ECO Farming: What is Sustainable Agriculture?
ECO Farming
ECO Farming stands for eternal no-till, continuous live cover and other best management practices. Proponents hope to eliminate tillage as much as possible.
Every day, farmers around the world develop new, innovative strategies to produce and distribute food, fuel and fiber sustainably. While these strategies vary greatly, they all embrace three broad goals:
- Profitability over the long term,
- Stewardship of the land, air and water, and
- Quality of life for farmers, ranchers and their communities.
Sustainable agriculture is the practice of farming using principles of ecology and the study of the relationships between organisms and their environment. It has been defined as "an integrated system of plant and animal production practices having a site-specific application that will last over the long term".
This means satisfying human food and fiber needs while making the most efficient use of non-renewable resources, and on-farm resources and integrate, where appropriate, natural biological cycles and controls, sustaining the economic viability of farm operations and enhancing the quality of life for farmers and society as a whole.
As consumer and retail demand for sustainable products has risen, organizations such as Food Alliance and Protected Harvest have started to provide measurement standards and certification programs for what constitutes a sustainably grown crop.
Farming and Natural Resources
Practices that can cause long-term damage to soil include excessive tillage (leading to erosion) and irrigation without adequate drainage (leading to salinization). Long-term experiments have provided some of the best data on how various practices affect soil properties essential to sustainability. In the United States there is a federal agency, the USDA-Natural Resources Conservation Service, that specializes in providing technical and financial assistance for those interested in pursuing natural resource conservation and production agriculture as compatible goals.
The most important factors for an individual site are sun, air, soil and water. Of the four, water and soil quality and quantity are most amenable to human intervention through time and labour. Although air and sunlight are available everywhere on Earth, crops also depend on soil nutrients and the availability of water. When farmers grow and harvest crops, they remove some of these nutrients from the soil. Without replenishment, land suffers from nutrient depletion and becomes either unusable or suffers from reduced yields.
Sustainable agriculture depends on replenishing the soil while minimizing the use of non-renewable resources, such as natural gas (used in converting atmospheric nitrogen into synthetic fertilizer), or mineral ores (e.g., phosphate).
Possible sources of nitrogen that would, in principle, be available indefinitely, include:
- Recycling crop waste and livestock or treated human manure,
- Growing legume crops and forages such as peanuts or alfalfa that form symbioses with nitrogen-fixing bacteria called rhizobia,
- Industrial production of nitrogen by the Haber Process uses hydrogen, which is currently derived from natural gas, (but this hydrogen could instead be made by electrolysis of water using electricity (perhaps from solar cells or windmills), or
- Genetically engineering (non-legume) crops to form nitrogen-fixing symbioses or fix nitrogen without microbial symbionts.
The last option was proposed in the 1970s, but is only recently becoming feasible. Sustainable options for replacing other nutrient inputs (phosphorus, potassium, etc.) are more limited. More realistic, and often overlooked, options include long-term crop rotations, returning to natural cycles that flood cultivated lands annually (returning lost nutrients indefinitely) such as the flooding of the Nile, the long-term use of biochar, and use of crop and livestock landraces that are adapted to less than ideal conditions such as pests, drought, or lack of nutrients.
Crops that require high levels of soil nutrients can be cultivated in a more sustainable manner if certain fertilizer management practices are adhered to.
Water Usage
In some areas, sufficient rainfall is available for crop growth, but many other areas require irrigation. For irrigation systems to be sustainable they require proper management (to avoid salinization) and must not use more water from their source than is naturally replenished, otherwise the water source becomes, in effect, a non-renewable resource. Improvements in water-well drilling technology and submersible pumps, combined with the development of drip irrigation and low pressure pivots, have made it possible to regularly achieve high crop yields where reliance on rainfall alone previously made this level of success unpredictable. However, this progress has come at a price: in many areas where this has occurred, such as the Ogallala Aquifer, the water is being used at a greater rate than its rate of recharge.
Several steps should be taken to develop drought-resistant farming systems even in "normal" years, including both policy and management actions:
- Improving water conservation and storage measures,
- Providing incentives for selection of drought-tolerant crop species,
- Using reduced-volume irrigation systems, or
- Managing crops to reduce water loss.
Sustainable agriculture depends on replenishing the soil while minimizing the use of non-renewable resources, such as natural gas (used in converting atmospheric nitrogen into synthetic fertilizer), or mineral ores (e.g., phosphate).
