@農자료창고

Beijing has been battling an unwelcome, unrelenting and "very unhealthy" smog for many months, much of it made up of particulate nitrogen compounds suspended in the air. Nitrogen pollution in China has kept pace with the country's rapid growth. A study published in Nature last week finds that the rate of nitrogen pollution grew by more than half in the last 30 years.

Researchers from China Agricultural University analyzed data from across the country and found the amount of nitrogen expelled into its surroundings every year rose by 8 kilograms per hectare every year between 1980 and 2010. While most of the nitrogen still comes from waste fertilizer, the source of nitrogen pollution is shifting from agriculture to industry and transport.

One of the byproducts of this saturation is nitrous oxide, one of the most threatening global warmers along with carbon dioxide and methane.

The levels of nitrogen now seen in China are similar to the levels in Europe in the 1980s, before it implemented countermeasures to protect its environment. The deposition is also well in excess of all defined threshold limits and critical load levels, said Peter Vitousek, ecologist at Stanford University and co-author of the study.

Most of China's nitrogen pollution is in the form of ammonia compounds, the kind found in fertilizer. "In the highly productive regions of China, they are putting on often two or three times more fertilizer that a Midwestern American or European farmer would use. It is often in excess of what the crop can take up, and then that is lost to the environment," Vitousek said. "There isn't any way to use fertilizer without some loss to the environment, but in China the amount is far in excess of what's required."

Senior scientist at Woods Hole Research Center Eric Davidson said the excessive fertilizer use is inspired by the need for food security. one of the biggest drivers of nitrogen pollution in China is that they are increasing their agricultural productivity."

'Astounding' levels of fertilization
"Food security is a very big issue in China, so the Chinese government has been subsidizing fertilizer costs, and as a result farmers in China are using fertilizer rates that are astounding," said Davidson, who is one of the authors of a recent U.N. Environment Programme report on global nutrient supply.

While ammonia compounds associated with farming were five times as prevalent as nitrogen oxides in the 1980s, they are now only twice as common in China's water, soil and air. The rise of coal plants, industrial production and motor vehicles spewing nitrogen oxides has tilted this balance. Coal consumption in China has risen more than threefold since the 1980s, and there are close to 21 times more wheels on China's roads.

The study, which divided the country into six economic regions, reveals that most areas that have the most factories and farms have nitrogen deposition rates higher than the national average. "The difference was really to separate the areas where economic development has been most rapid and where there's not," Vitousek said. "It is also to provide information to the Chinese authorities, who will have to take action regionally."

Both nitrous and ammoniacal pollutants are continuously and rapidly accumulating in China's environment and contribute to aerosol formation. Oxidized nitrogen becomes part of photochemical smog and ozone and is a major component of the infamous PM 2.5, particulate matter less than 2.5 microns in diameter that decreases visibility and is harmful when inhaled because it can penetrate deeply into the lungs.

A half-life of 100 years
"The problem with nitrous oxide is that its half-life in the atmosphere is more than 100 years. Even if we were to mitigate nitrous oxide now, we would still be paying the price for many generations to come," Davidson said.

The varied and widespread symptoms of nitrogen pollution are grassland changes, acidic soils, stressed biodiversity, marine pollution, algal blooms and dying fish. Even areas of China far away from the source of pollution are feeling these symptoms as surplus nitrogen cascades through its habitats.

The China Agricultural University researchers studied the increased nitrogen uptake in plants that received no nitrogen fertilizer to drive home their point that "all these changes can be linked to a common driving factor, strong economic growth."

The study calls for Chinese authorities to reduce ammonia emissions from agricultural sources and curb nitrous oxide pollution from industry and traffic. "The tricky thing about nitrogen is it's related to food production. So there is no question that we need to have nitrogen added to crops. It's inevitable that there will be some leakage of nitrogen from the croplands. But you have to have it to grow food for 7 billion people," Davidson said.

"We know a lot about how to reduce emissions from smokestacks and tailpipes and agricultural runoff," he added, explaining that it's not a question of how to do it but that it requires personal, political and economic incentives.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500

먼저 캐나다에서 공부하고 계신 박성실 님(https://twitter.com/GorillaGreen) 덕에 재미난 분을 알게 되어 감사의 인사를 전합니다. 

박성실 님이 올리신 트윗을 보고 '아키츠 모토키'라는 일본 교토대학의 농대 교수를 알게 되었습니다(https://www.gcoe-intimacy.jp/staticpages/index.php/akitsu_en). 프로필을 보면 한국에서 현지조사를 한 적도 있는 사람인 것 같네요.

이 사람이 박성실 님이 계신 캐나다에서 일본의 도시농업과 관련하여 발표를 했다는데, 그 내용이 흥미롭습니다. 한국에 몇 번 왔던 요시다 타로 씨보다 '도시농업'과 관련해서는 더 풍부한 내용을 이야기해줄 수 있는 사람인 것 같습니다.

