The goal of a soil test is to take a representative sample from a highly
complex system and use the results to make the best possible management
decision. Neither testing method is “correct” in an absolute sense, but both
are valuable tools. Each method presents its own useful information. When
making potassium assessments, both data sets offer useful agronomic
information. Looking at only wet K
test results ignores the portion of the
potassium that is slowly available and
that which can be released through
the normal biological and chemical
processes. Utilizing only a dry K test
ignores the fact that potassium moves
between the two phases of available
K and slowly available K. This process
is what causes potassium soil test
levels to vary from one year to the
next. Together, wet and dry test data
sets act as a double check of soil
potassium fertility levels.