Testing a Low Cost Apparatus to Monitor Soil Salinity in Plant Physiology Experiment Using Arduino Platform

Soil salinization is a common problem impacting plant physiology and agricultural productivities. In order to monitor soil salinization in plant physiological experiments, a salinity monitoring system - SProb - was produced to improve our understanding of plant responses to salinity, using open hardware Arduino platform. An experiment was performed and designed to calibrate and check the viability and accuracy of SProb to be used in scientific researches. Salt concentrations were manipulated to identify sensor ability in determining salt accumulation or leaching in soils. Also, two mangrove plant species were grown to identify if root presence would affect soil salt measurements. The soil osmotic potential (psi(s)) was estimated from SProb results and correlated with predawn and midday leaf water potential (psi(l)) of the mangrove plants, to identify if psi(s) would affect plants water regulations. It was also shown that SProb described well the soil salt accumulation or leaching along the time, and the measurements were not affected by the presence of roots. The ranges of psi(s) matched with the range of mangrove psi(l), and the psi(l) decreased with the decrease in psi(s) (increase in salinity). It was confirmed that the SProb sensor is efficient, cheap and has enough accuracy to monitor soil salt concentration. Thus, SProb can be used in plant physiological experiments increasing our ability to make accurate science when such technology is not available in research centers.