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亚热带和热带土壤的磁化率X变化大,高的达2000—6000单位(昆明玄武岩红壤),低的只几个单位(沼泽土、强还原性水稻土、磷质石灰土)。大体上是:自型土>潮土>水稻土>沼泽土。在自型土中,砖红壤、红壤的X值大于石灰岩土和紫色土。红壤的磁性受母岩和发育度的影响大。各地的玄武岩红壤的X值为3×10~2—6×10~3单位,其他红壤多为100—40单位(中性和酸性岩浆岩,多数沉积岩),或40—10单位(一部分石灰岩、凝灰岩)。灼烧土壤而得到的X-t曲线和“转化率”E,可粗略地反映磁赤铁矿生成的相对程度,进而估计红壤化的程度,似可在红壤的诊断、鉴定中试用。
The susceptibility X of subtropical and tropical soils varies widely, up to 2000-6000 units high (Kunming basalts red soil), low only a few units (swamp soil, strongly reducing paddy soil, phosphorus lime soil). In general: self-type soil> Chao soil> paddy soil> swamp soil. In self-contained soil, the X value of red soil and red soil is larger than limestone soil and purple soil. The magnetism of red soil is greatly influenced by the parent rock and the degree of development. The X value of the basalt red soil is 3 × 10 ~ 2-6 × 10 ~ 3 units, and the other red soil is mostly 100-40 units (neutral and acidic magmatic rocks, most sedimentary rocks) or 40-10 units (some limestone, Tuff). The X-t curve and “conversion rate” E obtained from the burning of the soil can roughly reflect the relative degree of maghemite formation and thus the extent of reddening, which may be used in the diagnosis and identification of red soils.