Counting the twin costs
There are two reasons to compare moisture when you compare yield.
November 13, 2007 By Top Crop Manager
No wonder it is so expensive to dry corn. On a 300 acre crop that yields 150
dry bushels per acre, each point of moisture at harvest equates to an extra
50 barrels of water that must be evaporated off.
Across that same crop, if a grower plants a hybrid that hits the combine at
24 percent instead of a competitor that would have yielded the same but would
also have field dried to 22 percent, there is an incredible 100 barrels of extra
water. That is like having to boil away a trough two feet wide by two feet deep,
and 100 feet long.
Worse, the water is hard to get at. It is hidden inside millions of kernels
where it not only takes extra energy to pull it out, but also extra finesse,
because going after it too aggressively and with too much heat will cause grain
quality to suffer and in today's markets, damaged grain is a tough sell.
So it is also no wonder that growers feel like they dodged a bullet when fuel
prices unexpectedly slumped last summer, or that they are wondering how high
their drying bills will climb next fall if there is a hurricane in the Gulf
of Mexico, or unrest in the Middle East, or any other price inflaters.
"Harvest moisture has become crucial to any hybrid comparison," says
Bob Thirlwall, Dekalb agronomist based at Glencoe, who has launched a new series
of drydown trials. "It was always a consideration. Now it's a management
Thirlwall's trials are looking at rates of drydown after physiological maturity.
In side-by-sides, he is recording the black layer dates of hybrids which have
the same advertised maturities. Then he tracks their moisture toward harvest.
"As seed companies and agronomists, we need to provide growers with more
and better information on maturity and drydown," Thirlwall says. "Drying
has become a major cost, but there's also more to it than that. Moisture also
tells us a lot about how to maximize the number of bushels we get out of each
In the real world, moisture at harvest means maturity, and maturity in turn
is tightly linked to yield potential. "You can even put it in hard numbers,"
says Greg Stewart, corn specialist for the Ontario Ministry of Agriculture,
Food and Rural Affairs (OMAFRA), who supervises the province's official corn
trials. "On average, a point of moisture at harvest equates to four bushels
per acre in yield."
Based on the trend he has observed, the hybrid that comes out of the field
at 24 percent should have yielded 158 dry bushels, compared to the 150 bushels
for the hybrid that finishes at 22 percent.
It is not that the entire eight bushel yield boost would be needed to pay for
the extra drying, Stewart explains. However, if the hybrid is wetter at harvest
but only has the same yield as a dryer hybrid, growers should take a hard look
at whether it is a second rate bet.
Traditional advice has been to follow the 20:60:20 rule, planting 20 percent
of the crop with hybrids that are 100 heat units longer than the farm's average,
60 percent of the crop with hybrids rated right at the average, and the final
20 percent with hybrids rated 100 heat units lower.
Stewart, however, favours stretching maturities, providing planting is timely.
"We don't get paid for yield we don't produce," he says. "If
you're planting after mid May, I agree you need to go to Plan B and to reduce
maturities, but if you're able to plant late April or early May, I don't see
why you should go to an earlier hybrid and give up yield before the seed is
even in the ground."
At the heart of that recommendation, however, is a need to make accurate economic
comparisons between hybrids, Stewart adds. Hybrids that come out of the field
wetter without a corresponding yield increase start and finish with a disadvantage.
On top of the yield losses, what drying cost should you factor in? Provincial
agricultural engineer and dryer specialist, Helmut Spieser says it is more than
fuel. In fact, for on-farm dryers, fuel is usually about half the total cost,
with electricity, depreciation, maintenance, insurance and a list of other indirect
expenses making up the other half. When doing calculations, therefore, local
commercial rates are often a good starting point.
Genetics are providing more opportunities to manage yield and moisture, believes
Glanworth based Dekalb breeder, Jon Popi, but it does not have to be complicated.
While growers are sometimes loaded with phrases like 'early flowering' and 'fast
drydown', Popi recommends they keep their eyes mainly on harvest moisture.
"Flowering date, husk characteristics and drydown rates are all vital
elements for the breeder," Popi says. "I would prefer a hybrid that
flowers early, with adequate husks that open in the fall and that provides consistently
high test weight.
"In the final analysis, though," Popi explains, "our approach
is similar to the grower's. We select for yield and we select for earliness.
Other critical features such as plant health and stress tolerance are essential
additional selection criteria, but without excellent yield and earliness, the
hybrid will not be advanced."
Spieser agrees genetics are the best hope for reducing future drying costs
per bushel. "There's nothing in the way of hardware coming down the pipe
that is going to revolutionize drying," Spieser says. "Burners are
a bit more efficient and heat-recovery is helping us dry a bit more corn with
a bit less fuel, but basically, what happens under the sheet metal is going
to stay pretty much the same. If we're going to make progress on drying costs,"
Spieser says, "it's going to have more to do with the moisture of the corn
going into the dryer than with the dryer itself."
Thirlwall sees growers embracing the genetic approach by asking more and tougher
questions about hybrid selection, and about how to appropriately compare the
performance of competitive hybrids. Says Thirlwall: "The key is to ensure
that the hybrids you're looking at really are competitive. In other words, it's
whether they come out of the field at the same moisture.
"We're working hard to get a better understanding of yield and drydown,"
Thirlwall adds. "Growers are demanding to know which hybrid is going to
generate the best net return." -30-