必修四Unit 2 Working the land教案（集體備課）

structure of the text
i using chemical fertilizers for a long time can hurt the land and also people’s health
ii problem caused by chemical fertilizers
1. damage the land by killing the helpful bacteria and pests as well as the harmful ones
2. lead to cancer or other illness.
3. food grown with chemical fertilizers look beautiful, but inside there is usually more water than vitamins and minerals.
ⅲ organic farming is becoming more popular with some farmers and many customers after these discoveries came out.                
iv other methods to keep the soil fertile.

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is organic food safe?
yes. organic food is as safe to consume as any other kind of food. just as with any kind of produce, consumers should wash before consuming to ensure maximum cleanliness. as cited above, organic produce contains significantly lower levels of pesticide residues than conventional produce. it is a common misconception that organic food could be at greater risk of e. coli contamination because of raw manure application although conventional farmers commonly apply tons of raw manure as well with no regulation whatsoever. organic standards set strict guidelines on manure use in organic farming: either it must be first composted, or it must be applied at least 90 days before harvest, which allows ample time for microbial breakdown of any pathogens.
 why does organic cost more?
 the cost of organic food is higher than that of conventional food because the organic price tag more closely reflects the true cost of growing the food: substituting labor and intensive management for chemicals, the health and environmental costs of which are borne by society. these costs include cleanup of polluted water and remediation of pesticide contamination. prices for organic foods include costs of growing, harvesting, transportation and storage. in the case of processed foods, processing and packaging costs are also included. organically produced foods must meet stricter regulations governing all these steps than conventional foods. the intensive management and labor used in organic production are frequently (though not always) more expensive than the chemicals routinely used on conventional farms. there is mounting evidence that if all the indirect costs of conventional food production were factored into the price of food, organic foods would cost the same, or, more likely, be cheaper than conventional food.