Evaluación de la salinidad del sustrato usando la conductividad eléctrica del medio en la producción de hortensia en maceta

Abstract

The availability of soil moisture sensors that are also capable of measuring permittivity, temperature and soil bulk EC (ECB), such as the Hydra Probe II (Stevens W.M.S. Inc.), has opened up new possibilities for the automatic control of saline water irrigation schemes in potted crops. The pore water EC (ECPW) is estimated using the sensor measurements of ECB, permittivity and temperature. However, under conditions of high salinity and low humidity, the estimation of ECPW becomes inaccurate and even invalid. Faced with this problem, the purposes of this paper were: i) to assess whether the measurements of the ECB in saturated substrate can be used to maintain different substrate saline levels, and ii) to evaluate the growth and development of potted hydrangea under saline irrigation. Three ECB thresholds (1.1, 1.7 and 2.3 dS m-1) were studied. The irrigation system used saline water (4 dS m-1), and when the ECB threshold was exceeded, it supply non-saline water (nutrient solution of 1.5 dS m-1). The results indicate higher morphological damage in plants as the ECB threshold increased. Therefore, despite not being a real reading of the soil solution salinity, it is a closely related parameter, which can be regarded as a useful tool for mitigating the negative effects of salinity in potted ornamental plants.