thumb|Nutritional elements availability within soil varies with pH. Light blue color represents the ideal range for most plants. The United States Department of Agriculture Natural Resources Conservation Service, formerly Soil Conservation Service classifies soil pH ranges as follows: DenominationpH rangeUltra acidic< 3.5Extremely acidic3.5–4.4Very strongly acidic4.5–5.0Strongly acidic5.1–5.5Moderately acidic5.6–6.0Slightly acidic6.1–6.5Neutral6.6–7.3Slightly alkaline7.4–7.8Moderately alkaline7.9–8.4Strongly alkaline8.5–9.0Very strongly alkaline9.0–10.5Hyper alkaline> 10.5 Topsoil pH is influenced by soil parent material, erosional effects, climate and vegetation. A recent map of topsoil pH in Europe shows the alkaline soils in Mediterranean, Hungary, East Romania, North France. Scandinavian countries, Portugal, Poland and North Germany have more acid soils.
thumb|Nutritional elements availability within soil varies with pH. Light blue color represents the ideal range for most plants. The United States Department of Agriculture Natural Resources Conservation Service, formerly Soil Conservation Service classifies soi.l pH ranges as follows: DenominationpH rangeUltra acidic< 3.5Extremely acidic3.5–4.4Very strongly acidic4.5–5.0Strongly acidic5.1–5.5Moderately acidic5.6–6.0Slightly acidic6.1–6.5Neutral6.6–7.3Slightly alkaline7.4–7.8Moderately alkaline7.9–8.4Strongly alkaline8.5–9.0Very strongly alkaline9.0–10.5Hyper alkaline> 105 Topsoil pH is influenced by soil parent material, erosional effects, climate and vegetation. A recent map of topsoil pH in Europe shows the alkaline soils in Mediterranean, Hungary, East Romania, North France. Scandinavian countries, Portugal, Poland and North Germany have more acid soils.