APES Unit 5

Irrigation Methods

Types of irrigation include drip irrigation, flood irrigation, furrow irrigation, drip irrigation, and spray irrigation. The largest human use of freshwater is for irrigation (70%).

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.

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.

Pest control methods

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

Methods to reduce urban runoff

Methods to increase water infiltration include replacing traditional pavement with permeable pavement, planting trees, increased use of public transportation, and building up, not out.

Integrated pest management (IPM)

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.

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.

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.

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.

Aquifers

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

mining coal

can destroy habitats, contaminate ground water, and release dust particles and methane. As coal reserves get smaller, due to a lack of easily accessible reserves, it becomes necessary to access coal through subsurface mining, which is very expensive.

Urbanization

can lead to depletion of resources and saltwater intrusion in the hydrologic cycle.

Urban sprawl

change in population distribution from high population density areas to low density suburbs that spread into rural lands, leading to potential environmental problems.

Ecological footprints

compare resource demands and waste production required for an individual or a society.

soil conservation

goal is to prevent soil erosion.

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.

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.

Mining

helps to provide low cost energy and material necessary to make products.

Impervious surface

human-made structures—such as roads, buildings, sidewalks, and parking lots—that do not allow water to reach the soil, leading to flooding.

Meat production methods

include concentrated animal feeding operations (CAFOs), also called feedlots, and free-range grazing.

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.

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.

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.

Desertification

is the degradation of low precipitation regions toward being increasingly arid until they become deserts.

Prescribed burn

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

Salinization

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

Overgrazing

occurs when too many animals feed on a particular area of land. Causes loss of vegetation, which leads to soil erosion and can cause desertification

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.

Impacts of agricultural

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

Sustainability

refers to humans living on Earth and their use of resources without depletion of the resources for future generations. Environmental indicators that can guide humans to sustainability include biological diversity, food production, average global surface temperatures and CO2 concentrations, human population, and resource depletion.

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.

Tragedy of the Commons

suggests that individuals will use shared resources in their own self-interest rather than in keeping with the common good, thereby depleting the resources.

Rotational grazing

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

Surface mining

the removal of large portions of soil and rock, called overburden, in order to access the ore underneath. An example is strip mining, which removes the vegetation from an area, making the area more susceptible to erosion.

Urbanization

through the burning of fossil fuels and landfills, affects the carbon cycle by increasing the amount of carbon dioxide in the atmosphere.

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.

Mining

wastes include the soil and rocks that are moved to gain access to the ore and the waste, called slag and tailings that remain when the minerals have been removed from the ore.