Matching Relationship Between Land Salinization And Land Use In Yellow River Delta And Its Functional Suitability Evaluation

Land Salinization is an important factor that leads to the decrease of land productivity,the deterioration of ecological environment and the poor sustainability of regional development.Land salinization has long plagued arid and semi-arid areas and the coastal area in agricultural production,economic construction,ecological protection and people's lives.It is the basis of scientific improvement and rational utilization of salinized land to grasp the salinization status and the matching relationship between salinization and land utilization in time and accurately,and to make clear the suitability based on the function of utilization type,it is of great significance for promoting regional economic and social development and improving ecology.The Yellow River delta is the fastest-growing estuary delta in China and even in the world,but it is affected by natural and human factors such as the confluence of rivers and seas,climate change and improper utilization,land salinization and secondary salinization have existed for a long time.Therefore,taking the Hekou District of the Yellow River delta as an example,based on 3S Technology,field survey,sampling and testing,statistical analysis and other methods,the land classification information is accurately extracted by the combination of remote sensing monitoring classification and spatial interpolation,this paper analyzes the characteristics of land salinization and land use and their matching relationship,and evaluates the suitability of agricultural land and construction land based on the function of land use type,in order to provide a basis for rational land use planning.The main results are as follows:(1)The characteristics of land use and salinization in Hekou District were analyzed.The results show that the spatial distribution characteristics of land use in Hekou District are obvious,the cultivated land is concentrated in the southwest and southeast,and a small amount in the central part,and the saline-alkali wasteland is concentrated in the northeast and northwest coastal areas,the water surface of aquaculture is concentrated in the northwest and the offshore area of the northeast corner.The construction land is concentrated in the south and the salt field is the main land in the northwest.In spring,the soil in Hekou District is heavily salinized,and the spatial distribution is aggravated from southwest to east and north,showing strong variability.(2)The matching relationship between land salinization and land use types in Hekou District was discussed.The results showed that the relationship between land use types and salinization in spatial distribution and quantity was“Overall matching,local mismatch”.In the quantitative matching relation,the proportion of heavy soil and saline soil in cultivated land is as high as 28.33%,and more than half of medium soil,which indicates that the salinization of cultivated land is serious.At the same time,affected by various aspects,part of the quality of cultivated land degradation.In 2019,the utilization rate of cultivated land in Hekou District was only 65.63%,which indicates that the utilization rate of cultivated land is not high although the quantity of cultivated land is large.The saline-alkali wasteland is67.85%above medium and heavy degree,and the location is remote,the water source is scarce,is not suitable for the agricultural reclamation.More than 60%of the construction land is medium or above salinized land,which indicates that the construction site is advantageous to the protection of light or medium land,but a small part of the construction land is selected in light or medium region.60%of the grassland was distributed in the salinized area.The salinization near the reservoir and river is light,but the salinization is serious in the north jujube forest and Tamarix chinensis forest which is far from water source and shallow groundwater.(3)The suitability of agricultural utilization and construction utilization based on utilization type function was evaluated.The results show that about 70%of the existing agricultural land in Hekou District is at or below the general suitability level,and about 40%of the construction land is at or below the general suitability level.The existing agricultural land area in Hekou District is 8.94×10~4hm~2,of which the highly suitable agricultural land is mainly distributed in the north of Dashan village in Xianhe Town and the south of Donghan village,accounting for 3.87%of the agricultural land area in Hekou District Higher suitable agricultural land is mainly distributed in Sanyi village in the northwest,Lixin village around Xinhu town,Dashan village in the south of Yihe town in the southwest and Dongcui village in the south-central part,accounting for 27.42%of the agricultural land in Hekou District Generally,it is suitable for the most western part of the agricultural land,such as Nanwang village and Xihua village,the southwest part of Zhonghetang village,the central part of Chen Zhuang House and Cui Li Village House,the southern part of Jiang Jia House,and some land in the south-central part of the country,58.46%of the agricultural land in Hekou District;the less suitable agricultural land is mainly distributed in the northeast corner of Hekou District,part of which is scattered,accounting for 10.17%of the agricultural land in Hekou District;the less suitable agricultural land is distributed in the northwest corner of the region,0.08%of agricultural land in Hekou District.The existing construction land area in Hekou District is3.24×10~4hm~2,the highly suitable land for construction is mainly distributed in Xinan and southeast village in the center of Yihe Town,Leyuan village and Xiyuan village in Gudao Town,haixing village in Xianhe town and the surrounding area of Dongying port,accounting for 12.17%of the area of construction land in Hekou District The relatively high proportion of suitable construction land is the largest,mainly distributed in northwest village and Northeast Village of Yihe Town,Zhenyuan village of Gudao town,Zhendong village of Xianhe town,etc,which accounts for 47.36%of the construction land in Hekou District;Generally,suitable construction land is mainly distributed around the government of Hekou District district and Dongshuangwu,etc.in the northeast,accounting for 34.55%of Hekou District's construction land area;The less suitable sites are scattered in Guoju village in northwest Hekou District,which accounts for 5.79%of Hekou District's construction land area,and 0.13%of Hekou District's construction land area in northwest Hekou District.In this paper,the land classification information of Hekou District was accurately extracted by using remote sensing and ground survey,and the characteristics of land salinization and land use and their matching relations were analyzed,the suitability of agricultural land and construction land was evaluated based on the use type function.It is suggested that Hekou District should strengthen the protection of cultivated land,develop the characteristic garden and forage grass industry,explore the multi-functional utilization ways of saline-alkali land resources,and optimize the land use structure and spatial distribution according to the results of suitability evaluation in the territorial spatial planning,to improve the matching of land use and actual conditions,to promote the scientific and efficient land use and regional sustainable development.