994 resultados para Classificação dos solos


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Giving a special emphasis on soil classification relative to their positions in the landscape, five soil profiles in the Barra Bonita-Jau area were characterized through morphological, granulometric and chemical routine soil analysis. It was observed that the soil structure gradually changes from strong blocks with cutans (lowlands and smooth parts - Jau). In this direction, the silt/clay ratio and the base saturation is reduced, and the aluminium saturation increases. -from English summary

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The following soil classes were identified in the studied area: Quartz Sands (AQ), Yellow Red Podzolic, Dusky Red Latosol (LR), 'Terra Roxa estruturada' (TE), Lithosol substrate sandstone (Lia) and Hidromorphic (Hi). The dimensional analysis method allowed: a) to group the watershed whose percentage (60%) are showing predominance of the same soil (Quartz Sands) and which located in the same relief; b) to group watersheds with different soil classes, but with similar percentages. -from English summary

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The objective of the present work was the improvement of the methodology for soil mapping through the drainage network with the aid of Landsat data. The drainage network of the area studied was delineated and the soils identified. The main problem of the method has been the characterization of the contact between soil units when it is not abrupt, and in this case field trips and the analysis of the relief has been used to solve doubts.-from English summary

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Analysis of the taphonomic signatures of a well preserved, silicifled coquina (Pinzonella neotropica assemblage) from the Camaquã outcrop, upper part of the Corumbataí Formation (Late Permian), in the Rio Claro region, state of Sáo Paulo, allowed interpretation of processes involved in its origin as related to high energy events (storms). The coquina occurs as a lenticular body, 2-11 cm thick and extending laterally for about 120 m. Basal contact of the coquina is sharp and erosive. Its upper contact is sharp. The concentration is dominated by pelecypods including the shallow burrowers (Pinzonella neotropica, Jacquesia brasiliensis), intermediate burrower (Pyramus anceps) and semi-infaunal forms (Naiadopsis lamellosus). All these species are suspension feeders. Besides sand-sized or even smaller shell fragments, there occur disarticulated, complete shells which are commonly abraded but do not show any signs of bioerosion or incrustation. In vertical side view, the shells are mainly convex-up, nested or stacked, while in plan-view they show random orientation. Multiple discontinuous grading is visible. These taphonomic signatures suggest that the origin of the skeletal accumulation is related to high energy events (possibly storm flows) in a proximal environment. The amalgamated nature of the Camaquã coquina records several episodes of erosion and deposition.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Soils submitted to the same management system in places with small relief variation manifest different spatial variability on their attributes. The objective of this work was to evaluate the spatial variability of the geometric medium diameter, aggregates in the >2 mm class, aggregates in the 2-1 mm class and organic matter of an Oxisol under culture of the sugarcane. Samplings of the soil in regular intervals of 10 m, in grid form, totaling 100 points, collected in the depths of 0.0-0.2 m and 0.2-0.4 m were made. Data were submitted to descriptive statistics, geostatistics and in sequence to kriging analyzes. Values of the variation coefficient were low for organic matter in the depth of 0.0-0.2 m, mean in the depth of 0.2-0.4 m, high for geometric medium diameter and mean for aggregates in the >2 mm class, aggregates in the 2-1 mm class in all studied depths. The occurrence of space dependence was observed for all the variables, and the largest ones were observed in the depth of 0.0-0.2 m. Small variations in the forms of the relief condition spatial variability differentiated for organic matter and stability of aggregates in the studied depths.

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One of the main problems in Computer Vision and Close Range Digital Photogrammetry is 3D reconstruction. 3D reconstruction with structured light is one of the existing techniques and which still has several problems, one of them the identification or classification of the projected targets. Approaching this problem is the goal of this paper. An area based method called template matching was used for target classification. This method performs detection of area similarity by correlation, which measures the similarity between the reference and search windows, using a suitable correlation function. In this paper the modified cross covariance function was used, which presented the best results. A strategy was developed for adaptative resampling of the patterns, which solved the problem of deformation of the targets due to object surface inclination. Experiments with simulated and real data were performed in order to assess the efficiency of the proposed methodology for target detection. The results showed that the proposed classification strategy works properly, identifying 98% of targets in plane surfaces and 93% in oblique surfaces.

