Sustainable agriculture
Encyclopedia
Sustainable agriculture is the practice of farming using principles of ecology
, the study of 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:
Sustainable agriculture in the United States was addressed by the 1990 farm bill. More recently, 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.
(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. There is a federal agency, 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:
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 annually flood cultivated lands (returning lost nutrients indefinitely) such as the Flooding of the Nile
, the long-term use of biochar
, and use of crop and livestock landrace
s 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.
s 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 that 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: 1) improving water conservation and storage measures, 2) providing incentives for selection of drought-tolerant crop species, 3) using reduced-volume irrigation systems, 4) managing crops to reduce water loss, or 5) not planting at all.
Indicators for sustainable water resource development are:
¤ Internal renewable water resources. This 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 proved 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.
is fast becoming one of the worlds greatest problems. It is estimated that "more than a thousand million tonnes of southern Africa's soil are eroded every year. Experts predict that crop yields will be halved within thirty to fifty years if erosion continues at present rates." Soil erosion is not unique to Africa but is occurring worldwide. The phenomenon is being called Peak Soil as present large scale factory farming techniques are jeopardizing humanity's ability to grow food in the present and in the future. Without efforts to improve soil management practices, the availability of arable soil
will become increasingly problematic.
Some Soil Management techniques
defines sustainability in this context in a much broader form, considering 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 material
s, labour, and transport
.
and soil amendment, both designed to ensure that crops being cultivated can obtain the necessary nutrient
s 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 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 season 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 to get around this problem local cities and farms can work together to produce the needed compost for the farmers around them. This combined with growing a mixture of crops (polyculture
) 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 that they got the recycled compost from. By using local recycling this will help move people away from the slash-and-burn techniques that are the characteristic feature of shifting cultivators
are 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. To 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.
Several attempts have been made to produce an artificial meat, using isolated tissues to produce it in vitro
; Jason Matheny's work on this topic, which in the New Harvest
project, is one of the most commented.
can be used as an ecological alternative to chemicals for soil sterilization. Different methods are available to induce steam into the soil in order to kill pests and increase soil health. Community and farm composting of kitchen, yard, and farm organic waste can provide most if not all the required needs of local farms. This composting could potentially be a reliable source of energy.
or animal manure
s, 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.
Many environmentalists advocate urban developments with high population density as a way of preserving agricultural land and maximizing energy efficiency. However, others have theorized that sustainable ecocities, or ecovillage
s which combine habitation and farming with close proximity between producers and consumers, may provide greater sustainability.
The use of available city space (e.g., rooftop gardens, community gardens, garden sharing
, and other forms of urban agriculture
) for cooperative food production is another way to achieve greater sustainability.
One of the latest ideas in achieving sustainable agricultural involves shifting the production of food plants from major factory farming operations to large, urban, technical facilities called vertical farms. The advantages of vertical farming
include year-round production, isolation from pests and diseases, controllable resource recycling, and on-site production that reduces transportation costs. While a vertical farm has yet to become a reality, the idea is gaining momentum among those who believe that current sustainable farming methods will be insufficient to provide for a growing global population.
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
, the study of 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:
- Satisfy human food and fiber needs
- Enhance environmental quality and the natural resource base upon which the agricultural economy depends
- Make the most efficient use of non-renewable resourceNon-renewable resourceA non-renewable resource is a natural resource which cannot be produced, grown, generated, or used on a scale which can sustain its consumption rate, once depleted there is no more available for future needs. Also considered non-renewable are resources that are consumed much faster than nature...
s and on-farm resources and integrate, where appropriate, natural biological cycles and controls - Sustain the economic viability of farm operations
- Enhance the quality of life for farmers and society as a whole.”
Sustainable agriculture in the United States was addressed by the 1990 farm bill. More recently, as consumer and retail demand for sustainable products has risen, organizations such as Food Alliance and Protected Harvest
Protected Harvest
Protected Harvest is an American non-profit organization heaquartered in Soquel, California that certifies sustainbly grown crops. The goal of the organization is to provide a standard measurement of what constitutes a sustainable product and use it to assure retailers and consumers that they are...
have started to provide measurement standards and certification programs for what constitutes a sustainably grown crop.
