Natural Areas, Agriculture, and Aquaculture

Genetic Engineering

  • The Green Revolution started a shift to new agricultural strategies and practices in order to increase food production, with both positive and negative results. Some of these strategies and methods are mechanization, genetically modified organisms (GMOs), fertilization, irrigation, and the use of pesticides.

    1. What are GMOs?

    2. Why are GMOs controversial?

    3. What are some pros and cons of GMOs?

    4. What was the Green Revolution?

  • Mechanization of farming can increase profits and efficiency for farms. It can also increase reliance on fossil fuels.

  • Crops can be genetically engineered to increase their resistance to pests and diseases. However, using genetically engineered crops in planting or other ways can lead to loss of genetic diversity of that particular crop.

Forests

  • Clearcutting can be economically advantageous but leads to soil erosion, increased soil and stream temperatures, and flooding.

  • Forests contain trees that absorb pollutants and store carbon dioxide. The cutting and burning of trees releases carbon dioxide and contributes to climate change.

    • Forests are known as carbon sinks. What does this mean?

    • What are some ecosystem services provided by forests?

  • Some of the methods for mitigating deforestation include reforestation, using and buying wood harvested by ecologically sustainable forestry techniques, and reusing wood.

  • Methods to protect forests from pathogens and insects include integrated pest management (IPM) and the removal of affected trees.

    • What is IPM?

    • Why is it important?

  • Prescribed burn is a method by which forests are set on fire under controlled conditions in order to reduce the occurrence of natural fires.

    • What are some benefits and drawbacks of this method of controlling fires?

    • Why does artificially controlling fires cause fires to be more intense when they occur?

    • How do the fires in California and Australia relate to this topic?

  • Some of the methods for mitigating deforestation include reforestation, using and buying wood harvested by ecologically sustainable forestry techniques, and reusing wood.

    • What are the major threats to a forest ecosystem?

    • How should we manage and sustain forests?

Desertification

  • Overgrazing can cause desertification. Desertification is the degradation of low precipitation regions toward being increasingly arid until they become deserts.

  • Desertification is permanent.

    • What are some things we can do to reduce the threat of desertification?

Irrigation

  • The largest human use of freshwater is for irrigation (70%).

  • Types of irrigation include drip irrigation, flood irrigation, furrow irrigation, drip irrigation, and spray irrigation.

    1. Which type(s) of irrigation use the most water? Which use the least?

  • Waterlogging occurs when too much water is left to sit in the soil, which raises the water table of groundwater and inhibits plants’ ability to absorb oxygen through their roots.

    1. What can happen if agricultural soils become waterlogged?

  • Furrow irrigation involves cutting furrows between crop rows and filling them with water. This system is inexpensive, but about 1/3 of the water is lost to evaporation and runoff.

    1. What are some economic advantages to this type of irrigation?

    2. What are some environmental drawbacks to this type of irrigation?

  • Flood irrigation involves flooding an agricultural field with water. This system sees about 20% of the water lost to evaporation and runoff. This can also lead to waterlogging of the soil.

    1. What are some economic advantages to this type of irrigation?

    2. What are some environmental drawbacks to this type of irrigation?

  • Spray irrigation involves pumping ground water into spray nozzles across an agricultural field. This system is more efficient than flood and furrow irrigation, with only 1/4 or less of the water lost to evaporation or runoff. However, spray systems are more expensive than flood and furrow irrigation, and also requires energy to run.

    1. What are some economic advantages to this type of irrigation?

    2. What are some environmental drawbacks to this type of irrigation?

  • Drip irrigation uses perforated hoses to release small amounts of water to plant roots. This system is the most efficient, with only about 5% of water lost to evaporation and runoff. However, this system is expensive and so is not often used.

    1. What are some economic advantages to this type of irrigation?

    2. What are some environmental drawbacks to this type of irrigation?

  • Salinization occurs when the salts in groundwater remain in the soil after the water evaporates. Over time, salinization can make soil toxic to plants.

    1. What are some causes of salinization?

    2. What are some things we can do to try and reverse salinization?

    3. What can happen if water with too much salt is used for irrigation?

  • Aquifers can be severely depleted if overused for agricultural irrigation, as has happened to the Ogallala Aquifer in the central United States.

    1. What happened to the Ogallala aquifer?

    2. What can happen if groundwater is depleted?

Rangelands and Overgrazing

  • Free range grazing allows animals to graze on grass during their entire lifecycle. Meat from free range animals tends to be free from antibiotics and other chemicals used in feedlots. Organic waste from these animals acts as fertilizer. Free range grazing requires large areas of land and the meat produced is more expensive for consumers.

