Study On The Spatial And Temporal Distribution Of Irrigation Water Demand Of Main Crops In Shandong Province

As a major agricultural province in China,Shandong Province is facing a severe water shortage.Agriculture in Shandong Province relies heavily on irrigation and uses more water for agricultural irrigation.Agricultural irrigation is in urgent need of improvement in management and water saving.Based on the meteorological data of 20 meteorological stations in Shandong Province for nearly 50 years from 1968 to 2016,this paper selected summer maize and winter wheat as the main crops in Shandong Province as the research objects,divided the irrigation zones according to Shandong provincial local standards,and used M-K test method and inverse distance weight interpolation method to divide the temporal and spatial variation of irrigation water demand of summer maize and winter wheat in Shandong Province.Pearson correlation analysis method was used to analyze and rank the influence of meteorological factors on irrigation water demand of summer maize and winter wheat,and the rational allocation scheme of irrigation water resources in different irrigation zones in Shandong Province was put forward.The main results are as follows:(1)Irrigation water demand of summer maize and winter wheat in Shandong Province showed no significant decreasing trend.From the growth season point of view,the irrigation water demand of summer maize is the lowest in June and the highest in August,the irrigation water demand of winter wheat is the lowest in December and February,and the largest in April and May.From the hydrological year point of view,the change trend of irrigation water demand of Summer Maize in different hydrological years is basically the same,showing the change of "first rising,then falling,dry year > flat year > high water year".The trend was that the irrigation water requirement of Winter Wheat in different hydrological years showed a trend of "slight decrease first,then significant increase,dry year > flat year > rich year".(2)The spatial distribution of annual average irrigation water demand of summer maize showed a general trend of "less in southwest and more in northeast,increasing from southwest to northeast".The spatial distribution of annual average irrigation water demand of winter wheat showed a trend of "less in Southeast and more in northwest,increasing from southeast to northwest".(3)Precipitation and sunshine hours are the main meteorological factors affecting irrigation water demand of summer maize.Sunshine hours,average temperature,maximum temperature and wind speed are positively correlated with irrigation water demand of summer maize,while precipitation,average pressure,minimum temperature and relative humidity are negatively correlated with irrigation water demand of summer maize.Relative humidity and sunshine hours are the main meteorological factors affecting irrigation water demand of winter wheat.Sunshine hours,average temperature,maximum temperature and wind speed were positively correlated with irrigation water demand,while relative humidity,average air pressure,minimum temperature and precipitation were negatively correlated with irrigation water demand.(4)Based on different hydrological years,a scheme of rational allocation of irrigation water resources is put forward,which is suitable for local conditions,irrigation according to needs and irrigation according to time.In conclusion,this study provides scientific and reasonable technical support for sustainable utilization and development of water resources in Shandong Province.