Sustainable Agriculture

SUBHEAD: Sustainable farms employ productivity systems inspired by nature.

By Jason Bradford & Craig Wichner 1 May 2009 Energy Bulletin -  

Image above: Restored taro loi at Limahuli Garden & Preserve of the National Tropical Botanical Gardens on Kauai, Hawaii. Visit Photo by Juan Wilson.
 Framing the Discussion: Sustainable Agriculture = Sustainable Society
Developing a sustainable agriculture is a necessary part of creating a sustainable society. The root of the word sustainable is the verb, to sustain, which means to nourish and prolong. In social and environmental contexts we say something is sustainable when we believe it can persist indefinitely without exhausting resources or causing lasting damage.

The actions we take as individuals are at the core of both the problems and the solutions. Just by purchasing conventional goods at your local supermarket, you cause 4 lbs of pesticides to be put into the environment each year. The food supply chain averages of 4200 miles to reach your plate, when it could come from local farms and use a fraction of the transportation fuels. And the 2.6 acres of U.S. farmland (your pro-rata share) have lost 50% of the carbon in the soil since 1907, the equivalent CO2 of burning 90 barrels of oil – on top of your normal carbon emissions.

Cumulatively, agriculture impacts our society at a scope and scale that few appreciate, far beyond the initial realms of our food safety, quality, and the local environment. Due to the scale of natural resources required to provide food, fiber and fuel to 6.7 billion people, agriculture requires continued global-scale supplies of fertile land, clean water, fossil fuels, fertilizers, pesticides, and transportation infrastructure. These issues underpin our civilization’s energy security, population distribution and capacity, national security, and cause agriculture to be a key player, for good and bad, in the fate of our planet’s climate.

A 2008 article in the popular journal New Scientist titled “How our economy is killing the Earth” included a number of graphics showing the exponential growth in consumption of planetary resources…leading to an exponential growth in problems. Agriculture, both directly or indirectly, contributes to resource consumption and pollution, and can be used to benefit or aggravate the situation.

...Exponential growth is by definition unsustainable, and signs such as fishery collapses, forest loss and species extinctions, and melted glaciers and other evidence of climate change all are warning signs at best…trip-wires at worst.

Discussions of an alternative path, or sustainable development, often begin by reviewing a schematic of development that balances social, economic and environmental parameters, which are often called the “three pillars”.

Ecological Economists would produce a different schematic that places the economy and all social systems as a subsets of the environment to reflect that humans are a part of and totally dependent upon the environment. In other words, these are not three parts in a balanced relationship but a nested set of parts with a clear hierarchy.

Both views of sustainability, however, establish criteria for understanding the long-term viability of related environmental, social and economic systems. This white paper will do so for agriculture.

The Impetus for Change
Our modern agricultural system, the so-called “green revolution,” has enabled tremendous productivity gains from the land, enabling us to grow from 2 billion to 6.7 billion people on the planet over the past 100 years.

Modern farming methods are designed to generate maximum financial and production returns, and they do this well over the short and even medium term. For example, conventional farmers usually grow a single crop over large acreage; use herbicides to sterilize the soil prior to planting, then add artificial fertilizers to stimulate crop growth and pesticides to treat overpopulated pests (caused by monocropping); all the while decreasing the productivity of the soil over time.

However, such practices have been shown to reduce returns (net of fertilizer, herbicide and pesticide costs) by 25% to 30% in as few as five years4, while requiring increasing amounts of costly and toxic artificial inputs. Unfortunately, once started, the system is very difficult to escape.

Even with its history of yield improvements, agricultural production today is no longer keeping up with current demands. For example, from 1998 to 2008 the global consumption of grain has outpaced total production in most years, leading to low carry-over stocks.

Achieving expected growth is daunting as well. If demographic trends continue, agricultural output will need to nearly double by 20506, yet the available fertile farmland per person will be one-third the levels in 1950. Demand for farmland production is increasing due to rising population, greater consumption of meat (requiring additional grains to feed the animals), and new biofuel mandates consuming corn and oil-seed crops. Meanwhile farmland acreage worldwide is decreasing due to land development, soil and water depletion, increasing soil salinity, and other factors.

Furthermore, these farm practices are environmentally unsustainable on a global level, as they:
  1. Degrade soil, air and water quality from tillage, chemical applications, and concentrated wastes. Topsoil with low organic matter content and little biological activity is unable to hold onto the added chemicals, with the runoff causing algal blooms and then “dead zones” in fresh water and oceans.
  2. Consume and deplete non-renewable resources such as ancient aquifers, natural gas and petroleum-based fuels, fertilizers, herbicides and pesticides, and use mined minerals such as rock phosphate to promote productivity.
  3. Put 5 billion pounds of potentially harmful chemicals into the environment each year through pesticide use (includes herbicides, insecticides and fungicides), with over a billion pounds in the U.S. alone. This goes directly into our food, with 77% of the food consumed in the U.S. containing pesticide residue, and 47% containing residue from multiple pesticides.
  4. Contribute to greenhouse gas emissions from the direct use of fossil fuels, and indirectly through the breakdown of soil carbon and the conversion of natural ecosystems such as forests and wetlands. About 16% of greenhouse gas emissions in the U.S. come from food production, distribution and retail.

