Suscetibilidade magnética na estimativa de atributos do solo e identificação de compartimentos da paisagem em latossolos de basalto no planalto do RS

Abstract

The variability of soil attributes is related to environmental factors affecting soil formation processes. Different techniques have been employed to map this variability, among these techniques, the reading of the magnetic susceptibility (MS) has been shown as an alternative due to its close relationship to the soil other attributes. This study aims to determine the magnetic susceptibility of Oxisol samples in a Rio Grande do Sul experimental area, related to different soil properties to understand the spatial distribution, as well to define different compartments of the landscape. The 350 ha study area is located in Santo Augusto city, three transects where were marked from the higher quota until the lower quota area, totaling 1450 m. In these transects we scored 29 points georeferenced, 50 m distance each one. Samples were collected at 0.00-0.05, 0.05-0.15, 0.15-0.30 and 0.30-0.60 meters depth where we determined the particle size distribution, soil organic carbon and the MS. Also we opened five trenches along the transects distributed over different locations in the relief along the topossequence, where the morphological description, chemical, physical, and mineralogical analysis and MS in the samples of each horizon. In study 1, the profiles data from the attributes were submitted to Pearson linear correlation test to determine the correlation of MS with the other attributes of the soil. With transects data we carried out linear regressions for each depth in order to assess how the MS contributes to the clay, sand, and soil organic carbon prediction. To verify spatial dependence of the attributes in the sample we used points geostatistics with variograms settings. The values were interpolated using the ordinary kriging and subsequently we generated maps of soil attributes on topossequência for the four depths. In the study 2 the data from transects were submitted to descriptive statistics and analysis of the "Split Moving Window" (SMW), to investigate the behavior of the MS in determining the limits of landscape compartments. According to two studies we can infer that the MS has potential for application in the mapping of certain soil attributes, as well potential for determination of landscape compartments limits.