Fabrício de Araújo Pedron

A aptidão de uso da terra como base para o planejamento da utilização dos recursos naturais no município de São João do Polêsine - RS

The lack of knowledge on land use suitability and appropriate planning of its use have been a frequent reality causing negative impacts on the environment. In this way, the objective of this research was to determine land suitability, current land use and conflicts of use, seeking to contribute for the rational planning of the natural resources in the Sao Joao do Polesine (SJP), RS. The environmental analysis was made through the integration of different plans of information as soils, relief, hydrography, agricultural suitability, land use and areas of permanent preservation (APP). SJP presents more than 50% of its area destined to agricultural activities, 14.8% of the SJP are framed as APP, with half of that area being used inadequately. The main problems of the county are related to the inadequate use of natural resources, without considering information regarding to the environmental legislation and land suitability, in the planning process.

Regressões Logísticas Múltiplas: fatores que influenciam sua aplicação na predição de classes de solos

More effective methodologies to determine the soil class distribution must be evaluated in order to meet the demand for soil maps at regional and global scales. In this study, logistic regressions were used as predictive models in an application of Digital Soil Mapping. The models were derived from an existing soil map as dependent variable and terrain attributes as independent variables. The probability of finding soil classes in the landscape at the 1st and 2nd Categorical Level of the Brazilian System of Soil Classification (SiBCS) was determined. The quality of the predicted map was tested using a contingency matrix. Approximately 85 % of the Acrisols (Argissolos) were correctly predicted, in relation to the original map. Of the hydromorphic soils, 75 % were correctly predicted. The prediction was inaccurate for classes in very similar positions in the landscape. It was also found that the non-representative soil classes of the landscape were not properly spatialized, due to sensitivity of the logistic models to the relative proportion of the samples used to adjust the models.

Parâmetros biométricos de fruto, endocarpo e semente de butiazeiro

The pindo palm (Butia capitata (Mart.) Becc.) occurs naturally in the south of Brazil. This specie has a high ecological, ornamental and industrial potential that have not yet been explored. Information about biometrical variations of size and weight of fruits and seeds, as well as their correlations, may support a selection of seeds with higher germination and vigor. The objectives of this study were to quantify fruit, endocarp and botanical seed size and weight variations of pindo palm and their correlation. There was a high, positive correlation between weight and size of fruits and endocarps. Endocarps with two seeds had the highest medium seed weight.

Utilização do sistema de avaliação do potencial de uso urbano das terras no diagnóstico ambiental do município de Santa Maria - RS

The accelerated urban expansion has promoted several negative impacts on the environment. The need of new methodologies that allows a more appropriate planning of the natural resources grows constantly. The objective of this research was to accomplish an environmental diagnostic in urban areas of Santa Maria - RS, Brazil, determining the land use conflicts through the Urban Land Use Potential System. Products and techniques of remote sensing and image geoprocessing were used. Improper land use is related to the fragility of the geological material and soil resources. Up to 33% of the area is used above its potential with inadequate construction and urban agriculture.

Extrapolação das relações solo-paisagem a partir de uma área de referência

The aim of this study was to apply an automated technique of soil mapping from predictive models developed at a reference area, into nearby areas of the same soil-landscape relationships. Generalized linear models were developed using nine terrain attributes derived from a digital elevation model as covariate predictors, with soil classes, obtained from a conventional soil survey, as dependent variables. The models were able to distinguish the three main forms of the local landscape. Soil classes with pedogenesis intimately tied to the predictive covariates obtained the best results. The soil maps generated, showed a reproducibility of 46.12% and an accuracy of 21.06%.

Morfologia dos contatos entre solo-saprolito-rocha em neossolos derivados de arenitos da formação caturrita no Rio Grande do Sul

The use of the shallow Neossolos (Leptosols and Regosols) is limited in view of the small depth and rock fragments on the surface. There is a lack of information about the definition of the contacts between soil, saprolite and rock in this soil class, as well as tools that would facilitate the morphologic field identification. The objectives of this research were an evaluation of the morphology of the contact between soil, saprolite and rock in the Neossolos derived from the sandstones of the Caturrita Formation, in the central area of Rio Grande do Sul State; to test and to adapt the weathering classes of Pedron et al. (2009) to the conditions of sedimentary rock; and to verify the correlation of the weathering classes with penetration resistance. It was stated that the morphology of the saprolithic layers of the Neossolos Litolicos (Leptosols) and Neossolos Regoliticos (Regosols) derived from sandstone are similar to the same soil classes derived from volcanic rocks in the State, allowing the adaptation of the same weathering classes proposed by Pedron et al. (2009). The tests with the impact penetrometer showed high correlation with the weathering classes adapted in this study. The following contacts were identified in the studied profiles: lithic contact, lithic fragmentary contact, and saprolithic fragmentary contact. The authors suggest, considering its importance, the inclusion of this latter in the Brazilian soil classification system.

