À procura de textos e pretextos, e dos seus contextos.

22/10/2009

Do Increased Energy Costs Offer Opportunities for a New Agriculture?

Frederick Kirschenmann

Let us accept the current challenge — the next great energy transition — as an opportunity not to try vainly to preserve business as usual (the American Way of Life that, we are told, is not up for negotiation), but rather to re-imagine human culture from the ground up, using our intelligence and passion for the welfare of the next generations, and the integrity of nature’s web, as our primary guides.

— Richard Heinberg, Peak Everything1

One of the great missteps in most of the future energy scenarios propagated in the popular media is the notion that we can transition to “alternative, renewable energy” and thereby “wean ourselves from Mideast oil.” The underlying assumptions in this scenario seem to be that energy supply is an isolated challenge that can be solved without major systemic changes, that we can meet that challenge by simply switching from one energy source to another — from fossil fuels to wind, solar, biofuels or a host of other alternatives — and that our current industrial culture and economy then can continue on the present course.

Probably nothing could be farther from the truth. As Richard Heinberg points out, “Making existing petroleum-reliant communities truly sustainable is a huge task. Virtually every system must be redesigned — from transport to food, sanitation, health care, and manufacturing.”2

As Heinberg implies, the transition we now must contemplate is a shift from an oil dependent society to an oil independent society. Such a transition must include, but is clearly not limited to, our food system. The transition must be comprehensive. We must “re-imagine human culture from the ground up.”

The “transition movement,” which was launched by Rob Hopkins, a permaculture teacher schooled in ecological design, acknowledges such a comprehensive approach, and the movement is designed to help communities make that transition. Originally focused on transitioning towns, the movement has now expanded to transitioning islands, peninsulas, and valleys, and it may serve as a model for the kind of transition we need to contemplate in our food and agriculture systems.

In his new book, Hopkins points out that the “transition initiatives are based on four key assumptions”:

  1. Life with dramatically lower energy consumption is inevitable, and that it is better to plan for it than to be taken by surprise.
  2. Our settlements and communities presently lack the resilience to enable them to weather the severe energy shocks that will accompany peak oil.
  3. We have to act collectively, and we have to act now.
  4. By unleashing the collective genius of those around us to design our energy descent creatively and proactively, we can build ways of living that are more connected, more enriching, and that recognize the biological limits of our planet.3

While “virtually every system must be redesigned,” the redesign of our modern industrial food and agriculture system is particularly urgent because food is essential and our current food system is almost totally dependent on vast petroleum inputs at every level. As Dale Allen Pfeiffer has put it, in our modern food system we are, in effect, “eating fossil fuels.”4 All of our fertilizers and pesticides are either made from, or acquired by means of, fossil fuels. Farm equipment is manufactured and operated with fossil fuels; irrigation is carried out using fossil fuels; and our food is processed, packaged, and transported from farm to table with fossil fuels. Without fossil fuels, our industrial food system likely would collapse.

The Limits of Industrial Agriculture

While the industrialization of agriculture was somewhat successful in achieving its limited goals of maximizing market-based production and providing short-term economic returns, it largely ignored many of its unintended negative consequences. Some of these unintended consequences now have been documented in the UN Millennium Ecosystem Assessment report. The most critical negative consequences include soil and water degradation and the loss of both human capital (farmers) and social capital (vibrant rural communities).

Industrial agriculture also largely overlooked the need for resilient production and a long-term view of the economic returns. Consequently, it ignored the erosion of the very capital that enabled it to be so successful — cheap energy, abundant, fresh water, stable climates, healthy soil, and vibrant communities. Since these resources are wholly interdependent, it is imperative that we account for the impact (costs) of their widespread depletion, even as we explore the possibility of bringing about a new agriculture.

