Calibração do sensor ECH2O, modelo EC-5 para latossolo vermelho distrófico

Abstract

The use of moisture sensors has increased by providing the current value of soil water content and allowing the continuous recording of this variation, important information for irrigation management. By determining the water content of the soil indirectly, it is essential to calibrate these sensors. The objective of this study was to adjust a calibration equation for the ECG2O sensor, EC-5 model from Decagon to dystrophic red clayey latosol. Undisturbed samples of soil in cylinders (ø = 0.07m; h = 0.15m) were collected in two profiles of dystrophic red latosol, with clay texture, at depths of 0-0.50; 0.50-1.00; 1.00-1.50; 1.50-2.00 m. The samples were oven dried for density determination and submitted to the gradual addition of water until saturation. Each column received a probe from the equipment for recording the water content, and was weighed for gravimetric (standard) moisture determination. A regression equation was fitted between the reading provided by the sensor and the water content obtained by the gravimetric method (specific equation). This equation was generalized to estimate the water content provided by the sensor in the second profile. The validation of the equation was performed through the regression and correlation (r) analysis, as an index of accuracy of the estimation, the concordance index "d" was used. The use of the generalized equation showed an absolute error in the soil moisture estimate between 10.46 - 63.03%, while the specific calibration indicated an absolute error of 0.03-13.50% between the evaluated depths.