Relação entre as características e o uso das informações de levantamentos de solos de diferentes escalas

The relationship between the characteristics and use of information of the reconnaissance soil survey map of the state of Rio Grande do Sul in the scale of 1:750.000 and the semidetailed maps of the Sao Joao do Polesine county (SJP), in the scale of 1:20.000, and Sao Pedro do Sul county (SPS), in the scale 1:50.000 was studied. For this purpose the total area, in hectares, was compared, and the percentage of area of the counties occupied by the different soil classes, delineated in different maps. Differences were verified concerning the main classes of soils delineated in the maps and also in the percentage of distribution of the area occupied by the classes in these maps. For this reason, the enlargement of soil maps of small scale doesn’t permit to identify and to delineate soils that occur in the studied area, and which were not mapped due to the limitations in scale. For planning use of soils in watersheds, counties and farm areas, detailed and semidetailed surveys should be elaborated.

Medida da cor em solos do Rio Grande do Sul com a carta de Munsell e por colorimetria

The soil color is easily determined through the visual comparison with the Munsell charts and relates with the presence of iron oxides and organic matter in the soil. The color measurement by instruments through remote sensing has greater precision due to controlled, non-subjective conditions. The aims of this research were to compare the color of different soils from Rio Grande do Sul State Brazil measured by the Munsell charts and colorimetry and to correlate the color with the soil characteristics. The smallest variability in determining color through Munsell chart was observed in the hue component and the largest in the chrome. The correlation coefficients showed that there is coherence among the color measurements using Munsell chart and the colorimeter. The colorimeter was efficient to quantify color, eliminating psicophysics errors typical of the visual method. The characteristics of the soils analyzed presented high correlations with the components of the color obtained by colorimetry, inidicating this technique as efficient and promising to obtain information of the soil in a simple way with low cost.

Identificação de fontes de produção de sedimentos em uma bacia hidrográfica de encosta

O uso do solo fora de sua aptidao agricola e o que norteia a degradacao dos recursos naturais por meio das atividades antropicas. As atividades agropecuarias estao entre as que mais perturbam o meio ambiente, expondo o solo a acao dos processos erosivos e acelerando a transferencia de sedimentos aos corpos de agua. Nos ultimos anos, o metodo fingerprinting para identificacao de fontes de sedimentos tem sido utilizado com sucesso no mundo, porem, trabalhos dessa natureza realizados no Brasil ainda estao em carater incipiente. O objetivo deste trabalho foi estimar a proporcao de contribuicao das principais fontes de producao de sedimentos de uma bacia hidrografica de encosta, onde predominam solos rasos e agricultura menos intensiva no sistema familiar. Essa bacia esta localizada na regiao central do Estado do Rio Grande do Sul, tendo por ocupacao do solo predominante areas de floresta nativa seguida das de campo nativo, capoeira, lavouras anuais e, em menor expressao, silvicultura (eucalipto) e area urbanizada. Para a identificacao das fontes, foi utilizado o metodo fingerprinting, que compara os solos de diferentes fontes, e os sedimentos, que sao encontrados em suspensao no canal de drenagem, usando elementos tracadores. As maiores contribuicoes na producao de sedimentos sao provenientes da erosao superficial do solo. Para o primeiro periodo de monitoramento, foi identificada uma producao relativa de sedimentos de 60 % das estradas, para o ponto T2; de 100 % da malha, para o T3; e de 77 % da malha, para o T4. Para o segundo periodo de monitoramento, as estradas contribuiram relativamente com 81 % do sedimento em suspensao no ponto T2 e com 76 %, no T3. Ja no ponto T4, a maior contribuicao foi da malha com 82 %. O metodo se apresentou sensivel em detectar mudancas na contribuicao de cada fonte em razao das caracteristicas apresentadas por cada uma delas, para o tipo de bacia hidrografica estudada.

An appropriate data set size for digital soil mapping in Erechim, Rio Grande do Sul, Brazil

Digital information generates the possibility of a high degree of redundancy in the data available for fitting predictive models used for Digital Soil Mapping (DSM). Among these models, the Decision Tree (DT) technique has been increasingly applied due to its capacity of dealing with large datasets. The purpose of this study was to evaluate the impact of the data volume used to generate the DT models on the quality of soil maps. An area of 889.33 km² was chosen in the Northern region of the State of Rio Grande do Sul. The soil-landscape relationship was obtained from reambulation of the studied area and the alignment of the units in the 1:50,000 scale topographic mapping. Six predictive covariates linked to the factors soil formation, relief and organisms, together with data sets of 1, 3, 5, 10, 15, 20 and 25 % of the total data volume, were used to generate the predictive DT models in the data mining program Waikato Environment for Knowledge Analysis (WEKA). In this study, sample densities below 5 % resulted in models with lower power of capturing the complexity of the spatial distribution of the soil in the study area. The relation between the data volume to be handled and the predictive capacity of the models was best for samples between 5 and 15 %. For the models based on these sample densities, the collected field data indicated an accuracy of predictive mapping close to 70 %.