Download - Weeds!!!
Weeds!!!Bart RennerNorth Carolina Cooperative Extension serviceMay 6th, 2013
What is a weed?
• Plant growing in the wrong place
• Generally very aggressive/ reproduces quickly
• Responds well to disturbance
Why are weeds a problem?
• Rob our desired crops of nutrients, sunlight, water.
• Create home for undesirable insects, fungus, snakes, rats, pests etc.
• Make harvest difficult
Weeds?
http://farm4.staticflickr.com/3193/2464758679_7b99c6e2a2_z.jpg?zz=1
Weed?
http://i276.photobucket.com/albums/kk17/kkozmins/volunteercornAug6-1.jpg
http://4.bp.blogspot.com/_b_MC5rbeRUc/TBqz2ESnPjI/AAAAAAAABe4/iqMyV943jeY/s1600/100_6085.JPG
An IPM approach to weed management
Weed information
Herbicides
Hand pulling
Tillage Cover crops
Crop rotation
Weed free periods
Hand pulling weeds
• Best for in between plants
• Understand when your weeds are beginning to harm your crops
• Best done in the morning
Tillage
Positive
• It is a mechanical way to destroy weeds.
• Ploughing loosens and aerates the top layer of soil which can facilitate the planting of the crop.
• It helps in the mixing of residue from the harvest, organic matter (humus) and nutrients evenly throughout the soil.
• Dries the soil before seeding.
Tillage
Negative
• Brings up weed seed buried in soil
• Soil dries faster
• Erosion of soil / Higher rate of fertilizer and chemical runoff.
• Reduces organic matter in the soil (Microbes, carbon compounds, earthworms, ants, etc.).
• Destroys soil aggregates.
• Aeration and mineralization may cause lower soil fertility.
http://en.wikipedia.org/wiki/Tillage
Cover crops
http://www.waldeneffect.org/20110824covercrops.jpg
Rye
• Important to understand the difference between ryegrass and cereal rye.
• Generally most cold tolerant cover crop.
• Produce allelopathic chemicals
• Can mine nutrients from deep in the soil
Cereal rye
http://upload.wikimedia.org/wikipedia/commons/thumb/7/79/Ear_of_rye.jpg/800px-Ear_of_rye.jpg
Ryegrass
http://upload.wikimedia.org/wikipedia/commons/thumb/3/32/Starr_001026-9002_Lolium_perenne.jpg/754px-Starr_001026-9002_Lolium_perenne.jpg
Cool season grass
Deep roots
Allelopathic
Vetch
http://upload.wikimedia.org/wikipedia/commons/thumb/5/53/Vicia_orobus1_eF.jpg/417px-Vicia_orobus1_eF.jpg
•Great nitrogen fixer
•Very effective at out competing weeds (once established).
•Good for the bees!
Cereal Rye and vetch
http://www.uvm.edu/vtvegandberry/factsheets/vetch%20and%20rye.JPG
Clover
• Cold tolerant, can be planted in the fall or spring
• N fixing
• Great for the bees!
• Needs a higher pH (6.5-7)
http://upload.wikimedia.org/wikipedia/commons/thumb/6/6d/Trifolium_pratense_0522.jpg/220px-Trifolium_pratense_0522.jpg
Clover
http://www.extension.org/sites/default/files/w/1/17/Crimson_clover_cover_crop_small.jpg
Buckwheat • Rapid growth in
the summer
• Great for a smother crop in between spring and fall plantings
• Rapid growth cycle
Brassicas
• Produce plenty of biomass
• Have shown good pest and nematode control
• Good for the bees!
• Deep rooted
http://www.extension.org/pages/18643/brassicas-and-mustards-for-cover-cropping-in-organic-farming
Synthetic Ground covers• Can be permeable
or impermeable
• biodegradable
http://www.johnnyseeds.com/images/Product/large/9302.jpg
http://2.bp.blogspot.com/_FQwY2pRG6O8/ShiGsswp8DI/AAAAAAAAAHg/71iqXYbP_Ng/s400/Tomatoes+mulched.JPG
http://2.bp.blogspot.com/-f-IaFYVlbPM/TZL5vv5waeI/AAAAAAAAANY/Mz7uJ1PcIq8/s1600/100_5303.JPG
Timing of weeding
http://www.omafra.gov.on.ca/english/crops/facts/09-045wf1.jpg
http://www.nzdl.org/gsdl/collect/fnl2.2/archives/HASHd3b4.dir/p090.gif
Chemicals• Round up-
Glyphsate
• Crossbow- Tychlopyr, 2,4-D
• Dicamba- broadleaf weeds
• Many more
Questions?
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