Are your customers applying the right nitrogen rate?

Eric Scherder

Eric Scherder,
Customer Technical Specialist – Western Region, 
Dow AgroSciences

A combination of three nitrogen tests is a powerful decision-making tool for farmers when evaluating nitrogen fertilizer needs. The tests provide accurate estimates of available nitrogen at various times during the season.

Each test provides farmers with the best information for making nitrogen management and application decisions. Whether farmers are applying nitrogen in fall, early spring or split, the tests help farmers manage nitrogen based on science and laboratory results instead of guesswork.

Dow AgroSciences, along with fertility experts at Iowa State University, recommend farmers employ a combination of late-fall, early spring and late-spring (pre-sidedress) soil testing. It is important to use all three tests in combination by sampling at various locations in a field to get an accurate reflection of nitrogen availability and future needs.

The three tests are:
Preplant soil nitrate test — A preplant soil nitrate test measures the amount of residual or carryover nitrate-nitrogen in the soil profile, typically sampled to a 2- to 3-foot depth in the fall or early spring. The preplant test measures the amount of nitrogen remaining from the previous crop year.

Pre-sidedress soil nitrate test — If nitrogen applications are lowered based on soil profile nitrate-N sample results, farmers should complete a pre-sidedress soil nitrate test. This test allows farmers to adjust nitrogen applications before peak growth at critical nutrient uptake stages.

Fall stalk nitrate test — After harvest, a fall stalk nitrate test provides information on the relative nitrogen program results that year. Taking fall stalk nitrate tests over a period of years can help farmers fine-tune nitrogen management. Test results are not simply to be used to adjust rate for the next year, rather longer-term evaluation.

Protect your nitrogen investment
Using a nitrogen stabilizer such as N-Serve® or Instinct® has long proven effective in reducing nitrogen loss into groundwater and surface water.

N-Serve and Instinct protect applied nitrogen by keeping nitrogen in the ammonium form longer by inhibiting the conversion process to nitrate nitrogen, which is moveable in the soil. Both products slow down the conversion so your nitrogen fertilizer investment is available when the corn plant actually needs the nitrogen later in the corn plant life cycle. Stabilizers ensure that applied nitrogen will still be there in the soil profile where a corn plant needs it and won’t end up moving lower in the soil profile out of a corn plant’s reach.

There’s no arguing that nitrogen stabilized with N-Serve and Instinct can increase yield potential. Ultimately, using a stabilizer is going to help make farmers more profitable while also being a sound approach to protect precious groundwater supplies.

To calculate your customers’ return when using Instinct or N-Serve, use the profit calculator at

Advantages of using N-Serve® nitrogen stabilizer are clearly evident in this side-by-side comparison. Rows on the left, where N-Serve was applied, are taller, greener and healthier while rows on the right appear stunted, yellow and show firing of lower leaves — all symptoms of nitrogen deficiency.

®Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow. Instinct is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Do not fall-apply anhydrous ammonia south of Highway 16 in the state of Illinois. Always read and follow label directions. ©2017 Dow AgroSciences LLC