Industrial agriculture finds itself in a predicament: how does it fulfill its stated goal of “feeding the world” when the resources on which it depends are being depleted, and the social and physical infrastructure on which it has relied is collapsing? As the authors of the recent United Nations report, the International Assessment of Agriculture Science and Technology for Development (IAASTD), have indicated, “Agriculture [is] at a Crossroads.”5

The global expansion of industrial agriculture was based on a set of core assumptions, namely that technology, trade, and aid could successfully address global food shortages and inequities, and that maximum production, short-term economic return, unlimited growth, the free market, and labor efficiency were the key components that would bring about this industrial food miracle.

As we begin to assess its overall results, many questions are now being raised about our industrial food system. These issues are of concern, not only to food activists, health care professionals, nutritionists, and farmers, but increasingly to the scientific community, as well.

As the authors of the IAASTD report put it:

Recent scientific assessments have alerted the world to the increasing size of agriculture’s footprint, including its contribution to climate change and degradation of natural resources. By some analyses, agriculture is the single largest threat to biodiversity. Agriculture requires more land, water, and human labor than any other industry. An estimated 75% of the world’s poor and hungry live in rural areas and depend directly or indirectly on agriculture for their livelihoods. As grain commodity prices rise and per capita grain production stagnates, policy-makers are torn between allocating land to food or fuel needs.

The authors then propose that “The governance of agriculture requires new thinking if it is to meet the needs of humanity now and in the future.”6

At the same time that we recognize the many negative, unintended consequences of our industrial agriculture, we must take note of the fact that the planet’s human population has tripled in our lifetime, and is reportedly headed toward a peak of nine billion people by mid-century. This burgeoning human population is also rapidly increasing its rate of consumption as individuals change diets. According to some estimates, global meat consumption will double or triple by 2070. The production of meat using grains such as corn and soybeans that could be directly consumed by humans as food is an inefficient way to supply both calories and protein to people.7 Furthermore, Jared Diamond has calculated that, if everyone on the planet now consumed at the rate we do in the United States, our agriculture would need to be capable of supporting 72 billion people.8

We know that over half the world’s population lives on landscapes classified as marginal. We also know that agricultural systems based on the long-term needs, both of people and the environment, need knowledge and attention from more people than those involved in highly mechanized industrial agriculture. But the large number of small farmers that would be needed to design and implement the new agricultural systems that regenerate the soil and local habitat has shrunk dramatically, especially in the regions of the world where industrial agriculture has been practiced. For example, as of 2002, in the United States, there were only a little more than 400,000 farmers producing over 94 percent of our total agricultural commodities, and only 5.8 percent of all farmers were under age thirty-five.9 In the poor countries of the world, the decades-old mass migration to the cities, in which people mainly ended up in slums without work, has seriously depleted the farming population, as well. This means that, by mid-century, we may be trying to feed almost twice as many people with half the topsoil, and very little experience-based wisdom in managing that soil.

Challenges and Opportunities of Establishing a More Sustainable Agriculture

All of this leaves us with formidable challenges. How do we put a “sustainable” agriculture on the landscape in the decades ahead, assuming that: as oil becomes more scarce, its price could well be $300 a barrel; we will only have half the fresh water available to produce and process our food, fuel, and fiber; we will have twice as many severe weather events; and we will have a tiny fraction of the human population possessing the acquired skills to grow food, conserve water, manage soil restoration, or imagine new production systems that are less dependent on all the natural resources that so effectively fueled our industrial economy?

Fortunately, there are some hopeful developments on the horizon that may provide us with new directions. Health care professionals and nutritionists have begun to point out the necessary changes in the quality of our food, if we are to address some of the day’s critical health issues. We are discovering that fresh, diverse, whole foods, less meat, and foods produced on biologically healthy soils may offer very beneficial health effects. Experiments conducted in some of our school systems (such as the Appleton, Wisconsin public schools) where junk food, sodas, and highly processed foods were replaced with fresh fruits and vegetables, milk, fruit juices, and whole grain breads, dramatically changed the behavior and academic performance of students, and saved the school system money at the same time.10

