Services and Methods

Soil analyses enables the client to be able to determine the correct amount of fertilizer and lime to appy to their crops based on the best availiable science.  All routine soil test analyses are provided at "no direct cost" to Arkansas farmers because of the funding derived from the Arkansas Fertilizer Tonnage Inspecion Fee(pdf). Analysis of soil pH and extractable nutrients are part of the routine soil test package.

Rountine soil analyses includes: Water soil pH and extractable soil nutrients; Ca, Mg, Na, K, Fe, Mn, Zn, Cu, B, S, and P.

Routine Soil Analyses price:

  • Arkansas Farmer: No charge
  • Other Routine Analysis: $10.00 per sample

Other testing done by the laboratory for a fee is nitrate-nitrogen, electrical conductivity, soil texture and organic matter,

All soil samples must be submitted through your local Cooperative Extension Service County Office(CES)*. The CES office will provide sample containers and sample submission forms as well as instructions for proper soil sampling submission and will review the fertilizer and lime recommendations. You may submitt your samples to the laboratory if you have your paper work and boxes properly completed.

*Researchers may submit soil samples directly to the Soil Testing Laboratory. Please contact the laboratory directly to make arrangements.

Mehlich III Soil Analysis

Mehlich III extractible analyses includes P, K, Ca, Mg, S, Zn, Mn, Fe, Cu, and B. These are run using the Mehlich III Extraction Method that is found in Zhang, H., D.H. Hardy, R. Mylavarapu, and J.J. Wang. 2014. Mehlich-3. In: Sikora, F.J. and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. Clemson Univ., Clemson, S.C. p. 101-110.

Water 1:2 pH

A 1:2 soil water pH is a routine analyses for our soil samples. The method that we use is in Sikora, F.J., and D.E. Kissel. 2014. Soil pH. In: F.J. Sikora and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. p. 48-53.

Soluble Soil Nitrate-Nitrogen or -- Request Only

One component of the soil nitrogen suite, this selective-ion electrode test is used as an estimate of readily available nitrate nitrogen to the plant. The results are mainly used to adjust crop N recommendations. The interpretation of the information is best for samples collected down to a depth of at least 18 inches just prior to planting. The method used to run the Nitrate- Nitrogen is in Gordon, G.V. 1992. Determination of nitrate-nitrogen by specific-ion electrode. In: S.J. Donahue, editor, Reference soil media diagnostic procedures for the Southern Region of the United States. . Southern Coop. Ser. Bull. 374.  p.25-27. 

Nitrate Analysis $5.00 per sample

Soil Organic Matter - Request Only

Determination of the organic matter content of the soil is performed by the loss on ignition method. Because this analysis is labor intensive and slow, it is not part of the routine package. The method used for loss on ignition is in Zhang, H., and J.J. Wang. 2014.  Loss on ignition method. In: F.J. Sikora and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. p.155-157. Wolf, A.M. and R.O. Miller. 1998. Development of a NAPT program for soil and plant analysis. Commun. Soil Sci. Plant Anal., 29:1685-1690.

Organic Matter Analysis $6.00 

Electrical Conductivity Analysis - Request Only

The method for the Electrical Conductiviey analysis that measures soluble salts is a 1:2 soil water method. The method used to analyze the electrical conductivity analysis is in Wang, J.J., T. Provin, and H. Zhang. 2014. Measurement of soil salinity and sodicity.  In: F.J. Sikora and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. P.185-193.

Elictrical Conductivity Analysis $3.00

Soil Texture Analysis

Soil texture has an impact on soil water and nutrient holding capacities, water and air movement, pore sizes and plant root growth. We use the method to analyze soil texture analysis in Huluka, G. and R. Miller. 2014. Particle Size Determination by Hydrometer Method..  In: F.J. Sikora and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. P.180-184.

Soil Texture Analysis $15.00