Nitrogen Loss Depends on Days of Saturated Soil

Even if you lost N, over-the-top applications soon may not pay.

Published on: Jun 10, 2008

You may have lost 5 pounds of actual N per acre fro every day soils were saturated, extremely full of water, either at or almost at the point of standing water. That’s the word from Jim Camberato, Purdue University soil fertility specialist. That assumes you applied urea, If you applied 28% N, you might be worse off- if you applied anhydrous ammonia, perhaps better. Form of N makes a difference when it comes to potential loss in saturated soils.

Does that mean you ought to hire a custom applicator to come back in with drops when it dries up, or even toward the end of June, and add back nitrogen. If you’re talking a wet-hole situation with pumpkin yellow corn, it’s not even a consideration, Camberato says. Roots are likely damaged as well and your chance of getting payback may be minimal.

But if the corn wasn’t drowned out, and you’ve got a good stand, would it pay to add more N? The answer may surprise you.

“You could expect a yield increase if you lost 20 to 25 pounds per acre and applied that rate back with a high-clearance sprayer,” he says. “But if you applied the correct amount of N in the first place, then you’re probably talking about a 3 bushel increase by adding the extra N.”

Three bushels? That doesn’t sound like much. But if you applied the right amount in the first place, it takes several pounds of N to produce a bushel of corn toward the top end, Camberato notes.

So at 60 cent per pound N plus application cost, if you dribble on 25 pounds and spend $16 to $18 per acre to get three extra bushels, with corn 1t even $6.50 per bushel, that’s only a break-even situation. It wouldn’t appear to be a smart move, and barely worth the effort.

But here’s just how unusual this situation is and how strange this year ahs become. “What if corn goes to $10 per bushel? Camberato wonders out loud. Not likely, but currently not impossible. Then suddenly there’s almost a 2 to 1 payback for going back in with 20 to 25 pounds of N per acre

It’s just another decision you may face in a year where the only rule for crop farmers seems like this ; there are no rules to fall back on. Indiana farmers seem to be in uncharted territory weather-wise this season.

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