Mendel in the Kitchen A Scientist's View of Genetically Modified Foods (2004) / Chapter Skim
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13 Sustaining Agriculture
13 Sustaining Agriculture
Pages 263-278
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From page 263... ...
In May 2002 the United Nations Environment Programme released a report on environmental trends. The New York Times account stated: "Expansion of cities, destruction of forests, erosion of fields, and rising demand for water are likely to threaten human and ecological health for at least a generation." The growth of agriculture "is damaging landscapes, depleting aquifers, raising the level of salt in the soil, and reducing habitat for wildlife." The Times continued, "The report says an important cause is the accelerating growth of vast, poor, and largely unplanned cities in developing countries, most of them near coastlines." A month earlier, in April 2002, the New Yorker magazine published an article called "Leasing the Rain.""The world is running out of fresh water,"the cutline read,"and the fight to control it has begun."Between 1950 and 1990, worldwide, the demand for fresh water tripled.
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From page 264... ...
Economist Indur Goklany has calculated that if we tried to feed today's six billion people using the mainly organic farming methods of 1961, we would need to cultivate 82 percent of the earth's land surface instead of the current 38 percent. The additional acreage amounts to the entire Amazon Basin, the Sahara Desert, and the Okavango Delta, also known as the Okavango Swamp, an area rich in African wildlife.
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From page 265... ...
For the past 45 years people have been taking less land from nature than their parents." And yet, as an article by Jonathan Rauch published in the same magazine six years later pointed out, the percentage of the earth's land surface that is farmed is still rising:"The increase has been gradual, only about 0.3 percent a year; but that still translates into an additional Greece or Nicaragua cultivated or grazed every year." The Green Revolution has had its ecological downside as well. "Pest and disease outbreaks have been an especially severe consequence," wrote Gordon Conway, due most often to "a combination of factors -- higher nutrient levels, narrow genetic stock, uniform continuous planting, and the misuse of pesticides." Erosion and salinization (from too much or improperly designed irrigation)
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From page 266... ...
When farming methods are not ecologically wise, Conway argues, "agriculture is both culprit and victim."In the twenty-first century, the central questions about sustainable agriculture raised by Howard and Rodale and the other pioneers of organic farming remain with us. But are the methods that have come to be called organic -- and codified in the Organic Rule -- the best we can do?
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From page 267... ...
"In 1999 I visited New York City for the first time ever," plant pathologist Jim Cook of Washington State University recalled in 2003. "I took my wife.
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From page 268... ...
The notion that valuable insights can be gleaned from both conventional and organic approaches and combined is almost unthinkable -- right now-as is using molecular methods to increase yields and protect crops from diseases and pests. In a book with the uncompromising title Saving the Planet with Pesticides and Plastic: The Environmental Triumph of High-Yield Farming, Dennis Avery describes a conference of the Organic Farming Association in 1993: I spoke to the conference on biotechnology's potential to produce more food from fewer acres.
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From page 269... ...
But to build your marketing on a negative has no future. The next generation of transgenic crops may be more interesting to organic farmers." Plant pathologist Jim Cook was asked, also at the AAAS meeting, how scientists could encourage biotechnology and organic agriculture at the same time.
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From page 270... ...
He means those genetically modified crops most vilified -- and least understood -- by the press: Roundup Ready soybeans and other herbicide-tolerant crops. He is particularly interested in one that has been developed but not yet marketed: herbicide-tolerant wheat.
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From page 271... ...
The best, called conservation tillage, is defined by the Conservation Technology Information Center at Purdue University as "any tillage and planting system that covers more than 30 percent of the soil surface with crop residue, after planting, to reduce soil erosion by water."Achieving this, however, meant putting up with weeds until herbicides were introduced that were effective enough to replace the plow. The first was atrazine, brought out in 1959.
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From page 272... ...
You're not sequestering carbon anymore, you're basically burning up the whole season's residue." In no-till agriculture, on the other hand, the turnover of organic matter happens in such a way that carbon is sequestered. Said Cook, "You're saving the photosynthate that was manufactured by the plant and returned to the soil as crop residue." The organic matter in the soil holds more carbon than is in trees or living plants or anything else on land.
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From page 273... ...
"Farmers are reluctant to change, and so are scientists," he noted. The Conservation Technology Information Center reports that in 1991, when Iowa farmers were asked why they didn't switch to conservation tillage to control runoff and erosion, they answered: weeds.
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From page 274... ...
Reaching the chloroplasts, where the plant produces its energy through photosynthesis, glyphosate latches on to an enzyme called 5-enolpyruvylshikimate-3-phosphate or EPSP synthase. This enzyme controls a key step in making the amino acids phenylalanine, tyrosine, and tryptophan.
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From page 275... ...
Steve Padgette, an enzymologist, was hired by Monsanto in 1984."Jaworski had a clear vision that resistance to glyphosate would be valuable," he recalled. "He just knew if we could do it, it would work." By 1984 Monsanto researcher Ganesh Kishore had identified a change in the enzyme EPSP synthase that would make a plant tolerate Roundup.
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From page 276... ...
The nitrates are first turned into ammonia, from which an enzyme called glutamine synthase makes the amino acid. Glufosinate disables this enzyme.
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From page 277... ...
Having three kinds of herbicide-tolerant varieties of wheat available to farmers, Cook believes, could give the same boost to conservation tillage in the Pacific Northwest that Roundup Ready soybeans did in the Midwest.Yet so far two of these varieties have stayed on the shelf, the companies choosing not to commercialize them because of political opposition to genetically modified foods. "In Washington, we're a big wheat-producing state," Cook explained, "and 90 percent of our wheat is exported.
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From page 278... ...
You improve soil structures, stop erosion, sequester carbon, improve water filtration, rather than letting it run off the land, and store more water in years of drought."The stubble left behind provides habitat for birds and small mammals, which could lead to an upsurge in the number of their predators, including hawks, owls, and coyotes. Compared to conventionally tilled farmland, Cook considers no-till "a whole new ecology" and "a huge step toward being environmentally benign and toward contributing services with social value." Farmers can achieve these goals, he believes, with a three-year rotation of herbicide-tolerant cereals using three different herbicides-Clearfield, Roundup, and Liberty.
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