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Chesley, Ontario | One quarter of the N in 28% is in the nitrate form, so it doesn't stick to the soil and can leach out over winter (if it doesn't denitrify). The only reason fall applied NH3 or urea work is that they convert to ammonium, which does bind to the soil, and if the soil stays cool enough most of it stays in that form until the weather warms up in the spring and the ammonium is converted to nitrate. 28% is missing that advantage for the nitrate part...to be economically equal as far as N for next spring's crop, you would need to be buying the N in 28% at three-quarters the price of the N in urea (or the price per ton should only by 46% of the price per ton of urea).
Personally, I don't think fall application of N is a good idea in most areas east of the Missippi, but some of my colleagues in the land grant universities don't agree.
As far as a P source, if you can buy 10-34-0 for the same phosphorous price as the 11-52-0, it would be equally effective as a P source, fall or spring. Price will be the issue. | |
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28% v.s 46-0-0
