Weed Control
In southern Manitoba, the conditions and farming inputs necessary
to produce high yields and good quality also favour vigorous weed
growth. Corn, owing to its erect habit of growth, competes poorly
with weeds until mid-July when the leaf canopy has closed over the
inter-row area. For this reason, the control program for May and
June must be well planned. Weeds in corn may be controlled by two
basic methods - cultural or chemical - or by combination of both.
Cultural Weed Control
Cultural, or mechanical weed control has been the age-old method
since the beginning of domestic corn production. At present,
cultural weed control mainly involves removing weeds from the
inter-row area with various types of tillage equipment. However,
this leaves weeds in the rows, and the number of entries into the
field must be limited to reduce root pruning to the corn and the
cost of the fuel, and to avoid numerous tillage operations on light
soils. Mechanical weed control will be restricted by weather, the
height of the crop and the spread of the corn root system.
Chemical
Chemical control of weeds in corn involves the use of various
registered herbicides singly or in combination.
Herbicides are divided into two broad classes: pre-emergence and
post-emergence.
The need to choose a product from these two classes is governed
by many considerations, including:
-
the weed types occurring in the field;
-
the density or potential density of weed growth;
-
the need to control grassy, broad-leaved weeds, or both;
-
the presence of volunteer crops;
-
rotation- is corn being grown for several years or is it in a
rotation with other crops; and
-
the need to control only a single particular weed.
For information regarding identification and specific weed
control measures, consult the
Field Scouting Guide and
Guide to Crop
Protection, available from Manitoba Agriculture, Food and Rural
Initiatives.
Cultural Plus Chemical
This method involves the use of inter-row tillage equipment
combined with herbicide application only to the rows. In parts of
Europe and North America, this method of controlling weeds in corn
has gained some acceptance but, with the rising costs of fuel, a
change to a chemical program rather than this integrated form is
probable. The practice results in a clean field until wet weather
make infield machinery use impossible. The only advantage of this
system is that less herbicide is used, with a resulting cost saving,
but this has to be balanced against the farmer's time, the number of
entries that must be made to maintain mechanical weed control, and
yield potential of the field.
| Introduction to Corn Production |
How a Corn
Plant Grows |
Choosing a Corn Hybrid |
Soil, Nutrition and Fertilizers |
Seed Bed Preparation
|
Weed Control | Diseases and Disorders of Corn
| Insects in Corn |
Trouble-Shooting |
Harvesting and Storage of
Grain Corn
| Corn Stover and Silage |
Marketing Grain Corn |
New
Uses for Corn |
Cost of Corn Production |
|
