\nwhich the mighty engine of U.S. agriculture depends: water, fuel, and synthetic
\nnitrogen. Like water, nitrogen is elemental to life. It’s the essential
\nbuilding block of the plants we eat.
\nFarmers remove it from the soil when they harvest the year’s crop, and they
\nmust replenish it for the following year’s.<\/p>\n
<\/p>\n
Compared with water and fuel,
\nnitrogen is actually in one sense quite plentiful: it makes up about 80 percent
\nof the air we breathe. Yet for all that ubiquity, it’s also in a sense scarce:
\nits extremely strong chemical bond—it exists in the air in triple-bonded
\npairs of nitrogen known as N2—makes it difficult for plants to use.<\/p>\n
<\/p>\n
The N of the world as we know it <\/strong><\/p>\n <\/p>\n Less than 100 years ago, we <\/p>\n This series has explored how the annual cascade of synthetic nitrogen fertilizer isn’t just <\/p>\n And because of the <\/p>\n Globally, <\/p>\n Infertile ground for techno-fixes<\/strong><\/p>\n <\/p>\n But what to do about this genuine <\/p>\n Encouragingly, that question <\/p>\n And last fall, the Economist breathlessly heralded<\/a> seeds <\/p>\n “Imagine,” the <\/p>\n The subject of all this wonder: a gene identified by Arcadia Biosciences in Davis, Calif., that, when <\/p>\n Peter Vitousek, a professor of biology at Stanford and a leading ecologistI asked Stanford’s Vitousek what he <\/p>\n “There <\/p>\n But <\/p>\n Plant <\/p>\n Another <\/p>\n According <\/p>\n Eating and farming our way to sustainability <\/strong><\/p>\n <\/p>\n Like all the experts I <\/p>\n Today, Americans consume an <\/p>\n Corn is our most nitrogen-intensive <\/p>\n And just as consumers will <\/p>\n <\/a>Billions of dollars in <\/p>\n In organic agriculture, crop <\/p>\n “The principles of <\/p>\n Vitousek stressed that he <\/p>\n In the current <\/p>\n In addition to eating much <\/p>\n To get involved in that Related Links:<\/strong><\/p>\n USDA research chief concerned about ‘safety of organic food’<\/a><\/p>\n Tracking down the public-health implications of nitrogen pollution<\/a><\/p>\n
\nlearned—in the process of perfecting bomb-making technology—how to create
\nreadily available nitrogen on a vast scale. The introduction of mass-produced
\nsynthetic nitrogen fertilizer revolutionized agriculture, freeing farmers from
\nthe burdens of nitrogen fixation and allowing them to grow more food than ever before.
\nSynthetic nitrogen revolutionized society, too: the explosion in crop yields
\nthat it helped drive made food cheaper and more plentiful than ever, setting the
\nstage for the 20th century’s population boom.<\/p>\n
\nhelping farmers grow tremendous quantities of food; it is also generating serious problems
\nfor soil quality, public health, the climate, and more. As my article on the
\ngeopolitics of our N dependency showed<\/a>, the process of generating synthetic
\nnitrogen requires massive amounts of increasingly scarce natural gas. (In China, the situation is even worse<\/a>; that nation, the globe’s largest consumer
\nof nitrogen, uses coal, a fuel source significantly dirtier than natural gas, to produce 70 percent of its N supply.)<\/p>\n
\nphysiology of plants and the pressure to maximize yields, farmers routinely
\nover-apply nitrogen. According to Peter Vitousek, a professor of biology at
\nStanford and a leading scholar on the nitrogen cycle, under optimum conditions
\nand using best practices, plants take up only “50 or at best 60
\npercent” of the nitrogen laid on by farmers. So
\nif so much of their fertilizer is going to waste, why do farmers apply so much?
\nVitousek explained that plants
\ntake up different amounts of nitrogen at different points in the growing cycle.