Meanwhile, small farmers around the world have been abandoning high-energy input monoculture farming systems that are especially vulnerable to unstable climates. In their place are diverse, biological polyculture farms wherein there are biological synergies that tend to store energy, are highly productive, and use very few energy inputs from off the farm.11 Research is now beginning to corroborate the benefits from these diverse farming systems that farmers are introducing.12

Another positive movement on the horizon is the dramatically increased interest in urban farming. Urban farming is evolving in cities throughout the world, from Havana, Cuba to New York City, Detroit, and many other urban centers. New York City recently hosted a “Food Summit” organized by Mayor Michael Bloomberg and other city leaders that attracted more than 500 food activists who rolled up their sleeves to begin developing a new “food charter” for the city.

The Stone Barns Center for Food and Agriculture, a nonprofit entity located on eighty donated acres on the Rockefeller estate in Pocantico Hills, New York, just outside New York City, has been exploring ways to produce food in an ecologically sound way in urban and suburban settings. Stone Barns is now demonstrating, in suburban surroundings, how vegetables can be grown year-round with minimal energy inputs and how animals can be produced on grass to the benefit of both animals and the environment.

All of these activities are creating interest among a new generation of farmers who want to grow healthy foods, by means of intensive growing strategies, based on low-energy input and requiring limited acreage.

Evolving along with this food revolution is a new paradigm that may replace the technology, trade, and aid system with a new approach suggested in the UN IAASTD report. That new direction is grounded in principles articulated at the New York City food summit: food justice, food democracy, and food sovereignty. This underlying new concept has been framed as a food system based in “foodsheds.”

A foodshed is a regional food concept that is based on a new set of priorities. The first priority of a foodshed is to feed people within the foodshed by people in the foodshed, making them as food self-sufficient as possible, and only then fulfilling other needs through trade.13 This new vision of our food future gives people in each community (“foodshed”) much more authority over the food they will produce and consume, and allows them to determine how it will benefit their own communities. This new movement has the potential to grow rather rapidly and eventually evolve into effective rural-urban food coalitions with farmers and consumers working together as food citizens to create food systems that are based on resilient production and long-term return. This can benefit their own communities economically, ecologically, and socially, rather than making them totally dependent on distant enterprises from which they gain little and over which they have little control. And, as John Cobb put it some time ago, they will recognize that trade is only free when they are free not to trade.14

Since agriculture is now at a crossroads, it provides us with an unprecedented opportunity to initiate some of the changes we need to make if agriculture is going to be sustainable in the future. And our new energy future will likely be one of the principal drivers contributing to those changes. For reasons already mentioned, the end of cheap energy will be especially challenging to our industrial food enterprise. Since petroleum provides the energy for almost every aspect of industrial agriculture, costs will spiral upward, rendering industrial agriculture increasingly untenable — especially for farmers. For example, as the cost per barrel of oil climbed from $50 to $140 in 2007, the cost of anhydrous ammonia fertilizer for Iowa farmers went from $200 per ton to over $1,300 per ton. When oil climbs to $300 a barrel, as it is expected to do sometime during the next decade, it may well render industrial agriculture cost-prohibitive.

Our New Energy Future Provides an Opportunity to Design a Better Food System

There are no alternative, renewable sources of current energy that can produce anywhere near the energy efficiency ratio of stored, concentrated hydrocarbons that accumulated over millions of years. The energy return for energy invested that we have enjoyed with fossil fuels simply cannot be achieved with any alternative energy source. This is the principal reason that our agriculture “systems must be redesigned.”

The popular media also almost never mention the laws of thermodynamics when they discuss our energy future. Those laws are another important reason why we must redesign the agriculture of the future.

