Definition And Evaluation Of The Rare And Endangered Soil Types For Case Areas In Henan Province

More attention should be paid in the protection of soil resources by keeping pedodiversity patterns in good order as a new focus under the background of the rapid urbanization development worldwide.It is important to realize the definition and evaluation of the rare and endangered soils in this effort.Anyang City in the northern of Henan,Zhengzhou city in the central of Henan and Xinyang city in the south of Henan were selected as the case study areas.Firstly,based on the soil map and topographic map of Henan Province,the spatial distribution pattern of soil in Henan and the distribution pattern of soil types at different taxonomic levels under different terrain conditions were analyzed by using pedodiversity measurement.And the distance index,area index and diversity index were calculated before an application of the clustering method to define and evaluate the rare soil types under the natural conditions in Henan province.Land use classification was worked out based on remote sensing images of four different periods(1988,2004,2009 and 2015)before the disturbance of land use change on soil in recent 27 years for the studied areas was analyzed by using multi temporal continuous contrast method combined with the soil map.Finally,combining traditional methods and pedodiversity method,the definition and evaluation of rare and endangered soils in the case study areas were defined and evaluated.The main conclusions are as following:(1)The distribution of soil types in Henan province is relatively uniform.And the spatial distribution patterns at different taxonomic levels are similar in general,assuming the feature that the lower the taxon level,the greater the soil diversity.The distribution of soil types in the regions with large topographic relief is more complex than that in the flat terrain.There are 38 rare soils at soil group level which accounts for about 0.93% of the total area of Henan.Among them,there are 4 extremely rare species,which accounts for only about 0.01% of the total area of Henan.(2)From 1988 to 2015,the non-agricultural construction land(urban construction land,mining warehouse land and traffic land)increased in different degrees,and the cultivated area was largely decreased in three studied areas.Thecomprehensive rate of land use change in Zhengzhou city(0.31%,0.41%,1.05%)was the fastest.(3)From 1988 to 2015,the soil disturbance in Zhengzhou was the most severe,and the disturbance velocity in Anyang was close to Xinyang.The disturbance of non-agricultural construction land to soil satisfied in general such a trend in the three studied areas that the disturbance speed of urban construction was larger than the road traffic and the industrial and mining storage disturbance while the least was the industrial and mining storage disturbance.(4)The degree of the non-agricultural construction disturbance to soil in different studied area is different.Compared to the other soils,there was only one soil family type disturbed more violently in Anyang,and the amplitude of disturbance was greater than 30%.There were 5 soils disturbed more sharply in Zhengzhou,and the amplitude of disturbance was greater than 40%.There were 2 soils disturbed relatively larger in Xinyang,and the amplitude of disturbance was only greater than10%.(5)There are 11 rare soils in Anyang accounting for about 1.33% of the total soil area,of which there are 3 extremely rare soils accounting for only about 0.10% of the total soil area.There are 10 rare soils in Xinyang,accounting for about 0.81% of the total soil area,of which there is 1 extremely rare soil,accounting for about 0.02% of the total soil area.There are 16 rare soils in Zhengzhou,accounting for about 2.01%of the total soil area,of which there are 2 extremely rare soils,accounting for about0.11% of the total soil area.(6)There are 9 endangered soils in Zhengzhou,of which there are 6 rare and endangered soils.About 46.52% of the endangered soils were disturbed,while17.03% of rare soils were disturbed.The protection of soil in Zhengzhou should be strengthened due to severe soil disturbance.There are only 0.25% of the rare soils disturbed in Anyang,while there are only about 0.71% of rare soils disturbed in Xinyang.There is no endangered soil at present in Anyang and Xinyang.