A Study On Irrigation Adaptation Decision Of Rural Farmers In Henan Province Based On Crop Irrigation Water Demand

Water resource is the most important support and guarantee for agricultural production,and it is also an important factor restricting the development of agriculture.With the global warming,the further change of precipitation intensity and pattern aggravates the instability of water resources and the contradiction between supply and demand,and the problem of agricultural water shortage is gradually emerging.As the main body of agricultural production activities,farmers should not ignore the adaptation strategy of climate change.Based on meteorological data and crop water demand data from 1980 to 2015,firstly,the Mann-Kendall trend test method and GIS spatial analysis method are used to analyze the spatio-temporal changes of the six climatic factors of the annual average temperature,the annual maximum temperature,the sunshine hours,the total amount of precipitation,the number of precipitation days and the relative humidity in Henan province;secondly,factor contribution rate is used to analyze the influence of climate change on crop irrigation water demand and define the contribution rate level region,and predict the spatio-temporal changes of crop irrigation water demand under the future climatic conditions;finally,according to the difference of contribution rate,different areas are demarcated,and typical village areas are selected to carry out farmer surveys in different regions,and the perception of climate change and irrigation adaptation strategies are compared and analyzed.The following conclusions are obtained:(1)From 1980 to 2015,the average temperature and the annual maximum temperature in Henan Province showed an increasing trend,the number of precipitation days decreased,the number sunshine hours,the total amount of precipitation,and the relative humidity increased or decreased in the regional scope,the overall performance was a decreasing trend.These agricultural climatic elements were basically mutated in 1997.(2)The water demand and irrigation water demand of winter wheat in henan province showed an increasing trend,and the dependence of irrigation was decreased from north to south;the water demand and irrigation water demand of summer maize are decreasing,and the dependence on irrigation is increasing from southeast to northwest.From the points of crop,the effect of heat factors on the irrigation water requirement of winter wheat shows a pattern of high in the south and the north,and the influence of precipitation factors on the irrigation water demand of winter wheat shows a pattern of high in central and northern regions;for summer maize,the influence of the heat factors on the irrigation water demand of the western and central regions is high,and the influence of precipitation factors on its irrigation water demand is high in the north and east.Comprehensive analysis of the effects of various agricultural climate resources on the irrigation water demand of winter wheat and summer maize,and divided the study area into different contribution rate levels,the high positive contribution rate and high negative contribution rate are distributed in the central and northern regions of Henan Province;and the low positive contribution rate regions are mainly distributed in the western and southern parts of Henan Province;the low negative contribution rates are mainly distributed in the north,west,and east regions.(3)From the perspective of farmers' perception,the regional farmers with high negative contribution rate are more concerned with climate change,while the high positive contribution rate has a strong perception of the causes of climate change.In terms of specific climatic factors,farmers have the strongest sense of temperature,most farmers believe that the temperature is rising,and they will adjust the irrigation water according to the change of temperature;the majority of farmers believe thatthe total amount of precipitation and the number of precipitation days are decreasing,which is consistent with the actual situation,and will adjust the irrigation water accordingly;the perception of sunshine hours is weak,and most farmers believe that the number of sunshine hours is unchanged.(4)From the farmer's adaptation strategy,the farmers are more willing to adopt the expansion strategy(increase irrigation)and adjustment strategy(using improved seeds and changing fertilizer use).Whether farmers regulate irrigation is affected by various factors,among which natural capital(cultivated land area)and social capital(whether farmers help each other)are the most influential.By education level,cultivated land area and whether farmers help each other to influence the high contribution rate regional farmers' irrigation behavior;the total population of the family,the cultivated land area and whether farmers help each other to influence the irrigation behavior of the regional farmers with low contribution rate.It is the gender,cultivated land area,whether farmers help each other and how to make a living;it is the age and total population of the family that affects the irrigation behavior of the farmers in the region with negative contribution rate.(5)In the future climate scenario,the overall water demand of food crops in henan province shows an increasing trend,the irrigation water demand of summer maize increased in different regions,while the irrigation water demand of winter wheat increased or decreased,farmers should adopt the "expanded + adjustment" adaptation strategy in the future to better cope with climate change.