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Little River, TX | This may interest some on these pages. It does not apply for calcareous soils!
Plant & Soil Sciences Newsletter Page 6
200 pounds is not the same as 2,000
By Jeff Edwards
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I have received several questions regarding liming materials and application. This is a good thing because it means that more people are soil sampling and addressing low soil pH. I am concerned, however, with the
types of questions I am getting regarding the application of pelletized lime. Most of these questions essentially ask if a couple hundred pounds of pelletized lime will perform the same as ½ or one ton of regular
Ag lime.
The answer is NO. If your soil test recommends one ton of 100% ECCE lime you will need one ton of ECCE lime, regardless of the source. I will attempt to explain why in the next few paragraphs.
What is soil acidity? Soil acidity is a measure of the amount of hydrogen (H+) ions in the soil solution. The lower the pH, the more H+ ions there are in the soil solution.
Lime (CaCO3) corrects soil acidity as it dissolves into Ca and CO3. Calcium (Ca) has a positive charge like H+ and displaces the H+ ions from the surface of soil particles, etc. The carbonate (CO3) reacts with
the H+ ions to form carbon dioxide (CO2) and water (H2O).
The purpose of this chemistry lesson was to show that one molecule of calcium carbonate will neutralize
two H+ ions. There is no shortcut around this reaction. The lime recommendation you receive with your soil test is calculated based on the amount of H+ ions you need to neutralize in your soil and the number of
calcium carbonate (CaCO3) it will take to get this done.
Can I get by with less pelletized lime than Ag lime? No. It is true that some liming materials are more effective than others.
The effectiveness of a liming material is expressed as the effective calcium carbonate equivalent (ECCE). The ECCE is based on the purity of the material and the fineness of the material (finely ground lime will react
more quickly than coarse-ground lime).
Most agricultural lime sources in Oklahoma are about 65 – 85 % ECCE. So, if the soil test called for one ton of lime, you would need to apply 1.33 tons/A of a 75% ECCE material to get the job done. If a pelletized
lime source were 90% ECCE it would take 1.11 tons/A of this material to get the same job done, not a few hundred pounds.
Once again, if the soil test calls for a ton of ECCE lime, you need a ton of ECCE lime.
What about banding pelletized lime?
We have two studies (near Altus and Wakomis) comparing broadcast Ag lime to in-furrow pelletized lime and in-furrow 18-46-0 (DAP). This research is still in its preliminary stages, so it is too early to glean
recommendations from the results; however, what we do know from previous research is that in-furrow DAP is an effective band-aid treatment in low pH soils. It is also important to note that the mixing of pelletized
lime and DAP is not recommend because the calcium in the pelletized lime can bind to the phosphorus in the DAP and make it unavailable to plants.
Jeff Edwards can be reached at [email protected].
Edited by Hay Wilson in TX 9/9/2010 14:07
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200 lbs of pelletized lime = >½-1 T of Ag lime. revisited
