A lecture on Cultural and Mechanical Control of Weeds

1. CULTURAL AND MECHANICAL
CONTROL OF WEEDS
Reported by:
Mark Lawrence B. Edullantes
BSA3-2 Crop Science

2. METHODS OF WEED CONTROL
The report covers the following methods of
weed control:
1. Cultural Management
2. Mechanical control

3. The practices used to restrict the growth and
spread of weeds may be grouped into three
general categories:
– Prevention
– Eradication
– Control

4. Prevention- is concerned with the measures
taken to prevent the introduction and/or
establishment of specified weed species in
areas that are not currently infested. (e.g.
legal control measures such as quarantine)

5. Eradication- is the ideal of weed control but is
rarely achieved. It infers that a given weed
species, its seed and all the vegetative parts,
have been killed or completely removed from a
given area and will never reappear. However it is
only economical and practical to be used on
small crop growing areas for high-value crops like
greenhouses and seed beds. It is very difficult to
be achieved on hectares of land which is grown
for many agronomic crops of importance like
rice, maize (corn) and soybean.

6. Control- it encompasses the practices
whereby weed infestation are reduced, below
economic threshold, and does not necessarily
eliminated.

7. What are weeds?
• Plants growing on unwanted areas such as
along cultivated crops (e.g. rice, vegetables),
roadsides, laws and sidewalks.
• Unloved and undesirable plant species
• Can be invasive under favorable conditions
especially when introduced in foreign places
without natural enemy/s.

8. CULTURAL WEED CONTROL
Cultural weed control refers to any
technique that involves maintaining field
conditions such that weeds are less likely to
become established and/or increase in
number.

9. Examples of cultural weed control would
be crop rotation, avoiding overgrazing of
pastures or rangeland, using well-adapted
competitive forage species, and maintaining
good soil fertility.

10. It includes:
1. Use of Weed-Free Crop Seed
Planting crop seed contaminated with
weed sees is one of the mostly common ways
of introducing weeds in cropland (especially in
field crops). Plant only those crop seed that
have been cleaned to remove as many weed
as possible (sorting and grading).

11. 2. Smother Crops
Smother crops are those crops that are
especially highly competitive with the weed
species infesting area for light, nutrients and
moisture, It includes crops of small and large
grains (barley, enlarge corn, millet rye,
sorghum) and legumes (alfalfa, clover etc.).
Smoother crops may be grown in rotation to
less competitive crops.

12. Examples of smother crops:
sorghum cowpea
Enlarge corn variety

13. 3. Crop Rotation
Crop rotation is practices as a means of
weed control to reduced build up of high
population of certain weeds common to a
particular crop. Any given crop, cultivated or
not cultivated, is plagued by certain weed
species that thrive under the same cultural
conditions provided for the crop and which
similar growth habits (eg.family Gramineae or
Poeceae , the grass family)
Examples of crop rotation: rice-peanut-
corn-rice-vegetables

14. Reference: growerslearning.com
Crop rotation plan for vegetables

15. MECHANICAL WEED CONTROL
Mechanical control of weeds can include a
number of activities. While these methods can be
quite specific for a particular target weed, they
can also be quite expensive, time- and labor-
intensive, and even very dangerous to life and
limb. More than one treatment is usually
required to contain an infestation. Native plants
may also be removed in the process of removing
targeted weeds. For these reasons, mechanical
methods are generally favored for small
infestations.

16. 1. Hand-Pulling- is an effective practice for
the control of weed seedlings and young,
established annual and perennial weed
species. It is a minor value in the control of
perennial weeds since underground
vegetative parts are not normally disturbed.

17. 2. Hoeing
Hoeing is an effective means of weed control and the how
remains one of the principal tools for weed control. However,
it needs human effort and time consuming. In addition, hoeing
(especially in filed crops) is not economical mans of weed
control because of the need to manage huge tracts of land.
Reference: dreamstime.com

18. 3. Mowing
Mowing has limited value as a means of weed
control. It is primarily used to reduce seed
production and to restrict unsightly or rank weed
growth. Mowing is commonly used for these
purposes in meadows and pastures, along
roadsides and in waste places.
Reference: http://dot.ny.gov.

19. 4. Flooding
-is an effective means of weed control under
certain conditions. It kills weeds by depriving the
plants aeration of the root system thus,
suffocating them and the inability to carry out
photosynthesis (as they are submerge in water).
It is an effective means of weed control only if
when the roots and shoots of the weeds are
completely covered or surrounded by water for a
long period of time. Use of flooding as means of
weed control is limited by soil type and available
water. It is commonly used in lowland rice
paddies.

20. Reference: http://ag-transition.org

21. 5.Mulching
Mulching is an effective means of weed control
under certain conditions. The objective is to
completely exclude light from the growing weed
plants, thereby preventing photosynthesis and further
growth. Materials used for this purpose include hay,
manure, grass clippings, straw, sawdust, wood chips,
rice hulls, paper and plastic film.
Reference: thailand-ipm.info.org

22. 6. Burning
Burning of flaming has been practiced for
many years as means of general weed control in
no cropped areas such as railroad, right of ways,
irrigation canals, drainage and roadside. The
practical application of flaming for selective weed
control in croplands begun in the 1940’s trough
use of burners. Selective flaming operates in
principle that crop plants are tall enough at the
time flaming is done directed to the ground near
the base of the plants, will not strike their leaves
and other tender parts, that their stems are
woody and resistant to the intense heat of the
flame.

23. Reference: bigpicturesagriculture.org

24. 7. Machine Tillage
Machine tillage or cultivation is and
continues to be one of the principal means by
which weeds are controlled. Tillage if row
crops refer primarily to cultivation operations
performed after the crop seed has been
planted. Machine tillage is similar to hoeing,
except that the power for the cultivating tools
is provided by animals or mechanical engines,
rather than man.

25. The main advantages of machine tillage over hoeing
are that a wider selection of cultivating tools may
be used and large areas may be weeded more
rapidly and economically.
Reference: http://tebben.us

26. 8. Soil Solarization
In solarization, soil is covered with black
plastic to trap the sun’s heat, increasing soil
temperatures to levels that kill plants, seeds,
plant pathogens, and insects. In addition,
sunlight is blocked, which can kill existing
plants.

27. Soil solarization, however, can cause long-
lasting changes to the soil that can deter growth
of desirable native species. The effectiveness of
this method depends largely on how susceptible
the weed is to high temperatures.
Reference: http://ucanr.edu

28. ANY QUESTIONS???

29. References:
• Anderson, Wood Powell (1977). Weed
Science Principles. Methods of weed control
pp. 63-91. West Publishing Company.
• National Forage and Grassland Curriculum
(2008). Oregon State University.
http://forages.oregonstate.edu
• Submodule 8: How Invasive Weed Species are
controlled (2008). Mechanical Control. Oregon
State University. http://forestandrange.org

30. Thank You for Listening !
God Bless :D