Indicators for sustainable water resource development are internal renewable water resources, which is the average annual flow of rivers and groundwater generated from endogenous precipitation, after ensuring that there is no double counting. It represents the maximum amount of water resource produced within the boundaries of a country. This value, which is expressed as an average on a yearly basis, is invariant in time (except in the case of proven climate change). The indicator can be expressed in three different units: in absolute terms (km3/yr), in mm/yr (it is a measure of the humidity of the country), and as a function of population (m3/person per yr).
Global renewable water resources. This is the sum of internal renewable water resources and incoming flow originating outside the country. Unlike internal resources, this value can vary with time if upstream development reduces water availability at the border. Treaties ensuring a specific flow to be reserved from upstream to downstream countries may be taken into account in the computation of global water resources in both countries.
Dependency ratio. This is the proportion of the global renewable water resources originating outside the country, expressed in percentage. It is an expression of the level to which the water resources of a country depend on neighbouring countries.
Water withdrawal. In view of the limitations described above, only gross water withdrawal can be computed systematically on a country basis as a measure of water use. Absolute or per-person value of yearly water withdrawal gives a measure of the importance of water in the country's economy. When expressed in percentage of water resources, it shows the degree of pressure on water resources. A rough estimate shows that if water withdrawal exceeds a quarter of global renewable water resources of a country, water can be considered a limiting factor to development and, reciprocally, the pressure on water resources can have a direct impact on all sectors, from agriculture to environment and fisheries.
Soil Erosion
A major environmental concern known as topsoil erosion occurs when the topsoil layer is blown or washed away. Without topsoil, little plant life is possible. Historically, farmers used the soil, depleted the soil and moved on. Even with current farming methods more topsoil disappears each year than is created. The estimated annual costs of public and environmental health losses related to soil erosion in the US alone exceed $45 billion per year.
Conventional agriculture encourages the depletion of topsoil because the soil must be plowed and replanted each year, while sustainable techniques attempt to slow erosion through the use of cover crops in order to build organic matter in the soil. The United States alone loses 2 billion tons of topsoil per year, a great ecological concern, as one inch of topsoil can take 500 years to form naturally.
Such poor management of the topsoil is not the failure of a single farm or even a single region, but a problem of worldwide dimension. The world's four top crop-producing areas (U.S.A., the countries of the Eastern Bloc, China and India) are all losing topsoil at a rate of over 13 billion tons per year.
Sediment from soil erosion is the single greatest pollutant of the world's oceans, lakes and rivers. Scientists estimate that before intensive agricultural cultivation began, approximately 9 billion tons of topsoil was carried into our waterways annually through runoff. Today the volume has tripled, exceeding 27 billion tons every year, and continues to increase.
Soil management techniques that can reduce or reverse topsoil depletion include:
- No-till farming
- Keyline design
- Growing wind breaks to hold the soil
- Incorporating organic matter back into fields
- Protecting soil from water runoff
"Our problem with erosion was very serious and it was very damaging to the environment to the extent that, in these crops, to produce one ton of grain in Brazil, we lost 10 tons of soil per hectare per year. We solved this problem by eliminating tillage," says Almir Rebelo, grower advisor and president of Friends of the Earth, a Brazilian grower organization influential in the adoption of no-till farming in Brazil.
Economics
The socioeconomic aspects of sustainability are only partly understood. Regarding less concentrated farming, the best known analysis is Robert Netting's study, "Smallholders, Householders: Farm Families and the Ecology of Intensive, Sustainable Agriculture," on smallholder systems through history. The Oxford Sustainable Group defines sustainability in this context in a much broader form, considering the effect on all stakeholders in a 360 degree approach
Given the finite supply of natural resources at any specific cost and location, agriculture that is inefficient or damaging to needed resources may eventually exhaust the available resources or the ability to afford and acquire them. It may also generate negative externality, such as pollution as well as financial and production costs.
The way that crops are sold must be accounted for in the sustainability equation. Food sold locally does not require additional energy for transportation (including consumers). Food sold at a remote location, whether at a farmers' market or the supermarket, incurs a different set of energy cost for materials, labour, and transport.
