A numeric vector containing top depth of argillic horizon, if
present, or NA.
Arguments
p
A single-profile SoilProfileCollection object.
clay.attr
OPTIONAL: horizon attribute name referring to clay content.
default: clay
Author
Andrew Gene Brown
Details
Uses crit.clay.argillic to determine threshold clay increase, and
get.increase.matrix to determine where increase is met within a
vertical distance of 30 cm.