Managing Irrigation of Winter Wheat to Maximise Water Use Efficiency and Net Profit in the North China Plain

摘要

Winter wheat is one of the staple crops in the North China Plain. High levels of production of this crop largely depend on the use of irrigation. However, irrigation is causing a rapid decline of the groundwater table. To assure sustainable agricultural development in this densely populated region, improvement is needed in farmland water use efficiency (WUE) to reduce the overall application of irrigation water. Irrigation scheduling could reduce the amount of water used to irrigate crops and help to achieve water balance in the North China Plain (NCP). A study at the Chinese Academy of Sciences' Eco-Agro-System Experimental Station in Luancheng in NCP during 1997 to 2000 investigated the effects of different irrigation regimes on grain yield and water use efficiency (WUE) and profits in winter wheat (Triticum aestivum L.) The results showed that yield and WUE did not appear to be linearly related to total evapotranspiration. Maximum profit and optimum WUE for winter wheat was obtained using less water than was needed for maximum yield. Based on the sensitivity indices to water stress at various growth stages, optimized irrigation schedule for high yield, efficient use of water and a net profit from winter wheat were established using one, two and three irrigations (60 mm of water per irrigation) in wet, normal and dry years, respectively. Thus, the general practice of irrigating winter wheat four times during the growth period could be changed to irrigation one to three times a year, a practice that would greatly reduce supplemental water use.