EFFECTS OF REGULATED DEFICIT IRRIGATION BASED ON ROOT ZONE MOISTURE ON YIELD AND QUALITY TRAITS OF WINTER WHEAT

Wheat is the second leading cereal crop in China, and it is mostly cultivated in the water shortage region of China. A field experiment was conducted in 2012-2013 and 2013-2014 to investigate the effects of root zone moisture-based regulated deficit irrigation (MRDI) on grain yield and quality traits of winter wheat. The results showed that wheat grain yield, water use efficiency, and nutrient and processing quality were improved by MRDI. The duration of grain filling and nitrogen accumulation was extended and the harvest index was increased under MRDI treatment. MRDI is characterized by the regulation of water deficit based on root zone moisture information. The lower limit of soil water content was set as 80%, 65%, 60%, 60%, 65%, and 55% of field capacity at sowing stage, seedling to prior to wintering, wintering stage to regrowth, jointing to booting, heading to 10 days after anthesis, and 11 days after anthesis to mature, respectively. The soil depths for calculating the lower limit of water content were 40 cm, 60 cm and 100 cm, respectively, for seeding, joint guidance and maturity stages. Studies have shown that MRDI is suitable for maintaining winter wheat yield and quality in water-deficient areas.