Agriculture conventionnelle

This page is an automatic translation to French of Conventional farming.This translation is distributed in the hope that it will be useful, but without any guarantee of accuracy.

L'agriculture conventionnelle , également connue sous le nom d'agriculture traditionnelle ou d'agriculture industrielle , fait référence à des systèmes agricoles qui incluent l'utilisation d' engrais chimiques de synthèse , de pesticides , d'herbicides et d'autres intrants continus, d'organismes génétiquement modifiés , d'opérations d'alimentation animale concentrée, d' une irrigation intensive , d' un travail intensif du sol , ou monoculture concentréeproduction. Ainsi, l'agriculture conventionnelle est généralement très exigeante en ressources et énergivore, mais aussi très productive. Malgré son nom, les méthodes agricoles conventionnelles n'ont été développées que depuis la fin du XIXe siècle et ne se sont généralisées qu'après la Seconde Guerre mondiale (voir : Wikipédia : Révolution verte .

L'agriculture conventionnelle est généralement opposée à l'agriculture biologique (ou parfois à l'agriculture durable ou à la permaculture ), car celles-ci répondent aux conditions spécifiques au site en intégrant des pratiques culturelles, biologiques et mécaniques qui favorisent le cycle des ressources, favorisent l'équilibre écologique et conservent la biodiversité. ^[1] Plutôt que d'utiliser des engrais synthétiques, des pesticides, des régulateurs de croissance et des additifs alimentaires pour le bétail, les systèmes d'agriculture biologique reposent sur la rotation des cultures, les fumiers animaux et végétaux comme engrais, le désherbage manuel et la lutte biologique contre les ravageurs. ^[2] Certaines opérations agricoles conventionnelles peuvent inclure une polyculture limitée ou une forme de lutte intégrée contre les ravageurs. (Voir : Agriculture biologique industrielle ).

Agriculture conventionnelle versus agriculture biologique

Avantages et inconvénients

Toute technologie nouvellement développée aura des conséquences positives et négatives. Si nous analysons les aspects positifs et négatifs de la façon dont nous produisons de la nourriture, nous pourrons peut-être améliorer les bonnes choses et réduire les impacts négatifs. Avec l'agriculture conventionnelle, il est possible de produire des quantités beaucoup plus importantes de nourriture, sur moins de terres et avec moins de travail manuel que jamais auparavant dans l'histoire.

Avec la hausse des prix des denrées alimentaires et des millions de personnes affamées dans le monde entier, il semble que nous ayons l'obligation morale d'utiliser des méthodes conventionnelles pour produire de grandes quantités de nourriture à des prix abordables. Cependant, étant donné que de nombreux effets de l'agriculture conventionnelle sont inconnus et que nombre d'entre eux peuvent être irréversibles et nocifs, il peut être plus sûr de s'en tenir à ce que nous faisons depuis des centaines d'années . Il peut être considéré comme irresponsable de continuer à utiliser des pesticides, des irradiations et des OGM alors que nous ne savons vraiment pas quels sont les effets secondaires.

Écologie

There is a common perception that organic farming is more ecologically sustainable than conventional farming. As a result of industrial farming conditions, today's mounting environmental stresses are further exacerbated, including:

• Water pollution, including fertilizer runoff causing eutrophication
• Chemical leaching^W

There are many factors in how sustainable farming practices are, besides use of artificial chemicals. E.g.:

• Land degradation^W
  • Erosion
  • Soil compaction
• Transport used - not just distance, but the type of transport.
• Water usage (including declining water table^Ws)
• Loss in biodiversity^[3]

Human health

Organic foods are usually assumed to be healthier than conventionally-produced foods. Hundreds of studies have attempted to assess the whether conventionally-produced foods have different health effects from organically produced ones. In the last few years a few meta-studies have drawn differing conclusions based on those earlier studies. One meta-study of 237 studies conducted at Stanford concludes that "There isn't much difference between organic and conventional foods, if you're an adult and making a decision based solely on your health.".^[4] Another meta-study lead by researchers at Newcastle University based on 343 earlier studies found that conventionally-produced crops contained 18-69% less antioxidants, were four times as likely to contain pesticide residues, and had, on average 48% higher concentrations of heavy metals (including cadmium) than organically-produced crops.^[5]

Potential conflicts of interest have been identified in both of these cases, as the institutions involved with these studies have received funding from agriculture business interests in both the conventional and organic sectors.

