Source: Purdue University

The accurate analysis of representative soil samples to determine lime and fertilizer needs is fundamental to crop production. Unfortunately, persistent dry weather resulting in prolonged periods of low soil moisture can affect soil test potassium (K) and pH, resulting in somewhat misleading results. Even so, dry weather soil tests can still be useful if one nderstands the potential impact of low soil moisture on soil test K and pH and uses this knowledge to adjust the interpretation of soil test results.

Typically, soil test K levels are lower than expected in a dry fall. One factor contributing to low soil test K is most of the K taken up by the crop during the growing season remains in the residue and has not been returned to the soil by rainfall.

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