Farming and Natural Resources
The physical aspects of sustainability are partly understood. Practices that can cause long-term damage to soil include excessive tillageTillage
Tillage is the agricultural preparation of the soil by mechanical agitation of various types, such as digging, stirring, and overturning. Examples of human-powered tilling methods using hand tools include shovelling, picking, mattock work, hoeing, and raking...
(leading to erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
) and irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
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. There is a federal agency, 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
Soil conservation
Soil conservation is a set of management strategies for prevention of soil being eroded from the Earth’s surface or becoming chemically altered by overuse, acidification, salinization or other chemical soil contamination...
and quantity are most amenable to human intervention through time and labour.
Although air and sunlight
Sunlight
Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...
are available everywhere on Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
, crops
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
also depend on soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
nutrients and the availability of water
Water resources
Water resources are sources of water that are useful or potentially useful. Uses of water include agricultural, industrial, household, recreational and environmental activities. Virtually all of these human uses require fresh water....
. When farmers grow and harvest
Harvest
Harvest is the process of gathering mature crops from the fields. Reaping is the cutting of grain or pulse for harvest, typically using a scythe, sickle, or reaper...
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
Crop yield
In agriculture, crop yield is not only a measure of the yield of cereal per unit area of land under cultivation, yield is also the seed generation of the plant itself...
. 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 livestockLivestockLivestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
or treated human manureManureManure is organic matter used as organic fertilizer in agriculture. Manures contribute to the fertility of the soil by adding organic matter and nutrients, such as nitrogen, that are trapped by bacteria in the soil... - growing legume crops and forages such as peanutPeanutThe peanut, or groundnut , is a species in the legume or "bean" family , so it is not a nut. The peanut was probably first cultivated in the valleys of Peru. It is an annual herbaceous plant growing tall...
s or alfalfaAlfalfaAlfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...
that form symbioses with nitrogen-fixingNitrogen fixationNitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...
bacteriaBacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
called rhizobiaRhizobiaRhizobia are soil bacteria that fix nitrogen after becoming established inside root nodules of legumes . Rhizobia require a plant host; they cannot independently fix nitrogen... - industrial production of nitrogen by the Haber ProcessHaber processThe Haber process, also called the Haber–Bosch process, is the nitrogen fixation reaction of nitrogen gas and hydrogen gas, over an enriched iron or ruthenium catalyst, which is used to industrially produce ammonia....
uses hydrogen, which is currently derived from natural gas, (but this hydrogen could instead be made by electrolysisElectrolysisIn chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...
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
Shifting cultivation
Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned. This system often involves clearing of a piece of land followed by several years of wood harvesting or farming, until the soil loses fertility...
, returning to natural cycles that annually flood cultivated lands (returning lost nutrients indefinitely) such as the Flooding of the Nile
Flooding of the Nile
has been an important natal cycle in Egypt since ancient times. It is celebrated by Egyptians as an annual holiday for two weeks starting August 15, known as Wafaa El-Nil. It is also celebrated in the Coptic Church by ceremonially throwing a martyr's relic into the river, hence the name, Esba`...
, the long-term use of biochar
Biochar
Biochar or terra preta is charcoal created by pyrolysis of biomass. Biochar is under investigation as an approach to carbon sequestration via bio-energy with carbon capture and storage. Biochar thus has the potential to help mitigate climate change, via carbon sequestration...
, and use of crop and livestock landrace
Landrace
A landrace is a local variety of a domesticated animal or plant species which has developed largely by natural processes, by adaptation to the natural and cultural environment in which it lives. It differs from a formal breed which has been bred deliberately to conform to a particular standard...
s 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
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 pumpSubmersible pump
A submersible pump is a device which has a hermetically sealed motor close-coupled to the pump body. The whole assembly is submerged in the fluid to be pumped. The main advantage of this type of pump is that it prevents pump cavitation, a problem associated with a high elevation difference between...
s combined with the development of drip irrigation
Drip irrigation
Drip irrigation, also known as trickle irrigation or microirrigation or localized irrigation , is an irrigation method which saves water and fertilizer by allowing water to drip slowly to the roots of plants, either onto the soil surface or directly onto the root zone, through a network of valves,...
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 that in many areas where this has occurred, such as the Ogallala Aquifer
Ogallala Aquifer
The Ogallala Aquifer, also known as the High Plains Aquifer, is a vast yet shallow underground water table aquifer located beneath the Great Plains in the United States...
