Time Nitrogen Delivery to Key Plant Growth Stages
DuPont Pioneer News
Nitrogen (N) is essential to plant growth and grain fill, making it critical for growers to monitor soil N levels at key points during the growing season. Wet conditions in May and June have raised concerns that Rescue applications of N may be needed as this essential nutrient can easily be lost from the soil by leaching or denitrification with excess rainfall.
Growers should be evaluating how much N remains in the soil and if it will be enough to meet crop needs. A quick response to N-deficiency stress is often required to minimize yield loss.
Soil tests are one way to gauge nitrogen levels prior to an in-season application. Optical sensors can also be mounted on fertilizer application equipment, enabling on-the-go N sensing, rate calculation and application all at once. Aerial imagery and chlorophyll meters are also good tools to evaluate crop N needs. Several research studies show that rescue N applications are effective at recovering yield — as late as three weeks after pollination.
If N is found to be lacking in the plants and soil, growers have several decisions to make, including:
- the type of N to apply
- application method
- timing
- volume of N needed
- need for a nitrification inhibitor