Wet harvest weather delays combining and often leads to stalk lodging. However,
balancing soil fertility levels is an important in-season management factor that helps minimize corn lodging. While stalk integrity can vary by hybrid or plant populations, understanding balanced soil fertility can keep corn plants healthy into late fall.
Why Nitrogen is NecessaryNitrogen, or N, is a key macronutrient for chlorophyll synthesis. Plants take up most of their N as ammonium (NH4+) or nitrate (NO3-). Since nitrogen is very mobile in the soil, it can be lost by dissolving in the atmosphere or leaching due to higher than normal rainfall. Unless additional nitrogen is applied to fields that received higher than average rainfall, corn plants are forced to rob the nutrient from the stalk to fill the ears. This results in increased lodging.
Nitrogen levels can easily be determined throughout the growing season by taking a tissue test. These tissue tests are an economical way to measure a field's nitrogen levels before making a sidedress application, and if so, determining how much.
The Montana State University chart above shows how much nitrogen (N), phosphorus (P), potassium (K) and sulfur (S) corn plants need to absorb throughout a growing cycle.The Importance of Phosphorus and PotassiumPhosphorus, or P, is essential during grain fill and has a short range of soil movement. If phosphorus is severely deficient, stalks may become thin and maturity delayed. In comparison, potassium, or K, is associated with drought tolerance and plays a critical role in stalk strength. Potassium helps move water, sugar and other plant nutrients.
Plants lacking adequate potassium will have difficulty absorbing sufficient nitrogen and water from the soil, eventually weakening stalk integrity. A critical balance between nitrogen and potassium is important for stalk strength and minimizing rots. When plants uptake sufficient potassium during vegetative growth and grain fill, corn stalk integrity is better maintained after maturity.
Nutrient Management- When determining how much fertilizer to apply before planting next spring, consider nutrient removal by both grain and stover, or leftover stalks and leaves.
- Acres that yield more than anticipated for several years tend to gradually deplete critical nutrient levels, including phosphorus and potassium. Without a solid plan to replace these nutrients, crops become more stressed and are at a higher risk of stalk rots.
- Be aware of the crop’s need for a balanced fertilizer program.
- Using different manures or poultry litters as a sole fertility source is becoming a popular management practice. While these manures are usually high in nitrogen and phosphorus, potassium levels may not be enough to supply the season-long needs of the corn crop. If so, applying potash can help supplement potassium.
Take advantage of in-season soil and tissue samples to help calculate how extra nutrient applications will benefit your field. When you balance soil fertility during the growing season, you’ll have stronger stands at harvest. Contact your
Golden Harvest Seed Advisor with questions or for additional agronomic insights.
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