Scouting Your Fields: What Lessons Can We Yet Learn From 1997?
September 10, 1997 4(24):140
Joe Lauer, Corn Agronomist
We are rapidly approaching the close of the 1997 growing season. Below are some
things to check in your fields yet this year, and to consider in your plans for
Scout for corn standability. Fields that have lodging problems can be identified
and targeted for the earliest possible harvest. Look for visible symptoms and test
stalk firmness by pinching the lower internodes with your thumb and forefinger.
Healthy stalks are firm and can't be compressed. If a stalk can be compressed or
feels soft, it is rotted and is a good candidate for lodging.
Check the maturity of hybrids in your fields and relate back to planting and emergence
dates. Following the rate of drydown using kernel milkline is a good way to predict
the order fields should be harvested. In a typical year a common benchmark is that
fields should be dented by the first week in September. It takes about 25 days to
go from dent to black layer (physiological maturity); about 13 days to get to 50%
kernel milk and another 12 days to black layer. Kernel moisture at black layer will
average 32 to 35 percent. The tightness of the husk, thickness of the seed coat
and daily weather conditions influence the speed of kernel drydown. After black
layer formation several hard frosts followed by sunny weather with temperatures
in the 80's and a slight breeze is the ideal drying environment.
Check for ear-tip fill. Incomplete ear-tip fill is not necessarily bad. If kernels
are filled out completely to the ear tip, plant populations are likely too low for
the environmental conditions of 1997. Expect about an inch of underdeveloped kernels
at the ear tip when plant populations are at the proper level for optimizing grain
Scout for pest problems. Hybrid differences for pest resistance and tolerance should
be monitored and noted all season, but will be most apparent in the fall.
Resist eyeballing yield differences between corn hybrids - measure it. Make notes
bout "ease of combining." Test weight and grain moisture can influence
hybrid yield. There are "quickie" measures of potential grain yield, but
you shouldn't expect much precision with these measures.