Economic and Marketing Information
FOR INDIANA  FARMERS
Prepared by the Agricultural Staff of Purdue University, Lafayette, Indiana   
May 29,  1970
CORN TILLAGE SYSTEMS
Paul R. Robbins and D. Howard Doster, Agricultural Economics*
A:
,S FARMS have gotten larger
and farmers have become more
specialized in corn production,
they have learned much about
growing corn. Top farmers have
put together a total package of
practices and newer technologies
which have greatly increased
yield and increased per acre
profits. In trying to put together
this improved package of practices and technologies in corn production, farmers have added more
fertilizer, used higher populations,
better weed control, better soil
insect control, better hybrids, etc.
Most everyone has reduced tillage
operations. Now some are trying
radically different methods of
tillage to put together a still more
profitable corn production package.
The reasons most often presented by farmers for going to
some form of limited tillage are:
1. To reduce costs. This may
or may not actually happen.
2. To save labor. This can often
be accomplished, but labor distribution is a more important consideration than saving some labor
during the slack reason.
3. To reduce erosion losses and
increase water infiltration. This
can be a very important plus
factor.
4. To reduce investment costs.
This can usually, but not always,
be accomplished.
5. To increase yields. The jury
is still out on this one. We must
have more years of research data
before it can be conclusively
stated what happens to yield. Also   the   answer   will   likely   not
be the same for different soils,
weather conditions, etc.
Minimum tillage began to catch
on about the mid-fifties. We have
made considerable progress in reducing the number of trips over
the field during recent years.
However, we still have a long way
to go in tillage research. In trying to find some needed answers,
Purdue started a comprehensive
research project in 1967 in which
several departments of the "School
of Agriculture are participating in
trying to compare eleven major
tillage systems. These systems are
being compared in northern Indiana at the Pinney-Purdue Agricultural Center, in east central
Indiana at the Davis-Purdue Agricultural Center, and in southern
Indiana at the Feldun-Purdue
Agricultural Center.
About 10 or 15 years ago when
we became interested in reducing
tillage operations in corn production, we still stuck with the mold-
board plow every year. A number
of systems caught on, and some
are still being used. The wheel-
track planting is a prime example.
In the last 5 years, we have
entered a new era. This might be
characterized as the no-plow, once
over era, where the moldboard
plow is not used every year and
in fact, might not be used at all.
Yield Losses from
Delay in Planting
With farms getting larger and
labor becoming more scarce and
higher priced and the importance
of timeliness being better documented as more research data
comes in, farmers are looking for
ways to get corn planted faster
and in a more timely manner.
Thus they are very interested in
any new tillage system that will
help them do these things.
Research from throughout the
Corn Belt in recent years has well
documented corn yield loss from
delay in planting. Thus any tillage system that reduces the rate
of accomplishment during the
critical plating period presents a
serious handicap. The rule of
thumb yield reduction often used
at Purdue for delay in corn planting is as follows:
1. Yields reduced 1 bushel per
acre per day from May 10 to
May 23.
2. Yields reduced 2 bushels per
acre per day from May 23 through
June 6.
Yield reductions of this magnitude put a high value on each
hour of the few good field work
days available during the prime
planting season.
Conventional Tillage
The term "conventional" means
many things to many people.
Farmers using a conventional tillage system on heavy soils may
work their plowed ground several
* The authors take full responsibility
for data interpretation appearing in this
article. However, they wish to express
thanks to various members of the
interdepartmental tillage research team
and especially to Don Griffith, Harry
Galloway and Jerry Mannering of the
Agronomy Department and Sam Parsons of the Agricultural Engineering
Department for helping provide much
of the basic data upon which the
economic  analysis was based.