Genetic Characteristics And Taxonomic Classification Of The Representative Soils In Semihumid Temperate District Of Inner Mongolia

At present,China’s soil classification in the Soil Genetic Classification to the Soil Taxonomy of the stage,Soil Taxonomy is directly related to the production and application,and it is the key bridge between the theory of soil discipline and the practice of production.With the increasingly detailed use of land use,soil system classification with the quantitative,standardized,internatioal characteristics of the has become the trend of international soil classification.Inner Mongolia Autonomous Region is located in the north of China,connecting the northeast,north and northwest three areas.Based on the field investigation,laboratory analysis and access to the relevant soil data,five typical profiles were selected,and the physical and chemical properties of semihumid temperate district of Inner Mongolia were studied systematically.According with the "Chinese Soil Taxonomy(3rd ed)"and"principle and Criteria for Establishment of Soil Family and Soil Series of Chinese Soil Taxonomy(The trial version)"for five typical profiles were systema tically classified,the diagnostic horizons and diagnostic characteristics of the profile soil were deter mined and their attribution in the Soil Taxonomy was discussed.Through the study,the main conclusions are as follows:(1)In the study area,the typical profiles of forest soil is deep,and the profiles shows strong humus accumulation and mild leaching.The upper layer of the soil is darker in color than the profile.The surface soil development is better,in the form of pellets,and the downward structure of the soil is in the form of lumps to weakly developed.Most of the soils are composed of sand or granules,and the soil texture is sandy loam or silt loam.Due to the different soil factors,the clay content of the section is leached and the clay content is clay loam.The content of organic matter and total nitrogen decreased gradually along the soil layer.The accumulation of organic carbon in the surface is affected by altitude.Forest soil developed by leaching,so that a large number。fsalt-based components from the soil leaching out,the soil was slightly acidic to acidic.The salt saturation of the soil is more than 50%,the surface cation exchange capacity is generally higher,and the exchange of salt ions is mainly calcium and magnesium.SiO2 in the mineral content of the highest proportion,accounting for about 55%of the total mineral content(2)The soil developed on the mountain meadow in the study area has the characteristics of meadow process,that is,the accumulation of humus and the oxidation reduction characteristics,but the oxidation reduction in the mountain meadow is very weak.The upper soil of the test profiles is darker and the lower soil is brown or yellow.The upper soil structure is agglomerate,and the developmental condition is better than the lower soil.The soil composition of the soil is mainly s and and grain,and the soil texture is mostly loam.Organic matter and total nitrogen content decre ased gradually along the profiles level,the parent layer content is very small.The salt saturation of the test area is ≥50%,and the exchangeable salt of the soil is the same as that of the mountain soil,with calcium and magnesium as the main and the pH value is slightly acidic to neutral.The content of various elements in the soil mineral content is very large,and the proportion of SiO2 is the largest.(3)According to the diagnostic horizons of the control layer in the third edition,the main diagnostic horizons of the typical profiles of the temperate and semihumid temperate district of Inner Mongolia were as follows,mollic epipedons,ochric epipedon,argic horizon;The diagnostic charact eristics as follows,isohumic property,mesic soil temperature regime,frigid soil temperature regime,ustic soil moisture regime and base saturation.(4)According to the diagnostic horizons and diagnostic characteristics of each profiles,the order,suborder,group,subgroup of each profiles were retrieved.The typical sections of the semihum id temperate district of Inner Mongolia are divided into three orders,three suborders,four groups and four subgroups.According to the index of Chinese soil basic taxonomy,the profiles have been divided into five soil families,at the same time five soil series such as Chamuhan in studied area were established.According to the second soil survey data of Inner Mongolia,correlation of soil taxa between Chinese soil genetic classification and Chinese soil taxonomy.