Spatial and temporal patterns of freezing injury during winter in Huang-Huai Winter Wheat Area under climate change

Abstract

Freezing injury is one of the most serious agro鄄meteorological disasters of winter wheat in North China, restricting yield and its suitability. Under the background of climate change, the warming trend in China is significant, especially in winter. However, freezing injury of winter wheat during winter still happened sometimes in Huang鄄Huai Winter Wheat Area (HHWWA) , therefore, identify the spatial and temporal patterns of freezing injury during winter under the background of climate change is very important to defense the freezing injury. In this study, based on the daily temperature data of 47 meteorological stations in HHWWA from 1960 to 2010, the trends of accumulated negative temperature and over鄄wintering durations were analyzed, and spatial and temporal variation of freezing injury during winter in HHWWA were identified, taking the accumulated negative temperature as freezing injury indices. Over the past 50 years, the average absolute values of accumulated negative temperature were ranged from 17.3 to 240.8 益 •d, increased from south to north. Moreover, the accumulated negative temperature decreased at a rate of 1. 8-38. 3益•d per decade from 1961 to 2010, and the higher

Risk assessment of freezing injury during overwintering of wheat in the northern boundary of the Winter Wheat Region in China

“…In this study, the starting and ending dates of the daily average temperature stably lower than 0 • C were calculated using a five-day moving average method-the daily average temperature for five consecutive days is lower than 0 (Yao et al, 2011). Intervals define the overwintering period (Zheng et al, 2015a;Zheng et al, 2015b).…”

“…Simultaneously, irrigation should be timely and sufficient before winter to avoid freezing injury caused by drought (Fischer, 1985). When breeding new winter wheat varieties, cold resistance should also be screened (Zheng et al, 2015a;Zheng et al, 2015b).…”

“…They obtained specific meteorological conditions for severe freezing injury and proposed that the complexity of the severe freezing injury mechanism was not explained by simple temperature data. Zheng et al (2015a) and Zheng et al (2015b) proposed that the absolute value of negative accumulated temperature during overwintering periods could be used as an index to divide the degree of winter wheat-freezing injury. Additionally, Bake et al (2006) comprehensively considered the cold resistance ability of varieties and environmental factors, and established a wheat-freezing injury early warning system in Beijing using the decision tree method.…”