Organic farming (of many particular kinds) was the original type of agriculture, and has been practiced for thousands of years. Forest gardening, a fully organic food production system which dates from prehistoric times is thought to be the world's oldest and most resilient agroecosystem. Organic farming is the form of agriculture that relies on techniques such as crop rotation, green manure, compost and biological pest control. Organic farming uses fertilizers and pesticides but excludes or strictly limits the use of manufactured (synthetic) fertilizers, pesticides (which include herbicides, insecticides and fungicides), plant growth regulators such as hormones, livestock antibiotics, food additives, genetically modified organisms, human sewage sludge, and nanomaterials. Organic farming is believed to improve soil fertility by enhancing soil organic matter (SOM) contents. An important co-benefit would be the sequestration of carbon from atmospheric CO.

Organic farming consists of a variety of measures that together constitute the 'organic' farming type. The goal of organic farming is to provide high-quality food with minimum environmental impacts in a sustainable way of production. With respect to soil, important aspects of organic farming are diverse crop rotations, cropping of legumes to supply the farm with nitrogen, low external inputs of nutrients, and of mineral fertilizers and synthetic chemicals used in conventional agriculture for crop protection. Organic farming has been shown to increase the SOC contents. Therefore, it is suggested as a measure to improve the overall greenhouse gas balance of agriculture compared to conventional farming ( Leifeld, and Fuhrer,2010).

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(Paull,2001). IFOAM defines the overarching goal of organic farming as:

"Organic agriculture is a production system that sustains the health of soils, ecosystems and people. It relies on ecological processes, biodiversity and cycles adapted to local conditions, rather than the use of inputs with adverse effects. Organic agriculture combines tradition, innovation and science to benefit the shared environment and promote fair relationships and a good quality of life for all involved..."
--International Federation of Organic Agriculture Movements

Organic farming offers an alternative that can eliminate many of the environmental problems of conventional agriculture in the industrialized world. Instead of using petroleum-derived chemicals to fertilize and protect crops, farmers manage their fields so as to take advantage of naturally-produced composts and mulches that recycle nutrients, and control pests and weeds (Jordan ,2004)

Since 1990, the market for organic products has grown from next to nothing statistically, reaching $55 billion in 2009 according to Organic Monitor ( demand has driven a similar increase in organically managed farmland which has grown over the past decade at a compounding rate of 8.9% per annum(Paull,2011). Approximately 37,000,000 hectares (91,000,000 acres) worldwide are now farmed organically, representing approximately 0.9 percent of total world farmland (2009). Modern organic farming has made up only a fraction of total agricultural output from its beginning until today. Increasing environmental awareness in the general population has transformed the originally supply-driven movement to a demand-driven one. Premium prices and some government subsidies attracted farmers. In the developing world, many producers farm according to traditional methods which are comparable to organic farming but are not certified.

In other cases, farmers in the developing world have converted for economic reasons. Fertilizing crops was a major problem for the preindustrial farmers, because animal and green manures were bulky and inconvenient to collect and spread. Industrial farming made agriculture much easier, but it also created environmental problems. Modern organic farming was founded as a reaction against agricultural practices that had the potential to harm nature and human health (Harwood 1990).

"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"
--Wendell Berry, "The Gift of Good Land"

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.

Environmental benefits from organic farming
1.Organic Farming Discourages Environmental Exposure to Pesticides and Chemicals
The Organic Trade Association notes that if every farmer in the U.S. converted to organic production, we could eliminate 500 million pounds of persistent and harmful pesticides from entering the environment annually.

2. Organic Farming Builds Healthy Soil
A large nine-year study by USDA Agricultural Research Service (ARS), shows that organic farming builds up organic soil matter better than conventional no-till farming. According to Dr. Elaine Ingham, just one teaspoon of compost-rich organic soil may host as many as 600 million to 1 billion helpful bacteria from 15,000 species. Ingham notes that on the flip side, one teaspoon of soil treated with chemicals may carry as few as 100 helpful bacteria.

3. Organic Farming Helps Combat Erosion
Not only does organic farming build healthy soil, but it helps combat serious soil and land issues, such as erosion. A major study comparing adjoining organic and chemically treated wheat fields, showed that the organic field featured eight more inches of topsoil than the chemically treated field and also had only one-third the erosion loss.

4. Organic Farming Fights the Effects of Global Warming
Organic agriculture contributes to mitigating the greenhouse effect and global warming through its ability to sequester carbon in the soil. ), increase the return of carbon to the soil, raising productivity and favouring carbon storage. A number of studies revealed that soil organic carbon contents under organic farming are considerably higher. The more organic carbon is retained in the soil, the more the mitigation potential of agriculture against climate change is higher.

5. Organic Farming Supports Water Conservation and Water Health
Organic farming also helps conserve water. Organic farmers, in general, tend to spend time amending soil correctly and using mulch both of which help conserve water. Cotton, an in-demand crop, requires a lot of irrigation and excess water when grown conventionally. However, organic cotton farming needs less irrigation and thus conserves water.

6. Organic Farming Discourages Algae Blooms
Algal blooms (HABs) result in adverse affects on the health of people and marine animals and organisms. Algal blooms also negatively affect recreation, tourism and thus, local and regional economies. While there is more than one cause of algal blooms, a primary human-based cause of algae blooms is runoff from the petroleum based fertilizers often used in conventional farming.

7.Organic Farming Supports Animal Health and Welfare
Insects, birds, fish and all sorts of other critters experience problems when humans swoop in and destroy their natural habitat. Organic farming not only helps preserve more natural habitat areas, but also encourages birds and other natural predators to live happily on farmland, which assists in natural pest control. Additionally, animals who live on organic farms are exposed to clean, chemical free grazing that helps keep them naturally healthy and resistant to illness. As a perk for organic farmers, happy and healthy organic animals are productive organic animals.

8. Organic Farming Encourages Biodiversity
In general, the more biodiversity there is on a farm, the more stable the farm is. Organic farming encourages healthy biodiversity, which plays a critical role in how resilient, or not, a farm is to issues like bad weather, disease and pests. Management of insect-pests using nanotechnology :as modern approaches

The applications of nanotechnology in agriculture, it can be suggested that the use of nanomaterials will result in the development of efficient and potential approaches for the management of insect pest in agriculture.

Previous studies confirmed that metal nanoparticles are effective against plants pathogens, insects and pests. Hence, nanoparticles can be used in the preparation of new formulations like pesticides, insecticides and insect repellants. Torney (2009) reviewed that nanotechnology has promising applications in nanoparticle mediated gene (DNA) transfer. It can be used to deliver DNA and other desired chemicals into plant tissues for protection of host plants against insect pests. Porous hollow silica nanoparticles (PHSNs) loaded with validamycin (pesticide) can be used as efficient delivery system of water-soluble pesticide for its controlled release. Such controlled release behaviour of PHSNs makes it a promising carrier in agriculture, especially for pesticide controlled delivery whose immediate as well as prolonged release is needed for plants. According to Wang et al. (2007), oil in water (nano-emulsions) was useful for the formulations of pesticides and these could be effective against the various insect pests in agriculture. Nano-silica, a type of unique nanomaterial, is prepared from silica. It has many applications in medicine and drug development as catalyst and most importantly is that it can be used as nano-pesticide. Yang et al. (2009) demonstrated the insecticidal activity of polyethylene glycolcoated nanoparticles loaded with garlic essential oil against adult Tribolium castaneum insect found in stored products. It has been observed that the control efficacy against adult T. castaneum was about 80 %, presumably due to the slow and persistent release of the active components from the nanoparticles.

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