Writing eloquently in his book, The Myth of Progress, Tom Wessels describes the essential components of the first and second laws of thermodynamics, and how they determine our energy world. The first law “simply states that energy can neither be created nor destroyed.” “The second law, also known as the law of entropy, states that, although energy can’t be created or destroyed, it can be transformed from one form to another.” In other words, although energy is neither destroyed nor created during transformations, nevertheless “within the system where the transformation occurs, some of the energy is lost from that system during the transformation. The energy isn’t destroyed; it simply leaves the system in which the transformation takes place…the loss of energy from a system results in entropy” and “entropy is a process where things naturally move from a state of order toward disorder.”15

It will be especially important for us to pay close attention to the first and second laws of thermodynamics as we consider food and agriculture systems for a post-petroleum world. These laws present us with at least three important realities that can guide us in redesigning our food system.

First, the laws tell us that energy cannot be fully recycled, therefore perpetual motion machines are impossible. There is, as Wessels puts it, no “free energy ride.” So, we should be skeptical about hypotheses that assure us that someone will invent a new miracle technology that will save us from the challenges of the end of cheap energy.

Second, it will be important to acknowledge that, while entropy is “a process in which things move from a state of complexity toward simplicity, or from concentration to diffusion,” it is equally true that “whenever energy is stored within a system, it is stored in ways that increase the system’s complexity or concentration of materials.” All of this suggests that when we create highly specialized, simplified systems that require large infusions of energy (the industrial model), we will experience a high degree of entropy. Conversely, complex systems “can take in energy from the larger system in which they are nested” since complex systems have “fuzzy boundaries.”16 This aspect of the laws of thermodynamics suggests that complex systems employing biological synergies nested in nature’s larger system likely will be the best way to produce food in our new energy future.

Third, as Wessels notes, we now also need to take “biospheric entropy” into consideration as we design our systems of the future. Wessels points out that, up to about a quarter of a billion years ago, the biosphere was an anti-entropic system. At that point, it entered a state of dynamic equilibrium as all systems do. However,

since the nineteenth century the increasing use of energy by humans, particularly fossil fuels, has pushed the biosphere out of its dynamic equilibrium state into one that is increasingly more entropic. Human activity on this planet is countering trends that have been developing for over 3.5 billion years. For the first time in the Earth’s history, a single species is responsible for the entropic degradation of the biosphere by releasing more energy through transformation than is being replaced by global photosynthesis.17

As we design our agriculture of the future, it is imperative that we consider this additional biospheric phenomenon if we want to have an agriculture that is sustainable for the long term. We can no longer simply position the development of a sustainable agriculture as an isolated activity that “greens up” our current agricultural activities. We now need to create a new agriculture and food system that is part of a much larger redesign that factors in the carrying capacity of the biosphere. We must balance the population of the human species as one member of the biotic community that lives in synergy with all of the other species to form a self-renewing and self-regulating biosphere, and that captures and retains more of the energy in the system. Therefore, it is imperative that we begin to recognize that our future energy challenge is not an isolated phenomenon that we can solve by simply finding alternatives to our present sources. Agriculture remains a key player with respect to biospheric entropy — not only because of the entropic degradation it unleashes, but also by virtue of the sheer number of humans and their rate of consumption on the planet.

Again, as Wessels points out, “every environmental problem we witness today is the result of entropy within the biosphere,” and how we carry out agriculture, to a large extent, determines that entropic scenario.

The loss of natural forest cover or its replacement with monocrop plantations results in simplification of ecosystems — entropy. The conversion of semiarid woodlands to desert through overexploitation results in ecosystem simplification — entropy. The erosion of topsoil results in diffusion of nutrients — entropy. The eutrophication of aquatic and marine environments from the diffusion of nutrients results in decreased biotic diversity and ecosystem simplification — entropy. The depletion of the world’s fisheries results in ecosystem simplification — entropy. The loss of global biodiversity results in simplification — entropy. Global climate change due to the build up of carbon dioxide in the atmosphere from the burning of fossil fuels in a process of diffusion of carbon — entropy.18

This cogent analysis of entropy in our industrial world makes it clear that industrial agriculture, and the new agriculture we must design to replace it is not an isolated phenomenon. The new systems we design need to envision ways of addressing, not only our immediate food, fiber, and fuel needs, but also the more complex issues surrounding those needs so that our agriculture can truly be part of our new efforts to restore the health of the biosphere. This likely means that we have to address this issue in stages, with each stage making at least a beginning contribution to the larger goal of the ultimate health of the biosphere. Designing the transition to take place in stages is also the strategy suggested by Rob Hopkins’s transition movement.

