Using Soil Depth Functions to Distinguish Dystric from Xanthic Ferralsols in the Landscape

Pedometric tools for classification of southwestern Amazonian soils: A quali-quantitative interpretation incorporating visible-near infrared spectroscopy

“…Standardized sketches for representation of soil profiles are useful for pedologists, since they portray the stratigraphy of horizons and their transitions. 9 The visualization of the sketches makes it possible to highlight predominance in the particle-size, chemical, and oxide compositions, as observed for the horizons of the different soil orders of the State of Rondônia (Figure 3), and also verified for the particle-size in studies of hydromorphic soils, 10 Ferralsols, 42 and collection of soil profiles of the Brazilian semiarid region. 11 Thus, the particle-size analysis showed higher values for clay in the Ferralsols, in surface and subsurface; in addition, these soils have higher clay content than those presented by Pinheiro et al 42 The highest SB contents throughout the profile were observed in Rhodic FR, followed by Hypereutric Katostagnic Gleysol, Katosideralic Nitisol, and Katolixic Ferralsol (Figure 3A).…”

“…Despite the similar behavior of some of the evaluated attributes, in general, a great variability is observed, which may be related to the geological diversity of the region 32 and the intense dynamics of pedogenesis in tropical environments. Due to this, other analysis tools are necessary for a better characterization and comparison of the particle-size, 10 chemical, and oxide composition of these profiles. SB, CEC, SOC, clay content, Fe 2 O 3 , and Ki per horizon of each of the soil profiles were selected (Figure 3).…”

“…These were followed by Katostagnic GL-RO.13 with high values of SB, pH, CEC, K + , Ca 2+ +Mg 2+ , and P in subsurface and the highest values of Na + and Ki along the profile (Figure 4). The total depth of the horizon as a function of the data collected in the field influences the calculation of the dissimilarity between profiles, 9,10 bearing in mind that in soils with less total depth, the absence of data in deeper layers does not allow their comparison with high depth soils. This can be observed in the dendrogram before the grouping of soils that are sometimes taxonomically distinct.…”

“…However, more research is needed to better understand the variability of soil properties in subsurface. 10…”

“…In addition, this package also features a slicing algorithm (called slice-wise algorithm) that allows harmonization of soil profile data and analysis of similarity between different profiles. [9][10][11] Another problem associated with studies of soil profile collections is the large volume of soil samples to be analyzed physically and chemically. As an alternative to traditional laboratory methods, diffuse reflectance spectroscopy in the visible (vis; 400-700 nm) and near infrared (NIR; 700-2500 nm) ranges has been widely used for predicting soil attributes in different regions of the world, [12][13][14][15] allowing faster, cheaper analyses with no use of chemical reagents.…”