Fertility and Nutrients
Grazing and growing
By Kevin Elmy
Seed farm demonstration provides good advice on crop value.
It is year three of the experiment at Friendly Acres Seed Farm of corn production
in eastern Saskatchewan. In 2005, there were 12 varieties of corn seeded from
Pickseed, Pride, Dekalb and SW Seeds. Two conventional, two Liberty Link and
eight RoundUp Ready seeded on 40 acres.
Seeding occurred on May 20 using a Bourgault air-seeder with openers on eight
inch centres and with four inch spread. Dry fertilizer was banded at 30 pounds
of actual phosphorus and 30 pounds of actual potassium plus 0.25 pounds of zinc.
Liquid fertilizer was dribble banded at 80 pounds of actual nitrogen and 10
pounds of actual sulphur as per Western Ag Labs nutrient planning recommendations.
Instead of showing what is in the soil, Western Ag Labs shows what the exchange
rates of the nutrients are for the crop. A huge difference, and something that
is highly recommended to anyone looking at growing any crop, especially corn.
|Ralph and Donalda Strand's calves compare different varieties.|
Seeding rates were targetted at 24,000 seeds per acre on a silty sand loam.
With corn, one cob per plant is the goal. If there is more than one cob, the
seeding rate was too low and the tonnes produced will be reduced. Accent and
MCPA was sprayed on the Liberty Link and conventional varieties and two passes
of WeatherMax on the RoundUp Ready. Weed population consisted of green foxtail,
volunteer winter wheat, wild oat, wild buckwheat and some quackgrass.
When looking at strip trials of corn, I suggest growers watch the seeding rates
between varieties. As the seeding rate changes, so does how the plant grows.
At lower seeding rates, more cobs are produced, stems get thicker and the stand
is shorter. At higher seeding rates, fewer cobs are produced and the corn races
to the sun because there is more competition. As a rule, grain varieties are
seeded heavier to compensate for their forage shortcomings. Conventional varieties
are normally seeded heavier also, but due to the competition factor for weeds.
Because corn seed is sold by 80,000 kernels per bag, the weight of the bag can
change between seed lots. Bag size can range from 35 to 65 pounds per bag (16
to 30 kilograms). Math is required if seeding is going to be done by pounds
per acre to reach the seeding density.
In June, it started raining. Flooding occurred on about five acres and the
third pass of RoundUp was not applied. The third pass has been required this
year due to the amount of rain and continual flushes of weeds. The key to corn
is keeping the stand clean until the crop is knee high. From there, management
goes into low gear with the cornfield because the corn is growing in high gear.
The quick rule of thumb for corn production is knee high by the first of July.
Corn does not like standing water on the ground it is in. Where water sat, there
was a big yield penalty. On areas that were well drained, there was a huge crop.
With no frost as of August 20, 2005, the corn grew into September. Once the
grain harvest finished, an electric fence was placed around the field and the
first couple of paddocks were created. Trails for the electric fence were made
in the corn with a front-end loader, which pushed the corn down with two passes
so the electric fence has room to work effectively. It is amazing how well the
cows clean up the pushed-over corn. It is crucial to have the second wire up
before taking the first wire down when opening up the next paddock, otherwise
there could be a game of 'hide-and-seek' with the cows in the corn field, which
makes it extremely challenging to get them back to where they should be.
Carol and Wayne Gibson of Lonesome Acres in Saltcoats, Saskatchewan, turned
33 purebred Black Angus cows into the cornfield on October 1. As of October
21, 2005, they were averaging just over 200 grazing days per acre on corn that
had significant flooding and waterlogged soil. With the input cash costs being
$110 per acre consisting of seed, fertilizer and herbicide, feed costs are $0.55
per cow per day plus the labour of moving the electric fence and watering. Moving
the electric fence takes about 30 minutes per week and the watering takes 15
minutes per day. Once snow falls, the cows eat snow, which will reduce the amount
of water they require. Putting in electric fences in cold soil is not as difficult
as some have indicated. There are effective ways of fencing. As the cows make
their way to the west side of the field where the corn is taller and thicker,
the grazing days per acre is going to jump up.
The $0.55 per cow per day includes manure hauling, feed cutting, baling, bale
hauling and all of the rest of the fun associated with baling, silaging, corral
cleaning and running a tractor when it gets cold. A bale of alfalfa is put out
once every seven days just to keep protein intake up, and to keep the cows in
the field longer.
The key to successful corn grazing is paddock size and stocking rates. If the
stocking rate is too low, too much corn will be trampled and wasted. Having
higher stocking rates creates competition for food, so the animals are not picking
what they want to eat, just what is in front of them before another animal eats
it. They may clean the frozen stalks up in the spring after the field dries
up. The cattle must be forced to clean up most of the field before moving them
into the next paddock. A quick rule of thumb is a maximum of seven days in one
paddock if there is low cob production. With higher amounts of mature cobs,
decrease the amount of days per paddock. All that should be left is some stalks.
As a rule, the fewer days required to clean up the paddock, the less amount
of feed is wasted.