From this perspective we can now, perhaps, address the initial question raised in this essay. Do increased energy costs offer opportunities to bring about a new agriculture? The short answer is, doubtlessly, yes. As the costs of fossil fuels escalate, our energy input-intensive agriculture will simply become unaffordable. This situation will give an initial comparative economic advantage to agricultural designs that are based on complex biological synergies nested in the larger complex systems of nature. Fortunately, a few farmers are already successfully exploring such complex biological farming systems.19 We would do well to put more of our scarce resources into research that further explores the possibilities of such systems in various eco-regions. That will likely be the first phase of the dramatic transition we will need to make.

Once we start down this path, we will no doubt experience many of the economic benefits of such redesigned systems. We already know from research that once we restore the biological health of the soil we dramatically reduce the need for irrigation as well as synthetic inputs, and, to some extent, we can also reduce machinery use — all energy inputs.

A few farmers are already disposed to move in these more ecological directions. Ecological farmer organizations have sprung up all over the United States in recent decades. These farmers are experimenting with more diverse rotation systems, exploring the advantages of cover crops and incorporating perennial pasture grazing into their cropping systems rotations.

Increasingly, we will have to perform full life cycle analyses of these new systems to make sure they are contributing to the ultimate goal of restoring the health of the biosphere by restoring complex natural systems that store more energy than they release. The object should be to reestablish, as much as possible, the larger self-renewing and self-regulating capacity of the biosphere, a critical component of any long-term sustainability scenario.

This brings us back to Aldo Leopold’s observation that conservation is not about preserving things, but about restoring the “health” of the land — land health being the enhanced capacity of the “land [the biotic community] to renew itself.”20

Since this new, diverse agricultural system, embedded in the larger system of nature, can take in more energy, it will likely have a comparative economic advantage over industrial systems. However, in the last analysis, all this cannot be driven by economics alone. Leopold, again, articulates the issue clearly: “To sum up: a system of conservation based solely on economic self-interest is hopelessly lopsided. It tends to ignore, and thus eventually to eliminate, many elements in the land community that lack commercial value, but that are (as far as we know) essential to its healthy functioning.”21

A New Ethical Imperative

Ultimately, in addition to the economic drivers that our new energy future will likely impose on us, we will need to develop social and human capital. That implies an ethical imperative that we must encourage as part of a new culture and a new post-industrial economy.

Throughout this paper there has, in fact, been an implicit, two-fold ethical imperative. On the one hand, our post-industrial understanding of the world (that it is a complex, highly interdependent biotic community replete with unanticipated and unpredictable new “emergent” properties) suggests an ethical imperative similar to Aldo Leopold’s “ecological conscience,” which embraces the value of the entire biotic community. On the other hand, the practical necessity of conserving our soil, water, climate, human, and social resources in order to feed our human population under challenging circumstances suggests a utilitarian ethic. I think both ethical perspectives will be important to our future, and must be incorporated into any economic incentives strategy.

As with all externalities of production, the depletion of our human and social capital — perhaps the worst toll exacted by our industrial agriculture — is a consequence of an economic system that promotes short-term profits for individuals and corporations at the expense of long-term sustainability. Industrialization of our farming systems has systematically eliminated the very farmers who were most closely connected to their land. Market forces in our capitalist industrial economy favor centralized farm management of large, consolidated operations that can reduce the transaction costs of transferring raw materials to large manufacturing firms. But our culture still seems to be largely oblivious to the impact that this erosion of indigenous human know-hot and creativity may have on our ability to address the challenges ahead. Here, an appeal to an ethic that stresses the outcomes (or consequences) may be the most compelling.

