Visual Evaluation of the Soil Structure under Different Management Systems in Lowlands in Southern Brazil

Abstract

The "Visual Evaluation of Soil Structure" (VESS) is a method used primarily to evaluate the soil structural quality of Oxisols in Brazil and secondly for more specific research, consultancy, and teaching purposes. Since the methodology was never applied and compared with laboratory evaluations of physical properties of hydromorphic soils of the Pampa biome in the south of Brazil, this study evaluated the use of VESS as a visual indicator of the structure quality of a typic eutrophic Albaqualf soil under native grassland, crop-livestock integration, no-tillage, and conventional management systems. Experimental areas with these different management systems were subjected to visual (VESS) and laboratory evaluation of the soil structure. The laboratory evaluation was based on traditional methods and on measurements of bulk density, porosity, aggregate mean weight diameter, aggregate tensile strength (ATS), and total organic carbon (TOC). It was concluded that VESS was efficient in differentiating the management system. The management systems based on minimum soil disturbance and mulching with crop residues improved the soil quality, as evidenced by the VESS scores, bulk density, porosity, aggregation, and organic carbon. The TOC content was inversely related with ATS. The quality of a typic eutrophic Albaqualf was benefitted by organic matter in the surface layer.

Evaluating the long‐term effects of tillage systems on soil structural quality using visual assessment and classical methods

“…The lower VESS scores under CT treatments compared to RT and NT systems indicated a reasonably good soil structural quality despite the increase in tillage density (Figure ). In contrast to our findings on good soil structural quality under CT systems, Tuchtenhagen, Lima, Bamberg, Guimarães, and Mansonia () reported better soil structural quality with the absence of tillage under native grass compared to CT system. Better soil quality under native grassland was attributed to the lack of tillage, high plant residue and higher organic matter content in surface layers.…”

“…Significant positive correlations ( p < 0.01) of PR measurements with VESS scores at three depths show the effectiveness of VESS method in detecting compacted layers (Table 6). Similar to our results, significant relationships have been reported between VESS scores and physical soil quality attributes for different types of soils (Castioni et al., ; Cherubin et al., ; Tuchtenhagen et al., ). The PCA analysis using the varimax rotation and components extraction with Eigenvalues ≥1.0 yielded four principal components (PCs) that collectively accounted for the 80.64% variance in data (Table ).…”

“…The compatibility of high and low VESS scores with PR values is an important indicator for the reliability of VESS method in assessing the structural soil quality. Similar to the high VESS scores in RT and NT systems in our experiment, clayey surface soils under long‐term NT system in Brasil were identified with 4.0 scores (Tuchtenhagen et al., ). Contrary to the reports of Johannes, Matter, et al.…”

“…Higher VESS values have been ascribed by higher compaction and greater resistance of aggregates to break into small pieces (Tuchtenhagen et al., ). The compatibility of high and low VESS scores with PR values is an important indicator for the reliability of VESS method in assessing the structural soil quality.…”

Visual Evaluation of Soil Structure in Maize and Forage Grasses Intercropping under No-Tillage

“…Also, it has been a great alternative for researchers and farmers, as it enables the analysis of soil layers via the verification of soil attributes such as aggregate stability, size, and porosity, besides root system behavior, among other characteristics. Many studies have used such method to distinguish management systems of both long term [14][15][16] and short term [17]. Munkholm and coauthors [18] found lower visual scores for a crop rotation system with barley and oat than for maize monoculture and maize-soybean succession, showing the effect of forage grasses on soil structural quality.…”