Methods
What grows where and how it is grown is a matter of choice. Two of the many possible practices of sustainable agriculture are crop rotation and soil amendment, both designed to ensure that crops being cultivated can obtain the necessary nutrients for healthy growth. Soil amendments would include using locally available compost from community recycling centers. These community recycling centers help produce the compost needed by the local organic farms.
Many scientists, farmers, and businesses have debated how to make agriculture sustainable. Using community recycling from yard and kitchen waste utilizes a local area's commonly available resources. These resources that in the past were thrown away into large waste disposal sites are now used to produce low-cost organic compost for organic farming. Other practices includes growing a diverse number of perennial crops in a single field, each of which would grow in separate seasons so as not to compete with each other for natural resources. This system would result in increased resistance to diseases and decreased effects of erosion and loss of nutrients in soil. Nitrogen fixation from legumes, for example, used in conjunction with plants that rely on nitrate from soil for growth, helps to allow the land to be reused annually. Legumes will grow for a season and replenish the soil with ammonium and nitrate, and the next season other plants can be seeded and grown in the field in preparation for harvest.
Monoculture, a method of growing only one crop at a time in a given field, is a very widespread practice, but there are questions about its sustainability, especially if the same crop is grown every year.. Today it is realized that to get around this problem local cities and farms can work together to produce the needed compost for farmers nearby. Combined with growing a mixture of crops (polyculture) this sometimes reduces disease or pest problems. But polyculture has rarely, if ever, been compared to the more widespread practice of growing different crops in successive years (crop rotation) with the same overall crop diversity. Cropping systems that include a variety of crops (polyculture and/or rotation) may also replenish nitrogen (if legumes are included) and may also use resources such as sunlight, water, or nutrients more efficiently (Field Crops Res. 34:239).
Replacing a natural ecosystem with a few specifically chosen plant varieties reduces the genetic diversity found in wildlife and makes the organisms susceptible to widespread disease. The Great Irish Famine (1845-1849) is a well-known example of the dangers of monoculture. In practice, there is no single approach to sustainable agriculture, as the precise goals and methods must be adapted to each individual case. There may be some techniques of farming that are inherently in conflict with the concept of sustainability, but there is widespread misunderstanding on impacts of some practices.Today the growth of local farmers markets offer small farms the ability to sell the products that they have grown back to the cities where they obtained the recycled compost. By using local recycling, this will help move people away from the slash-and-burn techniques that are the characteristic feature of shifting cultivators so often cited as inherently destructive. Yet slash-and-burn cultivation has been practiced in the Amazon for at least 6000 years; serious deforestation did not begin until the 1970s, largely as the result of Brazilian government programs and policies. It is worthy of note that it may not have been slash-and-burn so much as slash-and-char, which with the addition of organic matter produces terra preta, one of the richest soils on Earth and the only one that regenerates itself.
There are also many ways to practice sustainable animal husbandry. Some of the key tools to grazing management include fencing off the grazing area into smaller areas called paddocks, lowering stock density, and moving the stock between paddocks frequently.
Off-farm Impacts
A farm that is able to "produce perpetually", yet has negative effects on environmental quality elsewhere is not sustainable agriculture. An example of a case in which a global view may be warranted is over-application of synthetic fertilizer or animal manures, which can improve productivity of a farm but can pollute nearby rivers and coastal waters (eutrophication). The other extreme can also be undesirable, as the problem of low crop yields due to exhaustion of nutrients in the soil has been related to rainforest destruction, as in the case of slash-and-burn farming for livestock feed.
Sustainability affects overall production, which must increase to meet the increasing food and fiber requirements as the world's human population expands to a projected 9.3 billion people by 2050. Increased production may come from creating new farmland, which may ameliorate carbon dioxide emissions if done through reclamation of desert as in Palestine, or may worsen emissions if done through slash-and-burn farming, as in Brazil. Additionally, genetically modified organism crops show promise for radically increasing crop yields, although many people and governments are apprehensive of this new farming method.
Some advocates favour sustainable agriculture as the only system which can be sustained over the long term. However, organic production methods, especially in transition, yield less than their conventional counterparts and raise the same problems of sustaining populations globally.
Excerpts from: Conversations about plant biotechnology; Monsanto
Excerpts from The Freemont Tribune, Saturday, Mar 18, 2006
http://en.wikipedia.org/wiki/Sustainable_farming
"National Agricultural Library, Agricultural Research Service, U. S. Department of Agriculture."