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Omaha, NE (N41-15-42 )

Where should my Phosphorus levels be relative to my Potassium, Mg, and Calcium levels?

Thanks,

matt

4/6/2004 6:52:43 PM

Garden State Pumpkins

Great question Matt...ANd we should have been taking notes at Niagara...pretty sure Jerry Rose and Tim Parks gave their ratios there...I am almost positive that in a discussion with Nic Welty he said he liked his calcium to mag ratios as high as he dared...7 to 1 is what I'm thinking but hope some of the big guys chime in here...Andy W....what are we looking for???
chuck

4/6/2004 7:24:45 PM

Chesterfield, MO

Ca-P about 70:1 don't stress over getting it exact

4/6/2004 9:42:59 PM

Ctpumpkin@optonline.net

Applied commercial Phosphorus fertilizer lasts in the solution for 50-200 years depending on the source material used. So care must be exhibitted to not over apply.

I did take notes at Niagara. No mention was made of Phosphorus. Probably because once the minimum need is met, that level rarely becomes deficient again.

Soils differ though, so anual testing is prudent for all of us.

Diammonium Phosphate (DAP) is the quickest source to go into solution & takes about 50 years to complete its cycle.

Monoammonium Phospate (MAP) is slower & may take 100 years.

Triple & Super Phosphates are too slow & therefore have little relevance today unless the soil scientist graduated before 1980 & is really stuck in a rut.

Rock phosphates may never become available entirely. These are an absolute waste of money & due to their very poor solubility, may contribute to surface runoff & should be avoided. Undisolved soilds are prone to lateral runoff. Not leaching.

Believe it or not, more than a few of the Phosphorus rich Natural Organic fertilizers unfortunately fall into this category. Since it is challenging to produce good organics without Phosphorus, this is slowly becoming the red herring of my industry.

Steve

4/7/2004 6:15:52 AM