Calibração de um sensor capacitivo para estimativa da umidade em três classes de solos

Abstract

One of the largest agricultural challenges has been the practical, quick and precise measurement of water content at soils, thus requiring satisfactory equipment to perform such task. This research investigated capacitive soil moisture sensors defined by the manufacturer as Eletrodex, comparing its measurements to dry oven techniques for soil moisture determination at three soil classes: Argisol, Oxisol, and Nitosol. Soils were collected at the Campus of the Federal University of Lavras (UFLA), and the experiment was carried out at the Hydraulics Laboratory in Lavras, state of Minas Gerais. For calibration, seven moisture levels were used, which comprised different percentages of total available moisture (TAM). Results lead to the conclusion that the sensor does not satisfactorily estimate the volumetric water content for any soil class tested. Such conclusion is based on the fact that no adequate coefficients of determination could be obtained at calibration curves.