密歇根新闻广播 农耕产生了大量温室气体

 

We know that burning fossil fuels releases a lot of greenhouse gases. But there are other human-caused sources that contribute to climate change. As Lester Graham with the Environment Report found, one of them is how farmers plant crops.

All agriculture accounts for 23% of human greenhouse gas emissions¹, according to the International Panel on Climate Change. We’re going to look at a smaller, but still significant portion of that.

When we think just about cropping systems, we're looking at somewhere on the order of eight to 12 percent of total greenhouse gas loading. And eight to 12 percent is a lot when we think about what we need to do to rein² in greenhouse gases, said Phil Robertson, a Michigan State University professor who works at the Kellogg Biological Station near Battle Creek³.

When he says cropping systems, think row crops such as corn, wheat, and soy beans. Conventional tilling, that is plowing⁵ up the dirt, encourages microbial action. That can lead to CO2 emissions and the more potent⁶ greenhouse gases methane⁷ and nitrous oxide⁸.

And therefore the microbes go to town. And so we end up with a lot more CO2 being emitted than we would in a natural system, for example, or in a system that's no till, Robertson said.

That’s why Michigan State University researchers have been studying no-till and similar techniques.

No-till is a way of farming without plowing the soil, Robertson explained.

No-till can mitigate⁹ the greenhouse gases that contribute to climate change.

When it's time to plant the next crop, they'll use a planter that cuts a slit¹⁰ in the soil and the seeds go into that to let the plants come up and are just as happy as when they're being put into plowed¹¹ ground, Robertson said.

That keeps the carbon in the soil.

About 50 percent of corn, wheat, and soybean are planted using no-till. Each year the soil is not plowed up, more carbon is stored.

But, it can all be lost. Let’s say a farmer used no-till for four years. If that field is then conventionally plowed, that carbon stored over the years is released.

Farmers say it’s sometimes not practical to use no-till. They say they need to plow⁴ the field when it’s too wet to plant. It can help dry things out.

I don't agree with that statement, Blaine Baker¹² said.

He was working on his combine at his family's farm in Lenawee County. He's been using no-till for 23 years. He says there are years he's actually planting earlier than other farmers.

I mean, I'm not saying no-till is a cure-all for everything, but we planted days when other people weren't running and we didn't hinder our yields, Baker said.

He thinks the real barriers to no-till are these: first, is the idea that this is the way we’ve always done it; second is money.

There’s costs associated with it, and especially when you're sitting there and you got the full line of other equipment to go out and do it like you've always done. Why do you want to invest another, you know, 50, 60, 70 thousand dollars when I've got the equipment sitting there ready to go, he said.

There is a third factor: politics. Despite the preponderance of scientific evidence, climate change is still political. Some farmers simply dismiss climate change as fake science.

Baker says there are other benefits from no-till. One is preventing the erosion of rich topsoil.

And particularly now that we've gone to cover crops, we've got something growing out there all the time. So our erosion is pretty much nil¹³, he said.

Despite the benefits, few farmers use no-till consistently. Baker says that's a shame.

Huge, huge amount of carbon that is sequestered¹⁴, but every time you open it up, you're releasing it, he said.

A four year survey by the U.S. Department of Agriculture shows only about 20% of cropland was in no-till or similar techniques all four years.

Until more farmers commit to using no-till every year, planting crops will continue be a significant contributor to climate change.

1 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。

2 rein   

n.疆绳，统治，支配；vt.以僵绳控制，统治

参考例句：

• The horse answered to the slightest pull on the rein.只要缰绳轻轻一拉,马就作出反应。
• He never drew rein for a moment till he reached the river.他一刻不停地一直跑到河边。

3 creek   

n.小溪，小河，小湾

参考例句：

• He sprang through the creek.他跳过小河。
• People sunbathe in the nude on the rocks above the creek.人们在露出小溪的岩石上裸体晒日光浴。

4 plow   

n.犁，耕地，犁过的地；v.犁，费力地前进[英]plough

参考例句：

• At this time of the year farmers plow their fields.每年这个时候农民们都在耕地。
• We will plow the field soon after the last frost.最后一场霜过后，我们将马上耕田。

5 plowing   

v.耕( plow的现在分词 )；犁耕；费力穿过

参考例句：

• "There are things more important now than plowing, Sugar. "如今有比耕种更重要的事情要做呀，宝贝儿。 来自飘（部分）
• Since his wife's death, he has been plowing a lonely furrow. 从他妻子死后，他一直过着孤独的生活。 来自辞典例句

6 potent   

adj.强有力的，有权势的；有效力的

参考例句：

• The medicine had a potent effect on your disease.这药物对你的病疗效很大。
• We must account of his potent influence.我们必须考虑他的强有力的影响。

7 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。

8 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？

9 mitigate   

vt.（使）减轻，（使）缓和

参考例句：

• The government is trying to mitigate the effects of inflation.政府正试图缓和通货膨胀的影响。
• Governments should endeavour to mitigate distress.政府应努力缓解贫困问题。

10 slit   

n.狭长的切口；裂缝；vt.切开，撕裂

参考例句：

• The coat has been slit in two places.这件外衣有两处裂开了。
• He began to slit open each envelope.他开始裁开每个信封。

11 plowed   

v.耕( plow的过去式和过去分词 )；犁耕；费力穿过

参考例句：

• They plowed nearly 100,000 acres of virgin moorland. 他们犁了将近10万英亩未开垦的高沼地。 来自辞典例句
• He plowed the land and then sowed the seeds. 他先翻土，然后播种。 来自辞典例句

12 baker   

n.面包师

参考例句：

• The baker bakes his bread in the bakery.面包师在面包房内烤面包。
• The baker frosted the cake with a mixture of sugar and whites of eggs.面包师在蛋糕上撒了一层白糖和蛋清的混合料。

13 nil   

n.无，全无，零

参考例句：

• My knowledge of the subject is practically nil.我在这方面的知识几乎等于零。
• Their legal rights are virtually nil.他们实际上毫无法律权利。

14 sequestered   

adj.扣押的；隐退的；幽静的；偏僻的v.使隔绝，使隔离( sequester的过去式和过去分词 )；扣押

参考例句：

• The jury is expected to be sequestered for at least two months. 陪审团渴望被隔离至少两个月。 来自《简明英汉词典》
• Everything he owned was sequestered. 他的一切都被扣押了。 来自《简明英汉词典》