CALIBRATION OF SOIL WATER CONTENT MEASUREMENTS OBSERVED WITH CAPACITANCE PROBES
Lucía Curto, Mauro Covi, María Isabel Gassmann, Matías Cambareri, Aída Della Maggiora
Dpto. de Cs. de la Atmósfera y los Océanos, FCEyN, UBA. Piso 2, Pabellón 2, Cdad. Universitaria, C1428EGA, CABA, Argentina.
Unidad Integrada Estación Experimental INTA Balcarce – Fac. de Cs. Agrarias, Univ. Nac. de Mar del Plata. Balcarce, Prov. de Buenos Aires, Argentina.
Consejo Nac. de Inv. Científicas y Técnicas, Av. Rivadavia 1917, C1033AAJ, CABA, Argentina.
Manuscript received on 14th December 2015, in final form on 20th March 2016
Soil moisture or soil water content is an important variable for Meteorology, Agronomy, Hydrology and Soil Science. In Argentina, measurements of soil moisture are both spatially and temporally sparsely distributed. There are different methodologies of measuring soil moisture content like the gravimetric, neutron and dielectric methods, among others. During the growing season 2012-2013, soil moisture measurements were performed in a soybean crop field. The aim of this paper is to calibrate observed capacitive data with gravimetric and neutron methods as well as to build a high temporal resolution soil moisture database. Linear functions were used to calibrate data for each depth of measurement with the exception of the two deepest levels where retrieved functions have a poor data fitting. The quality of the observed data and the calibration functions have direct impact on the capacitive sensor errors. Gravimetric, neutron and capacitive soil moisture measurements were interpolated with the Kriging method to construct the high resolution database. Variability of soil water content was observed at different soil depths due to precipitation and plant water uptake.