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Competency Area 2: Weed Management

PO 16. Cultural or managerial - Understand the advantages and limitations of cultural practices that influence the competitinve relationship between crops and weeds including the role of the following in weed management:
A. Choice of crop and variety/hybrid selection including the advantages and disadvantages of herbicide-resistant crops.
B. Crop rotation
C. Soil management-pH, fertility, soil water
D. Planting date
E. Seeding rate/plant populations/row spacing
F. Nurse crops/cover crops

A. Choice of crop and variety or hybrid, including herbicide-resistant crops (HRCs)
Advantages or potential benefits of HRCs

  • New control options for hard-to-control weeds (i.e. perennials)
  • Increase success and adoption of conservation tillage
  • Encourage use of thresholds for weed management decisions
  • Aid resistance management
  • Use of environmentally and toxicologically friendly herbicides
  • Minimize herbicide carryover problems
  • Options for limited acreage crops
    Disadvantages or potential risks of HRCs
  • Unintentional application to, and/or spray drift on susceptible crops
  • HRCs could become weeds in rotational crops
  • Increase selection pressure for herbicide-resistant weeds
  • HRC pollen movement to organically grown crops
  • Invasive potential of HRCs into natural ecosystems
  • HRCs could outcross with closely related weedy relatives

B.Crop rotation

C. Soil management – pH, fertility, soil water
Soil water - drainage/irrigation
Soil fertility
Soil pH


D. Planting date

E. Seeding rate/plant populations/row spacing

F. Nurse crops/cover crops