A key to soil sampling is to get a final sample that accurately represents the whole field. Usually, enough soil cores are taken to fill a pint container.
Sampling is done in a zigzag pattern across the sampling area. Ideally, samples from the same field should be taken at the same time each year of sampling. Fall often is recommended as an ideal time to sample soil because it allows time for analysis, fertilizer recommendations, and fertilizer applications to occur before the following growing season. Soil sampling at consistent times each year helps to accurately determine soil fertility trends within a field. Consistent timing of soil sampling also helps producers better delineate “management zones” within fields.
Refer to soil test labs for correct sampling depth and overall sample area. For example, the University of Kentucky requires 4-inch cores for no-tillage fields and 6-inch cores for tilled fields. In addition, Kentucky recommends that samples be from a representative area of no more than 20 acres.
