유기농 음식이 해답인가?

저널리스트 Marc Gunther는 최근 미래의 지속가능한 먹을거리 체계에서 유기농업의 역할에 대한 대중의 인식을 논의하는 사려깊은 기사를 게재했다.

그는 많은 소비자가 먹을거리를 생산하는 데에는 두 가지 방식만 있다고 믿는다는 걸 발견했다:

"첫 번째는 크고, 빠르고, 현대적이고, 관행적이며, 산업형이고, 집약적이고, 화학적이고, 유전자조작이고, 가공되고 세계적이라고 기술할 수 있다. 그것은 대부분의 미국인이 먹는 식량의 대개가 오는 체계이다."

"두 번째는 유기적이고, 지속가능하고, 지역적이고, 소규모이고, 가족이 운영하고, 자연적이고, 생태농업적이고 느리다고 기술한다. 그것은 농민장터와 지역사회 지원 농업만이 아니라 온전한 음식의 성장이 동력이 되고, 점점 홀푸드, 월마트, 세이프웨이, 그로거와 같은 큰 회사에서 심각하게 고려하고 있다."

그러나 미국과 세계에서 농법은 그렇게 흑백이 아니다.

USDA의 National Organic Program Standards는 농장이 가족이 운영하고, 지역적이거나 소규모인 것을 요구하지 않는다. 예를 들어 Earthbound farm을 보자. 이 1억 2000만 평을 인증받은 엄청나게 큰 유기농 농장은 먼 지역으로 가공, 포장된 채소 상자들을 판매한다. Earthbound는 크고, 빠르고, 현대적이고, 산업형이고, 집약적이고... 인증받은 유기농이다. 그것이 반드시 부정적인가? 난 그렇게 생각하지 않는다. 그들은 인상적인 사업을 벌이고 훌륭한 채소를 생산한다. 그러나 그들 활동의 한 문제점은 세척하고 탈수하는 데 소비되는 시간을 줄이고, 해마다 수백 만 개의 플라스틱 용기를 발생시키는 편리한 포장재이다. 

가장 성공적인 유기농 농장의 일부는 거대학고 세계적일 뿐만 아니라, 유기농 먹을거리를 사는 기업(Whole Foods, Walmart, Safeway and Kroger)의 일부이기도 하다.

일부 지역의 딸기 생산자들이 반대의 예를 보여준다. 저쪽으로는 8000평 미만의 가족농이다. 그들은 해마다 끊임없이 작물을 돌려짓기하지 않고, 이삼 년에 한 번 그들의 밭을 덮고서 화학적 훈증을 하며 지역의 딸기를 기른다. 이러한 딸기는 지역적이고, 소규모이고, 가족이 운영하고 ...화학적으로 집약적이다. 우린 그들의 딸기를 사지 않고, 직접 기른다.

두 가지 농업 관점을 확 비트는 또 다른 원숭이는 유전자조작된 파파야이다. 내가 전에 다루었듯이, 유전자조작 파파야는 하와이에서 육종하는 지속가능하고, 소규모이고, 기업적 접근이 아닌 전형적인 예이다.

풀은 양분과 햇빛을 놓고 경쟁하기에 세계적으로 작물 생산의 주요한 장애물이다. 이러한 풀은 또한 동물에게 독이 될 수 있어 사료를 기르는 사람에게도 문제이다. 풀을 관리하는 하나의 방법은 그들을 죽이는 제초제를 치는 것이다. herbicide glyphosate(판매명 Roundup)와 같은 일부 새로 나온 제초제는 무독성으로 간주된다(class IV). 유전자조작된 제초제 라운드업 레디 저항성 알팔파의 사용은 더 많은 독성 제초제의 사용을 줄인다. 이는 유전자조작된 알팔파가 낙농업자에게 매력적인 이유의 하나이다. 그것은 그들의 비용을 줄이고 농장 일꾼에 대한 해를 줄이고, 동물들이 더 안전한 사료를 먹도록 한다.

유기농과 관행농의 농법을 비교하는 것은 또한 간단하지 않다. 돌려짓기와 유기물 주기는 유기농 재배자가 침식을 줄이는 데 도움이 되는 한편, 대부분의 유기농 재배자는 또한 흙을 저하시키고 침식에 기여하도록 농사철마다 밭을 갈아엎는다. 제초제 저항성 옥수수와 콩을 기르는 관행농 농민은 겉흙이 온전하게 남고 비바람에 쓸려가지 않도록 보호하는 저-경운과 무-경운 농업을 사용할 수 있다. 그러한 무-경운 방법은 수질을 개선하고 토양침식을 줄인다. 또한 트랙터 경운이 최소화되기 때문에 연료를 덜 소비하고 온실가스 배출도 줄어든다.

이는 농법의 복잡성에 대한 몇 가지 예를 지적한 것뿐이다. 정답은 없다. 이것과 다른 유전자조작 작물에 대한 동료의 평가, 과학에 기초한 정보는 최근의 review를 보아 달라.

Gunther는 이렇게 썼다,

"I'm skeptical in particular of the claim that organic agriculture is as productive or more productive than farming methods that use synthetic chemicals and genetically-modified foods. Partly that's because most farmers have embraced modern ag. Less than 1% of US farmland is farmed organically. If farmers could improve their yields by giving up chemicals and genetically modified seeds, why wouldn't they?"

