[Phosphatase activity in low activity tropical clay soils. Distribution in the various particle size fractions]

agricultural soils chimie du sol clay soils enzimas enzyme enzymes enzymic activity esterasas esterase esterases fracciones del suelo fraction du sol land organic matter phosphoric monoester hydrolases soil soil chemistry soil separates soil texture sol sol agricole sol argileux sol tropical suelo suelo arcilloso suelo tropical terre textura del suelo texture du sol tierras tropical soils