Organic farming is a form of
agriculture that relies on techniques such as
crop rotation,
green manure,
compost, and
biological pest control. Depending on whose
definition is used, organic farming uses fertilizers and pesticides (which include
herbicides,
insecticides and
fungicides) if they are considered
natural (such as
bone meal from animals or
pyrethrin from flowers), but it excludes or strictly limits the use of various methods (including synthetic petrochemical
fertilizers and
pesticides;
plant growth regulators such as
hormones;
antibiotic use in livestock;
genetically modified organisms;
[1] human sewage
sludge; and
nanomaterials.
[2]) for reasons including
sustainability,
openness,
independence,
health, and
safety.
Organic agricultural methods are internationally regulated and legally enforced by many nations, based in large part on the standards set by the
International Federation of Organic Agriculture Movements (IFOAM), an international
umbrella organization for organic farming organizations established in 1972.
[3] The USDA National Organic Standards Board (NOSB) definition as of April 1995 is:
“Organic agriculture is an ecological production management system that promotes and enhances biodiversity, biological cycles and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain and enhance ecological harmony."[4]
Since 1990 the market for
organic food and other products has grown rapidly, reaching $63 billion worldwide in 2012.
[5]:25 This demand has driven a similar increase in organically managed farmland which has grown over the years 2001-2011 at a compounding rate of 8.9% per annum.
[6] As of 2011, approximately 37,000,000 hectares (91,000,000 acres) worldwide were farmed organically, representing approximately 0.9 percent of total world farmland (2009).
[7]
Organic farming systems
There are several organic farming systems.
Biodynamic farming is a comprehensive approach, with its own international governing body. The
Do Nothing Farming method focuses on a minimum of mechanical cultivation and labor for grain crops. French intensive and
biointensive, methods are well-suited to organic principles. Other examples of techniques are
holistic management,
permaculture,
SRI and
no-till farming (the last two which may be implemented in conventional or organic systems
[23][24]).
Methods
"An organic farm, properly speaking, is not one that uses certain methods and substances and avoids others; it is a farm whose structure is formed in imitation of the structure of a natural system that has the integrity, the independence and the benign dependence of an organism"
Organic farming methods combine scientific knowledge of ecology and modern
technology with
traditional farming practices based on naturally occurring biological processes. Organic farming methods are studied in the field of
agroecology. While conventional agriculture uses synthetic pesticides and water-soluble synthetically purified fertilizers, organic farmers are restricted by regulations to using natural pesticides and fertilizers. The principal methods of organic farming include
crop rotation,
green manures and
compost,
biological pest control, and mechanical
cultivation. These measures use the natural environment to enhance agricultural productivity:
legumes are planted to fix
nitrogen into the soil,
natural insect predators are encouraged, crops are rotated to confuse pests and renew soil, and natural materials such as
potassium bicarbonate[25] and
mulches are used to control disease and
weeds. Hardier plants are generated through
plant breeding rather than genetic engineering.
While organic is fundamentally different from conventional because of the use of carbon based fertilizers compared with highly soluble synthetic based fertilizers and
biological pest control instead of synthetic pesticides, organic farming and large-scale conventional farming are not entirely mutually exclusive. Many of the methods developed for organic agriculture have been borrowed by more conventional agriculture. For example,
Integrated Pest Management is a multifaceted strategy that uses various organic methods of pest control whenever possible, but in conventional farming could include synthetic
pesticides only as a last resort.
[26]
Crop diversity
Crop diversity is a distinctive characteristic of organic farming. Conventional farming focuses on
mass production of one crop in one location, a practice called
monoculture. The science of
agroecology has revealed the benefits of
polyculture (multiple crops in the same space), which is often employed in organic farming.
[27] Planting a variety of vegetable crops supports a wider range of beneficial insects, soil microorganisms, and other factors that add up to overall farm health. Crop diversity helps environments thrive and protect species from going extinct.
