CROP ROTATIONS
THAT WORK
Crop rotation is a topic that
we’ve all heard about before
but probably don’t take serious
enough.
We’ve all heard that crop
rotations can reduce fertilizer
costs, help control weeds and
insects, and give a yield kick to
crops like com and soybeans.
But, do they work in our mod
em crop production programs?
During the last five years,
I’ve been continually reminded
of the importance of crop rota
tions by com growers around
the state who are using syste
matic systems of crop rotation.
These folks are cleverly
YLVANIA MASTER
>RN GROWERS
ASSOCIATION
Between The Rows
Dr. Greg Roth
Penn State Agronomy
Assistant Professor
exploiting rotations to reduce
input costs, improve their
timeliness, reduce labor
requirements, and to set them
selves up for no-till crop
production.
In this column, I’d like to
review some of the successful
crop rotations I’ve encountered
during the past few years.
A few years back, I attended
the Top Farmer Workshop con
ducted by the Farm Manage
ment Faculty at Purdue. A con
siderable portion of the prog
ram was devoted to figuring out
the optimum machinery mix,
the best tillage system and the
best crop rotation for individual
participants.
I attended the conference
t *
with Rich Burd, who was a
900-acre mostly continuous
com grower. When we ran his
farm through the production
model, the system kept suggest
ing a 50:50 com/soybcan rota
tion. Since then, he has gradual
ly converted to that rotation and
has been very pleased with the
results. Now he finds he can get
most of his crop planted on lime
and he avoids some of the late
planting yield penalties he had
when he was fighting to get all
that com planted by the end of
May. He needs less storage
capacity, uses less N fertilizer,
uses no insecticide, and all of
his com is no-tilled into soy
bean stubble. When it gets dry
in July, having half his acreage
Corn Talk, Lancaster Farming, Saturday, February 11, 1995—page
in beans lets him sleep a little
easier at night. Changing to a
systematic crop rotation on this
farm has had a major impact.
On dairy farms, I’ve seen
systematic crop rotations work
just as well. I’ve seen several
folks using three-year com/
alfalfa rotations with really
good success. This rotation also
helps to reduce input costs. One
big advantage is that they
reduce the amount third, fourth,
and fifth year com in rotation.
These are the com fields that
have the heavy rootworm
levels, the perennial or triazine
resistant weeds, the soil com
paction and the generally lower
yields. By eliminating these,
we can help to increase com
yields and reduce the cost of
production.
We also help to avoid lower
yielding fourth and fifth year
alfalfa and the extra fertility
costs that are some times neces
sary to lopdress those fields
with P and K. This system
works especially well with no
lill spring seeding the alfalfa
into third year com stubble
harvested for silage and no
tilling the first year com into
fall killed sods. It also is best
adapted in southern Pennsylva
nia where alfalfa yields arc
relatively high in the establish
ment year.
The downsides are the need
to reseed alfalfa more often and
to discipline yourself to kill
some relatively good looking
three-year-old alfalfa stands.
In some areas with less pro
ductive soils, longer hay rota
tions seem to be favored by
many growers. Some produc
ers, such as Fred McGillvray, a
Cumberland County farmer
who spoke recently at the Pen
nsylvania Crop Conference,
have found effective com rota
tions in these areas. Fred uses a
five-year alfalfa rotation fol
lowed by com, rye grain, com,
soybeans and com silage and
then rotates back to alfalfa.
In Fred’s rotation, all of his
com follows a rotational crop,
giving him a yield benefit and
eliminating his need for insecti
cides and some fertilizer. His
cropping system is diversified
enough to give him some insur
ance in the dry years that occur
frequently in his area and to
provide options for manure
hauling when the ground is dry.
Crops such as soybeans and rye are more
drought tolerant than com and provide some
return in diy years when the com suffers. His
rotation and attention to details have also
helped him to eliminate tillage for the past
15 years.
In some areas, particularly those with
good, deep, level soils, continuous com has
continued to yield well. My biggest con
cerns with continuous com arise with conti
nuous com silage. On some soils, there
seems to be a potential for silage yields to
decline with time.
I’ve encountered several silage producers
who have gone to continuous no-till corn
rye and seem to be able to maintain com pro
duction at reasonable levels while protecting
the soil, conserving nutrients, minimizing
potential runoff problems and sometimes
producing a ryelagc crop. The rye and no-till
features of this rotation help to reduce the
decline in soil organic matter that can occur.
The downside is that rye can get out of hand
in the spring and cause planting and alleo
pathy problems. Because of this, 1 favor kill
ing the rye relatively early in the spring or
harvesting it for ryelage, especially in areas
where this can be done without causing
planting date delays. A mixture of oats and
rye or wheat and rye can help to reduce this
early season flush of growth from straight
rye seedings.
Another important management consid
eration in this rotation is that you have to be
able to stay off these fields when they are
wet or you’ll cause compaction problems
that will necessitate a tillage operation and
reduce the effectiveness of this rotation.
Well designed rotations are working for
growers around the state. For the most part
they stick to their systematic plan but are
flexible if market conditions dictate.
Many of the serious crop production
problems we try to address with quick and
often expensive solutions can frequently be
solved with a good crop rotation. If you’re
not satisfied with your present system, sit
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