativas, enquanto as informações espectrais permitiram caracterizar os solos em nível pontual. Métodos espaciais utilizando redes de drenagem e relevo e métodos espectrais utilizando amostras pontuais complementam-se na caracterização e discriminação de solos na paisagem.

Assessment of tropical forest degradation by selective logging and fire using Landsat imagery

Many studies have assessed the process of forest degradation in the Brazilian Amazon using remote sensing approaches to estimate the extent and impact by selective logging and forest fires on tropical rain forest. However, only a few have estimated the combined impacts of those anthropogenic activities. We conducted a detailed analysis of selective logging and forest fire impacts on natural forests in the southern Brazilian Amazon state of Mato Grosso, one of the key logging centers in the country. To achieve this goal a 13-year series of annual Landsat images (1992-2004) was used to test different remote sensing techniques for measuring the extent of selective logging and forest fires, and to estimate their impact and interaction with other land use types occurring in the study region. Forest canopy regeneration following these disturbances was also assessed. Field measurements and visual observations were conducted to validate remote sensing techniques. Our results indicated that the Modified Soil Adjusted Vegetation Index aerosol free (MSAVI(af)) is a reliable estimator of fractional coverage under both clear sky and under smoky conditions in this study region. During the period of analysis, selective logging was responsible for disturbing the largest proportion (31%) of natural forest in the study area, immediately followed by deforestation (29%). Altogether, forest disturbances by selective logging and forest fires affected approximately 40% of the study site area. Once disturbed by selective logging activities, forests became more susceptible to fire in the study site. However, our results showed that fires may also occur in undisturbed forests. This indicates that there are further factors that may increase forest fire susceptibility in the study area. Those factors need to be better understood. Although selective logging affected the largest amount of natural forest in the study period, 35% and 28% of the observed losses of forest canopy cover were due to forest fire and selective logging combined and to forest fire only, respectively. Moreover, forest areas degraded by selective logging and forest fire is an addition to outright deforestation estimates and has yet to be accounted for by land use and land cover change assessments in tropical regions. Assuming that this observed trend of land use and land cover conversion continues, we predict that there will be no undisturbed forests remaining by 2011 in this study site. Finally, we estimated that 70% of the total forest area disturbed by logging and fire had sufficiently recovered to become undetectable using satellite data in 2004. (C) 2010 Elsevier B.V. All rights reserved.

Dinâmica da ocupação do solo bacia do Rio Itiquira, Mato Grosso, Brasil

The study area corresponds to the basin of the Itiquira river high course, totalling 5,361km2. In this area a study of the environmental dynamics was made, applying SIG techniques and satellite images of the years 1966, 1985 and 1996. In 1966 the areas of natural vegetation (forests and groves) occupied 90.64% of the total of the area, which was diminished to 60.57% in 1985 and to only 36.66% in 1996. In this process, 289,382ha of a total of 485,928ha of natural vegetal covering had been lost. At the same time, the agrarian surfaces (agriculture and pasture) that occupied only 0.52% of the total area in 1966, increased to 34.89% in 1985 and to 59.04% in 1996. In 30 years there was an increase of 313,725ha of cultivated lands, corresponding to about 113 times the land occupation of the year of 1966 (2,798ha). The areas classified as urban show a gradual increase since 1966, from 39ha in 1996 to 58ha in 1985, and to 178ha in 1996. The other classes of soil use and occupation (reforestement areas, uncovered and affected by fire and humid areas) added were smaller than 4,27% in 1996.

