Mulching & Other Methods for Weed Control
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Transcript of Mulching & Other Methods for Weed Control
Mulching & Other Methods for Weed Control
Prepared by: L. Robert Barber, Frank Cruz, & Ilene Iriarte
For: Guam Cooperative Extension Service & Guam
Department of Agriculture
Funding provided by: United States Department of Agriculture Natural Resources Conservation Service, Western Region Sustainable Agriculture Research and Education,
Administration for Native Americans,, & Sanctuary Incorporated
What is a weed?
• Plant growing out of place• A plant can be desirable in one
situation and be a pest in another– Can be fast growing– Often produces a lot of seeds or has
persistent roots
How Weeds Harm Desirable Plants
• Competes for water, nutrients, light, and space
• Harbors pests and diseases• Can release toxins into the soil
Weed Management
• The best time to begin an effective weed management program is before planting
• Proper site preparation can reduce weed problems
• Monitor frequently for weeds• Remove weeds while they’re seedlings• Maintain a directed low volume irrigation
system• Minimize disturbances in the soil• Correctly maintain mulch
Weed Control Practices
• Mechanical – Hoeing/Hand weeding– Plowing, harrowing, cultivating, other
tillage
• Fire/Propane Burner• Mowing/Bush cutting• Ground Cover – Living Mulches• Chicken Tractor• Mulching
Mechanical Weeding - Cultivation
• Labor, equipment and energy intensive• Bare soil more susceptible to erosion• Frequent tillage speeds organic matter
decomposition.• Brings buried seeds to the surface
– Cultivate once germinated
• Plant spacing must allow for equipment
Fire
• Fire can be used to remove weeds in a big area– Burns the organic matter– Leaves soil bear and high chance of
erosion
• Propane Burner is used for spot treatments– Must be careful
Mowing & Bush cutting
• Benefits of maintaining a living cover and mowing or bush cutting– May reduce competition– Can help prevent soil erosion
• Disadvantages:– Often damages desired plants – Physically harms plants – Bush cutter
disease (careless cuts girdle tree) kills huge numbers of trees on Guam.
Ground Covers or Living Mulches
• Can be natural cover developed by frequent mowing, or can be planned planting like sweet potato or perennial peanut or other cover crop.
• Benefits– Prevents germination of weed seeds– Prevents soil erosion– Insulates soil– May add nitrogen to soil (ex. Perennial peanut)– Attractive
• Disadvantages– Can provide a habitat for pests– Can compete for water & nutrients
Chicken Tractor
• Mobile Pens• Weeding• Pest Control• Fertilizer• Food
Types of Mulch
• Two types of mulch; Organic & Inorganic
• Inorganic Mulch (Plastic sheets):– Does not decompose– Non-living– May prevent water loss, soil protection,
increase absorption– Does not improve soil or add nutrients– Good for walk ways, and paths
Benefits of Mulch
• Conserves water & reduces erosion• Improves soil structure, & absorption• Adds nutrients• Suppress weed growth• Prevents pathogens from splashing on foliage• Insulates soil• Increases microorganisms, earthworms, &
insects• Prevents trunk damage from bush cutter
– Limits weeds near plant so no need to cut close to plant
• Reduces landscape maintenance
Organic Mulch
• Organic Mulch:– Living Materials– Categorized by size; Fine or Coarse
Material– Fine Material:
• A lot of surface area• Can suffocate plants
– Coarse Material:• Doesn’t blow away as easily• Water & air can penetrate through
Organic Mulch
• Examples of Organic Mulch:– Grass clippings, small leaves*– Wood chips**– Pine needles (Gago Tree)**– Banana leaves & Palm fronds**– Coconut husks**– Branches**– Compost– Shredded paper*
*Fine Material & ** Coarse Material
What is in a Mulch
• Decaying organic material• Undecomposed compost• Applied to surface of the soil over time
blends with the soil• Consists of:
– Nutrients– Leaves– Branches– Microorganisms– Insects
Palm fronds around breadfruit tree
Now That You Have Mulch
• Apply in planting beds• Around established trees, & newly
planted trees• Mulch will eventually need replacing• Fine material need to be replaced
often• Coarse material can be replaced
either once a year to every two years
Mulched Raised Bed
Bed mulched with pine needles (Gago tree)
How To Apply Mulch
• Leave a 3-6” gap from the base of the plant to mulch
• For individual trees:– Make a circle that is 2’ in diameter for
every inch of trunk diameter– Increase size as tree gets bigger
• For planting beds:– Mulch entire bed
Undesirable - Mulch up Against Trunk
How Much to Apply
• Thickness depends on types of material
• Fine Material:– No thicker than 2 – 3 inches– Can mat together & suffocate plants
• Coarse Material:– At least 4 inches– Thinner weeds can penetrate through if
too thin a layer.
Possible Problems
• Mulch can turn “sour”– Air was not allowed to penetrate
through
– Toxic substances are produced
– Plants drop leaves, turn yellow, and can die
– Smells like sulfur, vinegar, or ammonia
Wire Chicken Barrier
Possible Problems
• Chickens and Pigs love it too– Can destroy plants, dig up roots
– Scatter mulch
– Where animals are a pest, create a barrier