Tensile strength values for the degrees of soil consistency using human perception and TS-Soil device

Tensile strength of aggregates, defined as the force per unit of area required to cause rupture of aggregates, is useful to quantify the effects of both use and management on soil quality. The present study considered the hypothesis that the evaluator’s perception, combined with the force applied to break the aggregate, measured by the TS-Soil device, can be used to define ranges of tensile strength for the degrees of dry soil consistency. The objective in this study was to define ranges of tensile strength for the degrees of dry soil consistency. For this purpose, aggregates (mean diameter of 22 mm after preparation) were collected in five horizons: A and Bi of a Cambissolo Haplico (Cambisol), Bt with a cohesive character of an Argissolo Vermelho Amarelo (Lixisol), Bt of a Luvissolo Cromico (Luvisol) and Bw of a Latossolo Vermelho-Amarelo (Ferralsol). One hundred aggregates of each horizon were evaluated for tensile strength, measured in the TS-Soil device, and, concomitantly, when pressed, were analyzed by an evaluator to assign the following scores to their consistency: 1- loose, 2- soft, 3- slightly hard, 4- hard, 5- very hard, and 6- extremely hard. Data were initially analyzed by descriptive statistics. Then, evaluator’s scores and tensile strength measured by the TS-Soil device were considered to define the ranges of values for the degrees of dry soil consistency. The following tensile strength (kPa) ranges were obtained: >0 to