Conventional vs. Organic Farming Series, Part I: Environmental Effects of Conventional Farming

organic vs conventional farming

If you were raised on a farm and your parents were organic farmers, you might be naturally equipped with everything you needed to get the best from the soil by using ecological principles. But if you were raised in an urban environment and your parents were, say, a journalist and a lawyer, your learning about the soil and farming methods might not come so easy. You might need to consult literature (and, most likely on your own) about different approaches to crop production and why they matter.

To an organic devotee like me, things in supermarkets and farmer’s markets look way much better today than they did ten years ago. However, judging by the variety of comments in response to articles (like this one) that dealt with the advantages of organic agriculture, the dialogue on conventional vs. organic is quite lively and kicking. Clearly, the conventional farming is not willing to leave the central stage yet. So, I felt like advancing things a bit with the series I’ll call: conventional vs. organic farming. In this four-part series I plan to look at the important features of both farming methods: environmental, health and socio-economic. So, here we go.

PART 1: ENVIRONMENTAL EFFECTS OF CONVENTIONAL FARMING

What is conventional farming?

Developed in response to market economy and profit incentives, the conventional agriculture is a farming method encouraged to move in the direction of greater efficiency and output production. The increase in efficiency has been the result of many factors, including the use of fertilizers, pesticides, introduction of farm machinery and fossil fuels. As agriculture has become more intensive, farmers have become capable of producing higher yields using less labor and less land. The intensification of agriculture has, however, raised worries about environmental, health and socio-economic effects of conventional agriculture.  The worry is based on the increased dependence on non-renewable resources, reduction of agricultural base through soil erosion, and environmentally damaging effects of fertilizers and pesticides.

What is organic farming?

Organic farming is a method of crop production employed through the history of human culture. Although ancient in principle, organic agriculture has been increasingly reconsidered as an ecologically friendly alternative to conventional farming. It seeks to avoid the use of synthetic chemicals including fertilizers, pesticides and growth regulators. The ultimate objective of organic farming is to be as much as possible in accordance with the universal ecological principles.

farmers market

Conventional Farming: The Problem

Researchers generally recognize that the motives of conventional farming have started agricultural practices that have brought severe crises to natural cycles. Although the intensification of agriculture has increased productivity and substituted machines and pesticides to replace the amount of human labor, it also has had a number of harmful environmental consequences, ranging from declining soil quality, pollution, loss of biodiversity, all due to intensive practices and synthetic chemicals used to enhance farmland productivity. These chemicals, it is more visible every day, have also very negative impact on food quality, not only because of lost nutrients, but also due to high food toxicity.

What are the most common environmental problems associated with the conventional farming?

  • Loss of land resources by erosion, desertification and decreased soil fertility
  • Loss of biodiversity
  • Global warming

Soil erosion

Soil erosion is said to be the main cause of soil degradation, and the major cause is poor agricultural practices that deplete the soil of its fertile cover that serves to protect it against wind and water erosion. Due to the fact that 300 years is needed to form 1 inch of topsoil, the soil losses are considered to be practically irreplaceable. The intensity of erosion varies with soil type, drainage patterns and crop management practices.

soil erosion

Why is soil erosion damaging for the soil?

The erosion removes the topsoil that has valuable organic matter, nutrients, and fine particles that can retain water and nutrients in the plant-accessible root zone. The lower soils are less fertile, absorbent and have the less ability to retain nutrients. As for the US, studies indicate that soil erosion has reached the excessive levels nationwide. The dangerous levels of erosion happen due to the utilization of practices with short-term benefit that also neglect the long-term losses such as soil fertility and soil water-holding capacity.  In order to compensate for these losses, conventional agriculture answers with methods such as increased fertilization and irrigation. However, by doing that, farmland productivity is further diminished and the environment is further damaged from eroded sediments. So, when increased productivity is set as a goal without estimating long term damages to the soil, the more excessive erosion occurs and threatens the productivity in the long term.

In an attempt to respond to the problems of soil erosion, many US farmers adopted methods of conservation tillage that prevents soil and water losses. Tillage is a method of leaving a protective crop residue on the soil surface thereby protecting it from wind and rain and thus reducing the erosion. However, the problems associated with tillage method is that weed control is accomplished by using chemical herbicides rather than using more preferable, physical methods.

The use of chemicals in tillage methods also results in loss of biodiversity by killing populations of beneficial insects and animals. In addition, the used chemicals can contaminate water supplies. The surface floods carry those chemicals towards exterior water bodies and groundwater. The analyses revealed the presence of eighteen different herbicides in the US groundwater.

Desertification

The causes of desertification are over-cultivation, overgrazing and deforestation. The impacts of desertification result in diminished soil productivity and food production and loss of the land’s vegetative cover. Desertification also hits the areas that are not directly affected by it, such as the impacts of floods, salinisation, decline of water quality, and the creation of sediments in waters.

Soil Fertility

Agricultural practices of crop production bring a faster loss of nutrients because the crop or its parts are removed from an ecosystem to be consumed by humans or animals. Although farmers practice to return unharvested parts of the crop to the soil along with valuable organic matter and nutrients, most of the required nutrients are eternally separated from the soil. Many organic farming groups say that soil imbalance leads not only to loss of nutrients in the soil, but to the loss of nutrient content in the food that is related to the humus content of the soil.

barley fieldAgricultural researchers consider that three main soil constituents are negatively affected by conventional farming and have impact on soil fertility. These are minerals, living organisms and remains of formerly living organisms. Minerals originate from the rocks through sand, silt and clay. Soils vary in their mineral content, but they usually have 20% of clay and 40% each of the other constituents.

