The amount of lime needed per acre depends on the current pH of the soil and the crop to be grown. A soil analysis obtained from a county agricultural extension service or professional testing service can provide guidance on how much lime to apply.
Lime is used to raise the pH of acidic soils. Most fruits, vegetables, lawn grasses and crops grow best in slightly acidic soils with a pH of 6.1 to 6.9. Blueberries are an important exception as they need a pH range of 4.9 to 5.5. All soils tend to return to their native pH levels over time, so for large-scale plantings, it's best to plant crops or grasses that need little or no modification to a soil's natural acidity or alkalinity.