Nitrogen:Corn Ratio Indicates Farmers Should Calculate Risks

By Phil Kaatz

Planting season is in full swing according to the calendar. While some farmers are waiting, others have nearly completed corn planting. Once the fields are planted, weed control and nitrogen (N) sidedress applications will follow. Michigan State University soil scientists have teamed with other land grant universities to encourage farmers to consider how much total N they apply using the Maximum Return to Nitrogen corn nitrogen rate calculator. The calculator is a tool farmers can utilize when considering how much total N should be applied economically. I think of the Maximum Return to Nitrogen as a tool for farmers to determine the level of risk they’re willing to take to get corn yields.

The rising prices associated with corn inputs means farmers should have an even sharper pencil when deciding how much N they can apply economically. Other sources of N such as manure, whether a pelleted fertilizer product, manure pack or a liquid effluent, will also have a cost and corresponding N value. This should be included in the total price of N.

Corn sidedressed with 28% UAN. Photo by Phil Kaatz, MSU Extension.

With the price of corn hovering near $3.35 per bushel and the price of 28% UAN near $250 per ton ($0.45 per pound) and urea near $360 per ton ($0.39 per pound) the N:corn ratios are 0.134 and 0.116 respectively. When the N:corn ratio rises, farmers may want to consider reducing their total N applied for the economical yield versus the maximum yield.

I like to think in the kind of terms I can understand easily when talking about total N applied. If I apply what I always apply, I might be able to get the maximum yield, but the additional N needed to get the yield either loses me money or I break even. It all comes down to whether or not farmers are willing to take a calculated risk to raise their corn crop at the economical yield or roll the dice and hope to get the maximum yield.

The Maximum Return to Nitrogen rates are much lower than previous N recommendations. Therefore, farmers may be hesitant to make a complete shift. To test the recommendations, farmers may want to put in strips with the Maximum Return to Nitrogen recommended rate as a comparison to their standard rate and then compare yield and economic returns.

To input your own prices of corn and nitrogen costs, go to the Maximum Return to Nitrogen rate calculator.

Source:msu.edu