Heterogeneous saline and nutritional conditions in the root-zone and its effect on water uptake and plant mineral content

Non-uniform saline and nutritional conditions in root sub-zones of tomato were evaluated using a split-root method. Tomato (Lycopercicum sculentum 'Heinz 5608'), with moderate sensitivity to salt, was tested. The root system of each plant was divided into two equal parts, completely independent and isolated from each other (Root A/Root B). Treatments consisted of paired combinations of 7 types of solutions: 1) control (C): well-balanced non-saline nutrient solution; 2) and 3) control depleted of N or K (C-N or C-K): control solution with absence of N or K; 4) control saline: control solution + 50 mM of NaCl (C+NaCl); 5) and 6) control saline depleted of N or K (C+NaCl-N and C+NaCl-K); and 7) saline only solutions (DI-water + 50 mM NaCl). Non-uniform treatments showed a clear morphological and physiological response, measured as root biomass, water uptake, and plant mineral content of Na⁺ and Cl^-, within 9 days of treatment imposition. This experiment provides insight into expected plant responses under heterogeneous field conditions created in the root zone that develops when using micro-irrigation strategies in arid environments.