How Indiana Soils Become Acidic

Soil pH is the measure of hydrogen ion activity in the soil solution and reflects soil acidity. A pH of 7.0 is considered neutral; less than 7.0 pH is considered acidic. A pH greater than 7.0 is considered alkaline. When fields are not limed regularly, they become acidic. Erosion, leaching, acid rain, even the normal growing of crops all contribute. Erosion and leaching physically remove calcium and magnesium from the soil. In addition, plants naturally consume calcium and magnesium as they grow. Rain containing debris from the burning of fossil fuels deposits nitric and sulfuric acids into the soil. Although the annual application of nitrgen fertilizer is essential to the efficient production of many crops, its continued use actually promotes the development of acid conditions in the soil. The result...Indiana fields can quickly become acidic.

Aglime for Healthy Soils and a Better Environment

In addtion to neutralizing soil acidity, the benefits of the regular application of aglime often include the addition of needed calcium or magnesium. Further, the effectiveness of certain herbicides is enhanced and the total soil environment is made more favorable for soil organisms. All this leads to a more healthy soil condition where the potential for the leaching of harmful chemicals into your ground water is greatly reduced or eliminated. Aglime is especially critical in minimum tillage operations. Farmers who practice reduced tillage methods should test their soil and apply aglime more frequently in order to avoid surface soil acidity. This is essential to ensuring proper fertilizer efficiency and herbicide effectiveness.

Effect of pH on the Yield Potential of Indiana Crops

Most Indiana crops achieve optimum yields when grown in soils which are slightly acidic to slightly alkaline. Regular application of aglime is the best way to achieve and maintain the ideal pH.


Relative yields at various pH levels


pH 4.7

pH 5.0

pH 5.7

pH 6.8

pH 7.5































Sweet Clover






Aglime Helps Improve Fertilizer Efficiency

If the soil pH is not correct, applying more fertilizer will not optimize yields because the crop cannot fully utilize the nutrients in the fertilizer. Therefore, the application of aglime could increase yields as well as provide greater ferilizer efficiency.

Test Soil Regularly

Conducting soil tests on every field at least once every three years (and applying aglime when needed) is the only way to ensure that the fields do not become acidic. Aglime is not an instant fix. Depending on the gradation of the aglime available in a particular area, the time required for aglime to have its full impact on the pH of the soil may be one to three years. Soil fertility consultants or fertilizer dealers in particular areas can make aglime application recommendations for achieving optimum pH for crops in that area.

The Best Time to Lime

Fall and early winter applications are recommended even if tillage operations are not performed until the spring. Early spring is also a good time to spread aglime. Because aglime reacts with the soil on contact, applying it at anytime is better than delaying the application another year.

How Aglime Works

All limestones are composed of calcium and magnesium carbonates responsible for neutralizing acids in the soil. The CCE (calcium carbonate equivalent) represents the sum of the calcium and magnesium carbonates in a liming material. The higher the CCE, the more acid neutralizing power in the lime. In order for aglime to work to its maximum efficiency, the carbonates must come in contact with the acids in the soil. Therefore, smaller sized particles react faster to neutralize the soil.

  • Aglime can improve the physical structure of the soil by reducing surface crusting, increasing a soil's water holding capacity, and reducing soil erosion. This is largely the result of an increase in the organic matter content of the soil along with calcium saturated soil colloids. This allows crops to better tolerate drought and wet conditions by increasing both root penetration and water percolation through the soil.
  • Aglime reduces toxic conditions caused by iron, aluminum, and manganese. Manganese and iron exhibit toxicity to plants at a low soil pH. aluminum increases in solubility as soil pH decreases. Too much aluminum can restrict root and plant development.
  • Aglime can increase nutrient availability to plants. Soil micro-organisms are responsible for the breakdown of organic matter and for nitrification (the conversion of ammonia to nitrate for uptake by plants).
  • Aglime adds calcium and magnesium to soil. Most micro-organisms responsible for the conversion of ammonia to nitrates require large amounts of calcium. Magnesium is an essential component of the chlorophyll molecule neccessary in photosynthesis.
  • Aglime increases herbicide effectiveness by the removal of hydrogen from the soil site and/or an increase in the micro-organism activity.
  • Aglime is the most cost-effective method available to correct soil acidity, provide calcium and/or magnesium, and maintain a proper environment for organic materials to decompose.