Re: Determining soil type by hand

[Richard Mead]

Dear subscribers to SoWaCs,

I thought I'd pose a soil question which indirectly has pertinence to
installing soil sensors due to potential idiosyncracies of certain soil
types (e.g. too sandy or cracking clay etc.). Please forgive me for going
out side the fringe of soil sensor discussion, but this group might have
more soils background than Irrigation-L or Trickle-L.

I am helping put together an ETo weather station irrigation scheduling
tutorial on the web for the average California homeowner. In trying to
describe how much water a particular soil holds, it is possible the
homeowner might not know anything about soil type.  Hence, I need some very
basic method for a lay person to determine the type of soil his/her shrubs
and lawn are growing in.

When I was an undergraduate, my basic soils professor described a generic
way to determine soil type within the three major categories (sand, loam,
clay). The method, involved using a handful of soil, wetting it slightly,
thereby trying to form a cylindrical shape. After forming this shape, one
would hold the column vertically to see if it held together. If it did not
form a column at all, it was definitely a sand, if it maintained a
cylindrical shape rather well but did not hold up to the vertical test, it
was a loam. Finally, if it formed a cylindrical shape and held up to the
vertical test it was definitely a clay.

Has anyone heard of this rather subjective yet quick and dirty way to
determine soil type? How about another way to determine soil type by hand?
I once heard a rumor at UC Davis that a professor there could determine
soil type within a certain degree of accuracy by putting soil in his mouth.
Don't think I'm going to recommend this procedure to a homeowner :-)


Richard Mead
Agrilink International