BOB LIPPERT'S FREQUENTLY ASKED QUESTIONS REGARDING SOIL TESTING, PLANT ANALYSIS AND FERTILIZERS Department of Entomology, Soils and Plant Sciences This is available for printing as a PDF file!

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Clemson University Extension Service, South Carolina, U.S.A.

The following is a listing of questions I have been frequently asked during my past 15 years with the Clemson University Extension Service. To find the answer, simply click on the appropriate question. To ask your own question, please send it to me via email BLPPRT@Clemson.edu I would also appreciate any suggestions about how to improve this site to make it as useful as possible. Thanks!

SAMPLING

• My soil sample has been sitting in the hot cab of my truck for several weeks. If I have it tested by the Ag Service Lab, will the results still be OK?
• How do I sample the soil for Conservation Tillage/No-Till situations?
• How do I sample the soil for pastures?
• What is a general guideline for sampling plant tissue?
• Where can I find leaf sampling guidelines and mineral sufficiency ranges for specific agronomic crops?
• Is splitting soil samples between two labs a good method for comparing lab quality?
• How do I save fertilizer and money by sampling the subsoil of the Coastal Plains soils? How should I do the sampling?

TESTING

• Information about the soil sample mailer for residents of South Carolina.
• How are soil samples analyzed by a soil testing lab? (Virtual Lab Tour)
• What is the buffer pH value on the soil test report?
• How reliable are the soil test kits found in gardening stores?
• Where and how should I get compost tested?
• What is the value of the organic matter test for soil samples?
• I noticed that the routine soil test doesn't include nitrogen. Is there any advantage in requesting that the lab test my soil for nitrogen?
• What is the use for the cation exchange capacity (CEC) and the percent base saturation on the soil test report?
• How should I interpret the copper and boron results on the soil test reports?
• How are the cation exchange capacity (CEC) and the percent base saturation calculated for the soil test report?
• Can Clemson University's fertilizer recommendations be used with the analytical results from other soil testing laboratories?
• What is a soil test extractant?
• What is the Mehlich-1 extractant?
• What is the Mehlich-3 extractant?
• What is the Bray P-1 extractant and is it used in the Southeast?
• Why do some states use the Mehlich-1 extractant and other states use the Mehlich-3 extractant?
• How does the Mehlich-3 extractant compare to the Mehlich-1 extractant?

SPECIFIC NUTRIENTS

• Is there a problem with loss of urea when used as a source of nitrogen?
• Why is phosphorus expressed as P2O5 and potassium expressed as K2O in the soil test report recommendations and by the fertilizer companies?

LIMING MATERIALS

• What is calcium carbonate equivalent?
• How safe is it to use wood ashes as a liming material?
• Can lime and fertilizer be applied at the same time?

SOIL AMENDMENTS AND MISCELLANEOUS

• What is gypsum? How does it help the soil? How much should I apply?
• My soil pH is too high. How can I bring it back down to the optimum pH range?
• How do flooded soil conditions affect the soil pH value and plant nutrient availability?
• How does the chlorine in pool water affect nearby plants?