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译:Can eco-farming help fight hunger?

来源: 时间:2011/5/4 9:54:00 点击:

A recent UN report says that combining ecology and agronomy can help smallholder farmers to increase food production. Jill Richardson examines the implications.


With food prices at an all time high, the number of people going hungry in the world may once again rise above one billion. For many years now, world leaders and international institutions like the United Nations and the World Bank have grappled with how to increase food production to feed a growing population while simultaneously mitigating climate change and confronting a shortage of resources like oil, water and topsoil.

Now a recent report by the UN Special Rapporteur on the Right to Food, Olivier de Schutter, has said that the approach known as agroecology has the potential to double food production in key areas within 10 years, while simultaneously providing rural livelihoods, sequestering carbon and building in resilience to climate extremes.

“To feed 9 billion people in 2050, we urgently need to adopt the most efficient farming techniques available. And today’s scientific evidence demonstrates that agroecological methods outperform the use of chemical fertilisers in boosting food production in regions where the hungry live,” said de Schutter. He added, “We won’t solve hunger and stop climate change with industrial farming on large plantations.” The majority of the world’s hungry are smallholder farmers. The evidence shows that, using agroecology, these farmers can increase their food production to provide for their families.

Agroecology combines the fields of ecology and agronomy, seeking to build sustainable, diverse and productive agroecosystems by mimicking nature. Often, agroecology begins by observing traditional or indigenous agriculture and analysing the scientific principles underlying them. In this way, modern science can help improve -- but not discard and replace -- traditional agricultural systems, effectively making use of local knowledge and resources. The new report describes one agroecological system used in east Asia, in which a farmer raises rice, ducks and azolla (an aquatic fern) together. The azolla suppresses weeds and provides nutrients to the rice and food for the ducks, while the ducks eat bugs that might otherwise become pests to the rice. Thus, the farmer will not need to purchase additional inputs like fertiliser, herbicides or insecticides in order to produce both rice and ducks.

Marcia Ishii-Eiteman, a senior scientist with Pesticide Action Network, summarised the benefits of agroecology: “Through ecological practices, farmers can increase biological diversity, decrease erosion, improve water and nutrient cycling, provide habitat for pollinators and build the soil’s organic matter.” Ishii-Eiteman was one of over 400 scientists who worked on the International Assessment of Agricultural Knowledge, Science, and Technology for Development (IAASTD) report, published in 2008. This report also found that agroecology promised a powerful means for smallholder farmers to increase food production and decrease hunger in the world.

According to Eric Holt-Gimenez, executive director of Food First, an organisation that works to eliminate the injustices that cause hunger, agroecology is used by peasant farmers throughout the developing world. For example, the Campesino a Campesino Movement has spread it throughout many parts of Latin America, Africa and Asia over the past two decades. Noting that agroecology has largely been ignored or even criticised by industry and governments as being unable to produce enough food to end hunger, he said: “Agroecology has been spread primarily by peasant and smallholder groups and NGOs, often working with independent scientists… Because of this, practice is racing far ahead of theory. It is actually a very exciting field of science because of its tremendously positive impact on the ground with relatively little investment.”

The only government in the world to promote agroecology in a significant way is Cuba, which adopted agroecology out of necessity: after the fall of the Soviet Union in 1989, the communist state was left outside the network of international trade others relied upon to produce and import food. Cubans refer to the years that followed as the “Special Period”. It was a time when Cubans, without access to the necessary oil, fertiliser and pesticides to grow their food using industrial methods, had their lives turned upside down. But Cuba acted quickly to adopt and disseminate agroecological farming methods among its people. Because of fuel shortages, it also had to locate farms and gardens in and around urban areas to minimise transportation needs. Holt-Gimenez calls Cuba “a very hopeful example of what could be if government really got behind the agroecological approach.”

To date, the United States has not embraced agroecology, either among its own farmers or in its efforts to provide agricultural aid abroad. In the US, a small percentage of farms are now organic and grow food without nitrogen fertiliser, toxic pesticides or genetically modified seeds. However, most American organic farms practice input substitution, an intermediary step between industrial agriculture and agroecology. In the input substitution stage, chemical inputs are each replaced with organic ones; manure is used instead of nitrogen fertiliser; and organic pesticides like Bt are used instead of more toxic and persistent ones. However, true agroecological design is “probably rare” in the US, said Holt-Gimenez, though he noted that some wineries were converting to agroecology.

