Effects of supplemental irrigation based on soil water content on water consumption, dry matter and yield of wheat

Water-saving cultivation in wheat (Triticum aestivum L.) is an important technique for achieving high yield and high water use eficiency (WUE) in the North China Plain (NCP) where water resources are in shortage. In order to determine the effects of supplemental irrigation based on soil water content on crop evapotranspiration (ET), DM, grain yield and WUE in wheat, treatments were designed to vary the relative soil water content at jointing and anthesis stages: I-70 (70%, 70%) and I-75 (75%, 75%) with rain-fed (I-0) and traditional irrigation (I-ck) as contrasts. The results indicated that the irrigation amount of I-70 and I-75 were significantly lower than that of I-ck by 45.1 to 132.4 mm, but soil water depletion increased by 23.5 to 35.4 mm. Although the total ET throughout the growing season (ETt) of I-75 was less than that of I-ck, the ratio to ETt from anthesis to maturity increased significantly. The DM partitioning ratio was decreased in vegetable organs, but increased in grain for I-75 compared with I-ck. The grain yield for I-75 was significantly higher than that of I-0 and I-70, whereas nonsignificant difference was observed between I-75 and I-ck, and the WUE and irrigation water use efficiency of I-75 were higher than those of Ick by 11.0% and 87.4% in 2008-2009 and 3.5% and 34.0% in 2009-2010. Thus, I-75 can be developed as an optimal water-saving irrigation regimes in the NCP.