When
conditions shorten the season
By Jan Youngquist |
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[November 02, 2015]
With
the rainy opening of this year's growing season, farmers were able
to slowly shake off the drought worries of 2012, '13, '14. The rains
were spaced in frequency and amount favoring the crop producer with
more field workdays and planting opportunity.
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 Yes, the 2015 season was shaping up with high expectations
until... the faucet just didn't shut off.
From mid-June to mid-July heavier frequent rains led to widespread
generalized flooding and kept soils saturated.
What happens to corn and soybeans under these conditions?
When the plants are submerged in flood water
- foliage may be damaged by debris.
- damaged and submerged foliage is more susceptible to fungal
and bacterial diseases.
- submerged foliage is not able to conduct photosynthesis and
any residue (mud) left on leaves after flooding subsides will
reduce the plant's ability to make its own food.
- According to researchers, corn with six leaf collars (V6) or
more have a greater chance of survival.
There are numerous other factors that will influence the
outcome of crops that receive too much and too frequent rains as
well.
What happens at the soil level
How long can corn or soybeans live in saturated soil?
In saturated soil, water replaces oxygen in spaces between soil
particles. Roots are dependent on oxygen for water and nutrient
uptake from the soil. Oxygen is depleted in saturated soil in 48
hours, but plants may tolerate four days with not too much
damage, and survive up to seven days if temps stay under the
mid-60 degree range, and the days are cloudy.
In general, a plant's root development varies in response to
temperature and water availability in a given soil medium. Under
wetter conditions a plant will develop a finer, widespread root
system that picks up moisture from the surface and seeks oxygen;
versus if developed under dryer conditions, roots will be
thicker for protection from drying out, and go deeper to seek
water. Deeper roots will also provide greater plant stability.
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 This year's crops would have had shallow, spreading, finer roots
develop early in the season.
In flood or high wind conditions, plants may even be pushed over.
Depending on the size or maturity of the plant material, degree
angle, and the depth, type and quality of root system, as well as
the overall vigor of the plant, even corn, may upright itself again.
Nutrients that were applied prior to planting are diminished by
washing away or leaching. As the plant matures, it needs various
minerals in different stages - for vegetation, root and grain or
bean production.
The maturity of the Logan County crops varied at the time when the
heaviest rains and longest flood and soil saturation periods took
place between June to mid-July. Too late to replant, farmers waited
for the outcome.
The upside for the Logan County area was that during the heavy rain
period the days were predominantly cloudy and temps cool, which
reduced foliar induced activity, as well as limited development of
rot diseases.
From late June forward, aerial views afforded identification of
large field losses and numerous, smaller yellowing areas where water
had sat too long. Go to
When conditions
shorten the season - Slideshow
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