, 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: 1) improving water conservation and storage measures, 2) providing incentives for selection of drought-tolerant crop species, 3) using reduced-volume irrigation systems, 4) managing crops to reduce water loss, or 5) not planting at all.
Indicators for sustainable water resource development are:
¤ Internal renewable water resources. This 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 proved 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
Soil erosionErosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
is fast becoming one of the worlds greatest problems. It is estimated that "more than a thousand million tonnes of southern Africa's soil are eroded every year. Experts predict that crop yields will be halved within thirty to fifty years if erosion continues at present rates." Soil erosion is not unique to Africa but is occurring worldwide. The phenomenon is being called Peak Soil as present large scale factory farming techniques are jeopardizing humanity's ability to grow food in the present and in the future. Without efforts to improve soil management practices, the availability of arable soil
Arable land
In geography and agriculture, arable land is land that can be used for growing crops. It includes all land under temporary crops , temporary meadows for mowing or pasture, land under market and kitchen gardens and land temporarily fallow...
will become increasingly problematic.
Some Soil Management techniques
- No-till farmingNo-till farmingNo-till farming is a way of growing crops from year to year without disturbing the soil through tillage. No-till is an agricultural technique which increases the amount of water and organic matter in the soil and decreases erosion...
- Keyline designKeyline DesignKeyline design is a technique for maximizing beneficial use of water resources of a piece of land. The Keyline refers to a specific topographic feature linked to water flow...
- Growing wind breaksHedgeHedge may refer to:* Hedge or hedgerow, line of closely spaced shrubs planted to act as a barrier* Hedge , investment made to limit loss* Hedge , intentionally non-committal or ambiguous sentence fragments-See also:...
to hold the soil - Incorporating organic matterCompostCompost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. At its most essential, the process of composting requires simply piling up waste outdoors and waiting for the materials to break down from anywhere...
back into fields - Stop using chemical fertilizers (which contain salt)
- Protecting soil from water runoff
Economics
Socioeconomic aspects of sustainability are also partly understood. Regarding less concentrated farming, the best known analysis is Netting's study on smallholder systems through history. The Oxford Sustainable GroupOxford Sustainable Group
The Oxford Sustainable Group is a sustainable development company operating across Europe and managing four stock market listed companies, as well as its own portfolio with a value of between 2.5bn and 5bn Euro, which makes it one of the largest sustainable development groups in the region...
defines sustainability in this context in a much broader form, considering effect on all stakeholders in a 360 degree approach
Given the finite supply of natural resources
Natural Resources
Natural Resources is a soul album released by Motown girl group Martha Reeves and the Vandellas in 1970 on the Gordy label. The album is significant for the Vietnam War ballad "I Should Be Proud" and the slow jam, "Love Guess Who"...
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
Externality
In economics, an externality is a cost or benefit, not transmitted through prices, incurred by a party who did not agree to the action causing the cost or benefit...
, such as pollution as well as financial and production costs.
The way that crops are sold
Selling
Selling is offering to exchange something of value for something else. The something of value being offered may be tangible or intangible. The something else, usually money, is most often seen by the seller as being of equal or greater value than that being offered for sale.Another person or...
must be accounted for in the sustainability equation
Equation
An equation is a mathematical statement that asserts the equality of two expressions. In modern notation, this is written by placing the expressions on either side of an equals sign , for examplex + 3 = 5\,asserts that x+3 is equal to 5...
. Food
Food
Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals...
sold locally does not require additional energy for transportation (including consumers). Food sold at a remote location, whether at a farmers' market
Farmers' market
A farmers' market consists of individual vendors—mostly farmers—who set up booths, tables or stands, outdoors or indoors, to sell produce, meat products, fruits and sometimes prepared foods and beverages...
or the supermarket
Supermarket
A supermarket, a form of grocery store, is a self-service store offering a wide variety of food and household merchandise, organized into departments...
, incurs a different set of energy cost for material
Material
Material is anything made of matter, constituted of one or more substances. Wood, cement, hydrogen, air and water are all examples of materials. Sometimes the term "material" is used more narrowly to refer to substances or components with certain physical properties that are used as inputs to...
s, labour, and transport
Transport
Transport or transportation is the movement of people, cattle, animals and goods from one location to another. Modes of transport include air, rail, road, water, cable, pipeline, and space. The field can be divided into infrastructure, vehicles, and operations...
