Spinach Plants Favor the Absorption of K+ over Na+ Regardless of Salinity, and May Benefit from Na+ When K+ is Deficient in the Soil

competition, and shoot biomass decrease was attributed to excessive NaCl accumulation. Overall, 'Raccoon' and 'Gazelle' biomasses were similar regardless of K dose but 'Raccoon' outproduced 'Gazelle' at 5.0 K at the two highest salinity levels, indicating that 'Raccoon' may outperform 'Gazelle' at higher NaCl concentrations. At low K, Na may be required by 'Raccoon', but not 'Gazelle'. This study suggested that spinach can be cultivated with recycled waters of moderate salinity, and less potassium than recommended, leading to savings on crop input and decreasing crop environmental footprint.