Short-Term Effects on Agricultural Soils Irrigated with Reclaimed Water in Baja California, México

In 2014 reclaimed water (RW) started to be used for agricultural irrigation of 200 ha in Maneadero Valley, Baja California, Mexico. The RW had relatively high electrical conductivity (4-5 dS m^-1), and K⁺, Mg²⁺, PO₄^3- and Cl^- concentrations relative to irrigation guidelines. However, no accumulation of these elements, nor total nitrogen, was observed in the studied soils. The main effect of RW irrigation was the downcore leaching of Cl^- and Na⁺ below 120 cm, causing an increase in electrical conductivity in the lower soil horizons. Al, Fe and Zn showed a twofold to eightfold accumulation in the top soil layer after 2 years. Moderate to severe chemical clogging of dripping systems and potential biological clogging are likely to occur. Mexican national guidelines for the reuse of RW do not take into account specific variables that could change the quality of agricultural soil or lead to clogging of drip irrigation systems.