.
Methods
What grows where and how it is grown are a matter of choice. Two of the many possible practices of sustainable agriculture are crop rotationCrop rotation
Crop rotation is the practice of growing a series of dissimilar types of crops in the same area in sequential seasons.Crop rotation confers various benefits to the soil. A traditional element of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals...
and soil amendment, both designed to ensure that crops being cultivated can obtain the necessary nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
s 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 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 season 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
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...
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
Monoculture
Monoculture is the agricultural practice of producing or growing one single crop over a wide area. It is also known as a way of farming practice of growing large stands of a single species. It is widely used in modern industrial agriculture and its implementation has allowed for large harvests from...
, 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 to get around this problem local cities and farms can work together to produce the needed compost for the farmers around them. This combined with growing a mixture of crops (polyculture
Polyculture
Polyculture is agriculture using multiple crops in the same space, in imitation of the diversity of natural ecosystems, and avoiding large stands of single crops, or monoculture...
) 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
Crop rotation
Crop rotation is the practice of growing a series of dissimilar types of crops in the same area in sequential seasons.Crop rotation confers various benefits to the soil. A traditional element of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals...
) with the same overall crop diversity
Crop diversity
Crop diversity is the variance in genetic and phenotypic characteristics of plants used in agriculture. Crops may vary in seed size, branching pattern, in height, flower color, fruiting time, or flavor. They may also vary in less obvious characteristics such as their response to heat, cold or...
. 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
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
. The Great Irish Famine (1845–1849) is a well-known example of the dangers of monoculture
Monoculture
Monoculture is the agricultural practice of producing or growing one single crop over a wide area. It is also known as a way of farming practice of growing large stands of a single species. It is widely used in modern industrial agriculture and its implementation has allowed for large harvests from...
.
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 that they got the recycled compost from. By using local recycling this will help move people away from the slash-and-burn techniques that are the characteristic feature of shifting cultivators
Shifting cultivation
Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned. This system often involves clearing of a piece of land followed by several years of wood harvesting or farming, until the soil loses fertility...
are 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. To note that it may not have been slash-and-burn so much as slash-and-char
Slash-and-char
Slash-and-char is an alternative to slash-and-burn that has a lesser effect on the environment. It is the practice of charring the biomass resulting from the slashing, instead of burning it as in the slash-and-burn practice....
, which with the addition of organic matter produces terra preta
Terra preta
Terra preta is a type of very dark, fertile anthropogenic soil found in the Amazon Basin. Terra preta owes its name to its very high charcoal content, and was indeed made by adding a mixture of charcoal, bone, and manure to the otherwise relatively infertile Amazonian soil, and stays there for...
, 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
Field (agriculture)
In agriculture, the word field refers generally to an area of land enclosed or otherwise and used for agricultural purposes such as:* Cultivating crops* Usage as a paddock or, generally, an enclosure of livestock...
, lowering stock density, and moving the stock between paddocks frequently.
Several attempts have been made to produce an artificial meat, using isolated tissues to produce it in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
; Jason Matheny's work on this topic, which in the New Harvest
New Harvest
New Harvest is a non-profit organization promoting research on the development of in vitro meat and other meat substitutes. New Harvest was formed by researchers actively promoting tissue engineering. In 2005, P. D. Edelman, M.Sc., D.C. McFarland, Ph.D., V.A. Mironov, Ph.D., M.D., and J.G. Matheny,...
project, is one of the most commented.
Soil treatment
Soil steamingSoil steam sterilization
Soil steam sterilization is a farming technique that sterilizes soil with steam in open fields or greenhouses. Pests of plant cultures such as weeds, bacteria, fungi and viruses are killed through induced hot steam which causes their cell structure to physically degenerate. Biologically, the...
can be used as an ecological alternative to chemicals for soil sterilization. Different methods are available to induce steam into the soil in order to kill pests and increase soil health. Community and farm composting of kitchen, yard, and farm organic waste can provide most if not all the required needs of local farms. This composting could potentially be a reliable source of energy.
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 fertilizerFertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
or animal manure
Manure
Manure is organic matter used as organic fertilizer in agriculture. Manures contribute to the fertility of the soil by adding organic matter and nutrients, such as nitrogen, that are trapped by bacteria in the soil...
s, which can improve productivity of a farm but can pollute nearby rivers and coastal waters (eutrophication
Eutrophication
Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...
