The Taibai Mountain, with an altitude of 3 767 m, is the highest peak of the Qinling Mountain Chain. There are many kinds
of climates, abundant
vegetation resources, and typical altitudinal belts of soils on the slopes of the Taibai Mountain. The variations in temperature, precipitation and vegetation type are caused by the descending altitude on the northern slope of the Taibai Mountain. In the middle zone, the vegetation type varies from the pure conifer forest to the mixed conifer and broad leaved forests. The climate on the middle zone of northern slope is frigid temperate monsoonal climate and temperate monsoonal climate. With the descending of altitude, vegetation varies from pure conifer forest zonation to conifer and broad leaved forest zonation. Great changes have taken place in the soil properties of this area. Abundent organic matter is contented in the Acid Udic Cambisols generated in the higher area. Compared with it, the Hap Udic Luvisols generated in the lower zone has less organic matter, but the structure of the organic matter is more complex. The claying horizon has formed in the Hap Udic Luvisols. The dissolution of the silicate mineral was accelerated because of the higher content and special composition of the organic matter under the conifer forest, then
iron oxide was liberated and cheluviated to B horizon for enrichment. Environmental factors, such as temperature and precipitation influnce not only the formation and illuviation of clay, but also the content of Free and Amorphous Iron Oxides, the free degree, and activation degree. Judged from conformation of the iron oxides, combining the genetic characteristics, the tested soils are in the process of desalinization and silica alumina enrichment.