Wendell Berry has perhaps articulated most clearly and succinctly the connection between human/social capital and our ability to maintain our productive capacity:

If agriculture is to remain productive it must preserve the land, and the fertility and ecological health of the land; the land, that is, must be used well. A further requirement, therefore, is that if the land is to be used well, the people who use it must know it well, must be highly motivated to use it well, must know how to use it well, must have time to use it well, and must be able to afford to use it well. Nothing that has happened in the agricultural revolution of the past fifty years has disproved or invalidated these requirements, though everything that has happened has ignored or defied them.22

Berry reminds us that we cannot reasonably expect ecological or agro-ecological systems to be managed well without people living in those ecologies long enough and intimately enough to know how to manage them well. And he correctly asserts that we need social, cultural, and economic support systems in place to sustain such wise management. Proper land management, in other words, is a practical, ethical imperative not provided for in industrial-capitalist economies, which are focused solely on maximum production and short-term economic returns.

The National Academy of Sciences (NAS) has articulated a similar position. Over a decade ago the NAS asserted that “soil degradation is a complex phenomenon driven by strong interactions among socioeconomic and biophysical factors.” The NAS recognized that proper soil management is a key factor in improving soil quality and that healthy soils provide the opportunity “simultaneously [to] improve profitability and environmental performance.”23 Long-term productivity and profitability, in other words, is not a simple business arrangement but is grounded in social and cultural factors that attend to the long-term care of the soil. A sustainable farm economy is ultimately tightly linked to social, cultural, and ethical commitments that safeguard the health of the land.

The core strategy of industrial farming systems has been to specialize in one or two crops with little or no biological diversity, and reduce production management practices to the use of one or two single-tactic inputs such as commercial fertilizers and pesticides. This approach has yielded production systems that are extremely labor saving but tend to be so focused on maximizing production and short-term economic returns that little consideration is given to the need for long-term resilience.

Another hallmark of agribusiness has been the systematic elimination of the very farmers with the ecological and cultural wisdom and commitment required to restore the physical and biological health of our soils. These farmers owned their land, lived on their land, were intimately related to their land, and planned to pass it on to future family members — all factors that nurtured a culture of caring for the land.

Fortunately, in the wake of this loss of human know-how and community (with the land, as well), some research continues to demonstrate the broad principles we must employ to restore soil health. Science magazine reported on a research project in Switzerland that traced the biological and physical properties of soils by comparing soils under conventional industrial management with soils under ecological management, over a twenty-one-year period. The researchers found that ecologically managed soils, using complex green manure and livestock manure to replenish soil nutrients, showed remarkably higher soil quality, including “greater biological activity” and “10 to 60 percent higher soil aggregate stability” (promoting better intake and storage of water for plants to use) than the conventional industrially managed soils.24

Such information suggests a critical ethical imperative. Since we have been able to conceal the decline in productive capacity arising from the loss of soil health over the past half century by applying cheap fossil-fuel based ingredients to the soil, we have not confronted the fact that ultimately soil health is crucial to maintaining productivity. The NAS study reminds us that “soil degradation may have significant effects on the ability of the United States to sustain a productive agricultural system.”25 That statement takes on new significance in light of the depletion of the very conditions that have allowed us to ignore the importance of the health of our soil: namely, cheap energy, surplus water, and stable climates. So one could argue that there is now a compelling, practical imperative for exploring nature’s ways of restoring soil health and employing the cultural, social, and economic incentives to put people on the land who know the land well and know how to use it wisely.

All of this indicates, I think, that we are increasingly recognizing that the health of the soil is, as Sir Albert Howard noted seventy years ago, an indicator of the health of the entire living community. Hopefully, the dual drivers of increased energy costs and a renewed land ethic will bring about the sustainable agriculture our children and grandchildren will need.

