Tension-based irrigation management and leaching monitoring using electrical conductivity in strawberry production

Strawberry plants have a shallow root system and are sensitive to water stress and salinity. Thus, strawberry crop needs frequent irrigations to ensure high fruit yield. Furthermore, each irrigation must be managed with precision to limit fertilizer leaching (e.g., nitrates) toward groundwater. The aim of this work was to compare over two growing seasons and two sites (sandy loam and clay loam) the leaching and salinity buildup associated with different irrigation managements. This work also examined whether EC measurements could be used to assess the concentration of nitrates in the soil and have a better control on nitrate leaching. For both sites, two irrigation managements were based on ET (50 and 100% ET) and four were based on the following soil matric potential (ψ) thresholds: (i) Wet (-10 kPa), (ii) Variable, (iii) Late (-35/-10 kPa) and (iv) Dry (-35 kPa). The variable matric potential threshold treatment was adjusted based on forecasted ET, while the Late threshold treatment was imposed -35 kPa at the beginning of the season and -10 kPa thereafter until the end of the season. Although large variations in EC were measured over the two seasons, no significant difference was observed among treatments for both sites. The nitrate concentration did not have a great impact on salinity models. Therefore, EC is not considered a reliable indicator to monitor changes in nitrate concentrations within the soil profile for these two sites.