acid soil Soil that has a pH less than 7.0. Degrees of soil acidity are recognized. Soil is regarded as ‘very acid’ when the reaction is less than pH 5.0. The USDA lists five standard ranges of soil acidity (less than pH 4.5, extremely acid; 4.5–5.0, very strongly acid; 5.1–5.5, strongly acid; 5.6–6.0, medium acid; and 6.1–6.5 slightly acid). Surface soil horizons of acid brown earths have a reaction of pH 5.0 or less.

acid soil Soil having a pH less than 7.0. Degrees of soil acidity are recognized. Soil is regarded as ‘very acid’ when the reaction is less than pH 5.0. The USDA lists five standard ranges of soil acidity (less than pH 4.5, extremely acid; 4.5–5.0, very strongly acid; 5.1–5.5, strongly acid; 5.6–6.0, medium acid; and 6.1–6.5, slightly acid). Surface soil horizons of acid brown earths have a reaction of pH 5.0 or less.

acid soil A soil having a pH less than 7.0. Degrees of soil acidity are recognized. Soil is regarded as ‘very acid’ when the reaction is less than pH 5.0. The USDA lists five standard ranges of soil acidity (less than pH 4.5, extremely acid; 4.5–5.0, very strongly acid; 5.1–5.5, strongly acid; 5.6–6.0, medium acid; and 6.1–6.5, slightly acid). Surface soil horizons of acid brown earths have a reaction of pH 5.0 or less.