The agronomy staff at ALGL is often asked what are the differences between pelletized lime and regular ag lime? Which one is better? Which one should I use? Is pelletized lime worth the extra cost?
Let’s start with the similarities between pelletized and al lime. Both forms of lime are a mixture of calcium carbonate and magnesium carbonate. The amount of calcium and magnesium vary based on the limestone mineralogy from which the material was mined. Both forms neutralize acidity through the same chemical reaction.
The differences between the two are the physical properties of each. Ag lime is simply crushed limestone and is comprised of particle sizes ranging from a fine powder to small pieces of gravel. For the lime to work, it must dissolve in the soil solution. The smaller the lime particle, the faster it dissolves and begins to neutralize the acidy. The benefit of having various particle sizes is that the small particles will start the process and the larger particles will continue to work for several years.
Pelletized lime is very finely ground limestone that is mixed with a binding agent and pressed into spherical pellets. The concept behind this is to produce a lime with the ability to react quickly but is easy to apply since it can be spread with any equipment used for spreading traditional fertilizer products.
One of the misconceptions about pelletized lime is that you get the same results as ag lime while using only a fraction of the amount. In the short term, this may be true since it does react faster, but it will also run out much faster. So, over the course of several years, it will take the same amount of lime to manage the soil pH, it just needs to be applied at lower rates more frequently. Typical application rates for pelletized lime usually do not exceed 500 pounds per acre and may only be effective for 1 to 2 years. Whereas an application of ag lime may be as high as 3 to 4 tons per acre in a single application and may effectively manage the pH for 4 to 8 years.
For large scale lime applications, it is hard to justify the additional cost of pelletized lime to completely replace traditional ag lime. However, pelletized lime does have its place in pH management. For small fields and wildlife food plots, where access prohibits a large lime spreader, it is a great fit. For land that may only be secured by a grower for a short period, pelletized lime may provide a short term improvement in soil pH without the long term investment of ag lime. Pelletized lime can also be blended with other fertilizers and be spread in a single application when only a low rate of lime is needed.
When it comes to deciding which form of lime to use, it is not about which form is better than the other. Pelletized lime and ag lime are both good products. It is about selecting the form that fits the situation in which it is being used.