아래는 박성실 님이 올린 트윗을 정리한 내용입니다. 같이 보시죠.

- 도쿄의 도시농업이 지역민의 소속감을 증진시킨 과정

도쿄의 도시화가 가속화되기 전 도쿄 안에서 농사짓던 농부들 중 땅을 팔지 않고 가지고 있던 사람들에게 일본 정부는 농사를 짓지 않으면 세금을 많이 물리고, 농사를 짓는 경우에만 농지로 적용하여 적은 세금을 물리려고 했다. 그래서 무거운 세금징수를 피하려면 계속 농사를 지을 수 밖에 없었는데, 가족농 체제가 와해되며 혼자서 농사짓기 힘들어져 농지를 이웃주민들에게 작은 구획으로 나누어 임대를 주게 되었다.

자신이 농사짓는 것을 증명해야 낮은 세금을 내기 때문에, 토지를 소유한 농부는 땅만 빌려주고 손을 놓아 버리는 것이 아니라 이웃주민들의 농사를 관리하는 역할을 하게 된다. 농업 교육과 농자재 관리 및 공동체 활동기획과 운영 등을 시작한다. 그러면서 작은 땅을 빌려 농사짓게 된 이웃주민들은 그 농장을 사랑방처럼 이용하게 되고, 그러한 과정을 거치며 지역공동체에 대한 소속감이 자라고 유기농업에 대한 실험과 헌신성이 커졌다. 그렇게 도쿄에는 도시 안의 공동농업 공동체들이 하나둘씩 생겨났고, 사람들은 자신이 사는 집 근처에 있는 농지 한 켠을 빌려 농사짓는 일이 늘어나 집과 텃밭까지의 이동거리도 많이 줄어들었다.

일본의 도시농업에서는, 농지를 빌려주고 활동 전반을 지도하는 "농부"와 농지를 빌려서 농부에게 농사를 배우며 지역공동체 활동에 참여하는 "사용자" 또는 "참여자"로 그 역할이 나뉘었다. 도쿄 안에서는 기존의 농부 혼자서 농사를 짓기가 어렵고, 소농은 땅값이 너무 비싸 땅을 사지 못하기에 도시로 진입하지 못한다. 그래서 여가를 활용해 텃밭 농사를 짓는 "참여자"와 그들을 관리해주는 "농부"의 관계가 정착되었다.

이상입니다. 

10년 전 한창 수도권의 농지에서 주말농장 붐이 일어났습니다. 위의 이야기를 들으니 그때의 모습이 떠오릅니다. 당시 우후죽순처럼 생기던 주말농장들 가운데 대부분은 몇 년 지나지 않아 운영을 그만두고 사라졌지만, 그렇지 않고 계속 운영을 하는 곳도 있습니다. 대표적인 것이 전국귀농운동본부와 함께 운영된 생태주말농장입니다. 

이 생태주말농장은 빠른 곳은 2000년 초반부터 운영을 시작했습니다. 이곳은 단지 도시민의 여가 활용을 위한 공간만이 아니라 일종의 귀농 실습지로 활용되었습니다. 당시 이 생태주말농장을 거쳐 귀농한 사람들이 지금도 전국 곳곳에 자리하고 있을 정도입니다. 

이후 귀농의 바람이 조금 가라앉으면서 새로운 바람이 불었는데, 그것이 바로 도시농업입니다. 그때부터는 꼭 귀농을 하겠다는 사람보다 도시에 살면서 생태적인, 친환경적인 삶으로 나아가려는 사람들이 하나둘 늘어나기 시작했습니다. 물론 그들의 최종 목표가 여전히 귀농인 사람들도 있습니다. 아무튼 개인적인 사정으로 바로 귀농을 할 수 없거나, 아니면 도시의 회색빛 삶에 지친 사람들에게 생태주말농장은 농사의 맛을 느끼며 함께 어울리는 공동체 문화를 향유할 수 있는 사랑방 같은 역할을 담당하게 됩니다. 

거기에서 농사짓는 사람들은 자연스럽게 선배 귀농자나 농민의 든든한 지원자가 되면서 그들의 농산물을 적극적으로 구매하고 홍보하는 역할까지 도맡는 도농 간의 연결고리 역할까지 담당하게 되지요. 그뿐만 아니라 자신의 텃밭에서 수확한 작물을 이웃과 나누면서 도시 안에서 농사의 재미를 알리는 홍보까지 담당하기도 합니다. 더 나아가 도시화와 개발로부터 농지와 그를 둘러싼 주변 자연환경을 지키는 농지와 자연 생태계의 지킴이 역할을 통하여 생물다양성을 풍부하게 하는 것은 물론, 유기농업을 실천하여 집에서 똥오줌과 음식물쓰레기를 받아다가 직접 거름을 만들어 씀으로써 환경을 보호하는 역할까지 담당하고 있습니다. 또한 일부 생태도시농업 농장에서는 토종종자를 활용하여 농사를 지으면서 사라져가는 토종 씨앗을 보존하는 역할까지 담당하고 있습니다. 이렇게 도시농업의 스펙트럼과 담당하는 역할은 엄청나게 다양합니다.

