For more information about soil sampling please view the following videos:

Soil Sampling Basics

Soil Nutrient Basics, Soil Sampling

Soil samples too old: Fields should be sampled at least every four years. SnapPlus identifies soil samples as being too old if they are four or more years older than the designated crop year.

Too few soil samples:  University of Wisconsin-Extension (UWEX) guidelines recommend 1 sample per every 5 acres for responsive fields.  The field is considered to be in the responsive range if either soil test phosphorus (P) or potassium (K) levels are in the high (H) category or lower.  A nonresponsive field is one where both soil test P and K levels are in the very high (VH) or excessively high (EH) categories.  

Note: Grid point sampling is used to map variability in soil test levels and guide precision nutrient application. Grid point sampling should always have fewer than 5 acres per sample. Ideal grid sizes have no more than 1 to 2 acres per sample.

Note for contour strips:  Verify that there is 1 sample per strip or 1 sample per five acres depending on the size of the  strip size.