Field Survey And Characteristics Of Soil Under Different Vegetation Types In Haituo Mountain

As an important part of terrestrial ecosystem,soil plays an important ecological service function.Topsoil is an important layer in the soil,containing a lot of humus,rich in mineral nutrients,good pores,dense roots,and storing a large number of seeds.The soil types,properties and ecological service function of different vegetation types are obviously different.In this paper,the characteristics of soil profile,physical and chemical properties and clay mineral composition of different vegetation types in Haituo Mountain were systematically studied by means of field investigation and lab analysis,so as to provide an effective basis for region forest management and ecological environment protection and recovery.Main research results showed that(1)The soil types in different vegetation types were different.The soil types in the distribution area of deciduous broad-leaved forest were brown soil and cinnamon soil.The soil types of evergreen coniferous forest and shrub forest were brown soil,and shrub meadow was meadow soil.(2)All studied soil profiles had typical A-B-C layer sequences.Layer A usually was loose,dark and densely rooted with low gravel content.With the increase of soil depth,the soil became more compacted and both the color value and the gravel content increased,but the root system gradually decreased to none.The thickness of the soil profile was between 62 centimeters and 100centimeters,and the thickness of the topsoil layer was 25 centimeters,mainly including layer O and layer A.The soil development was relatively young.(3)The soil texture of different vegetation types was mainly loam,sandy loam and silt loam.The soil density ranged from 0.86 g/cm~3to 1.76 g/cm~3,and the average soil density of shrub forest was the highest,with a value of 1.36 g/cm~3.The total porosity of soil ranged from 33.58%to 67.55%,and the best porosity was found in shrub meadow,with an average value of 60.38%.The soil porosity decreased with the increase of soil depth,while the soil density was opposite.(4)The soil p H value ranged from 5.28 to 7.73,ranging from acidic to alkaline.The content of soil organic matter ranged from 1.35 g/kg to 126.11 g/kg,and the average value of the topsoil was 51.41g/kg,higher than that of the substratum.The total nitrogen,available phosphorus and available potassium in the soil ranged from 0.07 g/kg to 4.95 g/kg,0.71 mg/kg to 15.21 mg/kg and 28 mg/kg to378 mg/kg,respectively.The average contents of the topsoil were 1.41 g/kg,6.81 mg/kg and 170.58mg/kg,which were significantly higher than those in the substratum.The nutrient status of shrub meadow was the best.(5)The clay mineral composition of soil of different vegetation types in this area mainly included Illite,Kaolinite,Chlorite,Vermiculite,I/S mixed layer and I/V mixed layer.The proportion of I/S mixed layer was the largest,and its relative content was between 42%and 86%.We concluded that vegetation types have remarkable effects on soil properties of the whole soil profile and especially on the topsoil.We suggested that vegetation types and soil properties should be considered in forest management,ecological environment protection and vegetation restoration,and more importance should be attached to the protection and utilization of topsoil resources.