Tensile Strength: A Pedologist's Perspective on Variability in Cohesive and Non‐Cohesive Horizons From Brazil's Coastal Tablelands

ABSTRACT Background Previous research has underscored the importance of evaluating soil consistency for accurate determination of cohesive character and mechanical properties. Although qualitative assessments by pedologists are pertinent, they exhibit inherent subjectivity that may compromise accuracy. This variability fosters the adoption of quantitative methods, such as dynamometer measurements, to enhance objectivity. Aims This study compared the variability in dry‐soil consistency assessments performed by pedologists with quantitative evaluations obtained using a dynamometer to establish tensile strength ranges corresponding to distinct consistency classes. Methods Soil samples from two Alfisols, differing in cohesive character, were collected from the Bt horizon at top, middle, and base positions. The focus was on aggregates ranging from 19 to 25 mm in diameter. Three pedologists conducted qualitative evaluations of 90 aggregates per horizon, whereas a dynamometer provided quantitative measurements. The results were subjected to exploratory and experimental statistical analyses, including variance analysis ( F test) and Tukey's mean comparison test, with assessment of data normality. To determine tensile strength for extremely hard consistency, the average percentage of aggregates classified in the highest cohesion class by pedologists was applied to the dynamometer data, thereby establishing a lower tensile strength limit, a method extended to other consistency classes. Results Pedologists’ assessments exhibited variability between 8% and 37% for one soil type and 0%–23% for the other, with dynamometer data reflecting similar variability. A threshold of 50 kPa was identified as indicative of cohesive soil character. Conclusion The findings indicate that integrating tensile strength ranges with pedological evaluations significantly mitigates subjectivity.