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The use of phosphate fertilizers and amendments in sugar cane crops may increase the concentration of some elements in soils, from where they would become available for plants (principally in acid soils) and transferred to me human food chain. This paper reports the transference of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn), fluorine and radionuclides ( 238U, 234U, 226Ra, 232Th and 40K) from phosphate fertilizers and amendments to agricultural soils at Corumbatal River basin (SP). The products utilized and colleted in sugar cane crops at Corumbatai River basin are: phosphate fertilizers NPK 5:25:25 (two samples), limestones (three samples), phosphogypsum (two samples) and KCl (two samples). The heavy metals were determined by atomic absorption spectrometry (AAS), fluorine by potentiometry and radionuclides by alpha and gamma spectrometry. Heavy metals (17.8, 31.2, 75.2, 69.5, 138.8, 114.9 and 342.9 g/ha of Cd, Cr, Cu, Ni, Pb, Zn and F, respectively) and radionuclides (0.47, 0.16, 0.17 and 6.33 Bq/kg of soil to 238U, 226Ra, 232Th and 40K, respectively) incorporated in phosphate fertilizers and amendments are annually added in the sugar cane crops, but if utilized in accordance with the recommended rates, they do not raise the concentration levels in soils up to hazards values.

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The chemical and physical degradation of the soils by salinity and sodicity problems constitutes a serious obstacle in productive irrigated areas in arid and semi-add regions. In order to eval mate the effect of gypsum on electrical conductivity, pH, exchangeable sodium percentage, sodium, calcium and magnesium content in saturation extract and exchangeable sodium of two saline-sodic soils: one from irrigated Perimeter Engenheiro Arco Verde in the municipality of Condado and another from irrigated Perimeter of São Gonçalo, in the municipality of Sousa both in the Paraiba State Brazil, an experiment was carried out in green house of the Departamento de Solos e Engenharia Rural, Centro de Ciências Agrárias, Universidade Federal da Paraíba, Areia, Brazil, in a factorial design 2 × 5 referring the two soils and five gypsum levels equivalent to 0; 3.2; 6.3; 9.4 and 12.5 g kg-1 to each soil. The gypsum application exercised positive effects on reduction of salinity and sodicity. The values of electrical conductivity, exchangeable sodium percentage, pH and contents of soluble and exchangeable sodium in relation to data of the soils before application of treatments with gypsum in both the soils were found to decrease.

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Forest roads are frequently pointed as source of environmental problems related to erosion and they also influence harvest cost due to maintenance operations. Roads not well designed are sources of hydrological problems on catchments and the current attention to sustainability of forest exploration projects point out to the need of diagnostics tools for guiding the redesign of the road system. At this study, runoff hydrological indicators for forest road segments were assessed in order to identify critical points of erosion and water concentration on soils. A road network of a forest production area was divided into 252 road segments that were used as observations of four variables: mean terrain slope, main segment slope, LS factor and topographic index. The data analysis was based on descriptive statistics for outliers' identification, principal component analysis and for variability study between variables and between observations, and cluster analysis for similar segments groups' identification. The results allowed classifying roads segments into five mains road types: road on the ridge, on the valley, on the slopes, on the slopes but in a contour line and on the steepest slope. The indicators were able to highlight the most critical segments that differ of others and are potential sources of erosion and water accumulation problems on forest roads. The principal component analysis showed two main variability sources related to terrain topographic characteristics and also road design, showing that indicators represent well those elements. The methodology seems to be appropriated for identification of critical road segments that need to be redesigned and also for road network planning at new forest exploration projects.

