There are four major reasons for soils to become acidic: rainfall and leaching, acidic parent material, organic matter decay, and harvest of high-yielding crops.
Areas with wet climates have greater potential for acidic soils. In time, excessive rainfall leaches the soil profile’s basic elements that prevent soil acidity.
Soils that develop from weathered granite are likely to be more acidic than those developed from shale or limestone.
Organic matter decay produces hydrogen ions (H+), which are responsible for acidity. An ion is a positively or negatively charged element.
Harvests of high-yielding crops play the most significant role in increasing soil acidity. During growth, crops absorb basic elements to satisfy their nutritional requirements. As crop yields increase, more of these lime-like nutrients are removed from the soil.
Some of the nitrogen fertilisers applied have ammonium elements, which in the long run also increase acidity in the soils.
The solution is to re-energise these soils by adding the required nutrients. However, with the removal of these soil nutrients, acidity levels are so high, that the fertilisers that you apply will not be effective.
