Nitrogen Fertilization of Plants Irrigated with Desalinated Water: A Study of Interactions of Nitrogen with Chloride

Abstract

The overall aim of this research was to optimize nitrogen (N) fertilization of plants under desalinated water and a wide range of chloride concentrations for high yield while minimizing downward leaching of nitrate and chloride. The response of two crops, lettuce and potato, to N concentration (CN) in the irrigating solution using desalinated and wide range of Cl concentrations (CCL) was evaluated. The yields of both crops increased with N up to optimal CN of the irrigating solution and decreased as CCL increased. Optimal CN in both crops was higher in the desalinated water than high CCL treatments. N uptake by plants increased with CN in the irrigating solution and the highest uptake was at low CCL. As expected, N fertilization suppressed Cl accumulation in plant tissues. Drainage of N and Cl increased with increase in CCL in the irrigating solution and N fertilization above optimal CN resulted in steep rise in downward N leaching. The overall conclusion is that as water quality is improved through desalination, higher N supply is required for high yields with less groundwater pollution by downward leaching of N and Cl.