英语听力：自然百科 绿色养牛法

 The Underhill Farm in Somerset, England, is the picture of rural tranquility. But the lush green pastures disguise the fact that farms like this are contributing to global warming. That's because just one cow can produce up to 500 liters of methane¹ gas a day. In fact the methane produced by the manure² of a typical cow translates to a little over one and half tones of carbon dioxide emissions³ per year, that's about the same amount generated annually⁴ by a commuter⁵ driving to and from work alone each day.

 

In a bid to turn that around, the cows here are being fed a new diet that can reduce gas and cut methane emissions by 20%. All farms have to do is feed the cows a more natural diet by mixing straw and hay with their food. But getting the cows to eat it is easier said than done. A special machine is used to cut the straw into strips which can be mixed with silage, weed, maize⁶, soil or sugar beet⁷.

 

What we’ve realized and seen and now scientifically proved and that’s part of our technology is that cows still actually need fiber⁸, but in that fiber we've got to make sure that they eat it. So we process it and that’s where we have a unique mixer-wagon that will process the forage⁹ and give us the forage that we believe are the right length for the cows.

 

The diet has the added environmental benefit that for each liter of milk only around 23 liters of methane is produced instead of previous levels of about 28 liters.

 

This is a win-win situation. It’s a good way of using straw which is a low value by-product¹⁰ essentially¹¹ of the bleaching¹² of cereal grain for a beneficial purpose in terms of increasing food productivity, might increase milk. (At) the same time it's reducing green house gas emissions which is a serious environmental problem associated with the rearing of cattle. 

 

Methane accounts for 16% of global green house gas emissions, that is far less than the most prevalent green house gas, carbon dioxide which accounts for about 75% of the global total.

1 methane   

n.甲烷，沼气

参考例句：

• The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
• Methane may have extraterrestrial significance.甲烷具有星际意义。

2 manure   

n.粪，肥，肥粒；vt.施肥

参考例句：

• The farmers were distributing manure over the field.农民们正在田间施肥。
• The farmers used manure to keep up the fertility of their land.农夫们用粪保持其土质的肥沃。

3 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。

4 annually   

adv.一年一次，每年

参考例句：

• Many migratory birds visit this lake annually.许多候鸟每年到这个湖上作短期逗留。
• They celebrate their wedding anniversary annually.他们每年庆祝一番结婚纪念日。

5 commuter   

n.(尤指市郊之间)乘公交车辆上下班者

参考例句：

• Police cordoned off the road and diverted commuter traffic. 警察封锁了道路并分流交通。
• She accidentally stepped on his foot on a crowded commuter train. 她在拥挤的通勤列车上不小心踩到了他的脚。

6 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。

7 beet   

n.甜菜；甜菜根

参考例句：

• He farmed his pickers to work in the beet fields. 他出租他的摘棉工去甜菜地里干活。
• The sugar beet is an entirely different kind of plant.糖用甜菜是一种完全不同的作物。

8 fiber   

n.纤维，纤维质

参考例句：

• The basic structural unit of yarn is the fiber.纤维是纱的基本结构单元。
• The material must be free of fiber clumps.这种材料必须无纤维块。

9 forage   

n.(牛马的)饲料，粮草；v.搜寻，翻寻

参考例句：

• They were forced to forage for clothing and fuel.他们不得不去寻找衣服和燃料。
• Now the nutritive value of the forage is reduced.此时牧草的营养价值也下降了。

10 by-product   

n.副产品，附带产生的结果

参考例句：

• Freedom is the by-product of economic surplus.自由是经济盈余的副产品。
• The raw material for the tyre is a by-product of petrol refining.制造轮胎的原材料是提炼汽油时产生的一种副产品。

11 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

12 bleaching   

漂白法，漂白

参考例句：

• Moderately weathered rock showed more intense bleaching and fissuring in the feldspars. 中等风化岩石则是指长石有更为强烈的变白现象和裂纹现象。
• Bleaching effects are very strong and show on air photos. 退色效应非常强烈，并且反映在航空象片上。