). 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
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
destruction, as in the case of slash and burn
Slash and burn
Slash-and-burn is an agricultural technique which involves cutting and burning of forests or woodlands to create fields. It is subsistence agriculture that typically uses little technology or other tools. It is typically part of shifting cultivation agriculture, and of transhumance livestock...
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
Palestine
Palestine is a conventional name, among others, used to describe the geographic region between the Mediterranean Sea and the Jordan River, and various adjoining lands....
, or may worsen emissions if done through slash and burn
Slash and burn
Slash-and-burn is an agricultural technique which involves cutting and burning of forests or woodlands to create fields. It is subsistence agriculture that typically uses little technology or other tools. It is typically part of shifting cultivation agriculture, and of transhumance livestock...
farming, as in Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
. Additionally, Genetically modified organism
Genetically modified organism
A genetically modified organism or genetically engineered organism is an organism whose genetic material has been altered using genetic engineering techniques. These techniques, generally known as recombinant DNA technology, use DNA molecules from different sources, which are combined into one...
crops show promise for radically increasing crop yields, although many people and governments are apprehensive of this new farming method.
Urban planning
There has been considerable debate about which form of human residential habitat may be a better social form for sustainable agriculture.Many environmentalists advocate urban developments with high population density as a way of preserving agricultural land and maximizing energy efficiency. However, others have theorized that sustainable ecocities, or ecovillage
Ecovillage
Ecovillages are intentional communities with the goal of becoming more socially, economically and ecologically sustainable. Some aim for a population of 50–150 individuals. Larger ecovillages of up to 2,000 individuals exist as networks of smaller subcommunities to create an ecovillage model that...
s which combine habitation and farming with close proximity between producers and consumers, may provide greater sustainability.
The use of available city space (e.g., rooftop gardens, community gardens, garden sharing
Garden sharing
Garden sharing is a local food and urban farming arrangement where a landowner allows a gardener access to land, typically a front or back yard, in order to grow food....
, and other forms of urban agriculture
Urban agriculture
Urban agriculture is the practice of cultivating, processing and distributing food in, or around, a village, town or city. Urban agriculture in addition can also involve animal husbandry, aquaculture, agro-forestry and horticulture...
) for cooperative food production is another way to achieve greater sustainability.
One of the latest ideas in achieving sustainable agricultural involves shifting the production of food plants from major factory farming operations to large, urban, technical facilities called vertical farms. The advantages of vertical farming
Vertical farming
Vertical farming is a concept that argues that it is economically and environmentally viable to cultivate plant or animal life within skyscrapers, or on vertically inclined surfaces...
include year-round production, isolation from pests and diseases, controllable resource recycling, and on-site production that reduces transportation costs. While a vertical farm has yet to become a reality, the idea is gaining momentum among those who believe that current sustainable farming methods will be insufficient to provide for a growing global population.
Sources
- Dore, J. 1997. Sustainability Indicators for Agriculture: Introductory Guide to Regional/National and On-farm Indicators, Rural Industries Research and Development Corporation, Australia.
- Gold, Mary. 1999. Sustainable Agriculture: Definitions and Terms. Special Reference Briefs Series no. SRB 99-02 Updates SRB 94-5 September 1999. National Agricultural Library, Agricultural Research Service, U.S. Department of Agriculture.
- Hayes, B. 2008. Trial Proposal: Soil Amelioration in the South Australian Riverland.
- Jahn, GC, B. Khiev, C. Pol, N. Chhorn, S. Pheng, and V. Preap. 2001. Developing sustainable pest management for rice in Cambodia. pp. 243–258, In S. Suthipradit, C. Kuntha, S. Lorlowhakarn, and J. Rakngan [eds.] “Sustainable Agriculture: Possibility and Direction” Proceedings of the 2nd Asia-Pacific Conference on Sustainable Agriculture 18–20 October 1999, Phitsanulok, Thailand. Bangkok (Thailand): National Science and Technology Development Agency. 386 p.
- Lindsay FalveyLindsay FalveyJohn Lindsay Falvey known as Lindsay Falvey, is an author who writes on topics concerning agricultural science and philosophy, religion, international development and more lately spiritual development...
