Source: Robert Mullen, Ed Lentz, Ohio State University
Some producers applied anhydrous ammonia a few weeks back and are concerned about nitrogen loss, so is your nitrogen at risk for loss? We have written articles on this in the past, but the difference between say last year's discussion and this year's is the impact of soil temperature on soil biological activity.
We are typically concerned about nitrogen loss a little later into the year, but what about the present heavy rainfall? The difference between last year (when concerns really became evident in mid-May) and this year are soil temperatures. Weather monitoring stations located at OARDC research locations across the state are revealing that we have not reached soil temperatures above 53 F for any extended periods. This is especially true for the northern half of the state. Additionally, water logged soils that may be warming are not likely to experience much in the way of nitrification of the applied ammonia. Remember, anhydrous applied during that very small window two weeks ago or even earlier has not really been subject to nitrification thanks to the cool, water logged soils.
So, should you be concerned? At this point, you should not be. This is especially true if you used a nitrification inhibitor.
Something needs to be mentioned about this compressed time frame for corn planting this spring. If you have yet to apply your N, and you were planning on using anhydrous ammonia, you must allow adequate time between application and planting and the anhydrous must be injected deep enough to prevent contact with the seed. Mismanagement of anhydrous ammonia applications close to planting can dramatically reduce stand and a thin stand is the easiest way to decrease yield potential.
We really want to caution growers in no-till systems that may be considering the use of the new anhydrous toolbars that apply ammonia shallower. These toolbars do reduce surface disturbance, and they do require less draft power to make the applications, but they can cause issues on corn germination. These toolbars are designed to apply N shallower in the soil, and planting to soon after application can cause some emergence issues. We are not running down the toolbars themselves as they do what they are marketed to do quite effectively. They allow no-till producers to supply anhydrous ammonia with minimal disturbance with less power. Shallower applications of anhydrous are a greater risk for germinating plants, so if you are going to be using these toolbars be prepared to wait at least a week (maybe longer) to plant, or apply the N diagonal to the direction of planting.