A field experiment was conducted to study cotton growth and nitrogen uptake in response to different water and nitrogen application rates under drip irrigation with saline water. Three irrigation water salinity levels were set as 0.35 (S 1), 4.61 (S 2) and 8.04 (S 3) dS/m; two water and nitrogen application rates were set as 405 (L 1), 540 (L 2) mm and 240 (N 1), 360 (N 2) kg/hm 2, respectively. The results showed that plant height of cotton were influenced significantly by water salinity, application rates of water and interaction between them, and the interaction among water salinity, water application rate and nitrogen application rate at earlier growth stage, but mainly affected by water application rate at the later stage. The order of plant height were S 2 > S 1 > S 3 with water application 540 mm (L 2), while no significant difference were found on the growth of plant height between two nitrogen rates. The dry matter accumulation of the cotton stem and leaves are influenced significantly by the interaction among water salinity, application rates of water and nitrogen application, but cotton bolls and total dry matter accumulation are not significantly influenced by the interaction. Nitrogen uptake of cotton was influenced significantly by water salinity, application rates of water and nitrogen, and interactions between two of them or among the three factors. Total nitrogen content of cotton reduced with water salinity increasing, but increased evidently when water application rate was increased. Those results suggest that higher water application rate can enhance nitrogen uptake of cotton under drip irrigation with saline water.