With 80-95% of all sugar beets, corn, soy and cotton in the US, grown from genetically engineered seed, many farmers have clearly made their choice. The reason is that GE crops can be more profitable due to reduced input costs (fewer insecticides and reduced tillage). Other benefits include massive reductions in insecticides in the environment (Qaim and Zilberman 2003; Huang et al. 2005), improved soil quality and reduced erosion (Committee on the Impact of Biotechnology on Farm-Level Economics and Sustainability and National Research Council 2010), enhanced health benefits to farmers and families as a result of re-duced exposure to harsh chemicals (Huang et al. 2002, 2005), economic benefits to local communities (Qaim et al. 2010), enhanced biodiversity of beneficial insects (Cattaneo et al. 2006), and reduction in the number of pest outbreaks on neighboring farms growing nongenetically engineered crops (Hutchison et al. 2010). Genetically engineered crops have also dramatically increased crop yields-- ca. 30% in some farming communities in developing countries (Qaim et al. 2010).

Another reason modern farmers don't switch to organic is due to the complexity and cost of organic fertilizers. Compost and cover crops are the two main nutrient sources of organic growers. To grow corn, at least 10 tons/acre of compost would be required. The cost of compost varies, but this could easily be $120/acre, plus the costs of delivery and spreading. For a 2,000 acre farm the costs of using compost would be high, if it was available. If a farm is not located near a city or a livestock operation, compost may not be an option. Green manure, cover crops that fix nitrogen, are wonderful, but they take time during the year to grow and there are costs associated with buying and planting the seed. In many areas of the corn belt, cover crops would need to be grown instead of corn or soybeans, and yields of the food crops would be reduced. Some of this can be mitigated if the farmer used a rotation of corn, soybeans, a small grain, and alfalfa, where the alfalfa (harvested for hay), which also is a nitrogen fixing legume, takes the place of cover crop. This kind of rotation requires the corn-soybean grower to buy new equipment and develop new markets, another obstacle to changing to organic.

At a recent meeting of organic advocates, Gunther asked the attendees why they are against genetically engineered crops in light of the contributions of such crops to sustainable agriculture.

He received diverse answers to his query. Here is a smattering:

"Big seed companies the market and push farmers towards GM crops".

Although many people feel comfortable buying their computers from Apple and their software from Microsoft, they still may not like large seed companies.This is partly because consolidation in the seed industry can be a problem for some growers. A few large corporations are controlling more and more of the seed used by conventional and organic farmers. Hybrid, non-hybrid, and genetically engineered crop seeds are increasingly being patented or protected through the Plant Variety Protection Act. While there are efforts within the organic community to reduce dependence on large seed companies, the challenges to produce high quality seed, containing the traits demanded by farmers and consumers in sufficient quantities for millions of acres, is immense.

" Because farmers, like the rest of us, are influenced by their peers, they have a reluctance to go against the grain."

Farmers are influenced by other farmers for good reason: other farmers have the on-hands experience with a particular seed or farming practice and therefore are often in the best position to provide information on whether or not a particular new approach can benefit sustainable practices and enhance profit.

"The scientific evidence for the health benefits of organic is a matter of great debate."

Actually, while you can still find ample debate on the blogs, the scientific evidence is clear:organically produced food is nutritionally equivalent to conventionally produced food. 

When it comes to nutrition there are limits to what conventional plant breeding can offer. Because organic farming prohibits the use of genetically engineered seed, potential nutritional benefits provided by modern seed varieties will not be available to organic consumers. For example, according to research published in the American Journal of Clinical Nutrition, daily consumption of a very modest amount of genetically engineered, Golden Rice - about a cup (or around 150 g uncooked weight) - could supply 50 percent of the Recommended Daily Allowance of vitamin A for an adult.

"Because a large proportion of vitamin A-deficient children and their mothers reside in rice-consuming populations, particularly in Asia, Golden Rice should substantially reduce the prevalence and severity of vitamin A deficiency, and prevent at least hundreds of thousands of unnecessary deaths and cases of blindness every year," says Alfred Sommer, professor and dean emeritus at the Johns Hopkins Bloomberg School of Public Health. Golden Rice is expected to cost farmers about the same as other rice, and they will be able to save seeds for replanting.

"it strikes me as entirely possible (albeit unproven) that chemical pesticides could do some of us some harm."

A correction for Marc. There is ample scientific evidence that some pesticides (both organic pesticides and conventional) do cause harm the health of farmworkers.

Chronic exposure to rotenone, a certified organic pesticide, can cause damage to liver and kidney. Methyl bromide, widely used on strawberries for years, is associated with an increased risk of prostate cancer in farm workers. There are many other examples of harm to farmworker health. Pesticide residues on food are generally so small that the consumer is not affected.

For these reasons, reducing the use of agricultural chemicals is one of the important goals of sustainable agriculture. It is clear that organic practices have reduced pesticides on 1% of US cropland. It is also clear that GE crops like BT corn and cotton have reduced insecticide use on hundreds of millions of acres throughout the world [10% of the ~1.5 billion hectares (3.7 billion acres) of global cropland]. In 2010, 90% of the15.4 million growers of these crops were small resource-poor farmers in developing countries.

As every farmer knows, farming practices span a continuum. Each season, crop and location brings challenges.

Pitting farming practices against each other only prevents the transformative changes needed on our farms. Without good science and good farming, we cannot even begin to dream about establishing an ecologically balanced, biologically based system of farming and ensuring food security.