Spatial And Temporal Distribution Of Winter Wheat Yield Gap In Henan Province Based On AEZ Model

The global warming trend has gradually increased and it has become a major ecological issue that has attracted worldwide attention.Climate change will invariably cause changes in the quantity,quality,and spatial and temporal distribution of climate resources related to agricultural production,and increase the degree of impact and volatility on agricultural production.Therefore,under the premise that the climate change caused by human activities has not yet been effectively controlled,we objectively evaluate the warming trend of Henan Province,and its impact on the potential of crop production in this area.It provides a scientific basis for Henan Province to formulate a rational farmland planting system for dealing with climate change and put forward practical and feasible countermeasures.This study has important theoretical and practical significance for excavating the potential of winter wheat production in Henan Province in the future climate and realizing the continuous increase of winter wheat yield.The analysis of the various yield gaps can reveal the limiting effects of the growth of production and the various limiting factors in the study area.Studying the yield gaps under the background of climate change helps us to understand the limiting effect of climatic factors on the crop yield gap.The current researches on the impact of climate change on crop yield gaps usually focus on larger scales.In order to improve the accuracy of the calculation results,this study divided Henan into five planting areas:Ⅰ,northern Henan;Ⅱ,eastern Henan;Ⅲ,shallow mountain hilly basin area;IV,Huaibei plain,Nanyang basin area;V,southern Henan.Using the meteorological data of 14 weather stations from 1961 to 2013 and from 2021 to 2050 under the RCP4.5 scenario the production potential of winter wheat in the province was calculated by AEZ model.Then YG1-2(The gap between Photosynthetic potential productivity and Photovoltaic potential productivity),YG2-3(The gap between Photovoltaic potential productivity and Climate potential productivity)and the YGZ-a(The gap between Photovoltaic potential productivity and average yield)was calculated according to the yield gap method.The main conclusions are as follows:(1)From 1961 to 2013,the sunshine duration of winter wheat during growth period in Henan Province was 1248.6h,and it showed a downward trend of fluctuation with the increase of time.The average temperature of winter wheat during growth period is 8.8°C,and it showed an increasing trend with the increase of time.The total precipitation of winter wheat of winter wheat during growth period is 240.2mm,and it showed an increasing trend with the increase of time.The spatial distribution shows that the Photosynthetic potential productivity and Photovoltaic potential productivity of winter wheat in Henan Province from 1961 to 2013 decrease from northeast to southwest,and the Climate potential productivity decreased from south to north.(2)The average yield of field in 14 research stations in Henan Province ranged from 1202-7498kg·hm-2 in 1981-2010.The analysis of field average yield of field showed that it was quite different in 14 stations,and it showed an increasing trend.The photosynthetic potential productivity of winter wheat in Henan province ranged from 47800 to 64983kg·hm-2 in 1961-2013,and it showed a decreasing trend;The Photovoltaic potential productivity of winter wheat in Henan Province ranged from 7157 to 9972kg.hm·2 in 1961-2013,and it showed a fluctuation increasing in every ten years;The range of climate potential productivity of winter wheat in Henan Province ranged from 1034 to 9417kg·hm-2 in 1961-2013,and there is no significant change in the climate potential productivity in the 14 sites in 53 years.(3)From the time point of view,the YG1-2 gap of winter wheat showed a decreasing trend,YG2-3 gap showed a "V-type",the valley was in 1981-1990,Ⅰ,Ⅱ,V areas’ YG2-a gap showed a decreasing trend,while the Ⅲ and IV regions showed a tendency to increase first and then decrease in Henan Province.From the spatial change point of view,winter wheat YG1-2 gap declined from north east to south west and YG2-3 gap declined from north to south,while the YG2-a gap increased from east to west in Henan Province.The order of yield-increasing potential of winter wheat in each region is:Ⅲ>Ⅴ>Ⅵ>Ⅱ.Agronomic factors were the main factors restricting the narrowing of the winter wheat yield gap in Henan Province.By improving agronomic factors,such as improving and updating winter wheat varieties,upgrading moderm agricultural technology,using pesticides and fertilizers reasonably,and rationally arranging high-quality wheat regions,it can reduce the winter wheat yield gap in this region.(4)In the RCP4.5 scenario,the mean annual sunshine duration of winter wheat will be 1360.6h in Henan Province in 2021-2050.The average sunshine duration showed a rising trend with the increase of time.Winter wheat The mean temperature in the growth period will be 9.5℃.The average temperature will increase with the increase of time.The average annual precipitation of winter wheat will be 517.7mm.The precipitation will not change with the increase of time,but it fluctuation will be large.(5)The photosynthetic potential productivity of winter wheat in Henan province will range from 52528 to 62735kg·hm-2 in 2021-2050;the photovoltaic potential productivity of winter wheat will range from 8012 to 11138kg hm-2;and the climate potential productivity of winter wheat will range from 2285 to 11138kg hm-2.The spatial distribution shows that the Photosynthetic potential productivity and Photovoltaic potential productivity of winter wheat in Henan Province from 2021 to 2050 will decrease from northeast to southwest,and the Climate potential productivity will decrease from northeast to southwest.There will be no significant change of the gap between Photosynthetic potential productivity and Photovoltaic potential productivity(YG1.2)of winter wheat in Henan Province from 2021 to 2050.The spatial distribution of YG1-2 will decrease from north east to south west in Henan Province,which indicate that the limitation of the caloric restriction on the photosynthetic potential productivity of winter wheat will decrease from north east to south west.The gap between photovoltaic potential productivity and climate potential productivity of winter wheat in Henan Province generally will show "V" type with valley in 2031-2040.There will be no significant change in 14 stations in 30 years.The spatial distribution of YG2-3 in winter wheat will decrease from north east to south west,which indicate that the restriction on the photovoltaic potential productivity of winter wheat will decrease from north east to south west.Compared with the baseline period(1961-2013),the constraints of the heat conditions on the photosynthetic production potential of winter wheat in future Henan will increase,and the restriction of water to winter wheat Photovoltaic potential productivity will reduce.