The researchers studied how adding acid and lime to sandy soil affects its pH and levels of calcium and magnesium. They did this by applying acid and lime treatments to the soil surface and measuring the changes in pH and calcium and magnesium levels at different depths over three years. The acid treatment lowered the pH, while the lime treatment increased calcium levels. Magnesium levels also increased after lime applications. The pH of the soil varied seasonally, and it's important to establish and monitor soil pH levels in advance to maintain desired levels.