Effects of deficit irrigation with brackish water on soil water-salt distribution and winter wheat yield

For the sake of improving water utilization efficiency and relieving the shortage of water resource in North China, field experiments on deficit irrigation with brackish water were carried out at Nanpi Ecological Experimental Station of Chinese Academy of Science in Hebei province from 2003 to 2005, which aimed at exploring the impact on soil salt content, winter wheat yield and yield constitute factors as well as water use efficiency caused by brackish water irrigation. The results showed that, soil salt content in winter wheat main root area had an increasing trend with growth duration development, salt accumulation in 0-100 cm soil layer increased gradually in company with water shortage stage postponement. Yield constitute factors most sensitive to water deficit in jointing period was the number grains per spike, water deficit in the tassel stage was the most influential factor to spikes per unit, water deficit in the grouting stage had critical negative effects to 1 000-grain weight. In general, with water shortage stage postponement, negative effect of water stress on winter wheat yield gradually decreased, and water use efficiency increased, the preferred order of deficit irrigation with brackish water was jointing stage irrigation, tassel stage irrigation and grouting stage irrigation. The study provides the scientific basis for determining suitable irrigation frequency and the normal amount of irrigation in winter wheat growth stage under condition of deficit irrigation with the brackish water in Huanghuaihai Plain, which is favorable for the rational exploitation and utilization of local brackish water resources.