Although spring flooding of crops is a much more common problem, heavy rainfall in late summer and fall occasionally leads to flooding of fields at or near crop maturity. The extent of damage from fall flooding depends on the crop, stage of maturity, depth of flood waters, period of flooding, amount of lodging caused by flowing water, and other environmental factors. This Field Facts will discuss fall flooding damage to corn.
By virtue of ear height alone, corn fields at maturity are tolerant to moderate levels of flooding. However, flood waters that encompass the ear can cause severe grain quality reductions. Flowing flood waters can also cause lodging of corn plants or weaken roots and stalks so that future lodging is a risk.
Milk line starting to appear at top of kernel
Grain Moisture: ~50-55%
~400 GDUs remaining to maturity
Yield loss ~35-40%
1/2 milk line
Grain Moisture: 40-45%
~200 GDUs remaining to maturity
Yield loss ~12-15%
Grain Moisture: 30-35%
0 GDUs remaining to maturity
Yield loss from killing frost at this stage = 0%
Figure 1. Kernel growth stages and approximate grain moisture, GDU’s to maturity (black layer or “no milk line”), and yield losses when photosynthesis ceases due to plant damage.
Figure 2. Corn ear with sprouted kernels.
Scouting fields and scheduling harvest based on crop condition as well as grain moisture are essential in flooded fields. Harvesting some fields early, at grain moistures near 25%, may be necessary to prevent further deterioration of grain quality. On other fields that have retained root, stalk and grain quality, compaction can be prevented by harvesting later, allowing fields to adequately dry.
When grain quality is low, adjust combine settings to minimize trash and broken kernels. Check with the combine manufacturer for machine-specific recommendations. (Combine mechanics or other dealership staff are often a good source for this information.)
Proper storing, drying and maintaining grain quality will minimize problems of flood damaged and sprouted grain.
The foregoing is provided for informational use only. Please contact your Pioneer sales professional for information and suggestions specific to your operation. Product performance is variable and depends on many factors such as moisture and heat stress, soil type, management practices and environmental stress as well as disease and pest pressures. Individual results may vary. Pioneer® brand products are provided subject to the terms and conditions of purchase which are part of the labeling and purchase documents. FF100928 (200811)
VOL. 10, NO. 9