Análise da incerteza na representação de classes de cobertura do solo urbano resultantes da aplicação de uma rede neural artificial

The great diversity of materials that characterizes the urban environment determines a structure of mixed classes in a classification of multiespectral images. In that sense, it is important to define an appropriate classification system using a non parametric classifier, that allows incorporating non spectral (such as texture) data to the process. They also allow analyzing the uncertainty associated to each class from the output alues of the network calculated in relation to each class. Considering these properties, an experiment was carried out. This experiment consisted in the application of an Artificial Neural Network aiming at the classification of the urban land cover of Presidente Prudente and the analysis of the uncertainty in the representation of the mapped thematic classes. The results showed that it is possible to discriminate the variations in the urban land cover through the application of an Artificial Neural Network. It was also possible to visualize the spatial variation of the uncertainty in the attribution of classes of urban land cover from the generated representations. The class characterized by a defined pattern as intermediary related to the impermeability of the urban soil presented larger ambiguity degree and, therefore, larger mixture.

Vulnerabilidade à erosão do solo da Região do Alto Rio Pardo, Pardinho, SP

This study aimed at the elaboration of a database with information and a map of erosion vulnerability for ecological zoning for the upper Pardo River, Botucatu, SP, by using the Geographical Information System - SPRING. The map of erosion vulnerability was made from spectrally homogeneous regions, producing a grid of zone averages, which was then subdivided, resulting in a vulnerability map to erosion. The results allowed us to conclude that digital imaging produced valuable information for mapping of soil use and database formation. The GIS - SPRING was efficient at identifying soil and vulnerability erosion classes and 95% of the basin presents a moderately stable vulnerability degree, through the presence of medium young soils in gently waring reliefs and covered by 49.27% of pasture and 29.88% crops.

Caracterização morfométrica da microbacia hidrográfica do Córrego da fazenda glória, Município de Taquaritinga, SP.

The analysis of morphometric characteristics is used to understand the relationship between soil and surface as a result of erosive processes on different structures and lithologies. The objective of this study was to study the morphometric characteristics of Fazenda Gloria watershed from 1983 to 2000, a fourth-order watershed in Taquaritinga Municipality, São Paulo State. The study was based on photointerpretation techniques. Drainage net and the respective watersheds were selected and the morphometric variables were determined. The watersheds consisted of 7 second-order watersheds and 2 third-order watersheds. The morphometric characteristics showed a reduction in the number of segments of first-order rivers and in the length of the drainage net during the study period. These findings could be related to several influences on land development considering occupation and use of land. A different hydrological behavior could also be observed. The analysis of Fazenda Glória Watershed showed that the length of the segment of fourth order river remained constant during the study period.

Geoprocessamento e sensoriamento remoto aplicado na determinação da aptidão agrícola de uma microbacia

Soil use for the development of activities as agriculture and livestock has been causing great alterations in the environment, mainly when these are practiced intensively, disrespecting the fragility and aptitude of the natural resources. Therefore, it is essential that the planning of the agricultural activities is done, taking into consideration the several environmental criteria involved in the decision-making process. Thus, this study aimed to analyze the agricultural aptitude classes of lands from a watershed through geographical information system (GIS). The Arroio Ajuricaba watershed is located in the Municipality of Marechal Cândido Rondon - PR among the coordinates UTM 787309m E and 793892m E; 7275026m N and 7281310m N, in the Spindle 21, presenting an area of 1681ha. Soil maps, in semi detail scale, was the digital cartographic base used. The results allowed to conclude that 42.41% of the basin presented a good aptitude for farming in handling level of high technology (handling level C), regular aptitude for B, and restricted aptitude for A [class 1(a)bC] and that 12% of the area had regular aptitude for farming in the three handling levels (class 1abc). The watershed lands (14.24%) presented regular aptitude for farming in handling level C, restricted aptitude for B, and inapt for A [class of aptitude 2(b)c]; 15.85% presented good aptitude for planted pasture (class 4P) and 12.21% were considered without aptitude for agricultural use (class 6). We can say that 71.94% of the lands has aptitude for farming, although they present different degrees of limitations that request different treatments for its conservation.

