The supply of soluble phosphorus to the wheat plant from inorganic soil phosphorus

Summary Pots containing a slightly acid, red-brown soil were maintained at three moisture levels, in half the pots wheat was grown and in the remainder there was no plant growth. Fractionation of the soil phosphorus showed the aluminium phosphates fraction to be the main source of plant-available phosphorus, but at the same time the growth of the plants reduced the significant increase in iron phosphates which occurred during the period in the no-wheat pots. The plant roots compete with the iron phosphates for the soluble phosphate released from the aluminium phosphates fraction.