Is it clay: Or is it clay?

摘要

Frequently we hear comments about the clay content of various soils but unfortunately, the definition of "day" is somewhat variable, depending on whether you're talking to a soil scientist or a mineralogist. To the soil scientist a day is generally any particle that is less than 2 microns (4 microns by the Wentworth scale) [1 micron = 0.00004 in.], but to the mineralogist clays are fine particles but with specific chemical composition - principally aluminum silicates. The reason that one should be concerned about the composition of the day component is that most of the silicate day minerals have unique physical qualities, many which could have significant detrimental effects on soil permeability.