Measuring phosphorus in soils

Phosphorus (P) is an essential element in plant growth. Phosphate fertilisers are also an essential and major investment for growers. Making decisions on your phosphate fertiliser spend need to based on reliable information and sound advice.

The decision making process begins with a soil test. However many of these tests and associated target ranges for P and soil type have been developed for chemical / water soluble P fertilisers. When using BioAg’s reactive rock phosphate based fertilisers it is necessary to revisit the type of phosphate tests being done on your soils.

Measuring Phosphorus in soils when Using Phosphate Rock fertilisers

When using BioAg’s BioAgPhos® or its blends the phosphate is liberated with the breakdown of the reactive rock phosphate. To identify plant available P it is necessary to measure the BioAgPhos still present in the soil that will broken down by the organic acids produced by crops, pasture, vines or trees.

We recommend that a soil test include Bray 1, Bray 2 and PBI (Phosphate buffering Index) as a minimum. In combination these can be assessed by your BioAg representative to evaluate available P and importantly fertiliser requirements.