Cultural Control

Cultural Control Contents:

TYPES OF CULTURAL CONTROL:

  1. Purchasing weed free seed--the kind and percentage of weed seeds present in commercial seed should be listed on the bags.
  2. Crop rotation--certain weeds tend to plague a given crop. Rotation should include a crop with growth and cultural characteristics that are in sharp contrast to the previous crop and weeds.
  3. Planting schedule--establishing the crop prior to the emergence of weeds, when possible.
  4. Proper cultural practices--keep plants vigorous. Insect and disease control create healthy plants that can compete more successfully with weeds for the available light, water and nutrients.

Integrate numerous components to minimize the impact of weeds:

  • Select manageable fields (identify weeds and choose crop according to feasibility of weed management strategies)
  • Rotate crops (disrupt weed life cycles or suppress weeds in competitive crop followed by planting a noncompetitive crop).
  • Plant winter cover or competitive fallow crops in rotation to improve soils and crop management (specific cultivars are being evaluated).
    • Consider legumes to supplement nitrogen requirements.
    • Consider specific varieties of cereals with natural plant toxins (allelopathy); vegetation must remain uniform on soil surface; either perennial or large-seeded crops can be planted through undisturbed mulch.
    • Consider crops or cultivars that winter kill after vigorous growth during fall to avoid springtime controls.
  • Alter planting dates (plant for maximum growth or delay planting to control first weed flush).
  • Transplant slow growing crops.
  • Place and time fertilizer, especially nitrogen.
    • Band or spot fertilizer beside plant or seed (reduces availability to surface-germinating weeds).
    • Time additional side-dressings for maximum crop growth or to minimize weeds.
  • Develop crop canopy that shades weeds, suppresses weed germination.
    • Select crops or varieties that form canopy quickly.
    • Space plants in equidistant (triangular) arrangements and very density depending on crop management constraints or harvest requirements (e.g. product quality).
    • Interplant crops in space and time (consider mechanical limitations in commercial plantings).
    • Combine broadleaf and taller, narrowleaf crops (corn/beans/pumpkins).
    • Relay plantings or harvest short duration crops within longer maturing crops (bush beans-corn; cucumbers-peppers; tree crops-vegetables).
    • Manage appropriate living mulch (grass or legume) between perennial crop rows.
    • Improve pasture management by reseeding and/or fertilizing with or without control measures to reduce weed infestation (weeds often are a symptom of poor management)
  • Apply mulch or geo-textiles.
    • Organic Materials:
      • Straw (may reduce available N when decomposing; often infested with weed seed.)
      • Sawdust (avoid vertebrate pests by maintaining mulch free circle around tree; perennial weeds become a serious problem).
      • Bark Mulch
      • Newspapers (during emergence, rhizomes of some perennial weeds become disoriented when penetrating 6 to 16 layers of overlapped newspaper.
    • Plastic:
      • Black excludes light, controls most annual weeds. Clear acts like greenhouse; poor weed control.
      • New wavelength-selective plastics for pest management (research is progressing).
    • Geo-textiles (available at ag and garden supply stores):
      • Spunbonded fabrics (nonwoven): lightweight, extruded polypropylene fibers; requires mulch cover due to moderate UV light sensitivity; weeds roots and rhizomes can penetrate fabric unless removed before establishment; cheapest option.
      • Woven fabrics: moderate-weight polypropylene fibers woven into a mat; can be used without mulch cover due to UV light stability; weed roots and rhizomes can penetrate fabric although tightness of weave can prevent some weeds; moderate cost.
      • Laminates: highly porous, dense poly film bonded to capillary fibers with a pressed, nonwoven bottom layer. Surface is slick and causes rapid wetting and drying to prevent weed establishment except for perennial rhizomes which can penetrate the laminate; most expensive geo-fabric.
    • Solarization:
      • Thin plastic secured tightly over loose, moist soil for 10 to 12 weeks will suppress weed infestations and other pests during hot season.

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