Many supporters of organic agriculture rely on personal experiences and beliefs when choosing organic over conventionally produced food. "Although, as scientists, we may deplore the fact that people are swayed by non-scientific views, the fact is that a lot of them are. Despite the arguments presented by Trewavas, many people believe that organic production systems produce better food, care more for animal welfare and are kinder to the environment,".^[6]

Yield

It is generally recognized that conventional farming produces a higher amount of food than organic. One meta-study found organic yields to be on average 80% that of conventional, but "the organic yield gap significantly differed between crop groups and regions.".^[7] Another meta-analysis concluded that, "organic yields are typically lower than conventional yields. But these yield differences are highly contextual, depending on system and site characteristics, and range from 5% lower organic yields (rain-fed legumes and perennials on weak-acidic to weak-alkaline soils), 13% lower yields (when best organic practices are used), to 34% lower yields (when the conventional and organic systems are most comparable)."^[8]

Modern farmland is claimed to produce 200 percent more wheat than the same area did 70 years ago. Hence switching to organic farming would lead to a reduction in output, e.g. by 20% for corn.^[9] The figure is plausible, but we need more than one unattributed figure.^[10]

Biodiversity

Several studies have compared the local biodiversity of conventional and organic systems. A meta-study at the Swedish University of Agricultural Sciences concluded,

"Organic farming usually increases species richness, having on average 30% higher species richness than conventional farming systems. However, the results were variable among studies, and 16% of them actually showed a negative effect of organic farming on species richness. [...] Birds, insects, and plants usually showed an increased species richness in organic farming systems. However, the number of studies was low in most organism groups (range 2–19) and there was significant heterogeneity between studies. [...] On average, organisms were 50% more abundant in organic farming systems, but the results were highly variable between studies and organism groups. Birds, predatory insects, soil organisms and plants responded positively to organic farming, while non-predatory insects and pests did not. The positive effects of organic farming on abundance were prominent at the plot and field scales, but not for farms in matched landscapes.^[11]

Une étude de l'Université de Bristol comparant 10 paysages agricoles conventionnels et 10 biologiques a révélé que bien que les fermes biologiques aient une plus grande quantité de zones non cultivées ou "semi-naturelles", elles n'avaient pas une biodiversité plus élevée dans ces espaces. Cependant, il y avait une plus grande biodiversité dans les champs arables des fermes biologiques. ^[12]

Il existe une préoccupation commune qui relie rendement (voir ci-dessus) et biodiversité. L'hypothèse est que si l'agriculture biologique a des rendements plus faibles, cela augmentera le besoin de plus de superficies cultivées, et aura donc un impact négatif sur la biodiversité régionale ou mondiale. On ne sait pas si des études ont été faites pour tester cette hypothèse.

Aspects sociaux et économiques

Une étude sur la diffusion des connaissances agricoles de l'Université de Cardiff a révélé que "la chaîne alimentaire conventionnelle [...] a tendance à diffuser les connaissances vers les fournisseurs d'intrants, et la chaîne d'approvisionnement alimentaire biologique [...] redistribue les connaissances vers la ferme", en raison à leurs caractéristiques économiques différentes. ^[13]

Pesticides

 

Les pesticides sont des substances utilisées pour tuer les insectes, les plantes et d'autres organismes qui ont un impact négatif sur le rendement des cultures . Ils peuvent aller de produits chimiques dangereux isolés artificiellement, tels que de nombreux organochlorés, à des préparations à base de plantes relativement inoffensives, comme l'huile de neem . Les pesticides peuvent avoir des conséquences imprévues telles que la mort d'insectes prédateurs bénéfiques.

Most of the pesticides in our food, by far, are natural pesticides produced by the plants. This leaves open the question of whether the artificial chemicals are worse for us. After all, not all substances are the same, and some (such as DDT) linger in the environment for far longer. It's also true that something is harmful given to lab rats in large quantities, yet not significantly harmful in small quantities - or even beneficial, since there has been research suggesting that toxins in small doses actually benefit an organism by making it react to the mild stress.^{[verification needed]}

Many natural chemical compounds are also toxic or carcinogenic in large quantities, but we consume them in small quantities. Everything has a toxic dose - even water, salt or any nutrient.

