What is in this article?:
N risk management advice in a nutshell:
- Time in-ground and wild, wet springs reduce N availability.
- Delay N applications on lighter soils until spring.
- Don’t count on one-time fall-applied or even early spring-applied N to be there when and where corn needs it.
- Get more efficient N use by piggybacking N application with other field trips—apply N in as many operations as you can.
- Sidedress as soon as you can.
- Save N adjustments until final sidedress, then apply according to soil tests.
- Don’t fall-apply N on high-pH soils.
N-decision model boosts savings
Frank Moore, an independent agronomist who farms about 2,000 acres in Howard County in northeast Iowa and southeast Minnesota, has been testing Cornell University’s online nitrogen management tool, Adapt-N. The popular program uses a computer model, high-resolution weather information and grower information on soils, crops and management to more precisely assess how much N is needed at sidedress time, among other things.
Moore ran a couple of scenarios in mid-June on a Minnesota farm he operates to compare the quick and easy Minnesota N-decision tool to recommendations from Adapt-N.
“The first scenario was for a Minnesota farm I operate where 140 pounds/acre of anhydrous ammonia was fall-applied on corn following soybeans. The Minnesota tool called for 40 to 70 pounds of additional N, while Adapt-N suggested 100 pounds,” Moore says.
In a second comparison, with everything the same except spring-applied anhydrous, the quick and easy Minnesota tool called for 40 to 70 pounds of additional N again and Adapt N recommended 45 pounds.
“The Minnesota tool has some limitations—the 40 to 70 pounds spread can represent a significant range in cost over a lot of acres—but I would encourage people to use it,” Moore says after his quick comparison. “Using it helps create an awareness of how nitrogen management and weather are closely linked. It helps reinforce the thoughts that the earlier you apply N and the wetter the spring is, the more likely N will be lost. And lost N is reflected in how the crop looks. Using this tool with Adapt-N might also lead people to discover how Adapt-N (find it online at http://adapt-n.cals.cornell.edu) can further refine their nitrogen rates.”