Yet another important element of soil is organic matter originating from decayed remains of living organisms. Organic matter can be of two types: crude organic matter and humus. When soil is plowed, the humus content declines in the soil although it has a tendency to return to equilibrium. It is considered that humus can be eventually restored in soil under both organic and conventional agricultural practices. Nevertheless, in conventional agriculture that uses synthetic chemicals, the organic matter is maintained only because of the fact that soil life is so vulnerable and unable to break down the chemicals.

As for the soil life, it is another very important component of the soils and ranges from microscopic animals to small animals. The most soil-relevant group is that of bacteria and fungi. This group is important for soil, because it transforms humus into metabolites that are used by plants. It also creates energy by transforming ammonium form of nitrogen into its nitrate form.

There are three types of nutrients that have the most significant input on crop yield. These are nitrogen, phosphorus and potassium, which are also the three major nutrients in chemical fertilizers. The loss of these nutrients from agricultural fields happens through leaching, drainage or attachment to eroded soil particles. However, as in case of erosion, the amount of loss depends on several factors including soil type, organic matter content, the climate, slope of the land, depth to groundwater, and the amount and type of used fertilizer.

Nitrogen is one of the most abundant chemical elements in the atmosphere and biosphere. From the three nutrients, nitrogen is the easiest one to leach owing to its high solubility in the nitrate form. Leaching of nitrate from agricultural fields can raise its concentration in groundwater that surpasses the levels of tolerance for drinking water quality.

More than 99% of the nitrogen exists as molecular nitrogen which is not accessible to most organisms. A little percentage of the nitrogen exists as the so-called reactive nitrogen. In the industrialized world, reactive nitrogen is accumulating in the environment at alarming scales. During the past few decades, reactive nitrogen has been accumulating in the environment mainly due to the modern manufacture of nitrogen fertilizer by the Haber-Bosch method.

 What are the environmental concerns related to nitrogen?

  • Increases in the atmospheric nitrogen leads to production of tropospheric ozone and aerosols that cause respiratory diseases, cardiac diseases and cancer.
  • Increases in nitrate in groundwater has detrimental health effects (for example, high nitrate concentrations in water may cause death of infants and are very harmful to adults.).
  • Productivity of grasslands and forests is affected with loss of biodiversity in oligotrophic (relatively low in plant nutrients and containing plenty of oxygen) ecosystems.
  • Reactive nitrogen leads to acidification and biodiversity loss in lakes and stream.
  • It is further is responsible for eutrophication (excessive richness of nutrients in a lake or other body of water), biodiversity loss, hypoxia (oxygen deficiency) and habitat degradation in coastal ecosystems.
  • It is responsible for global warming and depletion of stratospheric ozone.

Phosphorus, does not runoff as quickly as nitrate because it is has a tendency to attach firmly to soil particles. However, phosphorus is then transmitted along with eroded soils into water bodies, where it is known for causing severe expansion of certain aquatic plant species. If this process goes too far, lakes and reservoirs can become asphyxiated with decaying particles of algae, known for bad odors from the resulting lack of dissolved oxygen, and the capability to kill fish as a result.

Potassium is known for its benign features and is neither hazardous in drinking water nor a limiting nutrient for growth of aquatic plants. Since it is tightly held by soil particles, it cannot be removed from soil by leakage, but only through erosion.

Loss of biodiversity

Loss of biodiversity means a reduction in the number of living species on the earth, loss of genetic resources and loss of ecosystem services in both natural and managed ecosystems. Both effects have dramatic long-term consequences for the interaction between the human population and the environment. Biodiversity is lost by number of agricultural activities, such as deforestation, reduction of field margins and hedgerows, drainage of wetlands, genetic uniformity in crop land and application of pesticides.

pelican

Populations of sea birds are endangered by synthetic pesticides, such as DDT. This ubiquitous pesticide is very damaging to the the eggs of pelicans and other birds.

Any approach of agricultural production will change the natural flora and fauna to some extent. However, the problems with conventional agriculture is that it takes these changes to extreme instead of trying to preserve ecological systems as much as possible. Research has shown that practices of conventional agriculture such as pesticide use, inhibit biodiversity and kill both invertebrates and vertebrates.  By definition, pesticides are designed to target some living organisms, but they often have extended effects on non targeted ones. The most direct effect of such use is habitat loss. The extent of currently used pesticides have the potential to exterminate many valuable, potentially endangered or even endemic plant species. Insecticides are especially harmful for animals and often kill non-targeted soil species such as earthworms and soil arthropods. In addition, researches reveal that insecticides have the ability to kill useful insects such as those from families Coccinellidae (ladybygs) and Apidae (bees).ladybug

Global warming

Global warming is a consequence of increasing emissions of greenhouse gases (carbon dioxide, methane, nitrous oxide and chlorofluorocarbons) to the atmosphere. The use of fossil fuels is the primary cause of these emissions. In OECD countries agricultural production contributes about 39% of the methane and 60% of the nitrous oxide emissions. Methane emissions from agriculture mostly originate from ruminant animals and the handling of manure, while the main source of nitrous oxide emissions are nitrogen fertilizers.  Carbon dioxide from deforestation, soil degradation and erosion is a major contribution to the global greenhouse gas emissions. As mentioned above, the use of fertilizer is associated with high energy requirements for their production resulting in additional carbon dioxide emissions.

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