Can I Improve My Soil Organic Matter?
Feb 23, 2011
Question: Is it possible to increase the organic matter and/or the CEC in soil? If so, how can I do it?
Answer: It may be possible to increase the organic matter and CEC in soil. Soils vary widely in their clay content and type of clay content. The clay in the soil contains negative exchange sites. Positive charged cations attach to negative charge clay particles or exchange site that are available or unfilled. So, if you apply fertilizer and lime to your soil it will increase the cation content in the soil, whether this increase is temporary or sustainable will depend on your soil type and your soils’ ability to absorb and retain the additional cations you applied. Once you’ve balanced the soil with the proper and maximum cations that it can hold, you’re fixed with the capacity Mother Nature has given you. Most soil tests that are used for fertilizer and lime recommendations only use a calculated CEC, which is usually adequate for fertility recommendations but leaves some room for error in determining the actual exchange capacity. Some labs can run an actual exchange capacity or TEC total exchange capacity of your soil. It may be best to better understand the soil test lab you’re using and the method the lab is using to report the CEC. You can slightly increase the organic matter of your soil by applying materials high in organic matter. Manure and/or compost with a high C/N ratio applied to soil will increase the organic matter. Remember that high C/N ratio products can temporarily tie up nitrogen that you’ll need available for crop growth, so be cautious when apply high C/N ration products. Keep in mind that different labs use different methods and ways to report results, so if you change labs it may appear that your OM and/or CEC has changed, but, in reality, the soil hasn’t.
This blog is provided as an interactive way for you to have your questions answered by our Farm Journal Agronomists. E-mail your nitrogen, soil fertility, soil density, planter set-up, scouting, and other questions to: TestPlots@FarmJournal.com.