Clay Mineral Composition And Its Spatial Distribution In Guangxi

The composition and content of different clay minerals in the soil reflect the occurrence and development of soil,and have strong regionality.It is an important basis for studying soil development and soil classification.In this study,the spatial distribution characteristics of soil clay minerals and the relationship between clay minerals and soil environment were analyzed by different latitudes and parent materials in Guangxi.The clay mineral composition was applied to distinguish mineralogy classes for soil family classification of clayed soil profiles.Get the following results:(1)The Sa ranges from 1.47 to 4.69 in different types of soil in Guangxi.Sa in different Order is Ferralosols < Ferrosls <Argosols <Halosols <Cambosols <Anthrosols <Vertosols<Gleyosols<Primosols.Soil clay minerals are rich in a variety of minerals including kaolinite,1.42 nm transition minerals,illite,montmorillonite,1.2 nm mixed minerals,vermiculite,gibbsite,and chlorite.and the average relative content of above clay minerals decreases in turn.(2)The composition of clay minerals has obvious regularity in latitude spatial distribution.With the decrease of latitude,the type of clay minerals gradually became single,the kaolinite increased,and the relative content of illite and 1.42 nm transition minerals decreased.In southwestern Guangxi,climatic condition is the decisive factors affecting the composition of clay minerals.In the region of latitude >23°N,the composition of clay minerals is closely related to parent material.(3)Anthrosols,Ferralosols,Ferrosls,Argosols and Cambosols have obvious zonal differentiation characteristics in spatial distribution,but they are not completely restricted to zonal spatial differentiation.The clay mineral composition and mineralogy types of soil families of Anthrosols,Ferralosols,Ferrosls with a latitude <23°N as an obvious boundary line.And Ferralosols both appear in the latitude <23° area.The clay minerals in this area are mainly kaolinite,containing illite and a small amount of 1.42 nm transition minerals.The mineralogy type of soil families for its clayed soil profiles was kaolinitic.In the region of latitude >23°N,the clay mineral composition of Anthrosols and Ferrosls is more complicated,which is related to parent materials and hydroponic.The main clay minerals of Anthosols include montmorillonite,illite,1.42 nm transition mineralsand kaolinite.The mineralogy types include kaolinitic mixed,mixed and illitic.The Ferrosls is dominated by 1.42 nm transition minerals,kaolinite and illite and the mineralogy types are kaolinitic,and kaolinitic mixed.Argosols are mainly distributed in the northwestern part of Guangxi.It is affected by the climate and the parent materials.The clay minerals are mainly 1.42 nm transition minerals and illite,followed by kaolinite.The mineralogy types are kaolinitic mixed and mixed;Cambosols are widely distributed,and the composition of clay minerals is affected by the climate,which varies with the parent material.Mineralogy types include kaolinitic mixed,mixed and montmorillonitic;In addition,Vertosols,Halosols,Gleyosols and Primosols are scattered.There are more montmorillonites in Vertosols and the mineralogical types are montmorillonitic and montmorillonitic mixed;the main mineral of Halosols is kaolinite and illite;the clay minerals of Gleyosols are illite,kaolinite and montmorillonite;Primosols contains a large amount of illite.(4)The paddy field use increases the illite,and the long-term planting of rice delays the weathering of the soil.The Sa of different land use patterns are in the dry land <woodland < paddy field;the clay mineral composition of the top layer and the B layer soil does not change much.