Sistema de informações geográficas aplicado à espacialização da capacidade de uso da terra

This research aimed to study land use capability classes in Pratânia, São Paulo State, Brazil, by using the Geographic Information System (GIS), in order to find out the appropriate planning system for soil use. The watershed covers an area of 21,773.61 ha and is located among the coordinates 22°44'48S and 22°52'17S and 48°38'21W and 48°48'07W. The land use capability map was made from the slope and soil maps, based on the features of each kind of soil and the land use capability table for class assessment. It was possible to conclude that IIIs was the most significant subclass. Slope classes from 0% to 20% were present in more than 97% of Pratânia, being the plane areas the most representative ones (55%). GIS showed to be an excellent tool for determining land use capability, because the geoprocessing use facilitates and activates the digital data crossing, allowing its storage for future environmental planning.

Geoinformação na gestão dos recursos hídricos em sub-bacia hidrográfica

By remote sensing, geodatabase digital processing, information and expeditions to Capivara's sub-basin, was possible to identify the changes in the landscape mainly the expansion of eucalyptus, sugar-cane, and orange trees, being the last two, mainly on the Periferic Depression of Basaltic Cuesta. A significant portion of the soil on this geological area is formed from sandstones, providing high permeability to them, making them important places to groundwater recharge areas as sensible to contamination by pesticides. Throughout last decade was observed that the native vegetation fragments stabilization, keeping a reason of 26.5% on the land used between 2000 and 2010. The pasture decrease being substituted by eucalyptus, sugar-cane and orange trees call attention for the changes in the agribusiness model demanded by the current economic and social necessity. Pasture decrease followed by erosions decrease on sub-basin is evidence that these two aspects are strongly related.

Zoneamento geoambiental aplicado ao planejamento da gestão ambiental e territorial do município de Colorado D'Oeste, RO

This research is based on the physical characterization of the environment to support definition of the best land use for the county of Colorado D'Oeste, in State of Rondônia, Brazil. Remote sensing and geoprocessing techniques were applied to support the preparation of a Geoenvironmental Zoning, which was used to define strategies of territorial and environmental management in that county. Digital and analogical remote sensing products, acquired by satellites, and additional cartographic and thematic maps allowed a morphostructural analysis to define low and high structural associated study site tectonic. Subsequently, this information was used to support analysis of the physiographic compartmentation of the study area. Based on this study information, it is possible to define geoenvironmental subzones and local hidrological regime, soils, mineral components, texture, color, and sedimentary materials. By integrating previous described information, a synthesis cartographic map generated. Accordingly, this Cartographic Sheet spatially defined the best land use over the study area, indicates zones for conservation, agricultural, and regeneration (areas that should be recovered). Finally, the results of this research can contribute and support governmental and non-governmental organization and local communities could improve land use and soil management, avoiding natural resource destruction and future land scarcity in the county of Colorado D'Oeste.

Análise de fraturamentos para determinação de áreas instáveis na faixa de dutos Osvat/Osplan - São Sebastião, em São Paulo

The present work aimed at characterizing geological features that identify areas with high ruptibility (fracturing) in the Osvat/Osplan pipeline in São Sebastião, São Paulo. The analysis of ruptile geological structures (lines of strikes and structural lineaments) through the use of orbital remote sensing was used as systematic mapping. The analysis of these features enables the inference of factors, such as permeability, infiltration and degree of shear in the region, factors which influence the processes of erosion and landslides in the area. On the map of structural lineaments, points of lineaments intersection from different directions were analyzed, followed by the counting of the frequency of these items per unit area, allowing the statistical modeling of spatial distribution, generating the map of density of structural lineament intersections, which allows determining areas with the highest percolation of fluid in the rock structure. However, on the map of lines of strikes, a space analysis was conducted to identify the two directions with higher frequency of lines of strikes in order to establish the maximums 1 and 2 and to identify the areas of abrupt changes of direction of these strike lines. In such areas where abrupt changes of directions of maximum lines of strikes occur, consequently there will be intense percolation of fluids, responsible for higher alterability of the rock/soil complex, facilitating the installation of erosion processes and landslides, increasing the area instability and consequently the vulnerability of the pipeline.

