How much phosphorus is in soils? There is about 1,000 parts per million of phosphorus in the earths crust. However, phosphorus is never found by itself in the environment, it is always attached to other elements.
So, if there is 1,000 ppm, then there is about 2,000 pounds of P in the top six inches of soil. To convert to P2O5, multiply by 2.3 which would equal about 4,600 pounds per acre! Lots there, but unfortunately not plant available. At any one time, there is less that one pound of plant available P per acre.
Soil tests will give us an indication of a yield response from added P, not that we will always get a response. Usually the P will be reported in ppm and rates will vary up to 30, 50 or even 100 ppm. At higher levels you will be told that you probably won’t get a yield response from added P. Is this always true? No, because environmental conditions have a huge impact on P availability. Cold, wet and high or low pH conditions will have a great impact on availability.
We have found that by using our FREE pHOS 8-24-0, we have been able to supply adequate amounts of phosphate to the plant. We have applied FREE pHOS as a pop up direct over the seed at rates as low as 3 gallons per acre. When we have made this application we have seen excellent yield responses. To view photos of results, please visit our FREE pHOS page and have a look, or better yet, give us a call or send an email, get some product and try it for yourself.