VOA慢速英语 2008 0212a

This is the VOA Special English Agriculture Report.    

Farmers in the United States sometimes plant switchgrass as a border crop. But could this tall grass lower the nation's dependence¹ on foreign oil?

 
South Dakota State University professor Arvid Boe with switchgrass plants
The Department of Energy plans to invest hundreds of millions of dollars to help produce fuels from materials that are not part of the food supply. Growing corn, or maize², for fuel has raised concerns about the supply and cost of corn available for food and animal feed.

Fuel made from switchgrass or forestry³ waste like sawdust is known as cellulosic ethanol. Department officials say it contains more energy and produces fewer greenhouse gases than ethanol made from corn. Switchgrass is also easier to grow.

Last month, the Proceedings⁴ of the National Academy of Sciences published a study of switchgrass grown on low-quality land. Government scientist Ken⁵ Vogel was the lead author. The study says the switchgrass produced five times more energy than was needed to grow it. Also, it says switchgrass, over its lifetime from crop to fuel, produces much less carbon compared to gasoline.

Fossil fuels like oil take carbon from the ground and release it as waste gas when the fuel is burned. Biofuels like corn and cellulosic ethanol also produce greenhouse gases, through growing crops and making the fuel. The difference is that biofuels remove carbon from the atmosphere through the growth of the feedstock, the material for the fuel.

Science magazine just published two studies of biofuels and the heat-trapping gases that scientists link to climate change. One of the reports notes that most studies have found that substituting biofuels for gasoline will reduce greenhouse gases.

But it says the earlier studies failed to count the carbon released into the atmosphere as farmers worldwide react to higher prices. They are clearing forests and grasslands⁶ to make way for new cropland to replace the grain used for biofuels. Doing so can release much of the carbon stored in the plants and soil, and sacrifice future storage.

The study found that corn-based ethanol could increase greenhouse gases for years from land use change. And it found that biofuels from switchgrass, if grown on American corn land, could also increase emissions⁷, though by less.

The study team, led by Timothy Searchinger at Princeton University, says the result shows the value of using waste products for fuel. The other report says carbon savings⁸ depend on how biofuels are produced.

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. I’m Jim Tedder⁹.

 

1 dependence   

n.依靠，依赖；信任，信赖；隶属

参考例句：

• Doctors keep trying to break her dependence of the drug.医生们尽力使她戒除毒瘾。
• He was freed from financial dependence on his parents.他在经济上摆脱了对父母的依赖。

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 forestry   

n.森林学；林业

参考例句：

• At present, the Chinese forestry is being at a significant transforming period. 当前, 我国的林业正处于一个重大的转折时期。
• Anhua is one of the key forestry counties in Hunan province. 安化县是湖南省重点林区县之一。

4 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

5 ken   

n.视野，知识领域

参考例句：

• Such things are beyond my ken.我可不懂这些事。
• Abstract words are beyond the ken of children.抽象的言辞超出小孩所理解的范围.

6 grasslands   

n.草原，牧场( grassland的名词复数 )

参考例句：

• Songs were heard ringing loud and clear over the grasslands. 草原上扬起清亮激越的歌声。 来自《现代汉英综合大词典》
• Grasslands have been broken and planted to wheat. 草原已经开垦出来，种上了小麦。 来自《简明英汉词典》

7 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

8 savings   

n.存款，储蓄

参考例句：

• I can't afford the vacation,for it would eat up my savings.我度不起假，那样会把我的积蓄用光的。
• By this time he had used up all his savings.到这时，他的存款已全部用完。

9 tedder   

n.（干草）翻晒者，翻晒机

参考例句：

• Jim Tedder has more. 吉姆？特德将给我们做更多的介绍。 来自互联网
• Jim Tedder tells us more. 吉姆？泰德给我们带来更详细的报道。 来自互联网