The researchers studied how soil pH varies across different areas by testing various soil sampling methods and geostatistical techniques. They found that the most accurate way to map acidic areas is by sampling within specific soil types and considering previous test results. Using interpolation methods like IDW, Simple Kriging, and Simple Cokriging, they discovered that acid areas on digital maps were smaller when soil sampling was done carefully. It is recommended to sample soil within specific soil types and previous test results for accurate pH data, especially when acid soils make up more than half of the area being tested.