Agriculture Reference
In-Depth Information
growth regulators. These examples further dem-
onstrate the need to manage wheat by a systems
approach rather than in piecemeal steps. The
profi tability of implementing any one improved
management factor such as increased nitrogen
rates or foliar fungicides depends heavily on
how and when other management factors are
implemented.
and Lowenberg-DeBoer 2004). That is, the skill
level required to follow a set of tramlines or a
differentially corrected GPS signal is much less
than that required to follow a foam marker. The
wider the implement being used, the greater is the
benefi t. Outfi tting farm equipment with a light-
bar guidance system, for example, would allow a
13% increase in fi eld speed (Watson and
Lowenberg-DeBoer 2004). Use of an autoguid-
ance system would allow a 20% increase in fi eld
speed. These technologies would allow farmers to
increase the size of their operation from 728 ha to
1,052 and 1,255 ha by implementing the use of a
light-bar or autoguidance system, respectively
(Watson and Lowenberg-DeBoer 2004). What-
ever the system, the ability to reduce dependence
on skilled labor while simultaneously increasing
precision and timeliness has been a positive devel-
opment in wheat production technology over the
past 10-15 years.
Timeliness and precision
An old adage states that the difference between a
successful farmer and an unsuccessful farmer is
about three to fi ve days. One cannot discount the
effect of timely and accurate application of yield
building factors and yield protecting factors such
as nitrogen fertility, weed control, insect control,
and foliar disease control. Tramlines have long
been used to aid in application precision and
timeliness (see Color Plate 3). Tramlines are
simply rows in the drill that are sealed off and
not planted. At fi rst, creating tramlines meant
having a sprayer with a boom width that was a
multiple of the drill width and then sealing the
appropriate planter rows with duct tape. As drills
and spray booms grew larger and as air drills
became more popular, the need for electronically
controlled tramline systems increased. Most
recently, GPS-enabled precision guidance
systems and autosteer technologies have allowed
producers to create tramlines after the fact. These
technologies allow producers to establish virtual
tramlines that can be followed year after year.
The essential concept, however, remained the
same: increase precision and limit traffi c. By
limiting wheel traffi c in fi elds, producers are able
to reduce the area affected by compaction and
reduce the area that may require subsoiling to
alleviate soil compaction (Sweeney et al., 2006).
If it is assumed that normal, unrestricted fi eld
traffi c results in 90% of the fi eld area being sub-
jected to wheel traffi c, implementing a light-bar
guidance system would reduce the area subjected
to wheel traffi c to 30% (Watson and Lowenberg-
DeBoer 2004).
In many cases producers have substituted pre-
cision-application aids for skilled labor (Watson
Previous crop management
Previous crop management is a rudimentary
component of intensive wheat production
systems. A maize (
Zea mays
L.)-wheat-soybean
(
Glycine max
L.) rotation, for example, is the
predominant cropping system in many areas of
the midwestern and midsouthern US. Selection
of the right maize hybrid in this rotation some-
times determines whether or not wheat sowing
will even be possible the following fall. Later-
maturing hybrids generally perform better than
earlier-maturing hybrids, but a gain in maize
yield can result in a signifi cant decrease in wheat
yield. Likewise choosing a late-maturing wheat
cultivar may adversely impact the subsequent
soybean crop. To combat this dilemma, some
producers have chosen to continue to produce
full-season wheat cultivars but elect to utilize
technologies such as stripper headers that allow
for harvest of higher-moisture grain. This in turn
allows the farmer to grow a full-season cultivar
but have the same harvest timing as that of a
short-season cultivar (see Color Plate 4). Simi-
larly, some maize producers have found they can
produce full-season maize hybrids prior to wheat
