【摘要】 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。更多还原

【Abstract】 In the present paper, the magnetic susceptibility （m. s.） of red earths, lateritic red earths, latosols, young calcareous soils and paddy soils in subtropic and tropic China is reported The m. s. is greatly influenced by parent rocks. The m. s. values of red earths and latosols derived from basalt and andesite amount to 300—500 units and even up to 2000—6000 units (10^-6 emu/g). Those of red earths and latosols on granite and other acid magmatic rocks amount to 40—100 units, and those of red earths and latosots on limestone, shale, sandstone and tuff amount only to 10—40 units mostly.The general tendency of variation of sail m. s. value is as follows: latosols, red earths>yellow earths>meadow soils>paddy soils>phospho-calcic soils. The maximum m. s. value （about 6000 units） is found in red earth derived on basalt in Kunmin. The minimum m. a value （2—4 units） is found in phospho-caleic soil on Xisha islands. In strongly reduced waterlogged paddy soils, the m. s. values amount only to 10—5 units or less.The m. s. value of defferent soils is changed significantly after burning treatment.The m. s. value of paddy soils derived from red earth is increased up to sixty times after burning to 700℃, due to that the ferrimagnetic minerals （maghemite） are formed to certain extent by oxidation of ferrous hydroxides and other ferrous minerals under heating. It is suggested that the variation of m. s. of soils by buring （variation ratio） may be used for indentification of developing degree of red earths.更多还原