    1. What are benefits of free-range agriculture?

    2. What are the negatives?

  • Overgrazing occurs when too many animals feed on a particular area of land. Overgrazing causes loss of vegetation, which leads to soil erosion.

  • Overgrazing can cause desertification. Desertification is the degradation of low precipitation regions toward being increasingly arid until they become deserts.

    1. What is desertification?

    2. Can it be reversed?

    3. What are some things we can do to reduce the threat of desertification?

  • Overgrazing occurs when too many animals feed on a particular area of land. Overgrazing causes loss of vegetation, which leads to soil erosion.

    1. Which industry is primarily responsible for overgrazing?

    2. In what area of the country is the land MOST susceptible to overgrazing?

    3. How should we manage and sustain grasslands?

Renewable vs. Nonrenewable Resources

  • Nonrenewable energy sources are those that exist in a fixed amount and involve energy transformation that cannot be easily replaced.

    • What are some nonrenewable energy sources?

  • Renewable energy sources are those that can be replenished naturally, at or near the rate of consumption, and reused.

    • What are some renewable energy sources?

    • How can a renewable energy source become nonrenewable?

    • What does it mean to use a resource sustainably?

Natural Resources

  • When humans use natural resources, they alter natural systems.

  • The global distribution of natural energy resources, such as ores, coal, crude oil, and gas, is not uniform and depends on regions’ geologic history.

Clearcutting

  • Clearcutting can be economically advantageous but leads to soil erosion, increased soil and stream temperatures, and flooding.

  • Forests contain trees that absorb pollutants and store carbon dioxide. The cutting and burning of trees releases carbon dioxide and contributes to climate change.

    • Forests are known as carbon sinks. What does this mean?

    • What are some ecosystem services provided by forests?

Sustainable Forestry

  • Some of the methods for mitigating deforestation include reforestation, using and buying wood harvested by ecologically sustainable forestry techniques, and reusing wood.

  • Methods to protect forests from pathogens and insects include integrated pest management (IPM) and the removal of affected trees.

    • What is IPM?

    • Why is it important?

  • Prescribed burn is a method by which forests are set on fire under controlled conditions in order to reduce the occurrence of natural fires.

    • What are some benefits and drawbacks of this method of controlling fires?

Agriculture to Feed the World

  • Agricultural practices that can cause environmental damage include tilling, slash- and-burn farming, and the use of fertilizers.

  1. What environmental problems arise from industrialized food production?

Meat Production

  • Methods of meat production include concentrated animal feeding operations (CAFOs), also called feedlots, and free-range grazing.

  • Meat production is less efficient than agriculture; it takes approximately 20 times more land to produce the same amount of calories from meat as from plants.

  • Concentrated animal feeding operation (CAFOs) are used as a way to quickly get livestock ready for slaughter. They tend to be crowded, and animals are fed grains or feed that are not as suitable as grass. Additionally, feedlots generate a large amount of organic waste, which can contaminate ground and surface water. The use of feedlots are less expensive than other methods, which can keep costs to consumers down.

    1. What are some problems with CAFOs?

    2. How can CAFOs contribute to water pollution?

    3. What are some benefits of CAFOs? Negatives?

  • Free range grazing allows animals to graze on grass during their entire lifecycle. Meat from free range animals tends to be free from antibiotics and other chemicals used in feedlots. Organic waste from these animals acts as fertilizer. Free range grazing requires large areas of land and the meat produced is more expensive for consumers.

    1. What are benefits of free-range agriculture?

    2. What are the negatives?

  • Overgrazing occurs when too many animals feed on a particular area of land. Overgrazing causes loss of vegetation, which leads to soil erosion.

  • Overgrazing can cause desertification. Desertification is the degradation of low precipitation regions toward being increasingly arid until they become deserts.

    1. What is desertification?

    2. Can it be reversed?

  • Less consumption of meat could reduce CO2, methane, and N2O emissions; conserve water; reduce the use of antibiotics and growth hormones; and improve topsoil.

    1. What is an ecological advantage of reduced meat consumption?

    2. How could reduced meat consumption increase the carrying capacity of the planet?

Green Revolution

  • The Green Revolution started a shift to new agricultural strategies and practices in order to increase food production, with both positive and negative results. Some of these strategies and methods are mechanization, genetically modified organisms (GMOs), fertilization, irrigation, and the use of pesticides.

    1. What was the green revolution?

  • Mechanization of farming can increase profits and efficiency for farms. It can also increase reliance on fossil fuels.

    1. What are some economic advantages of mechanized farming?

Irrigation

  • The largest human use of freshwater is for irrigation (70%).

  • Types of irrigation include drip irrigation, flood irrigation, furrow irrigation, drip irrigation, and spray irrigation.

