Bellringer

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Bellringer

• What types of crops are appropriate for our area?
• What things would be needed for a healthy crop?

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Crops and SoilSection 15.2

• Objectives
• Describe land-use practices that promote
  sustainability and economic growth.
• Identifying ways to manage waste.
• Describe the composition of soil profiles.
• Identifying various processes and activities that
  promote soil formation.
• Describe agents of erosion and methods for
  preventing soil erosion.

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Agriculture

• Arable land see your vocabulary for def.

Basic farming process Traditional methods Modern methods
Plowing Read p.384 to fill in this chart
Fertilization
Irrigation
Pest control
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Fertile Soil

• Can support healthy plant growth
• Topsoil
• surface layer of soil
• usually richer in organic matter than the
  subsoil
• where plant roots grow
• Formation of fertile soil
• Weathered rock particles supply mineral
  nutrients.
• Fungi and bacteria for decomposition
• Earthworms, insects, and small animals break up
  the soil, allowing air and water into it.

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Soil Profile (Fig. 8, p.385)
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Assignment

• Fold your paper in half hotdog style.
• Draw and color a soil profile showing details of
  all 6 layers. (Your drawing should take up the
  whole front of your folded paper.)
• Cut the layers apart, creating 6 flaps.
• On the inside, label and describe each layer.
  (Example O Horizon/Surface litter fallen
  leaves and dead animals)

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Soil Erosion and Land Degradation

• Erosion the wearing away of rock or soil by wind
  or water
• In the U.S., ½ the topsoil has been lost to
  erosion in the past 200 years. Why is this a
  problem?
• It takes a long time to form soil.
• Without fertile topsoil, crops cannot be
  supported. Most farming methods make erosion
  worse!!!
• Land degradation damaging land so that it can
  no longer support the local ecosystem.

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Soil Erosion and Land Degradation (cont.)

• Desertification the process by which land in
  arid or semiarid areas becomes more desertlike
• Human causes of desertification
• Overplanting planting too many crops too
  frequently
• Not enough fallow time (when land is left
  unplanted to allow it to recover)
• Overgrazing , which eliminates plants that hold
  topsoil in place

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Real-Life Examples

• Northern Africa
• Dust Bowl, 1930s

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Soil Conservation Methods

• In which direction would soil erode on any degree
  of slope?
• Ways to reduce erosion on sloped land
• Terracing stairsteps of level field areas going
  up a hill
• Contour plowing plowing along the natural
  contour of the land

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Soil Conservation Methods (cont.)

• No-till farming
• Leave crop remains to hold soil in place.
• Also saves time
• Soil may become too densely packed and lower crop
  yields.

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Enriching the Soil

• Traditionally vs. Chemically
• Advantages of each
• Disadvantages of each
• Compost partially decomposed organic material
  (both plant and animal!)

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Salinization

• Def. the accumulation of salts in soil
• A problem in areas of low rainfall
• Irrigation water comes from rivers or groundwater
  (saltier than rainwater)
• When water evaporates, the salts remain behind,
  accumulating in the soil.
• Too much salt plants cannot grow

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Assignment

• Both wars and drought can lead to famine. In what
  ways do they have similar effects, and in what
  ways are their effects different?
• Write a paragraph to explain your answers.

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Pest Control

• In North America, pests destroy about 13 of all
  crops in Kenya, more than 25 more than 33
  worldwide.
• Why the differences?
• Pest any organism that occurs where it is not
  wanted or that occurs in large enough numbers to
  cause economic damage NOT limited to insects!
• Pest control is one benefit of crop rotation.
  (Know why! p.389)

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Pesticides

• Def. ???
• Can also harm beneficial plants and insects,
  wildlife, and people
• Disadvantages of pesticide use
• Pests may develop resistance to chemicals.
• Human health concerns (cancer, nervous system
  disorders, etc.)
• Persistent pesticides (pesticides that do not
  break down rapidly) accumulate in the water and
  soil. (EX DDT, banned in the 70s, still
  detected in environment and breast milk)

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Biological Pest Control

• Def. Using living organism to control pests.
• All organisms have natural enemies!
• Types of biological pest control
• Pathogens organisms that cause disease (EX Bt,
  a bactrium, kills caterpillars of moths and
  butterflies)
• Plant defenses chemical compounds that repel
  insects, plants barriers such as tougher skin
• Disrupting insect breeding
• Growth regulators interfere with some stage of
  an insects life cycle
• Pheromones can be used to confuse mating habits
• Expose males to x-rays to sterilize them

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Genetic Engineering

• Def. genetic material in a living cell is
  modified for medical or industrial use
• Plants created by genetic engineering are called
  genetically modified (GM) plants.
• These plants are usually bred for their
  resistance.

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Sustainable Agriculture

• What do you think the phrase sustainable
  agriculture means?
• What techniques/products/resources do you think
  would be limited (used in limited amounts or not
  at all) in this type of farming?
• What techniques would be used more?

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GM Foods Project Assignment ?