Agronomic Row Crops
The Tools
A flexible combination of tools, timing and technique to suppress early season
weeds is the foundation of an integrated row-crop weed management program. Broadcast
weeding tools, used in conjunction with cover crops and primary tillage, offer
an alternative to herbicides at planting to control weed competition.
Rotary hoes, flex-tine weeders, spike-tooth harrows and rolling bar baskets
all provide shallow, thorough stirring of the soil that kills sprouting and
emerging weeds the full width of the tool. The action knocks soil from weed
roots, causing them to die. Control is best when field conditions are hot, dry
and sunny.
Flame weeding just prior to and just after crop emergence is also effective
in establishing early control in some crops. Of the entire group of broadcast
tillage or flaming tools, only specially designed rotary hoes work well in fields
with appreciable crop residue.
Post-plant treatment for weed control before crop emergence is a delicate,
time sensitive maneuver. It depends on the ability of an implement to kill surface
weeds without mortally disturbing the germinating crop. For preemergent treatments
to be effective, the crop must be planted deeper than the working depth of the
broadcast tillage tool. Postemergence, the crop must be more firmly rooted than
competing weeds to survive the weeding pass.
Years of crusted spring soils boost rotary hoe sales. In these times, the
tool’s flicking and shattering of soil particles to kill weeds takes second
place to its ability to aerate a rain-packed soil surface. Extra weight helps
crust penetration but makes gauge wheels a necessity. A pair of these supporting
tires, one under either side of the rotary hoe toolbar, maintains even penetration
by the hoe points. On rough fields, the tires prevent gouging by the hoe wheels
on one end of the toolbar.
Rotary hoes are not good weeders in tilthy, soft soils. In these conditions,
the dragging action of soil-stirring harrows and tine weeders tend to be more
effective.
The rotary hoe is an effective and efficient tool within a sharply limited
window of weed size. Once weeds form true leaves or you can see them while driving
by from your tractor seat, many will survive. Doubling back to cover the same
field a second time—in the same or opposite direction immediately, or
in several days when re-rooting of weeds begins—often boosts effectiveness
if weed pressure is strong, residue interferes, or cloudy, humid conditions
slow weed kill.
Crops at large vary in their tolerance of rotary hoeing, with species having
a strong but flexible center stem surviving best. Row crops—and even tomatoes—can
survive rotary hoeing at 8 to 12 inches tall if an emergency pass is needed
to control small weeds before a cultivator is available.
Note: This book presents tools in three categories by crop type where they
are commonly used. Many tools are employed effectively in diverse systems. The
farmer narratives show how the same tool works well in different crops and for
different purposes.
Next section
|