One of the most famous agroecological farms in the US is Polyface Farms, the Virginia farm of Joel Salatin. Salatin has carefully choreographed an “orchestra” of livestock, rotating each species around his farm to maximise productivity and ecological benefit. First, his beef cattle will graze a pasture before they move on to a new location. A few days later, after fly larvae have hatched and grown fat in the manure the cattle left behind, Salatin will bring in his portable chicken coop. The chickens eagerly eat the fly larvae, ridding Salatin of an insect problem while also spreading the manure so it can fertilise the soil. In this way, the cattle and chickens are moved around the farm, allowing each pasture to recover from grazing before the cattle return once again. He has similarly clever strategies for raising his pigs, rabbits and turkeys.

In his report, de Schutter wrote that agroecology’s “resource-conserving, low-external-input techniques have a proven potential to improve yields,” citing a study that found an average increase in crop yields of 79% once agroecological techniques were adopted. The report also noted the importance of biodiversity in improving the diets of smallholder farmers. While the majority of one’s calories may come from staple grains like rice, wheat or maize, supplementary foods grown in biodiverse agroecological systems will provide vital nutrients or even provide an important source of food during lean times.

The report also emphasised the importance of adopting agricultural techniques that can both mitigate climate change and provide resilience to the increasing climate extremes the world will likely experience in the coming years. First, it lauds agroecology for “delinking food production from the reliance on fossil energy (oil and gas)” and contributing to “mitigating climate change, both by increasing carbon sinks in soil organic matter and above-ground biomass, and by avoiding carbon dioxide and other greenhouse gas emissions from farms by reducing direct and indirect energy use.” Additionally, it notes agroecology’s ability to “significantly cushion the negative impacts” of extreme weather events like droughts or hurricanes.

In his report, de Schutter calls for nations to take actions to help smallholder farmers in developing nations adopt agroecological farming, like reinvesting in agricultural research and extension services, investing in forms of social organisation that encourage partnerships, empowering women and “creating a macro-economic enabling environment, including connecting sustainable farms to fair markets.”

The United Nations Food and Agriculture Organization has estimated that the world must increase food production by 70% by 2050 in order to feed a population of over 9 billion. If the world follows the path outlined in de Schutter’s report and attains the productivity gains that the research indicates are possible, then it could even exceed that necessary increase in food production -- and it could do so long before 2050.

(译文如有出入请联系本会,来源于chinadialogue)

译   文:

生态农业:饥饿的救星?

  一项最新的联合国报告认为,生态学与农学的携手可以帮助小型农户提高食品产量。吉尔•理查德森对此进行了探讨。


  随着粮食价格的持续增长,世界的饥民可能会超过10亿。如今,世界各国领袖和联合国、世行等国际机构也已经争吵多年,争吵的内容就是如何增加粮食生产,满足不断增长的人口的需求,同时还要减缓气候变化、应对石油、水和表土等资源的短缺。

  联合国粮食权利特别报告员奥利维·德·舒特在一份最新报告中指出,生态农业有望在十年内让主要产粮地区的粮食产量翻番,同时还能为农村开辟生路、实现碳隔离,并且建立对气候极限的适应性。

  “2050年世界人口将增加到90亿,为了养活他们,我们亟需采取最高效的农业技术。当前的科学证据表明,生态农业方式在提高饥饿地区的粮食产量方面的作用绝对胜过化肥,”德·舒特说,“靠着大型农场的工业化耕作,我们是无法解决饥荒、制止气候变化的。”世界饥民中的大多数都是小型农户,证据表明,通过生态农业方式,这些农户可以提高粮食产量来养活家人。

  生态农业就是把生态学和农学进行跨领域结合,力图通过模拟自然、建立可持续、多样性和高产出的生态农业系统。生态农业一开始经常要对传统或者原生农业进行观察,分析其背后的科学原理。通过这种方式,现代科学可以帮助改进(请注意,不是抛弃或替代)传统农业系统,有效地利用当地的知识和资源。德·舒特在新报告中提到了东亚的一种生态农业系统,即稻-鸭- 共作模式。浮萍能够抑制杂草的生长,为水稻提供了养料,为鸭子提供了食物,同时鸭子吃掉了可能危害水稻的虫子。这样一来,农民就不需要再进行肥料、除草剂和杀虫剂等额外投入。

  玛西亚·伊什-埃特曼是英国农药行动网络的高级科学家,他在总结生态农业的益处时说:“通过生态方式,农民们可以提高生态多样性,减少水土流失,改善水和养分的循环,为传粉昆虫提供栖息地,培养土壤中的有机质。”埃特曼是参与“国际农业知识与科技促进发展评估”报告撰写的四百位科学家之一,该报告于2008年发表,它也指出生态农业为小型农户提高粮食产量和减少世界饥饿提供了一种强有力的方式。

