Calibração de campo de uma sonda FDR (reflectometria no domínio de frequência) para estimativa da umidade do solo.

Abstract

Many soil moisture sensors are actually available for measuring the water content of soils. They vary according to the working principle, cost, precision, and skilled-personnel requirements. The objective of this work was to calibrate under field a FDR sensor model Sentry 200 AP, to estimate soil moisture in the cohesive soils of the Costal Tableland region of the State of Bahia. A field experiment was carried out at the School of Agronomy of the Federal University of Bahia. Soil samples were taken from the walls of a trench, from 10 to 110 cm, at 20 cm increments for gravimetric determination. Readings with the sensor were also taken at the same depths. An exponential and a linear model were fitted to the data. The dispersion of data increased with the depth mainly due to the variability in soil density. The higher determination coefficients were obtained with the exponential model. For any of the two models the sensor can be satisfactorily used for soil moisture determination in the field.