Knowt
Chapter 5: Land and Water Use
5.1: The Tragedy of the Commons
Garrett Hardin wrote “The Tragedy of the Commons” in 1968.
The essay parallels what is happening worldwide in regards to resource depletion and pollution.
The seas, air, water, animals, and minerals are all “the commons” and are for humans to use, but those who exploit them become rich.
The following environmental issues echo "The Tragedy of the Commons" sustainability issues:
Air pollution
Burning of fossil fuels and consequential global warming
Frontier logging of old-growth forests and the practice of “slash and burn”
Habitat destruction and poaching
Over-extraction of groundwater and wastewater due to excessive irrigation
Overfishing
Overpopulation
Limits to “The Tragedy of the Commons” include the following:
Dividing a "commons" into privately owned parcels fragments its policies.
Different standards and practices on one parcel may or may not affect all parcels. Environmental decisions are long-term, while economic decisions are short-term.
Investors would be encouraged to pay a short-term price for a long-term gain by including discount rates in resource valuation.
Market pressure affects privately owned land.
Controlling some "commons" is easier than others. Air and the open oceans are harder to control than land, lakes, rangeland, deserts, and forests.
5.2: Clear-Cutting
Clear-cutting: It occurs is when all of the trees in an area are cut at the same time.
Environmental impacts of clear-cutting include the following:
Habitat loss reduces biodiversity.
Allows sunlight to reach the ground, making it warmer and drier, unsuitable for many forest plants.
Temporary wood availability followed by long periods without wood Reduction in long-term and short-term carbon sinks, which increases atmospheric CO2
Runoff increases soil erosion.
Edge Effect: It refers to how the local environment changes along some type of boundary or edge.
Forest edges: These are created when trees are harvested, particularly when they are clear-cut.
Tree canopies: It provide the ground below with shade and maintain a cooler and moister environment below.
Deforestation: It is the conversion of forested areas to non-forested areas, which are then used for grain and grass fields mining, petroleum extraction, fuel wood cutting, commercial logging, tree plantations, or urban development.
Impacts of deforestation include the following:
Runoff into aquatic ecosystems, climate change, and erosion decrease soil fertility.
Without shade, forest soils dry out quickly.
Degrading environment(s) with decreased biodiversity and ecological services.
Forests house 80% of land animals and plants.
Increasing habitat fragmentation and CO2 emissions from burning and tree decay.
Reducing migratory bird and butterfly habitats
Endangering niche-specialized species.
Deforestation Mitigation
Adopting uneven-aged forest management practices.
Educating farmers about sustainable forest practices and their advantages.
Monitoring and enforcing timber-harvesting laws.
Growing timber on longer rotations.
Reducing fragmentation in remaining large forests.
Reducing road building in forests.
Reducing or eliminating the practice of clear-cutting.
Relying on more sustainable tree-cutting methods.
5.3: The Agricultural and Green Revolutions
Agricultural Revolutions
First Agricultural Revolution (2000+ B.C.E.)
People went from hunting and gathering to the domestication of plants and animals, which allowed people to settle in areas and create cities.
Settled communities permitted people to observe and experiment with plants to learn how they grow and develop.
Second Agricultural Revolution (1700–1900 C.E.)
Occurred at the same time as the Industrial Revolution—mechanization had a major role in this revolution and changed the way people farmed.
Advances were made in breeding livestock.
Increased agricultural output made it possible to feed large, urban populations.
Methods of soil preparation, fertilization, crop care, and harvesting improved.
New banking and lending practices helped farmers afford new equipment and seed.
New crops came into Europe from trade with the Americas.
Railroads allowed distribution of products.
The invention of the seed drill allowed farmers to avoid wasting seeds and to plant in rows.
The invention of the tractor, combined with other farm machinery, improved efficiency on farms.
Third Agricultural Revolution (1900 C.E.–present)
Mechanization such as tractors and combines requires less labor and makes food prices more affordable.
Scientific farming methods such as biotechnology, genetic engineering, and the use of pesticides are now beginning to focus on more sustainable methods.
Green Revolutions
First Green Revolution (1940s–1980s)
The introduction of inorganic fertilizers, synthetic pesticides, new irrigation methods, and disease-resistant, high-yielding crop seeds.
Second Agricultural Revolution (1980s–Present)
In the mid-1980s, new engineering techniques and free-trade agreements involving food production property rights shaped agricultural policies and food production and distribution systems worldwide.
This revolution saw the development and spread of genetically modified organisms (GMOs)—animals, plants, and microorganisms—with genes that don't exist in nature.
BT corn and Golden Rice, modified with daffodil genes to produce more beta-carotene (converts to Vitamin A), are examples (corn modified with a bacterial insecticide gene that produces insect toxins within the cells of the corn).
5.4: Agricultural Practices
Agricultural productivity: It implies greater output with less input.
As farms become more efficient, they are able to produce more products at a lower cost, which tends to stabilize food prices and make more food available to more people, which is vital for developing countries.
Desertification: It is the conversion of marginal rangeland or cropland to a more desert-like land type.
Overgrazing: A plant is considered overgrazed when it is re-grazed before the roots recover, which can reduce root growth by up to 90%.
Fertilizers: These provide plants with the nutrients needed to grow healthy and strong.
Inorganic Fertilizers: A fertilizer mined from mineral deposits or manufactured from synthetic compounds.
Organic Fertilizers: Any Any fertilizer that originates from an organic source, such as bone meal, compost, fish extracts, manure, or seaweed.
Genetically modified foods: These are foods produced from organisms both animal and plant) that have had changes introduced into their DNA.
Genetic engineering techniques: These allow for the introduction of new traits as well as greater control over traits when compared to previous methods.
