Abstract: The effect of different water and nitrogen management strategies on cotton was studied at two sites(Cele and Yuli) at the edge of Tarim basin of south Xinjiang. The result showed that the optimized irrigation and fertilization strategy based on soil nitrate quick testing and soil moisture measurement can dramatically reduce N fertilizer application rate from 432 kg?ha-1 to 256 kg?ha-1 at Cele and 310 kg?ha-1 to 137 kg?ha-1 at Yuli site. Meanwhile, irrigation water can be decreased from 660 mm to 427 mm at Cele and 600 mm to 402 mm at Yuli. The cotton yield, cotton fiber quality and N uptake of the optimized management strategies were similar to the conventional one, but significantly higher than the no N fertilization treatment at both experimental sites. The optimized strategies can dramatically increase N recovery and water use efficiency, and significantly reduce soil residual Nmin and apparent N losses.

Key words: Cotton, Nitrogen, Water, Nitrogen balance