Full explanation
Soil pH directly affects nutrient availability to plants. Below pH 5.5, phosphorus is locked up and potassium, calcium, and magnesium availability drops. Above pH 8.0, iron, zinc, and manganese availability drops. Ukraine's most problematic soils are the acidic sod-podzolic soils of Polissia (pH 4.5–5.5), which need liming at 2.5–6 t/ha of CaCO₃. The richest are the Forest-Steppe and Steppe chernozems with near-neutral pH 6.8–7.2. A pH test is the standard first step before designing a fertilization program for any field.