Phil Kelly is the new area manager for Bio Ag, Southern and Central West NSW INDEPENDENT government research shows that most Australian soils have low available levels of the phosphorous needed for plant growth. Only between five and twenty five per cent of the phosphorus applied is actually taken up by the plant. The rest is lost through “locking up” in the soil. The implication of this is that between 75% and 95% of the money spent on single superphosphate is wasted.
So why does the phosphorus in single superphosphate “lock up” in soils so readily?
Single superphosphate is made by treating phosphate rock with sulphuric acid to make the phosphorus water soluble. However, this makes it very unstable and it tends to bond with other elements, such as aluminium and iron, as soon as it is applied to the soil, particularly if the soil is acid (This story Administrator ready to work first appeared on Nanjing Night Net.