Taking a pasture soil sample
Testing your soil for nutrient levels is necessary to find out how much, if any, fertilizer may be needed in a horse pasture. Soil testing should be done every 3 years. The best time to take a soil sample is in the fall, but anytime the soil is relatively dry is acceptable. If the pasture area to be tested is consistent (similar soil type, drainage capacity, topography, etc.), use one sample for up to 20 acres. If the pasture has dramatically different areas, then use one sample for each area.
To collect a sample, walk in a 'W' pattern and use a shovel (or a soil probe) to dig down 6". Remove the sod and place the shovel full of soil in a bucket. Repeat this several times as you walk the 'W' pattern. When finished sampling, mix the soil in the bucket and use a subsample (about a sandwich bag in size or 2 cups) to send to the lab for analysis. Repeat this procedure for each unique area of the pasture.
Soils samples can be sent to the Soil Testing Lab at the University of Minnesota. There are several private labs that offer the service as well. For a University of Minnesota soil analysis, pick up a free soil test kit, which includes a form and bag(s), from your county's Extension office. The form included in the kit has additional instructions for taking the sample and where to mail it. Ensure the form is completely filled out and clearly state this is a pasture soil sample.
When the soil analysis is received, it will list phosphorus, potassium, nitrogen, pH, and organic matter levels. Based on this information, an accurate fertilizer mix and application can be made. As fertilizer prices and environmental concerns continue to rise, it is critical to base your pasture fertility on an analysis.