Effect of Salinity on Cotton Nitrogen Uptake and Assimilation of Urea Applied with N-(n-Butyl) Thiophosphoric Triamide and Dicyandiaminde

Salinity is an abiotic stress factor that can cause significant crop yield losses. Nitrogen (N) is an essential plant element that is usually limited in most agricultural soils. Recently, incorporation of additives such as N-(n-butyl) Thiophosphoric triamide (NBPT) and Dicyandiaminde (DCD) into N fertilizers has been done with the purpose of increasing N use efficiency of crops. To our knowledge little is known about the physiology of N metabolism in cotton plants grown in soils with condition of salinity stress. Hydroponic experiments with cotton indicated that high levels of salinity reduced N uptake and medium salinity increased tissue N concentrations (Pessarakli and Tucker, 1985). The toxic effect of DCD in cotton under high salinity has been reported (Reeves and Touchton, 1989), but studies on the performance of NBPT under salinity conditions are lacking.