Water and salt budgets in three permanent tree crops in Roxo’s irrigation district

Abstract

Irrigation is fundamental for agricultural production in Portugal. Climate change forecasts show a tendency towards warmer, drier summers, and a reduction in precipitation depths and frequency. The increase in evapotranspiration associated with irrigation mal practices may lead to a higher concentration of salts in the soil, and consequently to an increased salinization risk and loss of crop production. For these reasons, the monitoring and control of soil salinization are essential for the sustainability of irrigated agriculture. This study aimed to evaluate the water and salts budgets in three permanent crops (olive grove, almond, clementines) located in Roxo’s irrigation district, in Aljustrel, during the 2019 and 2020 growing seasons. The soil water content and the electrical conductivity of the soil saturation extract were monitored at different depths. The HYDRUS-1D model was then used to simulate the dynamics of water and salts in the soil profile and to evaluate the sustainability of existing agricultural practices. The results of this research showed that there is no increased risk of soil salinization in the three monitored sites, although it is important to improve irrigation practices to maximize the use efficiency of irrigation water.