by Dr. Darryl Warncke, Michigan State University
Lime not only neutralizes soil acidity, it also is a valuable source of calcium and magnesium, which are essential for producing good-quality vegetables. Calcitic limes primarily provide calcium, and dolomitic limes provide both calcium and magnesium. Agricultural lime contains a range of particle sizes. The small particles react quickly in the soil to neutralize acid conditions. The larger particles react slowly to continue neutralization of soil acidity and maintain the soil pH in a favorable range over a number of years, usually three to five.
When lime is needed, it is suggested to apply it six months prior to planting the next crop. This allows time for the lime to react and raise the soil pH to a more favorable level. Fall application after crops are harvested allows for this to occur. However, if soils are sampled in the spring and a need for lime is determined, application and incorporation prior to planting will still provide good benefit. When lime is needed, the most important thing to do is get the lime applied.
At $22 to $25 per ton, lime may initially seem like quite a large investment. But when one considers that yield is being lost under acid conditions, the investment may not be that great. Lime will provide benefit for many years. Push the pencil. How much increase in crop yield will be needed to cover the cost of 2 or 3 tons of lime (about $55 to $78, including a spreading fee)?
Depending on the crop, increasing the soil pH from 5.5 to above 6.0 may increase crop production by 25 percent or more. Therefore, chances are pretty good that investment in needed lime will pay for itself with improved crop quality and yields in one or two years. Over a four-year period, lime will definitely put more money in your pocket.
Investment in lime will need to be made at some point in time. It is better to make that investment before the soil becomes too acidic and starts costing crop yield.
Periodically applying 2 tons of lime per acre, as indicated by a soil test, stabilizes the soil pH and crop production and is easier on the budget. In addition to neutralization of soil acidity and improved crop productivity, other benefits from applying lime include: 1) increased supply of calcium and magnesium, 2) improved microbial activity, 3) improved soil structure and quality and 4) improved efficacy of herbicides.
Bottom line: When lime is needed, get it applied. It will put more money in your pocket.
Full article can be found in the September Issue of the Vegetable Growers News