[Effects of irrigation amount and stage on water consumption characteristics and grain yield of wheat].

Field experiment was conducted in 2005 -2007 to study the effects of irrigation amount and stage on the water consumption characteristics, grain yield, and water use efficiency of wheat. The results showed that the variation coefficient of the proportion of soil water consumption amount to total water consumption amount was significantly higher than that of precipitation to total water consumption amount, suggesting the relatively wide regulation range of soil water use efficiency. The proportions of irrigation amount, precipitation, and soil water consumption amount to total water consumption amount were 31.0%, 38.9%, and 30.1% in treatment W3 (irrigated at jointing and flowering stages, with total irrigation amount of 120 mm), and 51.7%, 32.4%, and 15.9% in treatment W5 (irrigated before winter and at jointing, flowering and grain-filling stages, with total irrigation amount of 240 mm), respectively, indicating that treatment W3 had a significantly higher proportion of soil water consumption amount to total water consumption amount than treatment W5. Though treatments W2 (irrigated before winter and at jointing stage) and W3 (irrigated at jointing and flowering stages) had the same irrigation amount (120 mm), the water consumption amount during the period from flowering to maturing was significantly higher in W3 than in W2, while the water consumption amount before jointing was significantly lower in W3 than in W2. The water consumption pattern in treatment W3 was in agreement with the water requirement pattern of wheat, which was the physiological basis of high water use efficiency.