Notes

  1. Richard Heinberg, Peak Everything (Gabriola Island, BC: New Society Publishers, 2007), 65. Go back
  2. Richard Heinberg, “Resilient Communities: A Guide to Disaster Management,” Museletter 192 (April 2008), http://www.richardheinberg.com/museletter/192. Go back
  3. Rob Hopkins, The Transition Handbook (White River Junction, Vermont: Chelsea Green Publishing, 2008), 134. Go back
  4. Dale Allen Pfeiffer, Eating Fossil Fuels (Gabriola Island, BC: New Society Publishers, 2008), 7. Go back
  5. E. Toby Kiers, et al., “Agriculture at a Crossroads,” Science 320 (April 18, 2008), 320-21. Go back
  6. Kiers, et al., "Agriculture at a Crossroads," 321. Go back
  7. However, when ruminants such as cows are raised exclusively on pastureland that cannot be converted to produce crops there is no conflict between meat production and grain production for direct human use. In addition, raising animals on integrated crop/livestock farms poses many ecological advantages and synergies that can both increase food production and enhance the capacity for self-renewal and self-regulation. Go back
  8. Jared Diamond, “The Consumption Factor,” New York Times, January 2, 2008. Go back
  9. Some early media reports have been euphoric about the increase in the number of farmers since 2002 based on the 2007 census data released on February 4, 2009. However, these reports do not take into account the fact that the USDA still uses the 1974 definition of a farm that counts anyone who produces a thousand dollars in gross sales, or who “could have” produced that much, as a farmer. Consequently, the presumed increase in the number of farmers is not being adjusted for inflation. Go back
  10. See “Impact of Fresh, Healthy Foods on Learning and Behavior,” 2004, http://www.naturalovens.com. Go back
  11. For a brief description of this new farming phenomenon, see Frederick Kirschenmann, “Potential for a New Generation of Biodiversity in Agroecosystems of the Future,” Agronomy Journal 99, no. 2, (March-April 2007): 373-76. Go back
  12. Erwin Dwiyana and T. C. Mendoza, “Comparative Productivity, Profitability and Efficiency of Rice Monocultures and Rice-Fish Culture Systems,” Journal of Sustainable Agriculture 29, no. 1 (2006): 145-66; Elizabeth A. Ogunlana, Vilas Salokhe, and Ranghild Lund, “Alley Farming: A Sustainable Technology for Crops and Livestock Production,” Journal of Sustainable Agriculture 29, no. 1 (2006): 131-43. Go back
  13. Jack Kloppenburg, Jr., John Hendrickson, and G.W. Stevenson, “Coming Into the Foodshed,” Agriculture and Human Values 13, no 3 (1996): 33-42. Go back
  14. John Cobb, Sustaining the Common Good (Cleveland: The Pilgrim Press, 1994). Go back
  15. Tom Wessels, The Myth of Progress (Burlington: University of Vermont Press, 2006), 41-42. See, also, Jack Hokikian, The Science of Disorder (Los Angeles: Los Feliz Publishing, 2002). Go back
  16. Wessels, The Myth of Progress, 43-44. Go back
  17. Ibid. 49-50. Go back
  18. Tom Wessels, The Myth of Progress (Burlington: University of Vermont Press, 2006), 51. Go back
  19. See Kirschenmann, “Potential for a New Generation.” Go back
  20. Aldo Leopold, A Sand County Almanac (New York: Oxford University Press, 1949), 221. Go back
  21. Leopold, Sand County Almanac, 214. Go back
  22. Wendell Berry, What Are People For (San Francisco: North Point Press, 1990), 206-07. Go back
  23. National Research Council, Soil and Water Quality (Washington, DC: National Academy Press 1993). Go back
  24. Paul Maeder, Andreas Fliessbach, David Dubois, Lucie Gunst, Padruot Fried, and Urs Niggli, “Soil Fertility and Biodiversity in Organic Farming,” Science 296 (May 31, 2002): 1694-97. Go back
  25. National Research Council, 1993, Soil and Water Quality (Washington, DC: National Academy Press) 196. Go back
Monthly Review - October 2009

Sem comentários:

Related Posts with Thumbnails