\nTo ensure that crops have sufficient N when they need it most, farmers
\nessentially have to over-apply.<\/p>\n
\n“about two-thirds of the nearly
\n$100 billion of nitrogen fertilizer spread on fields each year is wasted,”
\nestimates The
\nEconomist. That’s a lot of cash down the
\ndrain and a lot of nitrogen bleeding out of fields in various forms,
\nwreaking all manner of havoc: Exhibit A, the 8,000-square-mile dead zone that
\nblooms every year in the Gulf of Mexico, as Krysta Hozyash covered in this series<\/a>.<\/p>\n
\nN dilemma? Our food system has become reliant on an input that appears to be
\nunsustainable at current levels of use, while our population is growing. How
\ncan we maintain a robust, plentiful, growing food supply while also using less
\nsynthetic N?<\/p>\n
\nis being asked more and more in policy and academic circles. Even the
\nstaunchest proponents of industrial-scale agriculture acknowledge the need to
\nuse synthetic N more efficiently. But to date government
\nand agribusiness efforts to address the problem have focused on techno-fixes: for-profit
\nefforts to preserve the current food system while making it more
\nnitrogen-efficient. One such fix is seeds that
\nare genetically modified to use nitrogen more efficiently. The U.S. seed giant
\nMonsanto and the Israeli biotech firm Evogene are collaborating to identify
\ngenes that can “improve nitrogen use efficiency in corn, soybeans, canola
\nand cotton,” the companies announced<\/a> two years ago.<\/p>\n
\nengineered for nitrogen-use efficiency as “the next green revolution.”<\/p>\n
\nmagazine wrote, “you could wave a magic wand and boost the yield of the
\nworld’s crops, cut their cost, use fewer-fossil fuels to grow them and reduce
\nthe pollution that results from farming. Imagine, too, that you could both
\neliminate some hunger and return some land to rain forest.”<\/p>\n
\nspliced into corn or rice, might helps crops “flourish” despite
\nlimited access to N. Yet even The
\nEconomist rated the technology’s ultimate prospects for success in the
\nfield as a “mighty big if.” Arcadia’s seeds remain in the trial
\nstage.<\/p>\n
\nthought about GMO technology as a serious strategy for reducing nitrogen use.<\/p>\n
\nmay be something there, but honestly, I think I gains [in nitrogen-use
\nefficiency] will be marginal,” he replied. He explained that transgenic
\nplant-breeding technologies work well for things like pest resistance: if you
\ncan isolate a gene that kills insects and express it in a crop—as Monsanto
\ndid with a gene from the Bt bacteria—then you have a blockbuster.<\/p>\n
\nthe process by which plants utilize nutrients is much more complex, and
\ninvolves multiple genes working together, making it unlikely that a single gene
\ncould be a game changer. “Plants have been evolving for millions of
\nyears,” he said. “I doubt that plant breeders will be able to hit
\nupon anything for nutrient utilization that nature already hasn’t tried.”<\/p>\n
\nbreeders, he emphasized, are “likely playing at the margins” when it
\ncomes to nitrogen-use efficiency.<\/p>\n
\nstrategy is to push farmers to use best practices: align their N applications
\nmore closely with their crops’ needs, perform more soil testing, try applying a
\nlittle less and see if yields hold steady, as Stephanie Ogburn summarized<\/a>. But here,
\ntoo, marginal results may be the most that can be hoped for.<\/p>\n
\nto Vitousek, such efforts can push nitrogen-use efficiency up to the 50 percent
\nor 60 percent level, but not much beyond. In other words, even using best
\npractices, our farm fields are doomed to leak away 40 percent of the N applied.<\/p>\n
\ntalked to, Vitousek argued that real progress in solving our N problem can only
\ncome with fundamental changes in both our eating habits and farms’ growing
\npractices.<\/p>\n
\naverage of more than a half pound of meat per day each day. The
\nlivestock feed needed to generate all that meat—and our dairy and egg habits—consumes more than 40 percent [PDF<\/a>] of our entire corn crop,
