Abstract:In order to make clear the regulation effects of irrigation timing on water consumption and yield of wheat under limited water supply during spring growing season, a field experiment was conducted in the test station of Dryland Farming Institute, Hebei Academy of Agricultural and Forestry Sciences during 2013 to 2017. Winter wheat cultivar, Heng 4399, was used. The measurements were taken on irrigation timing for six treatments, jointing 0d (AJ0), 5d after jointing (AJ5), 10d after jointing (AJ10), 15d after jointing (AJ15), 20d after jointing (AJ20), and 30d after jointing (AJ30). Irrigation amount was 75mm. Irrigation was synchronized with topdressing. The results showed that evapotranspiration of different treatments was ranged within 361.1~505.8mm and grain yield was ranged within 6620.4~8650.5kg/hm2.Compared different treatments, with irrigation time delayed, evapotranspiration and yield were increased first and then decreased. The three indicators, transfer amount of dry matter before anthesis, transport rate and contribution rate to grains before anthesis, all increased with lapse of treatment time, and reached the peak between 5d and 15d after jointing, and then decreased. Transfer amount of dry matter in vegetative organs after anthesis, AJ10 and AJ15 were higher than other treatments, AJ0 was the lowest. The contribution rate of afteranthesis assimilated to grains was more than 60% and was the main component of grain yield. WUE was ranged within 1.32~2.54kg/m3 which was affected by both the yield and evapotranspiration. WUE of AJ0 was the best treatment except 2017. Treatments with higher evapotranspiration was also higher in its grain yield. Evapotranspiration and grain yield were positively correlated with soil water supply amount. These results indicated that irrigation between 10.d and 15d after jointing, could not only sufficiently use soil water storage, but also improve grain yield of wheat.
