ABSTRACT
The dominant characteristics of soil phosphate are very low solubility of phosphate minerals and its strong binding on to particle surfaces giving small soil solution concentrations. As a result phosphate deficiencies in crops are common. The strong adsorption of phosphate on to particle surfaces and the small solubility of phosphate minerals leads to concentrations in soil solutions between 1 and 50 M. Atmospheric inputs are shown in Colour and have been measured as part of the current interest in acid rain. Sulphur deficiencies have been recorded in many parts of the world where atmospheric inputs are low. Phosphorus is added to soil in plant residues and is released from soil organic matter by mineralization. For a soil in which the amount of organic matter is not changing. The significance of the low mobility of phosphate was demonstrated in a pot experiment carried out at Rothamsted in 1980.
