Effect of irrigation with saline water on water-salt dynamic and spring wheat yield

To obtain the suitable alternative of saline water irrigation for spring wheat, a field experiment was conducted in Huinong Irrigation District, Ningxia, North-West China in 2007 and 2008 respectively. The collected datum were used to analyze the effects of saline water irrigation on water-salt dynamics and yield of spring wheat. Results indicated that soil water content and salinity at the upper layer of 0-30 cm had relatively large variations, whereas the variations of soil water content and soil salinity in layers below 30cm were relatively small. Canal irrigation resulted in the desalination of root zone soils, while well-canal combined irrigation kept the salinity in root zone soils being stable even at relatively dry years, but irrigation with well water caused a significant salt accumulation in root zone soils. Evapotranspiration and water use efficiency of spring wheat decrease with the increase of irrigation water mineralization degree. Compared with Canal irrigation, the well-canal combined irrigation only led to a slight decrease of crop yield, whereas a 20%-30% decrease of crop yield was caused by the well irrigation. The alternative with 1:1 ratio of ground water to surface water is recommended for irrigation of spring wheat in Yinbei Huinong Irrigation District.