Estimativa da friabilidade de solos com dados de resistência tênsil

Abstract

Soil is considered a fragile and non-renewable natural resource due to its long period of formation. It is known that the greatest damage to soil structure occurs at the time of preparation for cultivation, especially when adequate moisture is not observed. Thus, indicators for soil structural assessment (are) required in the soil monitoring protocol when used and managed. One of the most used physical indicators for this purpose is the tensile strength of aggregates, since, given the standard deviation of the data, it is possible to estimate friability values and then make inferences about the workability, especially for soils that they manifest the cohesive horizons, in which the thickened horizon entails physical impediments to root growth as it gets drier. Starting from the hypothesis that soil horizons with cohesive character, although they present serious restrictions to their agricultural use when dry, being very resistant to the rupture, are of easy mechanical workability when moist, the objective of this study was to: i) measure tensile strength values and, with the standard deviations of the data, estimate the friability in soils with and without the cohesive horizon; and ii) make inferences about the management and preparation of soils. For this, soil samples were collected in six soils, in Bt horizons with and without cohesive character, located in the CE, PE and BA states. Then, the tensile strength of the aggregates was measured, and the friability was estimated. It was concluded that soils with cohesive character have higher values of tensile strength; Despite the higher values of tensile strength, cohesive soils were classified from friable to very friable, and did not present mechanical impediments to the preparation for cultivation when the adequate humidity was respected.