Changes And Safety Evaluation Of Grain Production In Yellow River Basin Under Water Resource Constraints

Climate change has continuously reduced river runoff,and water security has faced tremendous challenges.Water shortage will be the main constraint to increasing food production in the next few decades.Therefore,research on the changes in food production and safety conditions in the Yellow River Basin under water resource constraints are important for ensuring food security.Safety is of great significance.This article takes the Yellow River Basin as the research object,analyzes the current situation of grain production and water resource utilization in the Yellow River Basin,selects indicators to evaluate the food security status of the Yellow River Basin,and explores the main factors affecting food security.Based on the SDSM statistical downscaling,the meteorological factors under the future climate scenarios of the Yellow River Basin are estimated.Calculate the amount of agricultural demand in the Yellow River Basin,construct a water-resource allocation model with the maximum food production,and calculate the maximum food production that can be achieved in the Yellow River basin.The main research content and results of the thesis are as follows:(1)Based on the collected data to analyze the characteristics of the spatial and temporal changes of grain production and water resources utilization in the Yellow River Basin,the results show that the grain output and grain sown area in the Yellow River Basin from 2000 to 2017 fluctuated and increased,and the overall grain output in the Yellow River Basin went from west to west.In the east,the sown area of grain increased from west to east and from north to south.Industrial water and agricultural water in the Yellow River Basin increased first and then decreased,while domestic and ecological water continued to increase.In terms of space,the Inner Mongolia Autonomous Region has the largest total water consumption.(2)Classification of food security based on per capita food occupancy,analysis of the current situation of food security in the Yellow River Basin and the main factors affecting food security.The areas with higher security levels are mainly Inner Mongolia,Henan and Shandong;the five most obvious factors affecting food security in the Yellow River Basin are the amount of chemical fertilizers,the area of grain sown,the total power of agricultural machinery,the effective irrigation area,and the total amount of precipitation.(3)Based on SDSM statistical downscaling to estimate the meteorological factors of the Yellow River Basin in the future.And the results show that the correlation coefficients of each model and the measured precipitation are all above 0.74,and the correlation coefficient of temperature is above 0.9,and the future precipitation of each model has an increasing trend.(4)Localize the AquaCrop model,and use the correlation coefficient,standardized root mean square error(NRMSE)and synergy index(d)to evaluate the accuracy and adaptability of the model.The analysis results show that the model has good adaptability in the Yellow River Basin.Calculate the future agricultural water demand of the Yellow River Basin based on the future meteorological factor and the localized AquaCrop-OS model,and the results show that the agricultural water demand under different scenarios and models in the future will have a downward trend.(5)Building a water resource allocation model for the Yellow River Basin with maximum food output.The analysis shows that the grain production in the Yellow River Basin will decrease in 2030.The maximum is only 104.84 million tons,and the maximum level of food security is only well-off.The per capita food consumption in each scenario of CanESM2 and GFDL_ESM2G fluctuates around 450 kg/person,MIROC_ESM_CHEM mode Food security is in a relatively safe state.