[28]
Soil management
Organic farming relies heavily on the natural breakdown of organic matter, using techniques like
green manure and
composting, to replace nutrients taken from the soil by previous crops. This biological process, driven by
microorganisms such as
mycorrhiza, allows the natural production of nutrients in the soil throughout the growing season, and has been referred to as
feeding the soil to feed the plant. Organic farming uses a variety of methods to improve soil fertility, including crop rotation, cover cropping, reduced tillage, and application of compost. By reducing tillage, soil is not inverted and exposed to air; less carbon is lost to the atmosphere resulting in more soil organic carbon. This has an added benefit of carbon sequestration which can reduce green house gases and aid in reversing climate change.
Plants need
nitrogen,
phosphorus, and
potassium, as well as
micronutrients and
symbiotic relationships with
fungi and other organisms to flourish, but getting enough nitrogen, and particularly synchronization so that plants get enough nitrogen at the right time (when plants need it most), is a challenge for organic farmers.
[29] Crop rotation and
green manure ("
cover crops") help to provide nitrogen through
legumes (more precisely, the
Fabaceae family) which fix nitrogen from the atmosphere through symbiosis with
rhizobial bacteria.
Intercropping, which is sometimes used for insect and disease control, can also increase soil nutrients, but the competition between the legume and the crop can be problematic and wider spacing between crop rows is required.
Crop residues can be
ploughed back into the soil, and different plants leave different amounts of nitrogen, potentially aiding synchronization.
[29] Organic farmers also use animal
manure, certain processed fertilizers such as seed meal and various
mineral powders such as
rock phosphate and
greensand, a naturally occurring form of
potash which provides potassium. Together these methods help to control
erosion. In some cases
pH may need to be amended. Natural pH amendments include
lime and
sulfur, but in the U.S. some compounds such as
iron sulfate,
aluminum sulfate,
magnesium sulfate, and soluble
boron products are allowed in organic farming.
[30]:43
Mixed farms with both
livestock and
crops can operate as
ley farms, whereby the land gathers fertility through growing nitrogen-fixing
forage grasses such as
white clover or
alfalfa and grows
cash crops or
cereals when fertility is established. Farms without livestock ("stockless") may find it more difficult to maintain soil fertility, and may rely more on external inputs such as imported
manure as well as grain legumes and green manures, although grain legumes may fix limited nitrogen because they are harvested.
Horticultural farms growing fruits and vegetables which operate in protected conditions are often even more reliant upon external inputs.
[29]
Biological research into soil and soil organisms has proven beneficial to organic farming. Varieties of bacteria and fungi break down chemicals, plant matter and animal waste into productive soil nutrients. In turn, they produce benefits of healthier yields and more productive soil for future crops.
[31] Fields with less or no manure display significantly lower yields, due to decreased soil microbe community, providing a healthier, more arable soil system.
[32]
Weed management
Organic
weed management promotes weed suppression, rather than weed elimination, by enhancing crop competition and
phytotoxic effects on weeds.
[33] Organic farmers integrate cultural, biological, mechanical, physical and chemical tactics to manage weeds without synthetic herbicides.
Organic standards require
rotation of annual crops,
[34] meaning that a single crop cannot be grown in the same location without a different, intervening crop. Organic crop rotations frequently include weed-suppressive
cover crops and crops with dissimilar life cycles to discourage weeds associated with a particular crop.
[33] Research is ongoing to develop organic methods to promote the growth of natural microorganisms that suppress the growth or germination of common weeds.
[35]
Other cultural practices used to enhance crop competitiveness and reduce weed pressure include selection of competitive crop varieties, high-density planting, tight row spacing, and late planting into warm soil to encourage rapid crop
germination.
