Additions of lime and/or gypsum can improve most soils because these calcium products neutralize soil acidity (e.g., when soil pH tests below 6.2) and improve soil porosity and organic matter stabilization. Overall, this improves soil health by improving soil air and water balance.

Calcium plays an important role in maintaining soil structure, porosity, and an optimal balance of air and water. With its larger atomic radius, it occupies more space and retains water less strongly than the other common cations promoting greater porosity through soil flocculation. Additionally, those same atomic features help calcium to better stabilize organic carbon residues, increasing net water retention during the growing season.

Both lime and gypsum can be used to achieve positive results, but it’s important to know the pros and cons before deciding which product is best for a given farm. While less expensive, lime must be ground fine enough for rain and snow melt to dissolve the calcium in a timely and predictable manner, especially on no-till ground. In contrast, gypsum is more expensive but is more effective when soil pH > 6.8 to not reduce micronutrient availability which can happen when pH becomes alkaline.

The quality of these amendments greatly affects the results seen from them. By-product materials, including those received from ethanol, feed processing, power, and water treatment plants, need to be tested for heavy metals and other likely contaminants. Mined materials can vary depending on the location of each year’s digging. All sources should be tested annually to truly know their value and effectiveness. By knowing the material quality, a farmer could reduce their cost 2- to 3-fold!

Maximum Farming System representatives can help you find quality calcium sources. Contact us to talk with your local representative.

-by Dr. Brian Gardener, Technical Director