Research On Spatio-temporal Characteristics Of Agricultural Climatic Resources In The Yellow River Irrigation Area Of Henan Province Under The Background Of Climate Change

Global climate change has made the spatio-temporal pattern of agricultural climate factors such as light,heat and moisture more complicated,which has brought challenges to food security and sustainable agricultural production.This article takes the Yellow River Irrigation Area of Henan Province as a response area for climate change,sampling experiments and monitoring analysis of the agricultural environment.Based on the daily data of 43 meteorological stations in Yellow River Irrigation Area of Henan Province from 1960 to 2018,the climate tendency rate,moving average,Morlet wavelet analysis,Mann-Kendall test,Theil-Sen estimation,Kriging interpolation,EOF orthogonal decomposition and other methods are used to analyze the spatio-temporal dynamic characteristics of agricultural climatic resources in the past 60 years;on this basis,The Thornthwaite Memorial model was improved by the Penman-Monteith formula and simulates the climatic production potential of winter wheat in the Yellow River Irrigation Area of Henan Province,and finds out the climatic factors that restrict the potential yield through correlation analysis,with a view to providing a theoretical basis for the strategic decision of food security in the Yellow River Irrigation Area of Henan Province.The main conclusions of the study are as follows:(1)The runoff of the Yellow River is decreasing year by year.The artificial adjustment makes the Yellow River maintain a large runoff in the later stage of winter wheat growth,which is conducive to the irrigation of the winter wheat in the Yellow River irrigation area of Henan Province during the greening-maturity period.The soil water content of the farmland inside and outside the embankment have significant spatio-temporal dynamics.The soil water content was mainly affected by winter wheat growth and water consumption,precipitation recharge and irrigation replenishment.The precipitation recharge has hysteresis;the coefficient variation of the soil water content in different soil depths outside the embankment with the greatest degree of variation,and the soil layer below 20 cm is relatively stable.The soil in the study area as a whole is alkaline and medium fertility.The physical and chemical properties of the soil between the winter wheat field and the vertical soil layer inside and outside the dike are quite different.(2)From 1960 to 2019,the heat resources in the Yellow River Irrigation Area of Henan Province increased significantly,the sunshine and water resources decreased,and the extreme climate began to intensify since the 1990 s.(a)Air temperature,active accumulated temperature of ?0? and active accumulated temperature of ?10? increased significantly,and the frost-free period was slightly extended;the amount of evaporation decreased significantly,precipitation and relative humidity showed a downward trend as a whole,and the trend of “warming and drying” in the Yellow River Irrigation Area in Henan Province was significant.Sunshine hours have decreased significantly,and sunshine resources in the Yellow River Irrigation Area of Henan Province have decreased.The extreme temperature and extreme precipitation have obvious phase characteristics.The maximum temperature and minimum temperature in the growth period of winter wheat in the past 30 years have increased significantly.The maximum daily rainfall intensity,the number of heavy rain days,and the annual total precipitation have shown a downward trend and the intensity is more intense.(b)The changing trends of agro-climatic factors in the Yellow River irrigation area in Henan Province between generations,between seasons,and at different growth stages of winter wheat are more complicated.There have been multiple time-scale shock cycles and abrupt changes in the past 60 years,predicting future agricultural climate resources in the study area It shows that the heat resource is still on the rise,the sunshine resource is shortened and the water resource is reduced,and it is necessary to take timely agricultural measures to ensure the production of winter wheat.(c)The temperature in the study area is generally rising,and the heat resources in the western counties and cities will be more abundant in the future;the rising and falling hours of sunshine hours are complex,taking the Yellow River as the boundary,the daylight on the south bank increases significantly,and the daylight on the north bank decreases significantly;It decreases towards the northwest;the amount of evaporation is dominated by a downward trend,with the largest decline in Kaifeng City and its surrounding areas;the relative humidity in the irrigation areas has consistently decreased,with the decline in the southwest being higher in the east and the east.In the higher latitudes of Puyang,Xingyang and Xinxiang on the edge of the mountainous areas in western Henan,the extreme temperature of winter wheat increased significantly during the growth period;the extreme precipitation decreased from high to low in the north.(3)From 1960 to 2019,the climatic production potential of winter wheat in the Yellow River Irrigation Area of Henan Province fluctuated and increased with time;the spatial distribution was affected by the zonal distribution of temperature,light,water resources and their combined configuration,which was high in the southeast and northwest,along with the spatial change trend of heat resources and water resources,the high area of winter wheat climatic production potential has a tendency to shift from south to north and from east to west.Annual average temperature,?0? active accumulated temperature,?10? active accumulated temperature and evaporation are the limiting factors for winter wheat climatic production potential;in the future of climatic warming and drying,the winter wheat climatic productivity is decreasing with the rate of 35.64 kg/hm~2 per year.