Tuesday, May 24, 2011
Phosphorous is one of 3 major nutrients needed by plants of the 17 identified plant nutrients. Farmers in the corn belt are not applying enough phosphorous to replenish the amounts being removed by their primary crops according to a new nationwide survey of soil test levels.
The summary, completed by scientists with the International Plant Nutrition Institute or IPNI shows that soil test levels for phosphorous in the corn belt has seen a decline of 6 PPM or about 3 lbs per acre since the last survey was completed in 2005. The title of the summary is Soil Test Levels in North America, 2010.
This decline had major agronomic significance since a high percentage of samples from the region now test below critical levels and calls for annual phosphorous fertilizatuib ti avoid yield reductions. The 6 ppm decline was discussed in the Better Crops With Plant Food magazine.
I know more farmers are depending on cheaper manure to provide phosphorous in crops, even my neighbors are doing this. I don't have access to manure so I use more expensive commercail fertilizer to supply my phosphorous needs.
I have been able to keep my soil and tissue test levels to the desired amount with expensive commercial fertilizer and don't use any more than my crop needs or takes off.
I sampled an old hog lot last week and of course the soil test levels came back very high. I told the owner I wish I had 1000 acres of that soil. It only called for a little potassium for high yield crops and needed no lime. Livestock farmers feed a lot of calcium for healthy animals so manures can be high enough in calcium and magnesium to not require lime added to the fields treated with manure.
Phosphorous is usually sold in this area as monoammoium phosphate in a 11-52-0 analysis and is over $500 per ton. We used to be able to buy 0-46-0 but it is a thing of the past in most areas today. Even DAP or 18-46-0 diammonium phosphate is hard to obtain in these parts.
If you didn't get yours applied last fall, it isn't getting put on this year with this spring so wet we can't even plant let alone spray or fertilize.