How to Sample:
Farm/Commercial Horticultural Fields
Soil tests can be no better than the sample. Therefore, proper collection
of the soil sample is extremely important.
Divide the field into uniform areas
Each area should have the same soil color and texture, cropping
history, and fertilizer, lime and manure treatments. One sample
should not represent more than 20 acres on level, uniform landscapes,
or 5 acres on hilly or rolling land.
Sample each area
Within each area collect 15-30 subsamples (cores, borings, or spade slices)
in a zig-zag pattern throughout the designated field area. The more
variable the soil, the more subsamples should be combined per area sampled. Scrape off all surface residue from the subsample site. Sample to
a depth of 6-8 inches (plow layer) for cultivated crops, or 3 inches for
pasture or sod fields. Sample row crop fields between rows, except
for ridgetill plantings. Where RIDGETILL is used, take the sample
to a depth of 6-8 inches on the shoulder of the ridge, avoiding
the starter fertilizer band. Also avoid sampling dead or back furrows,
terraces, old fence rows, lime or fertilizer spill areas, headlands, eroded
knolls, low spots, or small saline areas. Sample at least 300 feet
away from gravel or crushed limestone roads because their dust changes
soil pH.
Mix the subsamples
Mix the subsamples thoroughly in a clean plastic pail, and fill the sample
box or bag to the fill line (1 pint). If the samples must be taken
wet, they should be dried before being mixed and submitted to the Laboratory. Do not exceed a drying temperature of 97F, and do not use a microwave
unless only the nitrate test is requested.
See also:
- Soil tests offered
- Farm/Field Sample Information Sheet (.pdf).
Includes prices and must be submitted with soil samples.
- Instructions for Soil Sample information Sheet
Soil Testing Lab, Rm. 135 Crops Research Bldg.,
1902 Dudley Ave, St Paul, MN 55108-6089
Email: soiltest@umn.edu,
Phone: 612 625-3101, FAX: 612 624-3420
Last updated:
October 22, 2007
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