Lime is to pH as antacids are to heartburn

Managing your pH is a simple way to start improving plant nutrient availability and increasing crop yield.

Soil physical and biological properties are always changing, and that includes soil pH. Over time, the pH of your soil can become more acidic. Rainfall, leaching of basic cations, breakdown of organic matter and application of nitrogen fertilizer can all play a contributing role. Testing your soil every two to three years is a great way to track changes in pH and determine lime application need.

Liming acidic soils does a whole lot more than simply changing a number on a soil test report, it:

  • Lowers the availability of aluminum and manganese in soil to levels less harmful to plants and crops
  • Promotes microbial activity for increased nitrogen and sulfur release from crop residues, increased soil tilth and structure, and increased N fixation by legume crops
  • Increases availability of nitrogen, phosphorus, potassium, sulfur, calcium and magnesium.

Many times a field that displays nutrient deficiencies may not actually be deficient of the nutrient; rather the nutrients are bound in the soil as a result of pH that is excessively acidic or alkaline.

When it comes to making a lime application, there are many things to consider. First, different crops are more tolerant of soil acidity than others. These soil pH ranges can be found in the table below. When dealing with rotational crops, remember to lime according to the crop with the highest pH range. Second, lime applications should not exceed four tons per acre per application with the total per season lime application not exceeding six tons per acre per year. Third, always remember changes in pH take time. Don’t expect it to change overnight.

Table 1. Desirable soil pH ranges for various crops grown on mineral soils.

Least Acid Tolerant More Acid Tolerant Medium Acid Tolerant
Alfalfa 6.3 to 7.8 Buckwheat 5.0 to 7.0 Corn 5.5 to 7.5
Asparagus 6.0 to 8.0 Oats 5.0 to 7.0 Grasses 5.5 to 7.5
Barley 6.5 to 7.8 Potatoes 5.2 to 6.5 Trefoil 5.5 to 7.0
Beans 6.0 to 7.5 Raspberries 5.0 to 7.0 Wheat 5.5 to 7.0
Peas 6.0 to 7.5 Rye 5.0 to 7.0
Red Clover 6.0 to 7.5 Strawberries 5.0 to 6.5 Strongly Acid Soils Required
Soybeans 6.0 to 7.0 Vetch 5.0 to 7.0 Blueberries 4.0 to 5.1
Sugar Beets 6.0 to 7.5 Cranberries 4.2 to 5.0
Sweet Clover 6.5 to 7.8

Want to know more about pH and lime applications? Check out the new bulletin, Lime for Michigan Soils, available through the MSU Extension Bookstore.

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