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In England, wildlife populations declined precipitously with the heavy use of herbicides in cereal crops because of loss of broadleaf herbs (weeds). A program has been implemented to encourage farmers to leave the outer 10 m unsprayed, and has proven to have very positive effects on conservation of herb and wildlife populations. Another approach is to practice mechanical control of weeds for the entire crop. With appropriate control, weed populations can be set back so that the crop gets and maintains a competitive advantage, but many weeds still come up and provide food for wildlife. (See vignette on Mechanical control of weed seedlings)The photos below illustrate two annual weeds that are common in cereal crops in Nova Scotia and are important sources of food for wildlife.
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| 1. WIld Radish (Raphanus raphanistrum). Photo at left shows wild radish in flower in a barley field. Wild radish is a member of the Family Cruciferae, whose flowers have four petals in a cross (see inset); it includes many vegetables (e.g. cauliflower, brocolli, kale, radish) that were probably domesticated from weedy plants in early grain crops. At right, pods have formed and matured; they contain seeds of the same shape, size and color as those of domesticated radish.
The wild radish goes to seed quite quickly, and most pods drop to the ground well before harvest of the crop. Very few can be found later in the season, being mostly consumed by small rodents. | |
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Lambsquarter (Chenopodium album). This weed produces a small high protein seed. It is a common weed in fertilized grain fields and, while never domesticated as a crop, has been identified as a major constituent of grain deposits in archeological digs. The leaves make a tasty and nutritious steamed green. The seeds are a favorite of many bird species. |