(2004) Sustainability - Elusive or Illusion: Wise Environmental Management. Institute for International DevelopmentInstitute for International DevelopmentThe Institute for International Development is an Australian company limited by guarantee, which provides professional services in support of equitable international development. It does this through consultancies to major international agencies and its own development, publication, exchange, and...
, Adelaide pp259. - Hecht, Susanna and Alexander Cockburn (1989) The Fate of the Forest: developers, destroyers and defenders of the Amazon. New York: Verso.
- Netting, Robert McC. (1993) Smallholders, Householders: Farm Families and the Ecology of Intensive, Sustainable Agriculture. Stanford Univ. Press, Palo Alto.
- Dedicated double issue of Philosophical Transactions B on Sustainable Agriculture. Some articles are freely available.
Further reading
- Laki, G. (2002): Added value as the basis of sustainable agriculture’s subsidy system. In: (Eds. Trebicky, V. - Novak, J.) "Rio+10 Transition from Centrally Planned Economy to Sustainable Society? (Visegrad Agenda 21)", Institute for Environmental Policy, Prague, 2002, 49. p.
- Laki, G., Szakál, F. (2002): Added Value as a key indicator for sustainable agriculture. In: A mezőgazdasági termelés és erőforrás-hasznosítás ökonómiája - VIII. Nemzetközi Agrárökonómiai Tudományos Napok, SZIE Gazdálkodási és Mezőgazdasági Főiskolai Kar, Gyöngyös, 6 p.
- Pender J., Place F., Ehui S. (2006) Strategies for Sustainable Land Management in the East African Highlands
- Pollan M. (2007) The Omnivore's Dilemma: A Natural History of Four Meals by
- Roberts W. (2008) The No-Nonsense Guide to World Food by Roberts W. (2008)
External links
- Africa Project 2020 An Effort to Eradicate Hunger in Africa by empowering Farmers through Sustainable Agriculture.
- Agricultural Sustainability Institute at UC Davis
- Biodynamic Agriculture Australia Promoting the practice and understanding of the Biodynamic system of sustainable agriculture.
- Center for Environmental Farming Systems
- Center for Sustaining Agriculture & Natural Resources (WSUWashington State UniversityWashington State University is a public research university based in Pullman, Washington, in the Palouse region of the Pacific Northwest. Founded in 1890, WSU is the state's original and largest land-grant university...
) - Food Alliance The most credible and comprehensive certification for sustainable agriculture and food handling in North America.
- A special issue of the Journal of Environmental Management focuses on farm management and sustainable agriculture.
- Greenpeace Sustainable Agriculture campaign
- The Land Institute Research on sustainable perennial crop systems
- National Sustainable Agriculture Information Service
- National Campaign for Sustainable Agriculture
- What is Sustainable Agriculture? (from SAREP: University of California Sustainable Agriculture Research and Education Program)
- Sustainable Agriculture Research and Education (SARE)
- SAREP: University of California Sustainable Agriculture Research and Education Program
- Sustainable Commodity Initiative
- Industry-based initiative promoting sustainable agriculture for the production of mainstream agricultural materials
- Rainforest Alliance's Sustainable Agriculture program
- The Vertical Farm Project Envisioning the future of human food production as a mechanism for environmental restoration, protection from infectious disease, and a source of sustainable energy
- SANREM CRSP Sustainable Agriculture and Natural Resource Management Collaborative Research Support Program at Virginia Tech
- Self Help Development International SHDI is an Irish agency engaged in promoting long term sustainable development projects in Africa.
- Spade & Spoon: Localizing the Way Westerners Eat
- SAFECROP Centre for research and development of crop protection with low environment and consumer health impact
- Sustainable Agriculture, Biodiversity and Livelihoods Programme, part of the Natural Resources Group, International Institute for Environment and Development (IIED)
- Research on Agriculture and its role in international development from the Overseas Development InstituteOverseas Development InstituteThe Overseas Development Institute is one of the leading independent think tanks on international development and humanitarian issues. Based in London, its mission is "to inspire and inform policy and practice which lead to the reduction of poverty, the alleviation of suffering and the achievement...
- A Natural Step Case Study: Planning for the future harvest: Sustainability in the food industry - The Organically Grown Company
- Sustainable Agriculture Portal on WiserEarth
- List of Sustainable Agriculture Organizations on WiserEarth
- Center for Sustainable Energy Farming
- Holistic Management International (HMI)