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The mineralogical composition of the soil plow layer (0-20 cm) was analyzed for the following soil suborders (according to the Brazilian soil taxonomy): Neossolo Quartzarênico. Argissolo Vermelho-Amarelo, Cambissolo Háplico and Latossolo Vermelho-Amarelo which samples were collected from different regions of the Ceará State. The present study had the objectives of identifying potential sources of both total and non-exchangeable potassium forms for plants located at the different soil fractions. Then highest content of K occurred in the Cabissolo Háplico soil, including both the total and non-exchangeable K forms. In the Neossolo Quartzarênico. Argissolo Vermelho-Amarelo and Latossolo Vermelho-Amarelo, the highest contents of both forms of potassium were impregnated at the sand fraction. The amount of potassium found in the both sand and silt fractions has its origin in the orthoclase mineral which was detected in the mineralogical analysis. In the clay fractio, the origin of the potassium is illite and a inter-stratified mineral (mica+montmorillonite). As compared with the total content, the amount of non-exchangeable potassium is low for all the four soils. It was more concentrated at clay fraction of the Cambissolo soil. The potassium content sequence in the soil was the following: Cambissolo Háplico > Argissolo Vermelho-Amarelo > Neossolo Quartzarênico > Latossolo Vermelho-Amarelo. The results showed that the distribution of the forms of potassium among the soils differ as a function of the nature of the dominating minerals detected in the mineralogical analysis (illite and orthoclase) which was discussed above.

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The studies were developed with plants of Eucalyptus urograndis under greenhouse conditions, at Paulista State University (UNESP), Botucatu - SP, from March to July, 2005. The objective was to evaluate hydric stress influence on morphological and physiological characteristics of plants in clayay (1) and medium (2) soil texture. Two water treatment were used: -0.03 and -1.5 MPa minimum soil water potentials (□w). Plants from soil 2 and - 1.5MPa showed 43% reduction on leaf área, 34% on base stem diameter, 54% on aerial vegetal dry matter and plants from soil 1 presented 42.3% reduction on leaf área, 39,5% base stem diameter and 42% dry matter root reduction in relation to -0.03 MPa. The lowest leaf water potential (□f) value was-17.166 MPa on □w = -1.5 MPa and soil 2 and the greatest one on soil 1 and □w = -0.03 MPa., -6.766 MPa. The treatment -0.03MPa showed about 11,3% higher transpiration values than those plants from -1.5MPa. The higher Rs value (2.149 s.cm-1) occurred on plants under -1.5MPa and soil 2. There was significant correlation between Tf and Rs, and the treatmens from medium soil were more sensitive, reaching until 32°C.

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Climatic classification defines the geographical limits of different climate types all over the world, and it is considered essential to study similar areas. This work updates the climatic classification of the municipal districts of Botucatu and of São Manuel, State of Sao Paulo, where the experimental farms of the Schools of Agronomical Sciences - UNESP, Campus of Botucatu, State of São Paulo, are located. Koppen's and Thornthwaite's methods were used for the air temperature and precipitation data, in a 36-year period (from 1971 to 2006). For both municipal districts of Botucatu and São Manuel, the climate was characterized as being Cfa, hot climate with rains in the summer and drought in the winter, and the average temperature in the hottest month is above 22 °C. According to Thornthwaite's classification, there was a small difference due to the humidity index, characterized as B2rB′3a′ (humid climate with small hydro deficiency - April, July and August, with annual potential evapotranspiration of 945.15 mm and concentration of the potential evapotranspiration in the summer of 33%) in the district of Botucatu, and as B1rB′3a′ (humid climate with small hidric deficiency - April, July and August, with annual potential evapotranspiration of 994.21 mm and concentration of the potential evapotranspiration in the summer of 33%)in the district of São Manuel.

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Despite being known to science for quite a long time, the phenomenon of seed dormancy still baffles the scientific community for the multiple complex underlying mechanisms. The current classification systems of seed dormancy attempt to condense all that is known about the phenomenon in an attempt to generate a conceptual database that would enable facilitated interpretation of upcoming information and allow for a better contextuation of research in this field. The present paper is a preliminary overview of the current panorama of concepts and classification systems of seed dormancy that intends to serve as a standpoint for future research in this field.