First, the differences noted between wet and dried soil sample methods and
the resulting potassium test results are not uniform across all soil types or
geographic regions. As clay mineral types change so do the comparison
statistics. Native potassium levels have an effect as well. When native
potassium levels are high, the difference between a wet K and a dry K test
is minimal. When native potassium levels are low, as is commonly the case
throughout the state of Iowa, the difference between a wet K and a dry K
test can be more noticeable