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Damaging the Land.

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Presentation on theme: "Damaging the Land."— Presentation transcript:

1 Damaging the Land

2 Soil is the top layer of land.
It is the most important resource for farmers, and, if used right, should be renewable. Over the past century, though, the land has been damaged by some environmental issues and bad farming practices.

3 Erosion Soil can be blown away by winds, or washed away by floods if not protected. Some farmers plant trees to keep soil from blowing away. Another method is “no-till cropping”, where the farmer leaves the stems of his/her plants in the ground over winter. The roots hold onto the soil, and the stems hold onto the snow, so that there will be moisture in the spring.

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5 Contamination Farmers use fertilizers, herbicides and pesticides to increase their yields. These can help plants, but lead to problems for the environment.

6 Fertilizers Chemical Fertilizers help plants grow, but can get into the water supply and increase algae. More algae means less oxygen in the water, which kills the fish. Farmers often use natural fertilizers instead, like manure.

7 Herbicides Herbicides kill weeds, which helps plants grow without competition. Herbicides can hurt animals and humans. Many crops have been genetically modified to resist certain kinds of herbicide. Farmers try to use less herbicides, but it’s hard to avoid.

8 Pesticides Pesticides kill insects that hurt plants.
Also kill many useful species of insects, and killing those insects upsets the ecosystem. Sometimes insects develop a resistance to chemicals, and stronger, more dangerous chemicals are needed to kill them. Biological control has been tried as an alternative. One example: introducing a predator species that eats the species you want to kill, like dragonflies to get rid of mosquitoes.

9 Loss of Farmland Most cities are built near or on very good farmland.
Most people moved to an area because that’s where they could grow food. The more people move there, the bigger the city gets. As a city gets bigger, the land becomes valuable, and farmers sell the land, rather than keep working in a financially risky job.


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