Links & Information: Soil Testing LR5

Links & Information: Soil Testing LR5

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Example Soil Tests Results

The image below shows the results of a soil test report from a new field for growing organic vegetables in central Tennessee. The pH of 5.5 is too acidic for most vegetables. Dolomitic lime is needed to build both Ca and Mg levels while correcting the pH. Potassium and boron are critically low and should be supplemented. SOM is medium and can be built up with cover crops and organic amendments.

In another example, we see a soil report from a high tunnel at a farm in western Virginia. This high-tunnel soil shows excessive P, while K is low and likely yield-limiting. The high sulfur (S) reflects the buildup of nutrients and salts in the topsoil that often occurs in high tunnels. In this case, soluble salts remained satisfactorily low.  

High iron (Fe) levels in both soil test examples reflect the mineralogy of the soil (most southeastern US soils are naturally rich in Fe). These Fe levels are not problematic if soil pH is kept at or above 6.0 by liming when needed.

Selecting Areas to Sample

In this example from an organic farm in Floyd County, VA, separate soil samples would be taken from the bottomland vegetable field (foreground), each of the high tunnels, and the upland pasture (background). To sample the vegetable field, the farmer would take ~15 individual cores, each measuring from the surface to 6 inches deep, from spots evenly scattered across the field.

The NRCS Web Soil Survey can be a helpful resource when sampling your soil and developing a management plan. The Web Soil Survey can provide valuable information on inherent soil properties, how to delineate areas for a soil sample, and where to consider relocating production areas.

Author Mark Schonbeck created this hypothetical example of a farmer working three different fields with varying success to demonstrate how to use Web Soil Survey data:

The map units and their capability classes include:

  • 8D Cowee loam – 6e – too steep and erodible for crops.
  • 13B Delanco fine sandy loam – 2e – prime farmland if drained, moderate risk of erosion.
  • 20B Elsinboro fine sandy loam – 2e – prime farmland, moderate risk of erosion.
  • 22C Glenelg loam 3e – High risk of erosion and compaction, conservation is critical.
  • 26A Hatboro sandy loam – 6w – too wet to farm.
  • 42C Tate loam, stony – 4s – abundant stones make this soil difficult to farm.

The farmer has noticed the stoniness in parts of Field 1 and, because of topography and erodibility, may consider converting it to permanent pasture, orchard, or other perennial crops. Field 2 lies within the Elsinboro map unit, which is prime farmland and has been the most productive field. Wet areas in Field 3 clearly reflect the soil types present. Management options include taking the wetter parts, especially the southeast corner (Hatboro), out of production and managing drainage in the rest of the field with permanent raised beds or tile drains.

Additional Information

Wondering what type of soil you have on your farm? The NRCS Web Soil Survey has soil maps and data for more than 95% of the nation’s counties. Explore the map for detailed descriptions of your soils.

Private labs that serve the Southeast U.S. and cover a wide range of nutrients, SOM, pH, and CEC include Waters Agricultural Laboratories in Camillia, GA and Waypoint Analytical (multiple locations in the Southeast U.S.).