VOA慢速英语2009年-Agriculture Report - Seeking Balance in Fe

This is the VOA Special English Agriculture Report.

Fertilizer use differs from country to country, and from too little to too much. Nitrogen and phosphorus can produce big crops. But they can also pollute water and air.

A recent policy discussion in the journal Science compared the nutrient¹ balances of different agriculture systems. Researchers compared the use of fertilizer in three areas that grow maize² as a major grain: China, Kenya and the United States.
　
A farmer in Amritsar, India, puts fertilizer on his rice crop

By two thousand five, they say, farms in northern China produced about the same amount of corn per hectare as farms in the American Midwest. But the Chinese farmers used six times more nitrogen, and produced almost twenty-three times more surplus nitrogen.

Government policies can have an influence. For example, as China sought food security, its policies increased fertilizer use.

The researchers note that farmers in the Midwest used too much fertilizer on their crops through the nineteen seventies. But improved farming methods later increased their yields and, at the same time, made better use of chemical nitrogen fertilizer.

Farms in western Kenya use just over one-tenth as much fertilizer as American farms. Corn harvests remain small. The researchers say farming methods in Sub-Saharan Africa need to improve or else poor quality soil will increase rural poverty. More than two hundred fifty million people do not get enough nutrients³ from crops to stay healthy.

Nutrient balances in agriculture differ with economic development. Farmers lack enough inputs⁴ to maintain soil fertility is parts of many developing countries, especially in Africa south of the Sahara. But countries that are developed or growing quickly often have unnecessary surpluses.

Ammonia gas released by fertilized⁵ cropland is a cause of air pollution. The land can also release nitrous oxide⁶, a heat-trapping gas.

Nitrogen runoffs from farms can create large dead zones, like those in the Gulf⁷ of Mexico. Algae⁸ microorganisms in the water overpopulate because of the surplus nitrogen. The algae take much of the oxygen from the water. Fish and other organisms die.

Laurie Drinkwater at Cornell University in Ithaca, New York, was an author of the report. Professor Drinkwater says farmers need to think about ways to solve some of the causes of nutrient loss from agriculture. She says different countries need different solutions based on location, environment, climate and population needs.

And that's the VOA Special English Agriculture Report, written by Marisel Salazar. I'm Steve Ember.

1 nutrient   

adj.营养的，滋养的；n.营养物，营养品

参考例句：

• Magnesium is the nutrient element in plant growth.镁是植物生长的营养要素。
• The roots transmit moisture and nutrient to the trunk and branches.根将水分和养料输送到干和枝。

2 maize   

n.玉米

参考例句：

• There's a field planted with maize behind the house.房子后面有一块玉米地。
• We can grow sorghum or maize on this plot.这块地可以种高粱或玉米。

3 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

4 inputs   

n.输入( input的名词复数 )；投入；输入端；输入的数据v.把…输入电脑( input的第三人称单数 )

参考例句：

• Uncheck the inputs checked for optimization in the previous stage. 不测试那些已经测试过的优化了的以前步骤的inputs.（变量参数）。 来自互联网
• Just in case, save in a file the inputs obtained at the previous stage. 以防万一，保存以前步骤获得的inputs（变量参数值）到一个文件中去。 来自互联网

5 Fertilized   

v.施肥( fertilize的过去式和过去分词 )

参考例句：

• The study of psychology has recently been widely cross-fertilized by new discoveries in genetics. 心理学研究最近从遗传学的新发现中受益匪浅。
• Flowers are often fertilized by bees as they gather nectar. 花常在蜜蜂采蜜时受粉。

6 oxide   

n.氧化物

参考例句：

• Oxide is usually seen in our daily life.在我们的日常生活中氧化物很常见。
• How can you get rid of this oxide coating?你们该怎样除去这些氧化皮？

7 gulf   

n.海湾；深渊，鸿沟；分歧，隔阂

参考例句：

• The gulf between the two leaders cannot be bridged.两位领导人之间的鸿沟难以跨越。
• There is a gulf between the two cities.这两座城市间有个海湾。

8 algae   

n.水藻，海藻

参考例句：

• Most algae live in water.多数藻类生长在水中。
• Algae grow and spread quickly in the lake.湖中水藻滋蔓。