Download Preemergence Weed Control - Lecture Slides | CS 053 and more Study notes Agricultural engineering in PDF only on Docsity! Preemergence Weed Control Before Weeds Emerge -- more importantly -- Before Weeds Germinate Preemergence weed control options Mulches prevent germination and establishment by excluding light Preemergence Herbicides Prevent seedling establishment Mulches Types: organic, inorganic, geotextile Function: exclude light to prevent seed germination and seedling establishment Also, holds moisture and improves aesthetics Kinds of mulches What makes a good Mulch? Coarse texture to dry out Aesthetically pleasing Will not wash Relatively weed free Not phytotoxic Bark nuggets wash easily Lava rock – some like it, some don’t Most annual beds are done this way How much mulch is enough? 0 10 20 30 40 50 60 70 80 90 100 0 no mulch 3 6 10 Mulch Depth (inches) % W ee d C ov er Source: Greenley and Rakow, 1991 Mulches -- How Much? Organic mulches: ~ 3-4 in Inorganic mulches: ~ 3 in With a geotextile: ~ 2 in Geotextile fabrics -- Advantages Long term annual weed control Soil stabilization Holds moisture Possible add-on service $$ Geotextile fabrics -- Disadvantages Annual weeds grow on top Mulches slip off In heavy soils, it may hold too much moisture Decomposing organic mulches create a humus layer where weeds can germinate Cost – materials and installation Site preparation: eliminate perennial weeds Must cover with mulch Perennial weeds can penetrate Geotextile fabrics do not control perennial weeds Vegetatively propagated perennial weeds can emerge through geotextile fabrics Bermudagrass Nutsedge Mugwort Biggest problem with geotextiles is proper installation Not installed correctly: Edges come up, mulch washes off. Unsightly and ineffective. Steps in proper installation Dig trench around perimeter of bed Step 2: place geotextile over bed Install geotextile over plants. Don’t try to plant through the bed Dirt on top of the fabric leads to weeds. Types of Geotextile fabrics Lots of different types: Spun bonded Woven Needle punched Yes, between consumer and professional grade products. Smooth vs. textured can make a difference on slopes. Mulches slip off smooth more easily. Install with fiber side up. Advice: if you use a geotextile Control perennial weeds before planting Use shallow layers of mulch Keep geotextiles totally covered Remove / kill emerged weeds when small Consider using inorganic mulches Consider preemergence herbicide with geotextile when weeds become abundant or for yellow nutsedge control Relative Weed Control Costs 0 10 20 30 40 50 60 70 80 90 100 2 in. bark 4 in. bark Geotex. + bark Herb + bark Herbicide Geotextile Bark Labor
