sábado, mayo 15, 2010

How Organic Agriculture and Sustainable Food Systems Can Feed the World

Pesticide-laden agriculture is not going to save the world.

By Rachel Cernansky
Boulder, CO, USA | Thu May 6, 2010

organic foods photo

AP Photo/Charles Krupa

A recent story in Foreign Policy calls attention to "Whole Foods Shoppers: Stop obsessing about arugula. Your 'sustainable' mantra -- organic, local, and slow -- is no recipe for saving the world's hungry millions." In it, Robert Paarlberg makes some valid points, but makes a much larger number of questionable claims.

Let's look at some of them.

Paarlberg says: "Food grown organically -- that is, without any synthetic nitrogen fertilizers or pesticides -- is not an answer to the health and safety issues. The American Journal of Clinical Nutrition last year published a study of 162 scientific papers from the past 50 years on the health benefits of organically grown foods and found no nutritional advantage over conventionally grown foods. According to the Mayo Clinic, 'No conclusive evidence shows that organic food is more nutritious than is conventionally grown food.'"

TreeHugger has already debunked this widely-discussed claim: organic foods tend to be more nutrient dense than conventional foods. Findings by [The Organic Center in a different review of the same literature] were similar when it came to some of the nutrients analyzed by the FSA team, but differed significantly when it came to two critical classes of nutrients "of great importance in promoting human health - total polyphenols, and total antioxidant content."

According to TOC's study, "The average serving of organic plant-based food contains about 25% more of the nutrients encompassed in this study than a comparable-sized serving of the same food produced by conventional farming methods."

Pesticide levels are not measured by these nutritional analyses studies—neither are many cancer-fighting micronutrients, which would be handy to have to fight the toxic effects of pesticides on the body.

Paarlberg says: "industrial food systems [are] the current bugaboo of American food writers. Yes, they have many unappealing aspects, but without them food would be not only less abundant but also less safe."

That seems incongruous with the countless associations of E. coli with large-scale meat and dairy production.

And the recurrence of salmonella and E. coli in Nestle products.

And remember the 2006 spinach scare? According to Scripps, "The nine bags of baby spinach now linked by DNA testing to the outbreak were 'conventionally grown spinach and not organic...' This problem is suggestive of large-scale, industrial agriculture."

Paarlberg says: "Where industrial-scale food technologies have not yet reached into the developing world, contaminated food remains a major risk. In Africa, where many foods are still purchased in open-air markets (often uninspected, unpackaged, unlabeled, unrefrigerated, unpasteurized, and unwashed), an estimated 700,000 people die every year from food- and water-borne diseases, compared with an estimated 5,000 in the United States."

Yes, food- and water-borne diseases are a problem, but they are a result of inadequate infrastructure for clean water and sanitation; open-air markets are not the problem. (And I can't not point out that, environmentally speaking, those markets have something to teach us: they discourage the incessant overpackaging that has overtaken U.S. supermarkets.)

Here's the crux of Paarlberg's article, and the real reason for writing this post:

Paarlberg says: "Less than 1 percent of American cropland is under certified organic production. If the other 99 percent were to switch to organic and had to fertilize crops without any synthetic nitrogen fertilizer, that would require a lot more composted animal manure. To supply enough organic fertilizer, the U.S. cattle population would have to increase roughly fivefold. And because those animals would have to be raised organically on forage crops, much of the land in the lower 48 states would need to be converted to pasture."

To address this point, I asked both the Rodale Institute and the WorldWatch Institute, two leaders in sustainable and organic research, for their take.

Alison Grantham, research manager at Rodale, had this to say:

The nitrogen fertility of organic agriculture is based on legumes (both crops and cover crops)—not on manure. A conversion to organic would require replacing the synthetic nitrogen currently used to maintain corn production with non-synthetic nitrogen sources like legume cover crops (crops grown for their soil fertility benefits and not for harvest), legume cash crops (like hay, or beans and peas, that are harvested), or outside inputs like manure or fish fertilizer.

Clearly, for organics to expand on a large scale, each land unit would have to be self-sufficient in nitrogen. One way to do this is with winter annual legume cover crops, like crimson clover, hairy vetch, or winter peas. These cover crops can be planted after small grain crops have been harvested in late summer or early fall, and then they can grow through the fall and in the spring to produce enough nitrogen to support a cash crop like corn through the late spring and summer.

This is from WorldWatch researcher Brian Halweil's response:

"The issue of nitrogen is different in different regions," says Don Lotter, an agricultural consultant who has published widely on organic farming and nutrient requirements. "Lots more nitrogen comes in as green manure than animal manure."

Looking at 77 studies from the temperate areas and tropics, the Michigan team found that greater use of nitrogen-fixing crops in the world's major agricultural regions could result in 58 million metric tons more nitrogen than the amount of synthetic nitrogen currently used every year. Research at the Rodale Institute in Pennsylvania showed that red clover used as a winter cover in an oat/wheat-corn-soy rotation, with no additional fertilizer inputs, achieved yields comparable to those in conventional control fields. Even in arid and semi-arid tropical regions like East Africa, where water availability is limited between periods of crop production, drought-resistant green manures such as pigeon peas or groundnuts could be used to fix nitrogen. In Washington state, organic wheat growers have matched their non-organic neighbor's wheat yields using the same field pea rotation for nitrogen. In Kenya, farmers using leguminous tree crops have doubled or tripled corn yields as well as suppressing certain stubborn weeds and generating additional animal fodder.

The Michigan results imply that no additional land area is required to obtain enough biologically available nitrogen, even without including the potential for intercropping... rotation of livestock with annual crops, and inoculation of soil with... free-living nitrogen-fixing bacteria.

READ THE REST AT: http://planetgreen.discovery.com/food-health/organicagriculture-sustainablefood-feed-world.html

Etiquetas: , ,

0 Comentarios:

Publicar un comentario

Suscribirse a Comentarios de la entrada [Atom]

<< Página Principal