I have not tried these new biological products that allow you to apply less nitrogen for corn. I want to cut nitrogen costs, so I am going to use one this year. Should I use it on all my acres? Can I cut my N rate by 40 pounds per acre?

 

Bower: I would not try the new biological products that claim to replace 40 pounds of traditional nitrogen on every acre. Trying these products is a gamble.

 

However, choose a field with consistent yield across the whole field. Test at least three rates of nitrogen with and without the biological N. Replicate trial strips at least twice, and test for differences.

 

For the three N rates, use your normal rate of N with and without the biological addition. Additionally, test your normal N rate minus 40 pounds per acre with and without the biological N product. And then, test your normal N rate minus 60 to 70 pounds per acre with and without the biological N product. If it is too much to check three N rates, compare at least your standard rate of N and 40 pounds per acre lower than your standard rate.

 

Nagel: Farmers have had three to four years to gain some biological experience on the farm, and more third-party research has been published. Although there have been some trials that showed a positive return on investment, the vast majority have not.

 

Approach these products with caution. Try some replicated trials on your farm. It’s critical to set up testing correctly. The best way is to have replicated strips with normal N rate, reduced N rate and reduced N rate with the biological product. Most companies omit treatment two, which is important to know whether there was a treatment effect or you could have just reduced your N rate.

 

Going into 2025, revisit your target total N rate with a trusted adviser. Use more proven strategies, such as split applied N and nitrification inhibitors.

 

Park: There has been a lot of progress with biological products, but they are not a substitute for sound agronomics. Test them for a couple years and look at the economics before committing the entire farm. Compare the biological product with your standard nitrogen rate program and reduced rates of nitrogen, as nitrogen-use efficiency can vary from year to year due to environmental conditions. 

Quinn: If you plan to use one of these products, do not put it on all your acres. Instead, put it in some test strips and alter N rates within those test strips to get a good idea if it is truly replacing any amount of N fertilizer.

 

The responses are often highly variable. In my experience, it is very rare that they provide supplemental N value or any response at all. However, there can be some potential benefits in very challenging soils. The best option is to just test them on your farm with strips to get a good idea of their performance. Do not just apply them on every acre.