phrase
English translation: explanation
| 04:08 Apr 30, 2005 |
| English language (monolingual) [PRO] Science - Agriculture | |||||||
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|  Selected response from: Robert Donahue (X) | ||||||
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| SUMMARY OF ALL EXPLANATIONS PROVIDED | ||||
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| 4 +4 | explanation |
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| 5 +1 | Explanation below |
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Answers
2 mins confidence: 
peer agreement (net): +1
peer agreement (net): +1Explanation below Explanation: Pre-emergent herbicides, which prevent germination of weed and grass seed, require specialized accurate spray equipment. Pump-up garden sprayers and most other types of hand-gun equipment are unsuitable. These chemicals should be used only by people who have the proper spray equipment and have a full understanding of calibration procedures. -------------------------------------------------- Note added at 3 mins (2005-04-30 04:11:50 GMT) -------------------------------------------------- Ref: http://en.mimi.hu/gardening/preemergent_herbicide.html -------------------------------------------------- Note added at 4 mins (2005-04-30 04:13:15 GMT) -------------------------------------------------- Pre-emergent herbicides or “weed preventers” are often used to control annual lawn weeds such as crabgrass, foxtails, barnyardgrass, spurge, knotweed, purslane and others. Examples include various “crabgrass preventers” on the market. A pre-emergent herbicide does not prevent weed seed germination or kill the seed. Instead, the root system development of a young weed seedling is severely limited by the action of the pre-emergent herbicide, killing it before it “emerges.” Pre-emergents will not control existing weeds, but will, if applied before germination, control seedlings of annual or perennial weeds. http://www.ext.colostate.edu/ptlk/2118.html |
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3 mins confidence: 
peer agreement (net): +4
peer agreement (net): +4explanation Explanation: A pre-emergent herbicide is a chemical applied to the surface of the soil that will kill the new shoots sprouting from seeds. Pre-emergents do not kill existing weeds. You must rid the areas to be treated of weeds first. The pre-emergent herbicides can either be in a liquid or granular form. To be effective they must be applied prior to seed germination. A chemical barrier formed at the surface of the soil prevents plant germination for extended periods. In some mild winter areas, pre-emergent herbicides must be applied twice yearly, once in the fall to prevent the winter growing weeds and in the early spring to control those that grow in spring and summer. After the pre-emergent is spread, do not disturb the treated soil lest you break the chemical barrier. http://www.osh.com/Cultures/en-US/Articles/GardenNursery/Art... Broad-spectrum pre-emergents Others are broad-spectrum types that will prevent up to thirty of the most common garden weeds from growing in flowerbeds, shrubbery borders and tree basins. Currently, the commonly available pre-emergents are Preen, Amaze and Weed Stopper. -------------------------------------------------- Note added at 6 mins (2005-04-30 04:14:55 GMT) -------------------------------------------------- So in layman\'s terms pre-emergent means a herbicide applied to the surface of the soil. It kills weeds before they are fully formed (as opposed to post-emergent). Broad-spectrum means that it is designed to kill more than one type of weed. |
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