Field calibration of water capacitive sensor in a Yellow Latosol of coastal region, in the of State Piaui, Brazil

Abstract

Capacitance sensors are alternatives to most common methods of quantitative measurement of soil water content, providing readings safely and rapidly with depth. In this study, a capacitance probe (Diviner 2000^®) was calibrated for a Yellow Latosol of coastal region in, Piaui State, Brazil. Six access tubes were installed in a 5 m by 2 m grid. Three moisture levels (wet, moist and dry) were applied in two replications. The device readings at interval of 0.1 m until 1.0 m depth were compared with volumetric measurements. The calibration equation, adjusted by regression analysis, was significantly (p < 0.001) related to measurements of equipment with high correlation (R² = 0.97) and lower standard error (RMSE) (0.01 m³ m^-3). Calibration provided by manufacture was suitable for this soil.