转基因农田超级野草崛起，美国农民焦头烂额 (转载)
【 以下文字转载自 Vegetarianism 俱乐部 】
发信人: purity (purity), 信区: Vegetarianism
标 题: 转基因农田超级野草崛起，美国农民焦头烂额
发信站: BBS 未名空间站 (Mon Oct 4 10:07:30 2010, 美东)
转基因农田超级野草崛起，美国农民焦头烂额
森·哈姆林是一名拥有相关证书的作物顾问和农学家，他正在田纳西的戴尔斯堡寻找对
草甘膦产生抗性的杂草。艾迪·安德森正往他的地里追加喷洒灭草剂，以对抗那些对草
甘膦产生抗性的杂草。安德森先生有着大约3，000公顷大豆田，他正在对付那些有害的
长芒苋。
在至少22个州立十种产生抗性的杂草感染了上百万公顷的土地。艾迪·安德森是田纳西
州戴尔斯堡的一名农民。15年来他一直是免耕农业坚定的拥护者。免耕农业是一种环境
友好技术，几乎排除了耕作导致的水土流失以及肥料和杀虫剂造成的有害残留。
但今年情况不一样了。“农达”（Roundup）是孟山都公司原创的拳头产品，但现在也
有其他公司用它的属名“草甘膦”来进行销售，这东西对于农民来说，曾一度几乎算得
上是种奇迹化学品。它有着广谱的除草功能，使用起来简单安全，降解迅速，减轻了对
环境的影响。
然而，美国农民们对却没想到，那种产生奇迹的化学品除草剂“农达”的广泛使用，却
导致了抗农达杂草在美国各地的传播。从2000年开始至少十种抗农达杂草已经在22个州
里感染里上百万公顷的耕地。最近一个下午，安德森先生看着拖拉机们在绵延起伏的田
野中纵横驰骋，它们正在把他的农田翻开，把除草剂掺进土里以杀灭杂草，好让地里等
下能种上大豆。
如同频繁使用抗生素会有引发抗药的超级细菌出现的风险一样，美国农民几乎人手一瓶
地使用杂草杀手“农达”已经导致了顽强的新型超级杂草迅速滋长。为了对抗这些新兴
杂草，安德森先生和遍及东部，中西部和南部的农民们正被迫向田里喷洒更大剂量的有
毒除草剂。他们用手去拔草并且用回了传统翻耕这类劳动密集度更高的法子。安德森先
生有3，000公顷大豆田，今春他将要翻耕其中的三分之一，这比他过去几年来的总量还
要多。他说：“我们又回到20年前的老路上去了，我们正在尝试看有什么办法。”
农业专家说这样的劳作会导致食品价格变高，农作物产量变低，农业成本上升，土地污
染和水污染更严重。“它是我所见到的对农业生产最大的一个威胁。”说这话的人是安
德鲁·沃戈三世，他是堪萨斯保护区协会的主席。这些对农业表现出严重威胁的物种最
早是在2000年于特拉华的大豆田里被人辨识出来的。从那之后问题蔓延了开来，至少22
个州里有10种抗性杂草感染了上百万公顷的田地，其中主要种的都是大豆，棉花和玉米
。这些杂草恐怕将要考验美国农业对于某些转基因作物的热情。通过基因工程所研发的
那些能够在喷洒“农达”后活下来的大豆，玉米和棉花已经成了美国农田里的标准作物
。然而，一旦“农达”无法杀灭杂草，农夫们便不再情愿把剩下的钱花在对付那些特殊
的杂草上。
中国的农民是否也要步美国农民的后尘呢？
本文引用地址： http://www.sciencenet.cn/m/user_content.aspx?id=369446
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http://www.nytimes.com/2010/05/0 ... html?pagewanted=all
Farmers Cope With Roundup-Resistant Weeds
Just as the heavy use of antibiotics contributed to the rise of drug-
resistant supergerms, American farmers’ near-ubiquitous use of the
weedkiller Roundup has led to the rapid growth of tenacious new superweeds.
To fight them, Mr. Anderson and farmers throughout the East, Midwest and
South are being forced to spray fields with more toxic herbicides, pull
weeds by hand and return to more labor-intensive methods like regular
plowing.
“We’re back to where we were 20 years ago,” said Mr. Anderson, who will
plow about one-third of his 3,000 acres of soybean fields this spring, more
than he has in years. “We’re trying to find out what works.”
Farm experts say that such efforts could lead to higher food prices, lower
crop yields, rising farm costs and more pollution of land and water.
“It is the single largest threat to production agriculture that we have
ever seen,” said Andrew Wargo III, the president of the Arkansas
Association of Conservation Districts.
The first resistant species to pose a serious threat to agriculture was
spotted in a Delaware soybean field in 2000. Since then, the problem has
spread, with 10 resistant species in at least 22 states infesting millions
of acres, predominantly soybeans, cotton and corn.
The superweeds could temper American agriculture’s enthusiasm for some
genetically modified crops. Soybeans, corn and cotton that are engineered to
survive spraying with Roundup have become standard in American fields.
However, if Roundup doesn’t kill the weeds, farmers have little incentive
to spend the extra money for the special seeds.
