Concept:Crop residue ash contains basic compounds, so it neutralises acids in the soil.
Explanation:The ash from burnt crop residues is rich in bases such as potassium, calcium, and magnesium compounds.
These bases react with hydrogen ions in an acidic soil.
As a result, the acidity of the soil is reduced and soil pH moves towards neutral.
Therefore, ash does not increase acidity or make the soil more alkaline.
Answer:The ash would decrease soil acidity.