| The Sanjiang Plain is an important commodity grain base in northeastern China.Agriculture is an important industry in the region.Therefore,on the basis of ensuring the continuous improvement of the regional social and economic level and the continuous improvement of the ecological environment,the future analysis of regional water under different climate change scenarios The problem of resource supply and demand balance and the development of optimal crop irrigation systems are crucial to regional sustainable development.This paper uses SWAT(Soil and Water Assessment Tool)model,selects the two future climate change scenarios mentioned in IPCC(Intergovernmental Panel on Climate Change)RCP4.5 and RCP8.5,couples 5GCMs(Global Climate Models),and develops A simulation study of the total water resources in the Sanjiang Plain area from 2020 to 2035.Set the value of the degree of development and utilization of water resources,with 2035 as the target year,predict the total amount of water resources that can be extracted in the future,and predict the consumption of living,production and ecological water according to the gray model,quota method,growth rate method,etc.Analyze the future supply and demand of water resources in the study area and propose sustainable development countermeasures.Finally,taking the large-scale irrigation area in the lower reaches of the Songhua River as an example,the critical growth period of crops was analyzed,and 16irrigation scenarios were set for dry field crops(maize and soybeans).The typical years and targets were obtained using analytic hierarchy process and gray correlation method The best irrigation plan for the year.The main conclusions of this article are as follows:(1)The calibrated and verified SWAT model is suitable for the simulation application in the research area.The five GCMs including BCC-CSM1-1,CCSM4,EC-ERATH,MIROC-ESM-CHEM,and GISS-E2-H-CC are coupled and perform well in the simulation of meteorological data in the study area,which can be used to predict future meteorological data.The change.The total amount of water resources under the two climate change scenarios is predicted.The total amount of water resources in the study area under the RCP4.5 scenario in 2035 generally shows an increasing trend,while the total amount of water resources under the RCP8.5 scenario shows a decreasing trend.The total amount of water resources is 19.172 billion m~3 and 17.538billion m~3,respectively.(2)The preset value of water resources development and utilization is 75%,and the regional available water resources under the RCP4.5 scenario is 14.379 billion m~3,and the regional exploitable water resources under the RCP8.5 scenario is 13.154 billion m~3.An analysis of changes in water use in various industries shows that domestic water,production water,and ecological water use in the future study areas all show an upward trend.In 2035,the total water demand of the Sanjiang Plain is 16.593 billion m~3,of which domestic water is 2.860 billion m~3,production water is 13.672 billion m~3,and ecological water consumption is 61 million m~3.An analysis of the balance between supply and demand of regional water resources reveals that the Sanjiang Plain will have a great water shortage problem in the future,especially the issue of agricultural water use,which should be highly valued.In order to ensure the sustainable development of regional water resources,reasonable suggestions are proposed for the water use of various industries in the Sanjiang Plain area.(3)By analyzing the coupling of water demand and effective rainfall and the sensitivity index of crop water production function of upland crops in the study area,the key growth period of maize is jointing-heading and heading-filling,and the key growth stage of soybean is flowering-knot Pod and pod-drum stage.16 irrigation scenarios were set for two crops in different historical typical years and future target years.The analysis showed that irrigation only during the key growth period can effectively save water and improve water use efficiency.The best irrigation method for maize during the high water season is to irrigate 4 waters during the critical growth period,and the irrigation quota is 210 m~3/hm~2;the average water period and the dry season are to irrigate 6 waters during the critical growth period,and the irrigation quotas are 840 m~3/hm~2and1341 m~3/hm~2is the best;under the RCP4.5 scenario in the target year,the irrigation is 6 times,and the optimal irrigation quota is 1227 m~3/hm~2;under the RCP8.5 scenario,the irrigation is 4 times,and the irrigation quota is 1450 m~3/hm~2.Soybeans are irrigated with 6 waters in the critical growth period in high water years,normal water years,and low water years,with irrigation quotas of 99m~3/hm~2,282 m~3/hm~2,and 888 m~3/hm~2.The irrigation quota is 1200 m~3/hm~2,the irrigation is 6times under the RCP8.5 scenario,and the irrigation quota is 1725 m~3/hm~2.In summary,this paper uses the SWAT model to analyze the trend of water resources changes in the Sanjiang region,the future exploitable water resources and the water consumption of various industries in the context of the Sanjiang Connection Project.By formulating the optimal irrigation system for dry field crops in typical irrigation areas,water conservation is achieved The win-win development goal of irrigation and improving agricultural benefits,the research results will provide a scientific reference for regional land and water resources management. |
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