Dissertations and Theses

Magnetic susceptibility and its association with soil and relief attributes in a topossequence of oxisols.

Author: Sammy Sidney Rocha Matias

Keywords: source material; geomorphic surface; specific areas of management

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Summary

The objective of the present study was to study the magnetic susceptibility and its association with soil attributes and relief in a topossequence of Oxisols. The soils were collected in a transect of 2,700 km with regular intervals of 25 m and randomly in the lateral areas of three geomorphic surfaces mapped in two depths (0.00-0.20 m and 0.60-0.80 m), totalizing 514 samples. Seven trenches were analyzed contemplating the slope segments inserted in the geomorphic surfaces. The soil samples were analyzed for soil density, porosity, flocculation grade, texture, pH (water, CaCl2 and KCl), organic matter, P, Ca, K, Mg, H + Al, Al. Calculated SB, CTC and V%. Also determined were SiO2, Al2O3, Fe2O3 (H2SO4), free Fe (Fe) oxides, iron with low crystallinity (Feo) and magnetic susceptibility. The data were analyzed by the univariate, descriptive, multivariate, Split Moving Windows and geostatistics statistics. The results showed that the division of areas through the geomorphic surfaces caused a better understanding of the variability of soil attributes in the slope. The geostatistical method SMWDA Moving Windows Dissimilarity Analysis "), confirmed the numerical division of the three geomorphic surfaces by granulometry and magnetic susceptibility. The magnetic susceptibility was the attribute that best identified the boundaries between the bodies mapped in the field, which indicates its potential of use to map homogeneous areas.