The LAW of MINIMUM (Liebig) states that it is the nutrient in least supply that limits productivity. In Australian soils this minimum or limiting factor is PHOSPHORUS. In the acidic soils it is locked up in the form that is inaccessible to any crop, in alkaline soils it becomes “FIXED” to soil particles in an insoluble form.

Independent studies by CSIRO and Charles Sturt University both confirm that only a small percentage of freshly applied phosphate fertiliser is actually in a “plant–available” form and is subsequently taken up by the crop.

Data compiled by the CSIRO indicates that at least 1/5th of the phosphorus applied to the soil is actually available to any crop/pasture. Confirming this Charles Sturt University have shown that only 1/8th of applied phosphorus of any phosphorus fertiliser is actually available to a crop/pasture.

FARMERS SUPERANNUATION FUND

The amount of phosphorus applied annually  therefore accumulates in the soil and compounds in what scientists describe as the “Phosphorus Bank.”

CSIRO estimates that $10 billion of phosphorus is stored in our soils.

A further study conducted by the CSIRO shows that for every 1mg/kg change in available phosphorus this equates to a $25/ha/pa adjustment in productivity.

This is why responses today are far less than what they were decades ago, using the same fertiliser but with increased rates.

A serious and challenging problem!

Through understanding the KEYS TO YOUR SOIL BANK and the technology whereby you can access this abundant supply of phosphorus and other nutrients this will increase your bottom line and reduce fertiliser input costs.

The “PHOSPHORUS BANK” is explained in the phosphorus cycle.

In the illustration above, the thickness of the arrows indicates the amount of Phosphorus present at eash stage of the cycle.

The keys to unlocking phosphorus in the soil relies on understanding where the phosphorus goes once it enters the soil.  The diagram explains that a small percentage releases to the bio-mass which is converted to organic phosphorus and is taken up by the plant whilst the majority travels over onto the cations in alkaline soils of Calcium and in Acid soils Aluminium which fixes the phosphorus it in the soil.

If the bio-mass is increased more organic phosphorus can be produced therefore more phosphorus is available to the plant. That is, if organic carbon levels are increased so does micro-activity improve, allowing phosphobacteria to work converting phosphorus.

Also pH plays a major part as high alkaline and acid soils fix phosphorus quickly as microbial action is reduced.

The major action that pulls phosphorus away from the positive cations is acid. Increased presence of acids improves phosphorus uptake in alkaline soils and natural acids such as humic and fulvic are as good as sulphuric acid used in chemical fertilisers.

Remember the ways to release Phosphorus:

• Balance soil (maintain 6. – 7 pH)
• Use natural acids (Citric, Humic acids etc)
• Provide food for phosphobacteria
• Use silicates

REMEMBER THAT ONLY 10-20% OF PHOSPHORUS IN ANY FERTILISER IS AVAILABLE WITHOUT THESE WAYS.

All this information, plus more is available in a printed booklet form.

INTERSTATE ENERGY GROUP. PO Box 1039, Bacchus Marsh VIC 3340. Ph. (03) 5367 0725, Fax. (03) 5367 0726.
© 2002 Copyright Maddingley Minerals. HumusPlus4 and OCCA are registered business names of Maddingley Minerals.