Spring Frost Impact on Winter Wheat Yield in China: A Review

Winter wheat is a major staple food crop in China, accounting for more than 15% of total crop planting area and more than 20% of total crop production in recent years (2010–2014) (National Bureau of Statistics of China, 2015), making China the largest producer of wheat in the world (FAO, 2016) (last visited 11 May 2018). Winter wheat is typically sown in autumn, growing through winter and harvested in the following summer in China (Jin, 1996). Previous studies have extensively investigated the spatio-temporal patterns of spring frost in China in recent decades (Li et al., 2015a; Yue et al., 2016; Zhong et al., 2007a,b). Spring frost is prevalent in approximately 85% of the total winter wheat planting area in China (Yue et al., 2016). It commonly occurs in March and April during the immature ear and early ear emergence period, although frost damage to winter wheat after flowering is infrequent (Li et al., 2015a; Wu et al., 2014). The Huang-Huai winter wheat growing region (110°E-118°E and 34°N-36°N) experiences the most severe spring frosts in China (Feng et al., 1999). In this region, the probability of spring frost has been increasing since the 1970s (Zhong et al., 2007b). In eastern China, spring frost events are frequent in the north of the Huaihe river valley (31°N–36°N), and the historical occurrence cycles of spring frost are 22 years, 11 years, 4 years, and 2 years depending on different stations (Bao et al., 2012). The average wheat grain yield variations caused by single spring frost in each decade during 1961–2000, ranged between -20.87% and 3.43%, based on six agrometeorological stations in Eastern China (Li et al., 2015a). Previous studies have characterized the spatio-temporal distribution of extreme temperature events, drought events, and their impacts on wheat yield in different areas.