  “粮食优先”是一个致力于消除引发饥饿的不公正的组织,其执行主席埃里克·霍尔特-吉莫涅茨认为生态农业主要被发展中国家的小型农户所采用。比如,“农夫农夫运动”过去二十年中在拉丁美洲、非洲和亚洲的很多地方大力推广生态农业。他指出,生态农业一直被产业界和各国政府忽视甚至批判,认为它无法生产足够的粮食来消除饥饿,他说:“生态农业的推广工作一直是由农民、小型农户组织和NOG进行的,他们的合作对象常常是独立科学家……正因为如此,生态农业的理论研究远远落后于实践。这确实是一个非常具有吸引力的科学领域,因为它效果非常积极而且投入相对很小。”

  唯一一个通过政府途径大力推广生态农业国家就是古巴,但它实施生态农业也是迫不得已的。1989年苏联解体后,古巴失去了赖以生产和进口粮食的国际贸易体系,古巴人将这一段时间称为“特殊时期”。在这一时期,由于无法获得必需的土壤、肥料和农药来进行工业化的粮食生产,古巴人的生活水平一落千丈。但该国很快就开始在群众中采取并推广生态农业的耕作方式。由于燃料短缺,他们不得不把农场和菜园设在城市周边,以便把运输需求最小化。霍尔特-吉莫涅茨说古巴“是一个光辉典范,充分展示了政府切实支持生态农业方式的强大效用”。

  迄今,美国政府还没有采取任何生态农业措施,无论是在国内农场还是为外国提供的农业援助里。在美国,有一小部分农场现在进行有机农业生产,在食品生产中不使用有氮肥、毒农药或者转基因种子。但是,美国大多数有机农场采取的都是“输入替代”方式,这是一种介于工业化农业和生态农业之间的中间阶段。在“输入替代”阶段,化学输入物被各自的有机输入物所替代;粪肥替代了氮肥;Bt等有机农药替代了毒性更大的或者残余性更久的。但是,霍尔特-吉莫涅茨说真正的生态农业实践在美国“凤毛麟角”,尽管他也注意到一些酿酒厂正在转向生态农业方式。

  美国最著名的生态农场之一就是弗吉尼亚州的多元农场,农场主乔尔·萨拉汀对他的畜群“管弦乐队”进行了精心的编排,让每个种群都在农场各处轮转,以求得生产力和生态效益的最大化。首先,他的肉牛集中在一块牧场上吃草,然后再移往下一块。几天之后,当牛粪中的蛆都孵化出来并且长肥变大的时候,萨拉汀就会搬来移动式鸡栏,蛆虫是鸡喜欢的食物,在帮萨拉汀解决了害虫的同时还借助鸡爪的抓挠把牛粪当作肥料撒进了土壤。就这样,牛群和鸡群在农场上不断游转,让每块牧场都得到了休养生息的机会。在猪、兔、火鸡等其它禽畜的饲养上,萨拉汀也采取了同样高明的策略。

  在报告中,德·舒特说生态农业的“资源保护和低外输技术提高产量的能力已经得到证明,”他还引用一项研究的结果,说采用生态农业技术的土地的粮食产量平均提高了79%。报告还指出了生物多样性在改善小型农户膳食方面的重要性。尽管一个人摄入的热量可能大多数都来自大米、小麦或玉米等主食,但在多样性生态农业系统中种植的副食也可以提供至关重要的养分,甚至在青黄不接的时期还可以充当重要的食物来源。

  报告还强调说,我们采取的农业技术应该既能够减缓气候变化,还能让世界在未来日益增加的气候极限面前拥有更强的恢复力。首先,它赞扬了生态农业可以让“食品生产摆脱对化石能源(油气)的依赖”,而且为“减缓气候变化”做出了贡献,“方式包括增加土壤有机质和地上生物量中的碳汇,以及通过减少直接和间接的能源是用来避免农场产生二氧化碳和其它温室气体排放”。此外,报告还指出生态农业有能力“显著缓解”旱灾和飓风等极端天气事件的破坏。

  在报告中,德·舒特呼吁各国采取行动帮助发展中国家的小型农户采取生态农业的耕作方式,比如对农业研究和推广服务进行再投入、投资建立促进(农业)合作的社会组织、强化女性能力以及“创造一个有利的宏观经济环境,包括将可持续农场与公平市场联系起来”。

  联合国粮农组织估计,到2050年要养活多达90亿的世界人口,粮食产量必须比现在增加70%。如果世界能够按照德·舒特报告中提出的路径前进,并且实现研究中所验证的生产力,到2050年甚至可以超出上述粮农组织提出的需求量。

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