中国冬小麦主产区气候变化及其对小麦产量影响研究

Climate change and its effect on winter wheat yield in the main winter wheat production areas of China

气候变化对农业生产具有重要影响,明确影响作物产量的关键生育期和限制性气象因子对保障粮食安全具有重要意义。本文基于气象站点和农业站点的观测数据及产量数据,采用趋势分析法和线性回归法分析了1960—2019年我国冬小麦主产区气象因子的时空分布特征,解析了产量与气象因子间的回归关系,确定了典型低产年影响产量的关键生育期和限制性气象因子。结果表明:1)1960—2019年,冬小麦主产区平均温度、有效降水和冷积温(日最低气温低于0℃的积温)的分布大致呈南高北低,而日照时数、气温日较差和热积温(日最高气温高于30℃的积温)为北高南低;平均气温和冷积温呈显著上升趋势,日照时数和气温日较差显著下降,有效降水和热积温的变化趋势无明显特征。2)2000—2019年,中国冬小麦主产区小麦年均单产为3426~5910 kg∙hm^(−2),各省(市)冬小麦产量均呈显著上升趋势(P<0.05);气象因子对产量贡献率的排序为气温日较差>日照时数>有效降水>冷积温>平均气温>热积温。3)典型低产年,抽穗至成熟期是气候因子影响产量的关键时期,限制性气象因子为有效降水、日照时数和气温日较差。综上,中国冬小麦主产区气候因子的分布特征和变化趋势存在空间异质性,在气候变化背景下,应关注气温日较差、日照时数和有效降水对冬小麦生长的影响,同时重点关注冬小麦抽穗至成熟期上述气象因子对产量的不利影响。

Climate change plays an important role in crop growth and grain yield.Therefore,there is an urgent need to understand the distribution characteristics and changing trends of climatic factors in the main crop production areas.Furthermore,analyzing the impact of meteorological factors at different crop growth stages is of great significance for maintaining food security and agricultural disaster prevention.In this study,the spatial distribution and variation trends of six critical meteorological factors during the winter wheat growing season in the main winter wheat production areas of China were investigated based on meteorological and phenological data from 69 meteorological and 77 agricultural stations located in the study area.The relationship between winter wheat yield fluctuation and meteorological factors was explored using a multiple regression model.The changing characteristics of meteorological factors in a typical low-yield year was evaluated to identify the key growth stage for winter wheat and the restrictive meteorological factors in the study area.The results showed the following:1)From 1960 to 2019,the spatial distribution of meteorological factors in the main winter wheat production areas of China was uneven and the variation trends were different.The mean temperature(Tmean),effective precipitation(Pre),and cooling degree days(CDD,the accumulated temperature for daily minimum temperature below 0℃)were higher in the southern regions,including Jiangsu Province,Anhui Province,and Henan Province;whereas the sunshine duration(SD),daily temperature range(DTR),and heating degree days(HDD,the accumulated temperature for daily maximum temperature above 30℃)were higher in the northern regions,such as Hebei Province,Shandong Province,Beijing,and Tianjin.The Tmean and CDD showed significant increasing trends with average rates of 0.33℃∙(10a)^(−1) and 43.42℃∙(10a)^(−1),respectively;whereas the SD and DTR significantly decreased at rates of 42.30 h∙(10a)^(−1) and 0.17℃∙(10a)^(−1),and the Pre and HDD trends were spatially heterogenous.2)The average annual winter wheat yield in different provinces and cities ranged from 3426 kg∙hm^(−2) to 5910 kg∙hm^(−2) with significantly increasing trends(P<0.05),but the interannual fluctuation was large in most regions.The determination coefficient for the effect of meteorological factors on winter wheat yield ranged from 0.15 to 0.80,and the winter wheat yield in Shaanxi Province was most affected by climate change(P<0.05).Over the whole growth period,the ranking of the meteorological factor’s contribution rate to yield was DTR>SD>Pre>CDD>Tmean>HDD.3)In a typical low-yield year,the key winter wheat growth period was from heading to maturity,and the restrictive meteorological factors during this period were SD,DTR,and Pre.Therefore,future agricultural management and wheat breeding programs must consider the current distribution characteristics and trends of meteorological factors for improving the winter wheat productivity.More importantly,we should pay special attention to restrictive meteorological factors,such as Pre,SD,and DTR,during the critical growing stage of winter wheat from heading to maturity so that it can better cope with meteorological disasters.