Better Farming - October 2016

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38 Farm News First > Better Farming October 2016
We are heading into harvest
of soybeans shortly,
followed closely by the
harvest of corn. With a dryer growing
season, the normal maturity patterns
have been shortened somewhat.
There is always something to be
observed and learned before harvest.
A pre-harvest visit presents the
opportunity to gain insight as to why
the yields have not met expectations.
It is far too easy to simply say it was
dry weather alone.
With soybeans, a great deal can be
learned by observing plant height and
the relative number of nodes and
branches. (Nodes are where the pods
are formed.) Looking at just plant
height does not necessarily mean a
better- or lower-yielding field. It is the
space between nodes that determines
height. The number of pods and
beans per pod at the nodes times the
number of plants per acre determines
yield.
Foliar leaf disease can be observed
prior to leaf drop. The one foliar
symptom that is showing very
prominently is Sudden Death Syn-
drome (SDS). This is not a foliar leaf
disease but is a fungal disease that
enters the plant early at emergence
time and expresses its symptoms at
flowering or later during bean fill.
The management of this disease starts
at planting.
Planting at appropriate depth and
preparing seedbeds for rapid emer-
gence is a good preventative practice.
The longer the soybean plant takes to
emerge, the greater the length of time
for infection to occur. Good drainage,
reduced compaction, proper fertility
to reduce early season stresses, and
crop rotation are all good practices to
embrace.
Most seed companies have re-
Consider the pre-harvest inspection
A pre-harvest visit provides useful insights about the challenges
that may have affected your yields.
by DALE COWAN
CROPS:YIELDMATTER$
moved susceptible varieties from their
offerings. There is, however, no
resistance to the disease. Varieties will
respond differently. Now is the time
to observe those differences.
Soybean Cyst Nematode (SCN) is
often associated with the disease and
typically the two are found together.
Feeding scars from the nematode
offer an entry point for the fungus to
gain a foothold through the roots.
Rotating SCN-resistant varieties is
also a good practice. Digging up roots
and counting SCN cysts gives some
insight about how some varieties
reduce the ability for SCN to repro-
duce.
The main way to manage the pest
is through reduction in cyst popula-
tion in the soil. There are currently
commercial seed treatments available
to suppress both SCN and SDS
infections; it is worth investigating
their efficacies. We will still need,
however, good stewardship around
these seed treatments to keep them as
viable options in succeeding years.
In the corn crop this year we can
see a lot of stresses due to hot weather
during the reproductive stages of VT
(tassel emergence) and R1 (silk
emergence). The incomplete fill on
the cob tips is evident. However, it is a
good practice to perform plant
population counts at pre-harvest and
to also count plants that have cobs.
There are a number of barren
plants lacking cobs. There will be an
environmental by genetic interaction.
Fields that could store higher
amounts of plant-available water
created an environment for the
hybrid to perform closer to its genetic
potential. Even in the most drought-
This soybean plant is affected by Sudden Death Syndrome, a fungal
disease that enters the plant early at emergence time and expresses its
symptoms at flowering or later during bean fill.