: The standard of soil pH is 6.0 to 8.0 , that is , if the pH starts to decrease from 6 , then the acidity of the soil will continue to increase. If the pH value is less than 3 , then the acidity increases. And the compound responsible for increasing the acidity of the soil is ammonium hydroxide. And the application of excess sulfur or sulfur in the soil increases the acidity of the soil.