[33]
Mechanical and physical weed control practices used on organic farms can be broadly grouped as:
[36]
- Tillage - Turning the soil between crops to incorporate crop residues and soil amendments; remove existing weed growth and prepare a seedbed for planting; turning soil after seeding to kill weeds, including cultivation of row crops;
- Mowing and cutting - Removing top growth of weeds;
- Flame weeding and thermal weeding - Using heat to kill weeds; and
- Mulching - Blocking weed emergence with organic materials, plastic films, or landscape fabric.[37]
Some critics, citing work published in 1997 by David Pimentel of Cornell University,
[38] which described an epidemic of
soil erosion worldwide, have raised concerned that tillage contribute to the erosion epidemic.
[39] The FAO and other organizations have advocated a "no-till" approach to both conventional and organic farming, and point out in particular that crop rotation techniques used in organic farming are excellent no-till approaches.
[39][40] A study published in 2005 by Pimentel and colleagues
[41] confirmed that "Crop rotations and cover cropping (green manure) typical of organic agriculture reduce soil erosion, pest problems, and pesticide use." Some naturally sourced chemicals are allowed for herbicidal use. These include certain formulations of
acetic acid (concentrated vinegar),
corn gluten meal, and
essential oils. A few selective
bioherbicides based on fungal
pathogens have also been developed. At this time, however, organic herbicides and bioherbicides play a minor role in the organic weed control toolbox.
[36]
Weeds can be controlled by grazing. For example, geese have been used successfully to weed a range of organic crops including cotton, strawberries, tobacco, and corn,
[42] reviving the practice of keeping
cotton patch geese, common in the southern U.S. before the 1950s. Similarly, some rice farmers introduce ducks and fish to wet
paddy fields to eat both weeds and insects.
[43]
Controlling other organisms
Chloroxylon is used for Pest Management in Organic Rice Cultivation in Chhattisgarh, India
Organisms aside from weeds that cause problems on organic farms include
arthropods (e.g., insects,
mites),
nematodes,
fungi and
bacteria. Organic practices include, but are not limited to:
Examples of predatory beneficial insects include
minute pirate bugs,
big-eyed bugs, and to a lesser extent
ladybugs (which tend to fly away), all of which eat a wide range of pests.
Lacewings are also effective, but tend to fly away.
Praying mantis tend to move more slowly and eat less heavily.
Parasitoid wasps tend to be effective for their selected prey, but like all small insects can be less effective outdoors because the wind controls their movement. Predatory mites are effective for controlling other mites.
[30]:66–90
Naturally derived
insecticides allowed for use on organic farms use include
Bacillus thuringiensis (a bacterial toxin),
pyrethrum (a chrysanthemum extract),
spinosad (a bacterial metabolite),
neem (a tree extract) and
rotenone (a legume root extract). Fewer than 10% of organic farmers use these pesticides regularly; one survey found that only 5.3% of vegetable growers in California use
rotenone while 1.7% use
pyrethrum.
[45]:26 These pesticides are not always more safe or environmentally friendly than synthetic pesticides and can cause harm.
[30]:92 The main criterion for organic pesticides is that they are naturally derived, and some naturally derived substances have been controversial. Controversial natural pesticides include
rotenone,
copper,
nicotine sulfate, and
pyrethrums[46][47] Rotenone and
pyrethrum are particularly controversial because they work by attacking the nervous system, like most conventional insecticides. Rotenone is extremely toxic to fish
[48] and can induce symptoms resembling Parkinson's disease in mammals.
[49][50] Although pyrethrum (natural pyrethrins) is more effective against insects when used with piperonyl butoxide (which retards degradation of the pyrethrins),
[51] organic standards generally do not permit use of the latter substance.
[52][53][54]
Naturally derived
fungicides allowed for use on organic farms include the bacteria
Bacillus subtilis and
Bacillus pumilus; and the fungus
Trichoderma harzianum. These are mainly effective for diseases affecting roots.
Compost tea contains a mix of beneficial microbes, which may attack or out-compete certain plant pathogens,
[55] but variability among formulations and preparation methods may contribute to inconsistent results or even dangerous growth of toxic microbes in compost teas.
[56]
Some naturally derived pesticides are not allowed for use on organic farms. These include
nicotine sulfate,
arsenic, and
strychnine.
