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Corn Nitrogen Response Curve

Nitrogen stabilizers

Nitrogen management has always been a challenge in high nitrogen demand crops such as corn and winter wheat.

The three pathways that can contribute to significant nitrogen loss are:

  • Volatilization (loss of ammonia nitrogen to the atmosphere from the soil surface),
  • Denitrification (which occurs when soils are saturated and in an anaerobic environment) and
  • Leaching (downward movement of nitrate nitrogen out of the rooting zone due to excessive rains)

The challenge has always been to make nitrogen available when the crop needs it and minimize the exposure of nitrogen to the weather scenarios that contribute to N loss. Consider the nitrogen response relationship for corn and winter wheat (below):

Corn nitrogen response curve

(Adapted from Richie, et.al, 2005, How a Corn Plant Develops).

Corn Nitrogen Response Curve

We often apply nitrogen early in the season before the crop actually utilizes it. For example, the demand for nitrogen in corn is at its peak at about the V10 growth stage (often around early to mid-July). Split-applying nitrogen has been a reasonably effective way to reduce the risk of nitrogen loss, however, with added application costs. Read more

corn held in farmer's hands

U.S. corn carryout could easily notch five-year low in 2019: Braun

By Karen Braun

CHICAGO (Reuters) – The U.S. Department of Agriculture’s stingy forecast for domestic corn plantings could be one of the first signposts toward an increasingly bullish corn environment over the next year or so.

Industry analysts had predicted that 2018 U.S. corn plantings would fall slightly from year-ago levels to 89.42 million acres, so USDA’s peg of 88.026 million last Thursday offered a surprising jolt to the Chicago futures market. Read more

Late Application of Nitrogen

Late season nitrogen application

Corn N ChartLate season nitrogen application has been a hot topic amongst farmers and uptake in this practice has increased in recent years. The expense and environmental impact has made growers think differently about nitrogen application.

Weather extremes has also caused growers to change the way they apply nitrogen to mitigate loses from excessive rainfall when applying all their nitrogen ahead of planting. Read more

Estimating Corn Yield


Early corn yield estimations are a great way to get out into your field and start to predict the yield of different varieties given the growing season. It allows a grower to start making harvest decisions, marketing decisions, and to estimate needed storage capacity.

How many spots should I sample from?

Generally doing a kernel count every 10-15 acres is recommended. For soils that are extremely variable, doing a kernel count every 5-10 acres would be beneficial. Select random spots in the field when walking through as you are trying to get the best representation of the field.

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Gibberella Ear Rot

Gibberella Ear Rot in corn

What is it?

Gibberella Ear Rot, or Red Ear Rot, is caused by the fungus, Gibberella zeae (Fusarium graminearum). This disease can occur throughout the U.S. Mid-West and Southern Ontario. The pathogen overwinters on corn, wheat and barley debris. Spores produced on the debris lead to infection during silking. Red Ear Rot is more prevalent when cool, wet weather occurs during the first 21 days after silking. Extended periods of rain in the fall, which delay dry down, increase the severity of the disease. Red Ear Rot will be most severe in fields where corn follows corn, or corn follows wheat that was affected by Fusarium head blight (scab), which is caused by the same pathogen. Read more

Ear Rots in Corn


Ear rots can be difficult to control since weather conditions are critical to the disease development. Rots can establish any time after pollination in wounds created by insects, birds, machinery, and even hail. Rainy weather or heavy, prolonged dews often lead to ear rots in these wounded cobs.

Why are rots a concern?

The direct concern for ear rot disease is yield loss due to poor quality grain. In years when conditions favour development, large portions of fields can be affected. Once fields are infected, other management practices should be followed which can increase cost of harvesting, drying, and storing the grain.

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Stalk rots in corn

The distribution and prevalence of stalk rot diseases vary from year to year. However, the diseases are present in most years even though it may be at low levels. The majority of stalk rot damage in Ontario is caused by three fungi, Anthracnose, Gibberella and Fusarium. However, Diplodia and Pythium have also been observed.

Although these fungi cause different symptoms, their ultimate effect on the corn plant is the same. They reduce grain fill, stalk integrity, and accelerate senescence. The severity of this damage increases when the crop is under stress.

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