2013-09-05 / Local & State

Conservation Corner

By Eric Cromer

Why Lime?

For farmers and gardeners, making sure soils don’t become too acidic is critical to getting good yields. It’s important to measure your soil’s acidity levels and take action if needed. An application of lime will reduce soil acid levels if they are too high and help keep plants healthy.

Soils that are too acidic can stunt root growth and inhibit plant development. Soils become acidic when levels of positively charged ions of hydrogen and aluminum grow too high. The high levels of hydrogen and aluminum prevent the plants’ roots from taking up nutrients within the soil. Fortunately, there is an easy solution. Applying lime to fields works by dissolving and releasing a base into the soil that reacts with the hydrogen and aluminum, lowering the acidity of the soil.

Benefits of lime applications

Farmers and gardeners will do well if they add lime when necessary to keep soils from becoming too acidic. Liming helps growers in a number of ways:

Ideal soil acidity levels boost the nutrients in the soil that are available to plants, effectively increasing their nutrient supply.

Plants develop healthier roots, which may enhance drought tolerance.

Lime adds calcium to the soil. Some limes also add magnesium.

For legumes, such as soybeans, liming improves nitrogen fixation, the process in which bacteria living on legume roots convert atmospheric nitrogen into a form the plant can use.

Ideal soil acidity levels improve the performance of certain herbicides and nematicides.

Ideal soil acidity levels promote the breakdown of some herbicides, preventing the residual effect of herbicides that damage crops planted later in the field.

When to apply

Winter and fall is a great time to apply lime to fields. Lime is not very leachable, except in very sandy soils, and so growers can generally apply it whenever practical. The slow winter months serve as a convenient time to get the task accomplished. Agronomists recommend putting down lime several months prior to planting, so that the lime has enough time to react with the soil and neutralize acidity.

The importance of pH

Before considering an application, you will need to determine your soil’s pH by taking a soil sample and submitting it to a state laboratory or any private laboratory. Often the report from your soil test will include a recommendation of how much lime you need to apply.

Soil pH values indicate the acidity or alkalinity of soil. A value of 7.0 indicates the soil is neutral. A value below 7.0 indicates acidic soil and values above 7.0 indicate alkaline, or basic, soil. The ideal soil pH for your farm or garden depends on your region of the country, your soil conditions and the type of plant. Most plants grow best in slightly acidic soils, from 6.0 to 7.0. Check with a specialist at your local extension or conservation district to help determine what pH levels work best for your area and crop.

If you have any questions or would like to obtain soil test kits, contact Eric Cromer of the Fulton County Conservation District at 717-485-3547, Ext. 117 or eric_ fccd@pa.net.

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