Correlação espacial do índice de vegetação (NDVI) de imagem Landsat/ETM+ com atributos do solo

The precision agriculture technologies such as the spatial variability of soil attributes have been widely studied mostly with sugarcane. Among these technologies have been recently highlighted the use of the vegetation index derived from remote sensing products, such as powerful tools indicating the development of vegetation. This study aimed to analyze the spatial variability of clay content, pH and phosphorus in an Oxisol in an area with sugarcane production, and correlate with the Normalized Difference Vegetation Index (NDVI). The georeferenced grid was created for the soil properties (clay, phosphorus and pH) and generated the maps of spatial variability. For these same sites were calculated the NDVI, in addition to mapping of this ratio, the evaluation of the spatial correlation between this and other studied properties. The clay and phosphorus content showed positive spatial correlation with the NDVI, while no spatial correlation was observed between NDVI and pH. The satellite images from the sensor ETM + Landsat were used to correlate to NDVI to observe the spatial variability of the studied attributes.

Geotechnology applied to land use and sealing in urban areas

Through the geotechnology's use, the aim of this study was to characterize the urban occupation interference and occurrence of floods in the upstream area of watershed from the stream Wenzel (Rio Claro-SP/Brazil). Urbanized watersheds are composed of a variety of features and the development of cartographic material allowed the analysis of the evolution of land used for 1958 and 2006 scenarios. The thematic maps were generated using software Spring 4.3.3, wherein it got the separation of matters from vegetation cover and other intra urban features. Procedures of digital processes and classification of surface cover allowed quantifying the occupied area by each coverage type: woody vegetation, grass, grass with bare soil, bare soil, building, asphaltic sheets and exposed soil. Quantification of the different covers' occupied areas allowed relating the parameter Curve Number (Soil Conservation Service) as efficient methodology for runoff values estimative. The results indicate vegetation cover's reduction, intensive surface's sealing and suppression of water bodies. These factors imply changes of hydrological dynamics of the source, increasing flow and transfer of larger volumes of water and flood peaks to downstream sectors. The use of geotechnology allowed analyzing the evolution of urbanization and it permits also to infer about trends for future or inadequate occupancy to hydrological and environmental point of view. © 2013 IEEE.

Greenhouse gas mitigation potential from green harvested sugarcane scenarios in São Paulo State, Brazil

Brazil is a major sugarcane producer and São Paulo State cultivates 5.5 million hectares, close to 50% of Brazil's sugarcane area. The rapid increase in production has brought into question the sustainability of biofuels, especially considering the greenhouse gas (GHG) emissions associated to the agricultural sector. Despite the significant progress towards the green harvest practices, 1.67 million hectares were still burned in São Paulo State during the 2011 harvest season. Here an emissions inventory for the life cycle of sugarcane agricultural production is estimated using IPCC methodologies, according to the agriculture survey data and remote sensing database. Our hypothesis is that 1.67 million hectares shall be converted from burned to green harvest scenarios up to years 2021 (rate 1), 2014 (rate 2) or 2029 (rate 3). Those conversions would represent a significant GHG mitigation, ranging from 50.5 to 70.9 megatons of carbon dioxide equivalent (Mt CO2eq) up to 2050, depending on the conversion rate and the green harvest systems adopted: conventional (scenario S1) or conservationist management (scenario S2). We show that a green harvest scenario where crop rotation and reduced soil tillage are practiced has a higher mitigation potential (70.9 Mt CO2eq), which is already practiced in some of the sugarcane areas. Here we support the decision to not just stop burning prior to harvest, but also to consider other better practices in sugarcane areas to have a more sustainable sugarcane based ethanol production in the most dense cultivated sugarcane region in Brazil. © 2013 Elsevier Ltd. All rights reserved.

Análise da incerteza na representação de classes temáticas resultantes da aplicação de uma rede neural artificial

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)