There is a common perception that "the poisons are killing us." So why are we living longer than ever? If there is a negative effect from these traces of chemicals, the effect is much smaller than positive changes in modern times (e.g. better medicines and medical treatments).

Note that these arguments are not saying that "pesticides are good for you" - using them inappropriately, without following directions, has the potential to be very harmful. But when used properly, they appear to not be significantly harmful, and may not be harmful at all. Worrying about them may do us more harm than the chemicals themselves.

Read more »

Fertilizers

 

Fertilisers are substances that can be supplied to the soil so as to improve the soil quality and promote the growth of any plants grown in this soil. Fertilisers come in several types and correct application differs depending on this type. Differences on application may include: method of introducing the fertiliser into the soil, the time of the year when the fertiliser is administered, etc...

There's actually little doubt that fertilizers harm ecosystems. But is this inevitable, and what are the alternatives? Limited use and precise application reduce the effect of eutrophication on waterways. More recent discoveries, e.g. the role of soil fungi, the impact of compost teas, and terra preta, show that there may be much greener ways to create abundance in food production.^{[verification needed]} However, this knowledge is still in its early years - the knowledge is still being developed, and the valuable knowledge that already exists has not yet spread widely.

Read more »

Nitrogen sources

Borlaug said:^[10]

Even if you could use all the organic material that you have--the animal manures, the human waste, the plant residues--and get them back on the soil, you couldn't feed more than 4 billion people (and) you would have to increase cropland area dramatically...

At the present time, approximately 80 million tons of nitrogen nutrients are utilized each year. If you tried to produce this nitrogen organically, you would require an additional 5 or 6 billion head of cattle to supply the manure.

This appears to not consider the impact of nitrogen fixation,^W for example by legume crops. (This is another argument for vegetarianism and veganism being greener - less methane-producing cows, and more legume crops to replace them, which will also produce nitrogen.)

Currently, enormous amounts of nutrients are thrown away in our sewage. Through humanure this can be salvaged, but may not be suitable for many food crops, especially where the food is close to the ground.

GMOs

 

Genetically modified apple

A genetically modified organism (GMO) is an organism whose genetic material has been altered using genetic engineering techniques. Genetic engineering essentially involves incorporation of gene(s) from an different species - even across Kingdom - into the host genome. Thus, genes from animals and bacteria may be inserted into a plant genome, to create a novel transgenic plant. Transgenic breeding is thus different from the traditional selective breeding, and therefore novel gene products (like proteins) from the GMO may have some unexpected environmental effects.

Several antibodies and medicines have already been commercially produced by using genetic engineering. For example, mammalian insulin is being produced by recombinant DNA in bacteria. This make the hormone much cheaper than natural insulin derived from conventional biosynthesis. However, when genetic engineering is applied in agriculture for production of crops, there are many uncertainties and risks.

Unlike insulin or other GM drugs and hormones manufactured in the laboratory, GM crops cannot be controlled or revoked, once they are released in nature.^[14] In addition to the possible harmful effects on ecosystems (including agro-ecosystems), introduction of the GMOs into the human food chain poses an unprecedented risk to public health.

Genetically modified food has caused considerable controversy since the early 1990s, when it was first introduced. However, this controversy only relates to GM organisms that have been created using the transgenesis method. Cisgenesis has been proven equally safe as regular plant breeding by the EFSA^[15]

Conventional food production often utilizes GMO's which are different from plants and animals that have been selectively bred. There are environmental drawbacks of using GMOs. One is that it is difficult to control the reproduction of plants, especially when they are growing in an open environment, and not contained within a structure such as a greenhouse. When there is a farm with GMOs nearby another farm, there can be a problem with crossbreeding between the two varieties of plant. This can result in genetic drift which can have negative impacts on farms that produce heirloom varieties. When this effect is coupled with the terminator gene (a gene inserted in plants by companies that produce GMO's, which prevents their seeds from producing viable offspring) this can have devastating effects on heirloom varieties, and for farmers who have been keeping their variety for generations.

Read more »

References