Roundup — originally made by Monsanto but now also sold by others under the
generic name glyphosate — has been little short of a miracle chemical for
farmers. It kills a broad spectrum of weeds, is easy and safe to work with,
and breaks down quickly, reducing its environmental impact.
Sales took off in the late 1990s, after Monsanto created its brand of
Roundup Ready crops that were genetically modified to tolerate the chemical,
allowing farmers to spray their fields to kill the weeds while leaving the
crop unharmed. Today, Roundup Ready crops account for about 90 percent of
the soybeans and 70 percent of the corn and cotton grown in the United
States.
But farmers sprayed so much Roundup that weeds quickly evolved to survive it
. “What we’re talking about here is Darwinian evolution in fast-forward,”
Mike Owen, a weed scientist at Iowa State University, said.
Now, Roundup-resistant weeds like horseweed and giant ragweed are forcing
farmers to go back to more expensive techniques that they had long ago
abandoned.
Mr. Anderson, the farmer, is wrestling with a particularly tenacious species
of glyphosate-resistant pest called Palmer amaranth, or pigweed, whose
resistant form began seriously infesting farms in western Tennessee only
last year.
Pigweed can grow three inches a day and reach seven feet or more, choking
out crops; it is so sturdy that it can damage harvesting equipment. In an
attempt to kill the pest before it becomes that big, Mr. Anderson and his
neighbors are plowing their fields and mixing herbicides into the soil.
That threatens to reverse one of the agricultural advances bolstered by the
Roundup revolution: minimum-till farming. By combining Roundup and Roundup
Ready crops, farmers did not have to plow under the weeds to control them.
That reduced erosion, the runoff of chemicals into waterways and the use of
fuel for tractors.
If frequent plowing becomes necessary again, “that is certainly a major
concern for our environment,” Ken Smith, a weed scientist at the University
of Arkansas, said. In addition, some critics of genetically engineered
crops say that the use of extra herbicides, including some old ones that are
less environmentally tolerable than Roundup, belies the claims made by the
biotechnology industry that its crops would be better for the environment.
“The biotech industry is taking us into a more pesticide-dependent
agriculture when they’ve always promised, and we need to be going in, the
opposite direction,” said Bill Freese, a science policy analyst for the
Center for Food Safety in Washington.
So far, weed scientists estimate that the total amount of United States
farmland afflicted by Roundup-resistant weeds is relatively small — seven
million to 10 million acres, according to Ian Heap, director of the
International Survey of Herbicide Resistant Weeds, which is financed by the
agricultural chemical industry. There are roughly 170 million acres planted
with corn, soybeans and cotton, the crops most affected.
Roundup-resistant weeds are also found in several other countries, including
Australia, China and Brazil, according to the survey.
Monsanto, which once argued that resistance would not become a major problem
, now cautions against exaggerating its impact. “It’s a serious issue, but
it’s manageable,” said Rick Cole, who manages weed resistance issues in
the United States for the company.
Of course, Monsanto stands to lose a lot of business if farmers use less
Roundup and Roundup Ready seeds.
“You’re having to add another product with the Roundup to kill your weeds,
” said Steve Doster, a corn and soybean farmer in Barnum, Iowa. “So then
why are we buying the Roundup Ready product?”
Monsanto argues that Roundup still controls hundreds of weeds. But the
company is concerned enough about the problem that it is taking the
extraordinary step of subsidizing cotton farmers’ purchases of competing
herbicides to supplement Roundup.
Monsanto and other agricultural biotech companies are also developing
genetically engineered crops resistant to other herbicides.
Bayer is already selling cotton and soybeans resistant to glufosinate,
another weedkiller. Monsanto’s newest corn is tolerant of both glyphosate
and glufosinate, and the company is developing crops resistant to dicamba,
an older pesticide. Syngenta is developing soybeans tolerant of its Callisto
product. And Dow Chemical is developing corn and soybeans resistant to 2,4-
D, a component of Agent Orange, the defoliant used in the Vietnam War.
Still, scientists and farmers say that glyphosate is a once-in-a-century
discovery, and steps need to be taken to preserve its effectiveness.
Glyphosate “is as important for reliable global food production as
penicillin is for battling disease,” Stephen B. Powles, an Australian weed
expert, wrote in a commentary in January in The Proceedings of the National
Academy of Sciences.
The National Research Council, which advises the federal government on
scientific matters, sounded its own warning last month, saying that the
emergence of resistant weeds jeopardized the substantial benefits that
genetically engineered crops were providing to farmers and the environment.
Weed scientists are urging farmers to alternate glyphosate with other
herbicides. But the price of glyphosate has been falling as competition
increases from generic versions, encouraging farmers to keep relying on it.
Something needs to be done, said Louie Perry Jr., a cotton grower whose
great-great-grandfather started his farm in Moultrie, Ga., in 1830.
Georgia has been one of the states hit hardest by Roundup-resistant pigweed,
and Mr. Perry said the pest could pose as big a threat to cotton farming in
the South as the beetle that devastated the industry in the early 20th
century.
“If we don’t whip this thing, it’s going to be like the boll weevil did
to cotton,” said Mr. Perry, who is also chairman of the Georgia Cotton
Commission. “It will take it away.” |
狗仔卡
发表于 2010-10-4 07:00 AM
发表于 2010-10-4 04:13 PM
