The ways used to grow crops and raise animals can have either good or bad impacts on biodiversity. On one hand, farmers can support biodiversity through careful farming methods
. On the other hand, if farmers are not careful, the environment and organisms on and near the farm can be harmed. This article explains how teachers can teach the possible impacts of farming on biodiversity and provides some ideas for what a farmer can do to mitigate negative consequences to biodiversity. Students can apply this information for projects or for interactions with a local farming community to share knowledge between each other.
- Explain the impacts of pesticides use. Using pesticides can have unexpected and unwanted side effects. Often, the same chemicals that farmers apply to get rid of crop pests harm other species living around the farm. Some of these species may actually help to control the real crop pests! For example, DDT (Dichloro-Diphenyl-Trichloroethane) is a powerful pesticide that is poisonous to not only insects, but also animals and humans. DDT is so powerful it was banned in many countries, however, some countries that face malaria problems still use it to kill mosquitoes.
- Teach about the impacts of overuse of natural resources. If farmers are not careful in their use of natural resources, farming activities can decrease the amount of resources available to grow food. When there are not enough nutrients in the soil, farmers often buy chemical fertilizers. Using fertilizers can help grow more food, but using too much can pollute the water. Polluted water affects organisms that drink the water or that live in it. For example, too many pollutants can kill fish. Water pollutants also affect our health, as it decreases the amount of clean water to drink, wash and grow crops.
- Explore the impacts of industrial farming. Some industrial farms mass-produce a few select breeds in their quest to produce more meat, milk or eggs. This practice, however, leads to a decline in livestock diversity. The same principle applies to crops. As the number of varieties decreases, existing crops become increasingly at risk to destruction by disease and pests. If crops are all identical, it is much easier for a new disease or pest to wipe out an entire harvest. The less diversity farmers maintain, the greater the risk of diseases and pests. This increase in risk means farmers apply more pesticides to the crop fields or administer antibiotics to the animals.
- Help students to be aware of the interconnections between farming and negative biodiversity impacts. Farming usually changes the landscape, the water, the air and biodiversity. For example:
- Construction workers build roads so that trucks can pick up farm produce and take it to markets.
- When farmers cut trees to create space for growing crops or raising livestock, they also reduce natural water filtration (cleaning) and available habitats for many species.
- Tractors and other farm machinery emit air pollutants.
- In some areas, farming brings enormous changes to the landscape. In parts of the Amazon, large tracts of forests have been cut down and replaced by monoculture (one crop) farming or pastures for cattle grazing. These changes reduce the number and variety of habitats available for species. Without suitable habitats, hundreds of species, including trees, vines, plants, birds, snakes, frogs and mammals, can no longer live in the area. The end result is a loss of biodiversity.
- Have the students research the positive interconnections between farming and biodiversity. There are also many positive examples of how farmers find a perfect balance between agriculture and biodiversity. For instance:
- In some areas, the land does not change much. Some farmers use the landscape as it is. For example, grasslands are natural pastures for many farm animals or wild herbivores. Many farmers do not fence in these natural pastures so that wild herbivores can use them too. Leaving the pastures open can be risky carnivores may prey on farm animals.
- Other farmers design their farms to minimize changes to the natural landscape. They might even try to enhance biodiversity on and around the farm. They can promote biodiversity by using sustainable farming methods such as including both plants and trees in one field, using little or no pesticides and planting a variety of crops.
- Explore the ways in which agricultural activities that promote and protect biodiversity. There are numerous ways that farming can promote biodiversity conservation. Here are just a few of them:
- Farmers who choose to spray chemicals, can make sure to always follow the instructions carefully to minimize the damage to other harmless species.
- Rotate crops. When farmers are careful and manage resources sustainably, they can help preserve biodiversity and the environment. Many farmers around the world use sustainable farming and organic or ecological farming methods. One method is to grow two or more crops in the same field. This helps the farmer reduce crop pests while using fewer pesticides. Another method is to avoid applying pesticides on rainy or windy days so less pesticide will enter waterways causing pollution or get blown away.
- Use trees as part of regular farming practice. Trees can act as natural water filters. Their roots absorb rainwater, and minimize the amount of runoff entering rivers and lakes. Runoff often carries pesticides from farmers fields that can damage aquatic ecosystems.
- Keep the soil filled with beneficial organisms. A handful of farm dirt is rich in biodiversity. Soil biodiversity includes animals, bacteria, fungi and even the roots of plants growing above. Soils form complex ecosystems that make farming possible. There are millions of organisms that live in soil microorganisms, such as bacteria and fungi, and macroorganisms, such as worms, mites, ants and spiders. These organisms can help farmers to reduce the negative effects of farming. When they eat and dig underground, earthworms, termites and other burrowing organisms mix the upper layers, redistribute nutrients and increase the amount of water absorbed by the soil. Some macroorganisms are critical to local farming techniques. Farmers in Burkina Faso and in other areas of West Africa encourage termites to live and burrow in their farm plots because they improve the soil.
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- Examples of farming practices - use magazines, TV, internet etc. to find examples
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