【摘要】 <正> 土壤中的含钾矿物是土壤的主要自然钾源。土壤矿物中交换性钾是作物直接可利用的钾素形态,但这部份钾在土壤中数量有限,往往反映不出土壤中钾的真正供给力。土壤中矿物全钾含量也不能反映其真正的供给力,有很多土壤全钾含量并不低,而钾素的供给更多还原

【Abstract】 The composition of clay minerals and the contents of K-bearing minerals and slowly available potassium of nine samples were determined by chemical and X-ray diffraction methods. The results showed that the clay minerals present in the clay fraction （<2μ） of all these samples were hydromica, chlorite, kaolinite and montmorillonite etc. The content of K-bearing minerals was very high （35%） in the soil derived from the pruplish shale, and followed by that in the soil derived from lacustrine deposits （25%）, while those in the other soils ranged only from 14—19%.Statistic data from the results revealed that there was no correlation between the amounts of slowly available potassium extracted by 1N HNO₃ and the content of potash feldspar, but the former was well correlated with the content of mica （r=0.957）. However, the amounts of the slowly available potassium extracted with 1N HNO₂ either by one time or by five times was significantly correlated with the mica content in the clay fraction <2μ of soil, but not correlated with the mica content in other fractions.The kinetic investigation appeares to indicate that the mica in the soils both derived from purplish shale and lacustrine deposits look like trioctahedral biotite, while that in the other soils generally belong to dioctahedral muscovite.更多还原