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Little River, TX | Urea is ammonium and carbon dioxide
UAN or 28% Liquid . Of the total 30.5% is urea, 30% is water, 39% is ammonium nitrate = 99.5%
UAN or 32% is 35.4% Urea, 20.3% water, and 44% ammonium nitrate = 99.7%
As you can see these three are predominantly the ammonium form of nitrogen.
The nitrate form is immediately available to the plant & is highl soluable and leachable.
The ammonium form is only slightly available, at best. It also ties to the clay and organic matter in the soil. It becomes available and leach able after the soil organisms convert it to the nitrate form.
Under ideal conditions urea becomes volatile and can disappear into the air. To avoid this apply to dry dirt. Apply to dirt rather than to surface trash/organic matter. The window of opportunity to volatilize is fairly small and little nitrogen is lost, unless you top dress a pasture or wheat right after a rain or while there is still a heavy dew. | |
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Forms of N
