一、红土层与土壤 我国发育於第四纪洪积期红土层之土壤主分二类,而以秦岭为分界。在秦岭以北多埋藏於黄土之下,其被冲蚀而暴露者,每见於割切沟面,已受复钙作用,盛呈石灰性反应,而成栗钙土,秦岭以南则尽暴露地面,无石灰性反应,而铝棕壤,大片分布於汉中盆地,豫鄂皖栏邱陵地带,以及南京附近,再南则以气候湿热泯於红壤分布区内,在四川境内多见於零散台 First, the red soil layer and soil China developed in the Quaternary Period of Hongqi red soil layer is divided into two main types of soil, and the Qinling Mountains as the boundary. To the north of the Qinling Mountains is buried beneath the loess, which is exposed by erosion and exposed. Each seen in the cut-ditch has been subjected to the action of complex calcium, which is characterized by a calcareous soil reaction, while the south of the Qinling Mountains is depleted Exposing the ground, no lime reaction, and aluminum brown, large areas are located in the Hanzhong Basin, Henan and Anhui Wuling Qiongling area, and near Nanjing, and then the climate is hot and humid in the distribution of red soil, more common in the territory of Sichuan Straddle