3. Definition of a weed
• A weed is an undesired
plant out of place
– Water hyacinth in a
aquatic garden
: not a weed
– Water hyacinth clogging
canals
: a weed
3
4. What is a Weed?
• A plant that is growing where it is not wanted
Roberts et al. 1982. Weed Control Handbook
4
5. What is a Weed?
• A plant that is successful in colonizing disturb,
and maintaining their abundance under
conditions of repeated disturbances
MohlerC., 2001. Ecological Management of Agricultural Weeds
5
6. Disturbance
• An event that disrupts ecosystem, community
or population structure
• Changes resources, substrate availability or
the physical environment
Pickett and White, 1985
6
8. Why Do We Have Weeds?
BECAUSE WE CREATE THE ENVIROMENTS
WHERE WEEDS THRIVE (go, develop or be
successful)!
8
9. What management practices contribute to
weed problems?
• Poor soil management
• Excessive use of manure
• Poor crop rotations using crops with similar
seasonal growth patterns which have similar
weed species associated with them.
9
10. Weed Management
• Goal
Manage cropping systems (not just weeds!) so
that the resources made available through
disturbances are captured by crop and not by
weeds
10
11. What are some conventional
treatments used to control weeds?
• Physical removal
– The use of agricultural tools such as hoe to
physically remove weeds
• Chemical suppression
– Herbicide application is not favored in ecological
farming
11
12. What are some basic principles for
ecological weed control?
• Create a diverse ecosystem. Use as many
species and types of plants as possible
• Use a good crop rotation
• Don’t over fertilize your soil with manure or
fertilizers as this will leave too much fertility
on the soil for weeds
• Use clean seed (free of weeds)
12
13. Crop Rotation
“Rotation of crops, when accompanied
by care in the use of pure seed, is the
most effective means yet devised for
keeping land free of weeds.”
Leighty (1938)
13
14. Crop rotation
• is the practice of growing a
series of dissimilar types of
crops in the same area in
sequential seasons.
14
15. Crop rotation: two considerations
3.Vary the seasonality of planting
Varying crop seasonality and management practices
prevent any one species from getting out of
control
5.Vary crops allow you to vary management
practices
15
16. How does crop rotation help control
weeds?
• Breaks weed multiplication cycles, as certain
weeds are associated with certain crops.
• Maintain soils fertility which helps crop
growth.
• Crops that have different season growth
patterns compete for weed space on the field,
as weeds have different growth cycles.
16
17. Cover crops
are crops whose main purpose is to benefit the
soil, to manage soil fertility, but is not intended to
be harvested for feed or sale.
17
18. What is a cover crop?
A crop whose main purpose is to benefit the
soil or other crops in one or more ways, but is
not intended to be harvested for feed or sale.
18
19. Cover crops
• Plants that are grown for various ecological
benefits other than as a cash crop (a crop that
is grown mainly to be sold).
• They may be grown in rotations during
periods when cash crops (main crops) are not
grown.
19
20. Advantages of cover crops
• Cover crops can also improve soil quality by
increasing soil organic matter.
Increased soil organic matter enhances
soil structure, as well as the water and
nutrient holding of soil.
• Weed suppression
20
Editor's Notes
Integrated Weed Management Fabián
Weed Biology and Management
Weed science focuses on mitigating the negative impacts of weeds on crops Landis et al. 2005. Weed Science
A plant that is successful in colonizing disturb, but potentially productive sites and at maintaining their abundance under conditions of repeated disturbances MohlerC., 2001. Ecological Management of Agricultural Weeds Search the causes of why we have weeds
Disturbance A discrete event that disrupts ecosystem, community or population structure Changes resources, substrate availability or the physical environment
Weed control.pdf
Weed control.pdf
Weed control.pdf Manure=excrement from animals, especially horses, which is spread on the land in order to make plants grow well
A good crop rotation plan is a seasonal dance in which the crops move from spot to spot creating a garden that is constantly new. constantly adverb all the time or frequently Intriguing = to interest someone a lot, especially by being strange, unusual or mysterious intrigue (SECRET) noun [C or U] (the making of) a secret plan to do something, especially something that will harm another person
Weed control.pdf http://deeprootsco.org/CropRotation.htm What are the benefits of rotating? Maintains soil fertility, reducing the use of fertilizers by preventing soil depletion One crop will pull a particular set of nutrients from the soil Other crops will give back Reduce or prevent common plant diseases Reduce soil erosion Helps control weeds reducing the need for herbicides Maintains soil structure (alternating between deep-rooted and fibrous-rooted crops)
Overview of cover crops and green manures
4 cover crops and weed management Cash crop=a crop that is grown mainly to be sold, rather than used by the people who grew it or those living in the area it is grown in
Cover crop From Wikipedia, the free encyclopedia Cover crops can also improve soil quality by increasing soil organic matter levels through the input of cover crop biomass over time. Increased soil organic matter enhances soil structure , as well as the water and nutrient holding and buffering capacity of soil.
