海南岛尖峰岭地区山地土壤发生特性

对地处热带的海南岛尖峰岭地区的山地土壤的发生和发育特性进行了研究。因母岩因素以及较弱的成土作用和较强的侵蚀作用 ,土壤质地普遍较粗 ,石砾含量高。由于山地气候的垂直分异 ,不同海拔高度土壤间的发生特性存在较大差异。高海拔地区土壤易风化矿物含量高 ,低海拔地区土壤中抗风化能力强的锆石含量高 ;高海拔区土壤中粘土矿物以三水铝石和埃洛石为主 ,含有一定量的铝蛭石 ,低海拔土壤以高岭石为主 ,有一定量的水云母。伴随海拔高度的增加 ,阳离子交换量 (CEC7)、盐基总量、盐基饱和度、pH下降 ,而代换性酸H 、Al3 却逐渐增多。高海拔区湿润的水分状况和酸性成土环境导致粘粒的硅铝率、硅铁铝率较低海拔土壤小。尖峰岭地区土壤类型以雏形土为主 ,山麓分布有淋溶土。

STUDY ON PEDOGENESIS AND DEVELOPMENT OF MOUNTAIN SOILS IN JIANFENGLING MOUNTAIN AREA

Granites predoninantly distribute in lithology in Jianfengling Mountain Area of Hainan Island,situated in tropoical region.The soils from the foothill to peak form a soil chimosequence in this area due to great vertical variation in mountain climate.It is favorable to research on pedogenesis and development of mountain soils in tropocal region.It has been studied that the change of pedogenic characteristics,e.g.mechanic compositon,make up of primary minerals and clay minerals,basic chemical features,exchange power,oxides of iron and aluminum, mangetic susceptibility,and chemical composition of clays in mountain soils at different elevation with mountain climates.The soil textrue is coarse and garvels content is high universally due to weathering_resistance of parent rock_granite,weak woil formation and strong soil erosion.Great variation of pedogenetic characteristics among soils at different altitude results from thevertical diversity of mountain climates. The cotent of weatherable minerals is great in soils at high elevation in contrast to high content of zircon,as a weathering_resistance mineral,in soils at low elevation.Gibbsite and halloysite are dominant clay minerals and Al_vermicuite is secondary in solis at high altitude while kaolinite is predominant and hydromica is secondary clay mineral at low altitude.With elevation increasing,CEC 7,sum of base,base saturation degree,and pH decrease,however,exchangeable hydrogen and aluminnum add gradually.the ratios of caly silica-alumina and silic_sesquioxide in soils at high elevation,which developed in perudic moisture regime and from acid leaching,are lower than those at low elevation.Cambisos mainly occupy in Jian Feng Ling Mountain Area,meanwhile Argisols distribute in foothill.