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?

http://3.bp.blogspot.com/-ranMxTMXrw0/TzG_0CbfpqI/AAAAAAAAAjc/vT_-khhblHo/s1600/weeding.jpg