Natural soil pH depends on the rock from which the soil was formed (parent material) and the weathering processes that acted on it—for example climate, vegetation, topography and time. These processes tend to cause a lowering of pH (increase in acidity) over time.
Use of litmus paper . A small sample of soil is mixed with distilled water, into which a strip of litmus paper is inserted. If the soil is acidic the paper turns red,if basic, blue
