Farming and soil

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This was created to meet the curriculum outcomes in New Brunswick's Grade 7 Science Earth's Crust Unit.

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Farming and soil

  1. 1. Thursday, January 29, 2015 The Earth’s Crust Farming and Soil
  2. 2. Farmers add: fertilizers manure compost insecticides and herbicides to their crops to help increase their yields.
  3. 3. As a result, we can now grow more food than at any other time in the history of the earth. However, this increase in food production does not come without a price.
  4. 4. The fertilizers and insecticides used can find their way into rivers and streams and have a negative impact on fish and aquatic ecosystems.
  5. 5. For example, these algae blooms were created when fertilizers from a farm ran into rivers and lakes. Algae blooms (when algae grow and die quickly) are bad for an ecosystem because when the dead algae decompose they use up all the available oxygen – and fish and other animals in the water die.
  6. 6. The smells associated with manure spreading can be very unpleasant for towns and neighbours of farms and have led to law suits.
  7. 7. When crops are cut, the soil is exposed to erosion by wind and rain. Topsoil can dry out and be blown away or carried away during rainstorms. Cutting and harvesting crops can also slow the development of new soil and can leach vitamins and minerals from the soil.
  8. 8. When this is done to land that receives little rain, plants do not return which can lead to the formation of deserts (this is called desertification – the dust bowl). Millions of tonnes of valuable top soil is lost every year because of erosion.
  9. 9. This animation shows how soil and sand from Africa (the Sahara Desert) can blow across the Atlantic Ocean and land in North America.

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