Q.We are an organic chicken fertilizer manufacturer, and we would like to use our product on Macadamia trees grown in South Africa
The question is what is the minimum phosphate (P)level in the NPK chain in soil and in the organic chicken fertilizer if the phosphate levels are too high what damage can it cause to the macadamia trees
And second question is what can we add to our organic chicken fertilizer to bring down the Phosphate level the test results from our lab shows a 1.13% Phosphate level Nitrogen is 2.6% and Potassium is 2.63%
Certified GKH Gardening Expert
The short answer is that 1.13% phosphate (P2O5) is not high in relation to the 2.6 for N and K. On that basis you need not worry about bringing down the P. In fact you might try to bring it up.
If your primary mission is to grow macadamia nuts, then of course it is far superior to test the soil and get agronomist recommendations for an Rx of mineral and biological amendments, based on actual defficiencies found. The general purpose fertilizer is OK, but may not address the actual needs for best plant health and productivity. And of course there are other factors in good soil and water managment, mulching, flood irrigating, legume green manure intercropping, no deep tillage to disrupt absorbing roots, etc., all these and more to be considered.