\nby far the world’s largest. Today, U.S. farmers grow 42 percent of the globe’s
\ncorn, more than twice the level of their closest competitors, Chinese farmers. (That doesn’t count the rapidly growing amount of
\ndistillers grains, an industrial waste product from the corn-ethanol stream that
\nends up in livestock rations.)<\/p>\n
\ncrop; and every year it blankets our best farmland. Moving away from
\nanimal-intensive diets, and restricting what meat we do eat to livestock in
\npasture-based systems, would greatly ease our need for synthetic N.<\/p>\n
\nhave to break the meat habit, farmers have to change their ways, too. The
\ncorn-soy-corn rotation that holds sway in the Midwest is deeply ingrained (so
\nto speak); it’s a tremendously productive system, underpinned by hundreds of
\nmillions of dollars in infrastructure. Think of all those vast grain elevators,
\nconcentrated-animal feedlot operations, and industrial-scale slaughterhouses,
\nto speak nothing of billions in annual crop subsidies.<\/p>\n
\nprofit for the meat and corn-processing industries rely on an ample supply of
\ncorn, and thus massive overuse of synthetic N. But if that inertia could be
\novercome—if new styles of agriculture could take root and flourish in
\nfarm-intensive areas like the Midwest—we could greatly decrease our reliance
\non synthetic N, Vitousek agreed.<\/p>\n
\nrotation is de rigueur. Moreover,
\norganic farmers apply no synthetic N, relying instead on organic N from animal
\nmanure and nitrogen-fixing legume cover crops. Where synthetic nitrogen
\nprovides a jolt of plant energy, organic nitrogen releases slowly—and is
\ntypically better matched to a plant’s hunger than is synthetic. And when
\nfarmers plant a fall cover crop like winter rye, the crop pulls up much of the
\nexcess nitrogen, keeping it in the field for the next spring’s planting,
\ninstead of letting it run off into springs or entering the atmosphere as
\nclimate-warming nitrous oxide.<\/p>\n
\norganic agriculture have a lot to say to us about maintaining nutrient balance in
\nthe soil and being able to sustain production in the long-term,” Vitousek
\nsaid.<\/p>\n
\nwasn’t preaching “fundamentalism” with regard to organic agriculture—the emphasis should be on minimizing agrichemicals like synthetic N, not eliminating them. He draw a parallel with integrated pest management (IPM), which views
\npesticides as merely one in suite of tools to control pests, not the only tool. “Integrated nutrient
\nmanagement, which draws tremendously on organic principles, is a crucial way
\nforward,” he emphasized.<\/p>\n
\nagricultural\/policy environment, “organic fundamentalism” seems like
\nan unlikely problem to have to worry about—not when the USDA’s research head is worried about the “safety” of organically fertilized food<\/a>—and even Vitousek’s vision of
\n“integrated nutrient management” seems far-fetched. The idea that
\n“organic can’t feed the world” has a stranglehold on public
\nconsciousness, thanks to million-dollar ad campaigns by biotechnology
\ncompanies designed to muffle international research<\/a> showing that world
\nhunger would best be tackled with sustainable small-scale agriculture
\nmethods and by increasing access to the more-than-adequate world supply
\nof calories.<\/p>\n
\nless meat and buying organic when possible, N-conscious citizens should prepare
\nto involve themselves in what promises to be a bitterly contested farm-policy
\ndebate. The 2012 Farm Bill may seem impossibly distant, but the lobbying for
\nthe principles that will form its foundation has already begun. The goal must
\nbe to shift federal funds from supporting large-scale corn production through
\ncommodity subsidies, to well-structured conservation programs that reward
\norganic-style production.<\/p>\n
\ndebate, keep an eye on the National Sustainable Agriculture Coalition<\/a>, which will be pushing a progressive agenda.<\/p>\n
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