Agriculture Reference
In-Depth Information
Table 10.3
Relative untreated area using two different patch spraying systems compared to a
uniform herbicide application across the whole fi eld (Gutjahr et al.
2012
)
% untreated area
Site-specifi c
control only
with uniform
tank mixture
Site-specifi c as well as species-specifi c weed control
with multiple-tank sprayer
Catchweed
(
G. aparine
)
Winter wheat 1 64 82 81 96
2 4 99 11 15
3 40 68 52 100
a
4 63 67 96 96
5 89 94 96 100
a
6 76 88 89 93
7 2 85 14 40
8 40 88 44 89
9 6 10 71 95
10 2 66 2 73
11 23 25 98 84
Mean 37 70 59 80
Broadleaf- weeds Grass- weeds Perennials
Maize 12 0 0 30 100
a
13 0 0 2 98
14 0 3 14 100
a
15 23 37 90 74
Mean 6 10 34 93
a
It was assumed that farmers always apply herbicides against all three weed- species groups in
uniform application.
Field
Broadleaf- weeds
Grass- weeds
well. The new “Clearfi eld” crop varieties verify this. However, one fundamental
problem may arise with herbicide resistant crops. Their outgrowth can appear in
subsequent crops of a rotation as weeds that cannot be removed by herbicides any
more. This might be important especially with rape (colza).
And still another alternative should be considered,
i.e.
future weed control by
small
robots
that might loiter through fi elds (Chap.
11
,
Fig.
11.6
)
. These robots
might remove weeds either by applying herbicides or by hoeing. It would be feasi-
ble to program the robots by precise georeferencing in such a way that they can
differentiate between weeds and plants of the crop. This can be achieved by meticu-
lously georeferencing all positions within a fi eld, where the seeds were placed dur-
ing the planting operation. This might not be feasible with small cereals or grass
crops, yet it is possible with more widely spaced crops such as maize, beans and
beets. In case of control by herbicides, the robots could by and large apply these
only on weeds and leave out any deposition on plants of the respective crop. Hence
there would be neither a need for herbicide resistant crops nor for selective herbi-
cides. If the control is done by hoeing, this could include the removal of weeds that
result from herbicide resistant outgrowth.