    1. Which type(s) of irrigation use the most water? Which use the least?

  • Waterlogging occurs when too much water is left to sit in the soil, which raises the water table of groundwater and inhibits plants’ ability to absorb oxygen through their roots.

    1. What can happen if agricultural soils become waterlogged?

  • Furrow irrigation involves cutting furrows between crop rows and filling them with water. This system is inexpensive, but about 1/3 of the water is lost to evaporation and runoff.

    1. What are some economic advantages to this type of irrigation?

    2. What are some environmental drawbacks to this type of irrigation?

    3. What can happen if water with too much salt is used for irrigation?

  • Flood irrigation involves flooding an agricultural field with water. This system sees about 20% of the water lost to evaporation and runoff. This can also lead to waterlogging of the soil.

  • Spray irrigation involves pumping ground water into spray nozzles across an agricultural field. This system is more efficient than flood and furrow irrigation, with only 1/4 or less of the water lost to evaporation or runoff. However, spray systems are more expensive than flood and furrow irrigation, and also requires energy to run.

  • Drip irrigation uses perforated hoses to release small amounts of water to plant roots. This system is the most efficient, with only about 5% of water lost to evaporation and runoff. However, this system is expensive and so is not often used.

  • Salinization occurs when the salts in groundwater remain in the soil after the water evaporates. Over time, salinization can make soil toxic to plants.

    1. What are some causes of salinization?

    2. What are some things we can do to try and reverse salinization?

  • Aquifers can be severely depleted if overused for agricultural irrigation, as has happened to the Ogallala Aquifer in the central United States.

    1. What happened to the Ogallala aquifer?

    2. What can happen if groundwater is depleted?

Food Insecurity

  1. What is food security and why is it difficult to attain?

Sustainable Agriculture

  • The goal of soil conservation is to prevent soil erosion. Different methods of soil conservation include contour plowing, windbreaks, perennial crops, terracing, no-till agriculture, and strip cropping.

    1. Know each of these methods of soil conservation

  • Strategies to improve soil fertility include crop rotation and the addition of green manure and limestone.

    1. When would you add limestone? Green manure?

    2. What is the goal of crop rotation?

  • Rotational grazing is the regular rotation of livestock between different pastures in order to avoid overgrazing in a particular area.

    1. How can we produce food more sustainably?

    2. What agricultural methods best limit soil erosion?

    3. What methods can restore soil fertility?

    4. Is organic better than non-organic?

Pesticides

  • One consequence of using common pest-control methods such as pesticides, herbicides, fungicides, rodenticides, and insecticides is that organisms can become resistant to them through artificial selection. Pest control decreases crop damage by pest and increases crop yields.

    • What are the advantages and disadvantages of modern synthetic pesticides?

    • What are the laws and treaties that protect us from the harmful effects of pesticides?

    • What problems are associated with chemical pesticides?

    • What are some effects of pesticide resistance?

  • Crops can be genetically engineered to increase their resistance to pests and diseases. However, using genetically engineered crops
    in planting or other ways can lead to loss of genetic diversity of that particular crop.

    1. What types of agricultural methods tend to promote pest species?

    2. What are some benefits of genetically modified crops? Negatives?

    3. What are the pros and cons of the genetic modification of crops?

    4. Are GMOs that are resistant to pests better than spraying non-GMO plants with pesticides?

Integrated Pest Management (IPM)

  • One consequence of using common pest-control methods such as pesticides, herbicides, fungicides, rodenticides, and insecticides is that organisms can become resistant to them through artificial selection. Pest control decreases crop damage by pest and increases crop yields.

  • Integrated pest management (IPM) is a combination of methods used to effectively control pest species while minimizing the disruption to the environment. These methods include biological, physical, and limited chemical methods such as biocontrol, intercropping, crop rotation, and natural predators of the pests.

  • The use of integrated pest management (IPM) reduces the risk that pesticides pose to wildlife, water supplies, and human health.

        1. What is a benefit of IPM?

  • Integrated pest management (IPM) minimizes disruptions to the environment and threats to human health but can be complex and expensive.

    1. What is IPM?

    2. What is required for a pest control strategy to be considered IPM?

    3. What are some examples of the different parts of IPM?

    4. What is a benefit of IPM? Drawback?

Blue Revolution/Alternative Agriculture

  • Overfishing has led to the extreme scarcity of some fish species, which can lessen biodiversity in aquatic systems and harm people who depend on fishing for food and commerce.

  • Aquaculture has expanded because it is highly efficient, requires only small areas of water, and requires little fuel.

  • Aquaculture can contaminate wastewater, and fish that escape may compete or breed with wild fish. The density of fish in aquaculture can lead to increases in disease incidences, which can be transmitted to wild fish.

    1. What are some negative environmental consequences of aquaculture?

    2. What are some economic benefits of aquaculture?