이러한 내용으로 조사하여 구조를 잡아 글을 쓰면 재미있는 논문 한 편이 탄생하겠네요. 주말농장에 관한 논문은 꽤 있는데, 주말농장 운영에 대한 것(http://goo.gl/rgnBU)이나 사회경제적 효과에 대한 것(http://goo.gl/nPV08), 재배하는 작물에 대한 것(http://goo.gl/mmt8h) 등이 보입니다. 헌데 도농교류, 공동체 문화의 회복, 도시에서의 생태적 삶, 토종 씨앗의 보존 등의 내용을 다루는 논문은 아직 없는 듯합니다. 누가 이러한 주제로 논문을 쓰지 않으시렵니까? 

CLOSE THE YIELD GAP:

An international research team led by Jon Foley at the University of Minnesota's Institute on the Environmenthas devised a 5-step plan to double global food production by 2050 as well as reduce the widespread environmental harm posed by contemporary agricultural practices. All maps here were produced by Jamie Gerber at the institute. Step 1 is to raise the crop yield of the world's most ineffective farms to 95 percent of the best yields attained by farmers in similar climates. Closing this "yield gap" for the top 16 crops worldwide could produce 50 to 60 percent more food.

MORE MAIZE:

Improving seeds, irrigation, fertilizer use and markets would drive up yield for many crops. For example, the yield for maize (shown) could rise significantly across parts of Mexico, Africa, Eastern Europe and elsewhere.

MORE MAIZE:

Improving seeds, irrigation, fertilizer use and markets would drive up yield for many crops. For example, the yield for maize (shown) could rise significantly across parts of Mexico, Africa, Eastern Europe and elsewhere.

CLOSE THE DIET GAP:

If the world's top 16 crops were grown only for human food, instead of the current mix that includes animal feed and biofuels, a billion tons more human food would be available—roughly equivalent to three quadrillion kilocalories. Reducing waste is a corollary step: Roughly 30 percent of the food grown worldwide is lost to failed crops, stockpiles ruined by pests, food that is never delivered because of bad infrastructure or markets, and food that spoils or is thrown away after purchase.

STOP BURNING TROPICAL FORESTS:

The industry of agriculture is so massive that it now constitutes a grave environmental threat. Producing even more food would severely damage the planet. Agriculture has expanded its output in recent years primarily by clearing land. Today humankind cultivates 38 percent of Earth's ice-free surface; pastures and rangelands for livestock cover two thirds of that area, and croplands cover the rest. Because most of the remaining land is desert, mountainous, tundra or urban, expansion today occurs mostly by burning down tropical forests and savannas, which releases vast quantities of carbon dioxide into the atmosphere and severely reduces biodiversity.

USE FERTILIZER MORE EFFICIENTLY:

Environmental damage also results from massive overuse of fertilizer. Incredible volumes of excess nitrogen, alone, run off crop fields into rivers and oceans, creating enormous "dead zones" like the one that develops annually in the Gulf of Mexico, which have grown in past years to cover areas the size of Connecticut or New Jersey. Farms in the central U.S. are extremely wasteful, but so are those in much of Europe, India and China. Foley's group estimates that 10 percent of the world's croplands account for 32 percent of the global nitrogen surplus—hot spots that could use much less fertilizer and still achieve the same yield.

To feed the world's growing and more affluent population, global agriculture will have to double its food production by 2050. More farming, however, usually means more environmental harm as a result of clearing land, burning fossil fuels, consuming water for irrigation and spreading fertilizer. Agriculture already imposes a greater burden on Earth than almost any other human activity, so simply doubling current practices would ruin large areas of land as well as poisoning rivers and oceans.

An international research team led by Jon Foley at the University of Minnesota has concluded that five basic changes in the way agriculture operates—and in the ways we eat—could double food production, yet decrease overall environmental impacts. The steps are as follows: improve crop yields, consume less meat, reduce food waste, stop expanding into rainforests, and use fertilizer and water more efficiently. The changes are reflected in a series of maps. For a detailed explanations, see "Can We Feed the World and Sustain the Planet?".

http://www.scientificamerican.com/article.cfm?id=foley-global-food-production-reduce-environmental-damage-maps

유엔 환경계획과 국제 수자원관리연구소에 따르면, 농업은 생태계를 보호하면서도 생산을 2배로 올릴 수 있다고 합니다. 자세한 내용은

http://www.iwmi.cgiar.org/Topics/Ecosystems/PDF/Synthesis_Report-An_Ecosystem_Services_Approach_to_Water_and_Food_Security_2011_UNEP-IWMI.pdf