Analysis Of The Variation Characteristics Of Wheat Season Climate And Yield And Its Main Influencing Factors In Winter Wheat Region Of China From 1986 To 2016

China is a big country producing and consuming winter wheat,and its production is very important for social stability and national food security.It is very important to analyze the variation trend and limiting factors of wheat yield in different winter wheat regions in China.Based on the total winter wheat yield data of each province from 1986 to 2016,eight provinces with an annual average yield of more than 3×106 t were designated as the study areas,namely shaanxi,Hebei,Shandong,Henan,Anhui,Jiangsu,Hubei and Sichuan,representing the northern wheat area,Huang-Huai-Hai wheat area,middle and lower Reaches of the Yangtze River wheat area and southwest wheat area,respectively.Thirty-two representative meteorological stations were selected from the above regions based on GYGA(Global Yield Gap Atlas)method.Based on the meteorological,soil and crop management data of 32 representative meteorological stations,the characteristics of climate factors in winter wheat season and main growth stages in China were analyzed.Based on the calibrated APSIM-Wheat model factor replacement method and residual analysis method,the contribution of comprehensive climate and key climate factors to winter wheat yield change of representative meteorological stations was analyzed.Based on the regional trial data of new winter wheat varieties in Hubei province from 2004 to 2016,the contribution of variety renewal to wheat yield was analyzed.Based on the above research,the contribution of cultivation management to winter wheat yield was analyzed by inverse method.The characteristics and main influencing factors of climate and yield change in different wheat regions were analyzed.The main results are as follows:(1)The calibrated APSIM-Wheat model can better simulate the wheat yield in the main winter wheat producing areas in China.That is,the observed yield value of each representative winter wheat variety is basically consistent with the simulated yield value,the coefficient of determination(R2)≥ 0.86,the root mean square error(RMSE)is between 136.03~271.28 kg ha-1,and the range of the normalized root mean square error(NRMSE)were 1.75%~3.65%,the agreement index(Dr value)was between0.54~0.87,and the mean percent absolute error(PMARE)ranged from 1.46%~3.32%.(2)From 1986 to 2016,the minimum temperature and maximum temperature of winter wheat season in the major winter wheat producing areas in China showed a spatial distribution of lower temperature in the north and higher temperature in the south,and the interannual variation trend showed an upward trend,with the growth rate of0.32 ℃ 10a-1 and 0.35 ℃ 10a-1,respectively.Precipitation was lower in the north and higher in the south,while solar radiation was higher in the north and lower in the south.The temporal variation of precipitation and solar radiation showed a decreasing trend,and the decreasing rates were-13.70 mm 10a-1 and-28.33 MJ m-2 10a-1,respectively.The annual variation range of seasonal climatic factors of wheat was different among regions.The increase of minimum temperature was the highest in the Huang-Huai-Hai wheat region,and the lowest in the middle and lower reaches of the Yangtze River wheat region.The maximum temperature increase was the highest in the northern wheat region and the lowest in the Huang-Huai-Hai wheat region.The decrease of precipitation was the largest in the wheat region in the middle and lower reaches of the Yangtze River,followed by the northern wheat region and the Huang-Huai-Hai wheat region,and the smallest in the southwest wheat region.In the past 30 years,the decrease of solar radiation was the largest in the Huang-Huai-Hai wheat region,and the smallest in the northern wheat area.(3)Based on the statistical analysis of the actual winter wheat yield of 32 representative meteorological stations,it was found that there was a great difference in the actual wheat yield between different wheat regions in China.The Huang-Huai-Hai wheat yield was the highest with an average of 4885 kg ha-1,followed by the middle and lower reaches of the Yangtze River with an average of 4290 kg ha-1,followed by the southwest wheat yield with an average of 3562 kg ha-1.The lowest value was 2802 kg ha-1 in the northern wheat region.The annual variation trend of the actual winter wheat yield in all wheat regions increased significantly.The fastest growth rate was found in the Huang-Huai-Hai wheat region,followed by the middle and lower reaches of the Yangtze River and the northern wheat region,and the slowest in the southwest wheat region.The range of change was 93.43 kg ha-1 yr-1,69.81 kg ha-1 yr-1,51.64 kg ha-1 yr-1 and 28.27 kg ha-1 yr-1,respectively.(4)The crop model factor substitution method showed that except for some regions,the decrease of seasonal precipitation,the increase of maximum temperature and the comprehensive climate change had negative effects on winter wheat yield.The increase of minimum temperature is beneficial to wheat yield in northern wheat region.The increase of radiation is beneficial to wheat yield in the northern wheat region.Residual analysis showed that the decrease of seasonal radiation,the increase of minimum temperature(except in southwest wheat region)and the overall climate change had negative effects on wheat yield.The decrease of precipitation was not conducive to the increase of grain yield in the northern wheat region.However,the increase of maximum temperature was obviously beneficial to the northern wheat region and unfavorable to the southwest wheat region,while the influence of other wheat regions was not significant.(5)Based on the actual winter wheat yield,climate factors and yield of new varieties tested in Hubei province from 2004 to 2016,the contribution of climate change,variety renewal and cultivation management to the change of winter wheat yield was preliminarily explored.It was found that the actual yield of winter wheat in Hubei province increased by 37.03 kg ha-1 yr-1.Climate change had a negative effect on winter wheat yield,while variety renewal and cultivation management had a positive effect on wheat yield.Further research found that in the past 13 years,the contribution rates of climate change,variety renewal and cultivation management to the increase in annual wheat yield in Hubei Province were-43%,55% and 88%,respectively.