FROM THE FARM REPORT: GETTING THE MOST OUT OF YOUR NITROGEN

May is the month when the majority of corn gets planted across the nation. It is also one of the months where the most fertilizer is applied. It’s a terrible time for fertilizer prices to spike, and yet, here we are…

While you may wish you could just take a year off from buying fertilizer, we all know that crop yield requires nitrogen, and the cows still need to eat. While we can’t take a year off, we can try to make cropping decisions that will allow us to purchase less and use nitrogen as efficiently as possible.

The first nitrogen we typically apply each year at Miner Institute is urea for grass fields. While we still get a grass crop without the green-up fertilizer, the crop really responds positively to it. Rather than skipping the application, consider applying a reduced rate. This will improve nitrogen utilization somewhat without causing yields or protein content to fall off a cliff. Potassium prices aren’t up nearly as much as nitrogen prices, so consider spending more of your fertilizer budget on potassium for alfalfa and mixed stands and less on nitrogen for grass.

For corn, I strongly recommend a spring manure application where possible prior to planting. Manure is an excellent source of nitrogen and other nutrients, but it needs to be incorporated into the soil as soon as possible to get the full nitrogen benefit. While injection equipment is ideal, it isn’t required. I have known farms that run a tillage tractor right behind the manure spreader with excellent crop response.

A spring manure application will allow you to cut your starter fertilizer rate. While you may not use much anyway, small reductions can add up significantly across large areas. Your biggest savings, however, will come from the nitrogen your corn can use later in the season, when the corn enters the rapid growth phase. The caveat is that this will only work if you properly adjust your sidedress rates. The best way to do this is to take a pre-sidedress nitrate test (PSNT). Many guidelines suggest that a PSNT value of 21 parts per million indicates that you can get by without applying any additional nitrogen fertilizer to the corn crop.

Another simple trick to cut down on your nitrogen fertilizer bill is to rotate grass fields into corn. Cornell research has shown that first year corn requires little or no nitrogen fertilizer. If that will put you short on feed, you can always take first cut and then plant a short-season corn after applying manure. The difficulty is getting it done in a timely fashion.

Other things that can help improve nitrogen use efficiency on your farm might include splitting up nitrogen applications, using nitrogen stabilizers, and biological and biostimulant type products. While these might not translate into huge savings, I believe they all can work under certain conditions. I like urease inhibitors for broadcast urea when no rain or tillage is expected. However, I don’t routinely recommend nitrification inhibitors that may alter the biological community of the soil. More research is needed on these and many of the biological products before we start using them routinely here at Miner Institute.

— Allen Wilder

wilder@whminer.com