题目内容
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Farmers use chemicals and fertilizers in order to ______.
A．improve their working conditions
B．increase the yields of their crops
C．provide their crops with more vitamins and minerals
D．improve the quality of goods grown in commercial farming areas
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更多“Farmers use chemicals and fert…”相关的问题
听力原文： Scientists have discovered that plants themselves produce many poisonous chemicals for defense against insects. But insects have developed ways of dealing with them and, in fact, have been eating plants for about 250 million years. Now insects are using these same mechanisms to deal with man-made poisons—insecticides. This is why resistance of insects to insecticides has developed so rapidly.
What should be done？ Scientists studying the problem suggest that farmers use less insecticides. At the moment, farmers regularly spray crops as a precaution against problems that are caused by large numbers of pests. They should, instead, spray only where pests have actually been seen. Secondly, farmers could use a combination of two or three insecticides at once. To survive, the insects would need to become resistant to two or more insecticides at the same time.
The most surprising suggestion, perhaps, is that at certain times of the year, farmers should actually try to attract insects onto the crops they are trying to protect. The new insects will mate with those which survived from a certain kind of insecticide and will lessen the latter's resistance to it.
Scientist hope that these and other measures will postpone the day when farmers and scientists will have to stand by while new super-bugs which may be resistant to all poisons invade our farms and devour our crops.
What have scientists discovered about plants and insects？
A．Plants produce many poisonous chemicals for defense against insects.
B．Insects develop ways of dealing with natural poisonous chemicals but not man-made ones.
C．Farmers must spray plants all the time.
D．Farmers must use different brands of insecticides.
听力原文： Farmers usually use plows to prepare their fields for planting crops. Plows cut into the ground, and lift up weeds, and other unwanted plants. However, plowing is blamed for causing severe damage to top soil by removing the plants that protect soil from being blown or washed away. Many farmers in South Asia are now trying a process called Low Till Farming. Low Till Farming limits the use of plows. In this method of farming, seeds and fertilizer are put into the soil through small cuts made in the surface of the ground. Low Till Agriculture leaves much or all the soil and remains of plants on the ground. They serve as a natural fertilizer and help support the roots of future crops. They take in rain and allow it to flow into the soil instead of running off. It has been proved that Low Till Farming increases har-vests and reduces water use, and this method reduces the need for chemical products because there are fewer unwanted plants. Scientists say Low Till Farming is becoming popular in South Asia, which is facing a severe water shortage. They say the area will become dependent on imported food unless water is saved through methods like Low Till Farming. Currently, more than 150 million people in South Asia depend on local rice and wheat crops. Farmers grow rice during wet weather. During the dry season they grow wheat in the same fields. Farmers are using the Low Till Farming method to plant wheat after harvesting rice. Scientists say Low Till Agriculture is one of the best examples in the world of technologies working for both people and the environment.
What is me main problem caused by the usual way of plowing？
A．The crop's blooming period is delayed.
B．The roots of crops are cut off.
C．The topsoil is seriously damaged.
D．The growth of weeds is accelerated.
What is the main problem caused by the usual way of plowing？
A．The crop's blooming period is delayed.
B．The roots of crops are cut off.
C．The topsoil is seriously damaged.
D．The growth of weeds is accelerated.
Organic Food
Organic farming was among the fastest growing segments of U.S. agriculture during the 1990s. The value of retail sales of organic food was estimated to be $16 billion in 2004. According to the Food Marketing Institute, more than half of Americans now buy organic food at least once a month. Why is organic food becoming so popular？
What is Organic Food？
In December 2000, the National Organic Standards Board of the U.S. Department of Agriculture (USDA) established a national standard for the term "organic". Organic food, defined by how it cannot be made rather than how it can be made, must be produced without the use of sewer-sludge fertilizers, most synthetic fertilizers and pesticides, genetic engineering (biotechnology), growth hormones, irradiation and antibiotics. A variety of agricultural products can be produced organically, including produce, grains, meat, dairy, eggs, and processed food products.
"Organic" does not mean "natural". There is no legal definition as to what constitutes a "natural" food. However, the food industry uses the term "natural" to indicate that a food has been minimally processed and is preservative-free. Natural foods can include organic foods, but not all natural foods are organic. Only foods labeled "organic" have been certified as meeting USDA organic standards.
Organic Farming
The phrase "organic farming" first appeared in Lord Northbourne's book Look to the Land, published in 1940.
But the truth is, organic farming is the oldest form. of agriculture. Be- fore the end of World War Ⅱ, farming without the use of petroleum-based chemicals (synthetic fertilizers and pesticides) was the only option for farmers, Technologies developed during the war were found to be useful for agricultural production. For example, the chemical ammonium nitrate(硝酸铵), which was used as munitions(军需品), became useful as fertilizer, and organophosphates(有机磷酸盐) used for nerve gas were later used as insecticide.
These days, farmers are switching to organic agriculture once again, but now 'with an eco- logically based, systematic approach that includes long-term planning, detailed record keeping and major investment in equipment and supplies. Although it is still only a small industry, the number of organic farmers is growing by about 12 percent per year and now stands at more than 12,000 nationwide.
Organic Farming in the U.S. Today
The USDA's Economic Research Service reports that in 1997, the latest year for which data are available, farmers in 49 states used organic production methods and third-party organic certification services on 1.35 million acres out of a total of 828 million acres of farmland. Approximately two-thirds of the certified U.S. organic farmland was used for crops, and one-third was used as pasture.
Large farms, mostly located in the Midwest and West, produced processed tomatoes, organic wine grapes and other high-value crops on a commercial scale, whereas numerous small farms, concentrated in the Northeast, specialized in mixed vegetable production for direct marketing to consumers and restaurants.
While organic food can be found throughout the country, California was the leader in production of organic fruits and vegetables in 1997, followed closely by Arizona, Florida, Texas, and Washington in decreasing order of total yield. Farmers and ranchers in 23 states raised a small number of certified organic cows, hogs and sheep. New York, Wisconsin and Minnesota were the top producers of organic dairy cows.
Production: Organic vs. Conventional
As you can imagine, organic agricultural practices are quite distinct from those of “conventional” farming.
Conventional farmers:
apply chemical, fertilizers to the soil to grow their crops
spray with insecticides to protect crops from pests and disease
use sy
A．Y
B．N
C．NG
"This practice" in Paragraph 4 refers to_______.
A.that farmers have lowered the yield of corn and soybean
B.that farmers have expanded croplands
C.that farmers have applied more chemical fertilizers
D.that the top soil has been decreased greatly
A．Because farmers use less insecticides now.
B．Because farmers have been using insecticides for many years.
C．Because insects use the mechanisms against plants to fight insecticides.
D．Because insects have been eating plants for many million years.
The Agricultural Adjustment Act encouraged American farmers to
A．reduce their scale of production.
B．make full use of their land.
C．adjust the prices of their farm products.
D．be self-sufficient in agricultural production.
14 The farmers also want to use the water to irrigate the barren land.
A empty
B hairless
C smooth
D bare
Farmers today use scarecrows to ______.
A．get rid of bad luck
B．decorate their houses
C．frighten the birds away
D．show that autumn has come
The farmers also want to use the water to irrigate the (barren) land.
A．empty
B．hairless
C．bare
D．smooth
