Organic Farming
During thousands of years of huma civilization,the raising of animals and growing of plants have always been organic.Chemicals for farming first came up at the turn of the 20th century.Widespread use of chemicals began after World War II.In the 1950s and 60s farmers started using chemical fertilizers and pesticides(杀虫剂).Recently,however,more and more farmers have been returning to organic farming.
In organic farming,farm products are produced in more natural ways.Crops,meat and other food are produced without chemicals.Chemical fertilizers,pesticides,and growth hormones(激素)are forbidden.Farmers enrich the soil with natural fertilizers.They pull out weeds by hand.Hay and straw are put between the rows of plants to stop weeding.They rely on the natural enemies of pests to control pests.Animals are fed organically and can eat grass outdoors.Cows,for example,are kept in pastures (操场) and fields.Vegetables and fruit are also produced with organic methods.
Organic farming enjoys many advantages.For example,crop rotation can preserve the good qualities of soils. The growing of different crops can keep soils healthy and fertile.Organic farming is healthier for farm workers,and there are fewer remains of chemicals in food.In the long run,organic farms save energy and protect the environment.It can slow down global warming and reduce the pollution of ground water.
Meanwhile,there are some disadvantages.Organic food is more expensive.Organic products may cost up to 40%more.Production costs are higher as farmers need more workers,and the land output is much less.Marketing and distribution is not efficient because organic food is provided in smaller amount.Crop illness may happen very often.Besides,organic farming cannot produce enough food for the world's population to survive.This could lead to starvation in countries that can produce enough food today.
The phrase “crop rotation”(Para.3)probably means “_____”.
A.growing high-yielding crops B.seasonal growing of crops C.planting soil-enriching crops D.regular changing of crops正确答案D
