Translations:Benutzer:Arian/Klett-Mini-Test/1089/en

On acid soils of advanced age, in extreme cases an amelioration of the phosphate balance may, alongside the amelioration of the base balance, also become necessary for the activation of soil life. While the basic constituents of the soil — calcium, magnesium, sodium and potassium — are subject to leaching, this is the case for phosphorus only to a small degree. In an acid medium it combines with aluminium, in an alkaline medium with calcium. Aluminium and calcium phosphates are sparingly soluble and are unlocked mainly through root exudates, symbiotic bacteria and mycorrhizae (*fungal hyphae*). Under normal conditions, in a biologically active soil the phosphate balance regulates itself.