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GEO 702 Study Guide - Final Guide: Crop Rotation, Mountaintop Removal Mining, Estuary

Course Code
GEO 702
Valentina Capurri
Study Guide

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Module 4: Food Resources
Food Resources: Why Should We Care?
1. We need a nutritious diet to stay alive and be healthy
2. Population is growing: do we have enough food for everyone?
3. The current food production system has a too high environmental
Energy Flow & Chemical Cycling
- Life on earth is possible thanks to 2 natural processes:
1. Energy flow
2. Chemical cycling
- The most important chemical cycles are:
1. Water cycle
2. Carbon cycle
3. Nitrogen cycle
4. Phosphorus cycle
The Importance of Soil
- Soil is composed of eroded rocks, mineral nutrients, decaying
organic matter, water, air, and a myriad of tiny organisms
- The soil has several levels, the top one being topsoil
- Topsoil is a renewable resource but its renewal process is very slow
- Soil provides nutrients for living organisms, helps purify water, and helps control the earth’s climate
Types of Agriculture
- Traditional subsistence agriculture relies on the labour of human and animals. It is practiced by 40%
of world’s farmers on 75% of the world’s farmland, yet it only provides 20% of food crops
- Traditional intensive agriculture also uses fertilizers. It can be practiced as monoculture or polyculture
- Industrial agriculture relies on use of machines. It is practiced on 25% of the world’s farmland but
produces 80% of the world’s food
Controlling Pests
- Pesticides are synthetic chemicals that destroy or control pests. They are distinguished into:
1. Herbicides
2. Insecticides
3. Rodenticides
- In a natural ecosystem, each species is held in check by others called natural enemies
- In monocultures, pests are controlled with 2 different kinds of pesticides:
1. Broad spectrum agents
2. Narrow spectrum agents
- Pesticides also differ in their level of persistence
Industrial Meat Production
- While in the past all beef cattle were raised in pastures, today half is raised in feedlot (densely packed
feeding areas) with grains and fishmeal
- Chicken, turkeys, pigs are also mainly raised in confined animal feeding operations
Fish & Shellfish Production
- A population of fish or shellfish harvested by commercial fishing operations is called a fishery
- Large factory ships (such as trawers) operate on the oceans or large lakes
- Fishing ships are equipped with high-tech systems such as GPS and sonar
- Aquaculture (aka fish farming) consists instead of raising fish and shellfish in confined areas such as
ponds, lakes and reservoirs or underwater cages suspended in saltwater lagoons, estuaries, and
costal and deep-ocean waters

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Crossbreading & Genetic Engineering
- Crossbreading (aka artificial selection) consists in selecting individuals in a species with desired
characteristics and pair them for reproduction in order to obtain offspring with the desired
- Genetic engineering consists in changing an organism’s genetic material by adding or removing
segments of its DNA so to obtain desired characteristics or eliminate undesirable ones
- Genetically modified organisms (GMO) are organisms resulting from genetic engineering
Organic Agriculture
- Organic agriculture is a form of farming that uses only organic (natural) fertilizers, no pesticides,
synthetic fertilizers or genetically engineered seeds
- The goal of organic agriculture is to reduce the environmental impact of food production
What Are the Problems?
- Hunger, malnutrition, and overnutrition
Developed countries enjoy relative food security while less-developed countries live with food
The main cause of food insecurity is poverty, followed by wars, government corruption,
degradation of land, flooding, and prolonged drought and heat waves
One billion people in the world suffer from undernutrition and malnutrition, while 1.1 billion
people suffer from overnutrition
- Topsoil erosion
Soil erosion is a process that involves wind and flowing water moving soil from one place to
Some soil erosion is natural, some is caused by human activities
Agriculture is the leading cause of soil erosion
Topsoil erosion removes nutrients that are essential to the ecosystem
- Soil degradation
Soil degradation occurs when topsoil loses its ability to support plant growth
Two types of soil degradation are:
1. Desertification
2. Soil salinization
- Overpumping of groundwater
Aquifers are bodies of water stored underground. They are recharged by precipitation
Today, particularly in India, China, and the US, water is pumped out of aquifers faster than they
can be recharged
- Harmful effects of pesticides
Some pesticides are toxic and many end up polluting air, water, and food crops
In the long run, pests develop genetic resistance to pesticides
Pesticides kill wildlife such as birds and precious insects as honeybees
Pesticides can cause cancer, birth defects, damages to the nervous system, and can affect the
immune system
- Water & air pollution
Water gets polluted with soil erosion from cropland when eroded soil ends up in nearby
surface water as sediment. It also gets polluted with inorganic fertilizers from farm fields,
lawns, and golf courses
Air pollution results from emissions of machinery used to plant and harvest crops, and to apply
- Potential hazards of genetic engineering
While genetic engineering can help solving the problem of food insecurity, it might also have
negative consequences
In particular, by mixing genes from different species, we could end up creating genetically
modified organisms that could be harmful to certain species, ecosystems, and human health
- Loss of biodiversity

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Loss of biodiversity is a threat to life on this planet
Current threats to biodiversity are:
1. Cutting and burning of forests
2. Elimination of a variety of vegetables, fruits, and grains (since industrialized crop
production only relies on few varieties of each type of food crop)
- Environmental impact of industrialized meat production
Meat production and consumption have a high environmental impact due to:
1. Overgrazing
2. Overproduction of animal wastes (manure)
3. Stressing of water supplies
4. Intensive use of antibiotics
- Environmental impact of fishing & aquaculture
Commercial fishing fleets have depleted 80% to 90% of the population of large ocean seafood
Industrialized fishing operations are also destroying the ocean floor
While aquaculture is more sustainable than industrialized fishing, it pollutes ponds, lakes, and
shallow coastal waters
How Can We Produce More Food?
- The are various way we could increase food production:
1. Clearing tropical forests
2. Cultivating marginal land
3. Irrigating more dry land
- However, all these solutions have serious drawbacks
Reducing Soil Erosion
- Soil conservation can be achieved through:
1. Terracing
2. Combining contour planting & strip cropping
3. Using alley cropping
4. Planting windbreakers
5. Practicing conservation-tillage farming
Restoring Soil Fertility
- Some ways to restore soil fertility are:
1. Using fertilizers (better organic fertilizers than synthetic ones)
2. Adopting crop rotation
Reducing Soil Degradation
- Desertification can be addressed by:
1. Reducing overgrazing of grasslands and pastures
2. Halting the clearing of trees
3. Using low-till cultivation
4. Limiting soil salinization by draining the fields so that water removes soil salts
5. Planting crops that tolerate salts
Fighting Crop Pests
- Since synthetic pesticides have drawbacks, pests can be better controlled by:
1. Importing natural enemies of the pests
2. Using naturally occurring chemicals that trap/interfere with the biological functioning of pests
3. Adopting integrated pest management (IPM) and using more polyculture
More Sustainable Meat & Fish Production & Consumption
- Meat & fish production & consumption has high environmental impact
- We should reduce consumption of meat
- We should consume herbivorous rather than carnivorous fish
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