The cows do all of the manure management in the field. By having high stocking
rates, the manure spread will be very uniform. The greatest unrealized benefit
of grazing in the field is the urine. Urine is a gold mine when it comes to
nutrient supply. Ralph and Donalda Strand in Preeceville, Saskatchewan, who
have grazed corn, took off a greenfeed oats crop the next year that yielded
six 1800 pound bales without using fertilizer. In 2005, they went back to corn
on that field with only two-thirds of the fertilizer that they required the
Another example of this nutrient management is Dirk and Marie Van As at Canora,
Saskatchewan. They had grazed their corn field from 2004, manured the area,
then through Western Ag Labs recommendations, applied very little fertilizer
to grow an 11 tonne per acre corn crop on lighter soil. That would put their
cash cost at $45 for seed and $10 for two passes of RoundUp. Both of these fields
were very impressive and easily met the yield expectations. The other impressive
observation was how clean the crops were. The amazing part is that the fields
are north of Highway 16!
Strands and Van As both used PS 2365RR corn in 2005. The Strands used PS 2601RR
in 2004 and had one bag in 2005 to use as a comparison for the PS 2365RR and
are likely to go back to the PS 2601RR for 2006 due to its improved lodging
resistance, less greensnap and slightly taller stand. There is a chance they
may get a couple of bags of ExPo RR extra leafy corn from Pickseed to try along
with a new very early grain variety, PS 2230RR.
The extra leafy trait is attractive because the plant is designed for silage,
which will work in the same way with grazing. They are larger plants with better
characteristics for silage production, like more leaves above the ear than conventional
grain hybrids and lower lignin. They are inherently big plants and will produce
high dry matter yields at populations of 26,000 to 28,000 plants per acre. Hybrids
are selected with highly digestible stover and large soft textured kernels for
better feed values and increased palatability.
The idea of having two varieties is that the late maturing variety should produce
more biomass and tonnes consistently, where the early grain will give more grain
more consistently. By growing a little of the PS 2230RR and the rest K183RR,
PS 2601RR or an extra leafy, this would manage risk by using the two varieties.
If the plan is to have a higher energy content in the feed, it is worth increasing
the grain variety and decreasing the silage variety. The compromise is that
the dry matter yield will decrease. The only concerns with early maturing varieties
are that they tend to be short and have higher lignin content. Usually as the
plant matures, the acid digestible fibre (ADF) increases, which will reduce
the amount the animals will eat, leaving more on the ground and wasted.
Another benefit of corn is the 'built in' shelter. The day of the grazing demonstration
at Friendly Acres was a cold and blustery October day. Yet when walking in the
corn, there was shelter from the wind which made standing in the field quite
pleasant. Which brings on the next grazing strategy: Start grazing on the corner
of the field away from the prevailing wind direction, which uses the corn as
a windbreak. The snow will be caught on the edge of the corn, leaving very little
in the middle of the field. The cattle will go to the edges to eat snow. If
the snow gets too deep for the cows to get at the corn on the edges, they will
clean it up in the spring.
From the trials at Friendly Acres Seed Farm in 2005, the cows are eating the
PS 2230 corn first. It is an early conventional corn variety. They are undoubtedly
attracted to the drier grain. Since they have only a relatively small area,
the competition is high for the cobs, so they eat most of the plant. Next they
tend to clean up the PS ExAlt, which is an extra leafy conventional variety
that is a true silage type, after the cobs are gone from the PS 2230. The Liberty
Link and RoundUp Ready varieties do not have any preferential grazing order
yet, but they also are the most flooded in this part of the field. With the
number of cows in the field in early November, assuming that the grazing days
per acre are constant (even though it will increase significantly in the last
20 acres of the field due to less drowned-out parts), 33 cows will be on the
40 acres for a total of 242 days at 200 grazing days per acre. Does anyone have
some cows that need to be fed? Because there is more feed than we require!
Strand has mentioned that off 10 acres in the first year he grew corn, he estimated
it was an equivalent of 100 round hay bales. Now he is sitting on two years'
supply of hay bales that he has as insurance. Pastures get properly rested.
Hay fields do not need to get cut every year. More holistic practices can be
used which helps with fertilizer, chemical and fuel costs.
For changes to the Friendly Acres Seed Farm corn demonstration next year, the
seeding rate is going to increase to 26,000 seeds per acre, and we will try
a couple of new extra leafy varieties along with a sweet corn, and see what
is new and exciting over this winter for corn varieties for western Canada.
Anyone who states that grazing corn does not pay needs to revisit corn agronomics
for western Canada. The aim is for 150bu/ac corn, and it needs to be managed
as such. Corn is one of the most water-efficient plants for biomass production,
so it helps drought-proof the farm. Ripe cob production is way over-rated for
beef cattle. Dairy animals are another story. Cheap tonnes of dry matter is
the goal for beef. Given proper corn variety selection, proper soil fertility
balance, good weed control and microclimate adaptation, adequate corn production
can be achieved. A row planter is great, but for grazing, an air-seeder works
well and drills get the job done. A proper soil nutrient plan is crucial and
using good soil fertility advice is highly recommended. Corn is a crop that
needs to be baby-sat for the first month. After, it will take care of itself.
Given the proper variety, cows will eat it as a preferred feedstock and do well
Corn is not for everyone, nor is it something that should comprise your entire
feed supply. It does require different grazing practices that most are not use
to and this is another method of risk management and workload. But it is something
worth taking a good look at. –
Kevin and Christina Elmy operate Friendly Acres
Seed Farm near Saltcoats, Saskatchewan. Kevin is also a crop advisor
for Western Ag Labs.
Top Crop Manager welcomes reports from demonstration farms.
Contact Peter Darbishire at:
145 Thames Road West Exeter, Ontario N0M 1S3 Canada
Telephone: (519) 235-2400, ext 235
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