What factors can a farmer manipulate to control weed seed dormancy?
Exposure to light breaks the dormancy of many imbibed small seeded weeds such as chickweed and dandelion. Shallow burial can prevent light from reaching these seeds. Also closed crop canopies, cover crops, and crop residues on the soil surface are all methods preventing light-requiring weed seed from germinating. Tillage or cultivation will expose seed to flashes of light and research as early as the 1960s showed increased weed seed germination after cultivation in light versus dark. Night cultivation is generally impractical and continuous night cultivation would likely cause shifts to weed species not needing light. (See Figure 4.) Weed seed predation can be an important method to reduce inputs into the soil seed bank. Weed seeds store high energy compounds that are also an excellent source for a variety of animals. Common seed predators include: ground beetles, crickets and mice. Significant seed predation occurs in crop fields, which may influence effectiveness of weed management.