Producers Blog

You’re reading Part 4 of a 4-part series. Start the series here.

Last, but certainly not least is Nitrogen (N).

N can be taken up by the plant in two forms: nitrate (NO3-) and ammonium (NH4+). In order to get (NO3-) and (NH4+) there has to be a biological transformation from organic N. Since the transformation is biological, N is sensitive to soil pH, temperature and moisture. Moisture, for example, would be saturated soils that would result in nitrates being lost in the form of leaching or denitrification.

Nitrogen is a key ingredient in amino acids and the creation of proteins, which are both essential for cell growth. Amino acids and proteins are the building blocks for essentially everything in the plant; therefore, N is correlated to overall gains in dry matter. Since N has involvement at every developmental stage of a corn plant, it has the greatest impact on yield among nutrients.

Recommended soil test levels: Soil test levels are really only relevant as credit to the current year’s application. Today’s yield demand is usually too high to be processed naturally in most cases so supplemental N is added for each growing season.

Crop removal: Nitrogen recommendations range from 1 lb to 1.2 lbs of N per bushel of corn, so on a 200-bushel yield goal you would need approximately 240 lbs of N. Crop removal is less than the recommendation but this allows for some N loss during the growing season. Residual soil nitrates (topsoil and subsoil), legume credits (i.e. soybeans), irrigation water credit and pre-applied fertilizer/manure can all be used as credits when calculating total N needed for the desired yield goal.

Deficiency characteristics: Interruption in the growth process that causes stunting due to poor cell development and yellowing due to decreased chlorophyll formation. Yellowing occurs on older leaves first then moves to newer leaves. The yellowing occurs at the mid-rib near the tip of the leaf moving inward with a distinct v-shaped pattern. High amounts of N can stimulate more vegetation but could lead to an under-developing root system compared to the above-ground growth. Lodging and/or greensnap issues could develop given the timing of application and wind events.

Check out the whole series:

Part 1: Understanding NPK and Their Effect on Your Field

Part 2: Understanding Potassium and Its Effect on Your Field

Part 3: Understanding Phosphorus and Its Effect on Your Field

Ward, Raymond C., Ph.D. “Ward Laboratories, Inc.: WardGuide.” Ward Laboratories, Inc.: WardGuide. Ward Laboratories, Inc., n.d. Web. 29 Nov. 2016.