Climate change and water supply issues are likely to significantly affect agricultural production. About 70-90% of global freshwater withdrawals are used for agricultural irrigation. Globally, crop models show a general decline in the yields of major food crops and livestock, with the carbon dioxide fertilization effect being overwhelmed by extreme events and trends in temperature, water availability and pest pressures.

For example, over the course of this century climate models show California's water supply declining overall, but especially during the spring and summer months when irrigation use is critical.

A recent study from a University of California agricultural economist projected that the productivity and value of California farmland could drop by about 50% (range 13% to 67% across several models) due to higher temperatures and reduced water availability.

In summary, demographic momentum is pushing the human population into a predicament where more and more food is expected to come from less and less land and water, all the while requiring full and growing production and keeping no reserve. While food today is still generally plentiful and inexpensive, the trends suggest we are nearing system limits. At the same time, most agricultural practices degrade key ecological assets, including topsoil, fresh water, and the climate system.

Unfortunately agriculture today cannot be easily relocated due to climate change, loss of topsoil or water – the loss of growing regions or growing capacity due to a degraded environment will have a direct affect on us.

Defining Sustainable Agriculture
With respect to the environment, society and economics, sustainable agriculture would:
  1. Not harm the environment from pollution,
  2. Not be reliant on non-renewable inputs or degrade renewable ones,
  3. Nourish people with non-toxic, healthy food and other useful feed stocks, and
  4. Provide a fair, steady, return on effective investment in labor and capital.
How can these goals be achieved?

Sustainable farms employ productivity systems inspired by nature to deliver high yields through ecological synergy, diversity and resilience. Sustainable farms are managed as fully-integrated ecosystems, where knowledge of soils, macro and microscopic organisms such as bacteria and fungi, water, crops, weeds, pests, equipment and techniques are used to maximize the long-term health, productivity and economic profitability of the farm.

To know if a farm is sustainable we should be able to measure its impact on the environment, society, and its finances. Does the balance of farm activities emit or sequester carbon dioxide? Is topsoil being lost or built? Is the runoff of water from the farm clean or a burden to local rivers?

 Metrics can be developed for a number of important sustainability indicators, including:

  1. No build-up of persistent pollutants into the environment,
  2. Development of soil carbon and a balanced soil food web
  3. Enhancement of regional biodiversity and ecosystem services,
  4. Use of renewable energy and recycled mineral resources,
  5. Humane care of farm animals,
  6. Food quality and health,
  7. Worker fairness and safety, and
  8. Economic viability.
For example, an idealized sustainable farm wouldn’t use non-renewable fossil fuels and would store at least as much greenhouse gasses as it emits. Energy use is a major area where “sustainable” goes beyond the soil management, pesticide and herbicide regulations of “organic” farming.

Farms are ideal places to deploy renewable energy systems, as they typically have abundant sunshine and may include significant wind or moving water resources. Liquid fuels are highly valued in farming because they can be used in machines to perform highly time sensitive work, such as planting and harvesting. Perhaps 20% of farmland would need to be set aside for biofuel crops for on-farm use. Some are exploring options to electrify tractors.

...What a Sustainable Agricultural System Will Look Like
Many terms are used to describe alternatives to conventional, industrial agriculture. Organic, local, and sustainable come to mind. Less often used is “agro ecology,” which views the agrarian landscape the same way an ecologist views the natural landscape. Farms also can’t exist in isolation from the broader society.

A truly sustainable farm is an integral part of the local community. There are biophysical reasons for this, as plants and animals essentially draw nutrients from the soil that in a closed-loop system must be returned. When food is exported across the globe, soils and water are being exported too. In ecosystems nutrient cycling is predominantly local, and this is why sustainable food systems must be locally oriented.

Because humans are omnivores, our normal diets tend to draw upon diverse agro ecosystems. Tree fruits and nuts are a type of forest. Pasture is a type of mature grassland that can raise meat. Fields of grains and legumes are immature grasslands. And vegetables and root crops represent very early successional plant communities. We evolved from people who combined hunting and gathering across fields and into forests with garden-scale plots. Sustainable farm landscapes reflect the omnivory of human diets.

...In summary, a transition to organic and sustainable farming is required for environmental, social and economic reasons. Fortunately, organic farming is a robust business model, delivering superior economics over conventional farming on a wide variety of metrics such as crop yields, gross and net income per acre, cost of inputs, per farm income and more.

As society provides the financial and organizational capital to re-create agriculture, the living soils, plants and animals will respond, over time, to support us. Each acre converted to organic, sustainable methods is one acre closer to a societal tipping point for sustainability – or at least one less acre as a source of harm.

Original PDF white paper available here

See also:
Ea O Ka Aina: Food For Thought 10/18/09
Ea O Ka Aina: Opportunities for a New Agriculture 10/20/09


1 comment :

modern farming methods said...

Thanks for the very nice inputs! Enjoyed reading it.

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