Chloride interaction with nitrate and phosphate nutrition in tomato (lycopersicon esculentum l.)

Tomato plants were grown in a greenhouse in 100 liter containers containing nutrient solutions. A 4 × 3 × 3 factorial experiment of Cl × N × P was conducted. The Cl concentrations were 0, 10, 35 and 70 meq/1; N0₃^- concentrations were 7.5, 15, and 20 meq/1; and H₂PO₄^- concentrations were 1, 2, and 5 meq/1. Fifteen different plant parameters were analyzed. There was a decline in dry matter yield with increasing Cl^- concentration in solution at all NO₃ and H₂PO₄^- levels. The effect of NO₃ levels on dry matter at each Cl level was varied and resulted in a significant Cl × NO₃ inter-action. The Cl^- affected all measured plant parameters but K and P content in the plant. Chloride content in the plant was depressed by increasing NO₃ concentration in the solution at all levels of Cl^- in the solution. There was a little effect of H₂PO₄^- on Cl^- and Mg content in the plant. The possibility of using NO₃^- fertilizers to depress Cl^- uptake by the plants is discussed.