[57]
Synthetic pesticides allowed for use on organic farms include
insecticidal soaps and
horticultural oils for insect management; and
Bordeaux mixture,
copper hydroxide and
sodium bicarbonate for managing fungi.
[57] Copper sulfate and Bordeaux mixture (copper sulfate plus lime), approved for organic use in various jurisdictions,
[52][53][57] can be more environmentally problematic than some synthetic fungicides dissallowed in organic farming
[58][59] Similar concerns apply to copper hydroxide. Repeated application of copper sulfate or copper hydroxide as a fungicide may eventually result in copper accumulation to toxic levels in soil,
[60] and admonitions to avoid excessive accumulations of copper in soil appear in various organic standards and elsewhere. Environmental concerns for several kinds of biota arise at average rates of use of such substances for some crops.
[61] In the European Union, where replacement of copper-based fungicides in organic agriculture is a policy priority,
[62] research is seeking alternatives for organic production.
[63]
Livestock
For livestock like these healthy cows vaccines play an important part in animal health since antibiotic therapy is prohibited in organic farming
Raising livestock and poultry, for meat, dairy and eggs, is another traditional, farming activity that complements growing. Organic farms attempt to provide animals with natural living conditions and feed. While the USDA does not require any animal welfare requirements be met for a product to be marked as organic, this is a variance from older organic farming practices.
[64]
Also, horses and cattle used to be a basic farm feature that provided labor, for hauling and plowing, fertility, through recycling of manure, and fuel, in the form of food for farmers and other animals. While today, small growing operations often do not include livestock, domesticated animals are a desirable part of the organic farming equation, especially for true sustainability, the ability of a farm to function as a self-renewing unit.
Genetic modification
A key characteristic of organic farming is the rejection of genetically engineered plants and animals. On October 19, 1998, participants at IFOAM's 12th Scientific Conference issued the
Mar del Plata Declaration, where more than 600 delegates from over 60 countries voted unanimously to exclude the use of genetically modified organisms in food production and agriculture.
Although opposition to the use of any transgenic technologies in organic farming is strong, agricultural researchers Luis Herrera-Estrella and Ariel Alvarez-Morales continue to advocate integration of
transgenic technologies into organic farming as the optimal means to sustainable agriculture, particularly in the developing world,
[65] as does author and scientist
Pamela Ronald, who views this kind of
biotechnology as being consistent with organic principles.
[66]
Although GMOs are excluded from organic farming, there is concern that the pollen from genetically modified crops is increasingly penetrating organic and
heirloom seed stocks, making it difficult, if not impossible, to keep these genomes from entering the organic food supply. Differing regulations among countries limits the availability of GMOs to certain countries, as described in the article on
regulation of the release of genetic modified organisms.
Standards
Standards regulate production methods and in some cases final output for organic agriculture. Standards may be voluntary or legislated. As early as the 1970s private associations certified organic producers. In the 1980s, governments began to produce organic production guidelines. In the 1990s, a trend toward legislated standards began, most notably with the 1991
EU-Eco-regulation developed for
European Union,
[67] which set standards for 12 countries, and a 1993 UK program. The EU's program was followed by a Japanese program in 2001, and in 2002 the U.S. created the
National Organic Program (NOP).
[68] As of 2007 over 60 countries regulate organic farming (
IFOAM 2007:11). In 2005 IFOAM created the
Principles of Organic Agriculture, an international guideline for certification criteria.
[69] Typically the agencies accredit certification groups rather than individual farms.
Organic production materials used in and foods are tested independently by the Organic Materials Review Institute.
[70]
Composting
Under
USDA organic standards, manure must be subjected to proper
thermophilic composting and allowed to reach a sterilizing temperature. If raw animal manure is used, 120 days must pass before the crop is harvested if the final product comes into direct contact with the soil. For products which do not come into direct contact with soil, 90 days must pass prior to harvest.
[71]