| Soils, Crops and Fertilizer Use |
|Chapter 11: Liming soils|
Avoid raising the pH by more than one full unit at a time, and don't raise it much above 6.5 . It may only be necessary to raise the pH up to 5.5 to 6.0 for best yields of most crops. Overliming can be worse than not liming at all because:
• Raising the pH above 6.5 increases the likelihood of micronutrient deficiencies (except for molybdenum), especially in the case of iron and manganese.
• Phosphorus availability starts declining above a pH of 6.5, due to the formation of relatively insoluble compounds with calcium and magnesium.