Rangelands: These are native grasslands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals.
These are managed through livestock grazing and prescribed fire rather than more intensive agricultural practices of seeding, irrigation, and the use of fertilizers.
Slash-and-Burn Agriculture: It is a widely used method of growing food or clearing land in which wild or forested land is clear-cut and any remaining vegetation is burned.
Soil Erosion: It is the movement of weathered rock or soil components from one place to another and is caused by flowing water, wind, and human activity.
Soil degradation: It is the decline in soil condition caused by its improper use or poor management, usually for agricultural, industrial, or urban purposes.
Desertification: Productive potential of arid or semiarid land falls by at least 10% due to human activity and/or climate change.
Salinization: Water that is not absorbed into the soil evaporates, leaving behind dissolved salts in topsoil.
Waterlogging: Saturation of soil with water, resulting in a rise in the water table.
Tillage: An agricultural method in which the surface is plowed and broken up to expose the soil, which is then smoothed and planted.
5.5: Irrigation Methods
Irrigation: The application of controlled amounts of water to plants at needed intervals and has been a necessary component of agriculture for over 5,000 years.
Ditch: Dug and seedlings are planted in rows.
The plantings are watered by placing canals or furrows in between the rows of plants.
Siphon tubes are used to move the water from the main ditch to the canals.
Drip: Water is delivered at the root zone of a plant through small tubes that drip water at a measured rate.
Flood: Water is pumped or brought to the fields and is allowed to flow along the ground among the crops.
Being simple and inexpensive, it is the method most widely used in less-developed countries.
Furrow (Channel): Small parallel channels are dug along the field length in the direction of the predominant slope.
Water is applied to the top of each furrow and flows down the field under gravity, infiltrating the ground more at the beginning and less at the end.
Spray: Uses overhead sprinklers, sprays or guns to spray water onto crops.
5.6: Pest-Control Methods
Pesticides: These can be used to control pests, but their use has drawbacks.
Integrated Pest Management (IPM): It is an ecologically based approach to control pests.
Types of Pesticides
Biological Pesticides: Living organisms used to control pests.
Carbamates: Also known as urethanes, affect the nervous system of pests, which results in the swelling of tissue in the pest.
Fumigants: These are used to sterilize soil and prevent pest infestation of stored grain.
Inorganic pesticides: These are broad-based pesticides that include arsenic, copper, lead, and mercury. They are highly toxic and accumulate in the environment.
Organic pesticides: These are natural poisons derived from plants such as tobacco or chrysanthemum.
Organophosphates: These are extremely toxic but remain in the environment for only a brief time.
Persistent Organic Pollutants (POPS)
Persistent organic pollutants (POPS): These organic compounds can pass through and accumulate in living organisms' fatty tissues because they don't break down chemically or biologically.
They also biomagnify food pyramids.
The Pesticide Treadmill
Pesticide resistance: It describes the decreased susceptibility of a pest population to a pesticide that was previously effective at controlling the pest.
Pest species: They evolve pesticide resistance via natural selection.
In response to resistance, farmers may increase pesticide quantities and/or the frequency of pesticide applications, which magnifies the problem.
Pesticide Treadmill: Also known as pest traps; farmers are forced to use more and more toxic chemicals to control pesticide-resistant insects and weeds.
Integrated Pest Management (IPM)
IPM: It is an ecological pest-control strategy that uses a combination of biological, chemical, and physical methods together or in succession and requires an understanding of the ecology and life cycle of pests.
Methods used in IPM include the following:
Construction of mechanical controls.
Developing genetically modified crops that are more pest-resistant.
Intercropping: A farming method that involves planting or growing more than one crop at the same time and on the same piece of land.
Natural insect predators
Planting pest-repellant crops
Polyculture: The simultaneous cultivation or raising of several crops or types of animals
Regular monitoring through visual inspection and traps followed by record keeping
Releasing sterilized insects
Rotating crops often to disrupt insect cycles
Using mulch to control weeds
Using pheromones or hormone interrupters
Using pyrethroids or naturally occurring microorganisms
When used effectively, IPM can reduce the following:
Bioaccumulation and biomagnification of pesticides
Pests’ becoming resistant to a particular pesticide
Genetic resistance: An inherited change in the genetic makeup of the pests that confers a selective survival advantage.
The destruction of beneficial and non-targeted organisms.
5.7: Meat Production Methods
Concentrated Animal Feeding Operations (CAFOs)
CAFO: It is an intensive animal feeding operation in which large numbers of animals are confined in feeding pens for over 45 days a year.
The large amounts of animal waste from CAFOs present a risk to water quality and aquatic ecosystems.
States with high concentrations of CAFOs experience on average 20 to 30 serious water-quality problems per year as a result of manure management issues.
Manure discharge from CAFOs can negatively impact water quality.
The two main contributors to water pollution caused by CAFOs are
soluble nitrogen compounds
phosphorus
Water pollution from CAFOs can affect both sources if one or the other is contaminated.
CAFOs release several types of gas emissions—ammonia, hydrogen sulfide, methane, and particulate matter.
The primary cause of gas emissions from CAFOs is the decomposition of animal manure being stored in large quantities.
5.8: Overfishing
Fishing is an important industry that is under pressure from growing demand and falling supply.
Marine life, including fisheries, as well as terrestrial life, depends upon primary producers.
Aquatic plants require sunlight and are therefore largely restricted to shallow coastal waters, which make up less than 10% of the world’s ocean area yet contain 90% of all marine species.
Aquaculture: Mariculture or fish farming. It includes the commercial growing of aquatic organisms for food and involves stocking, feeding, protecting from predators, and harvesting.
For aquaculture to be profitable, the species must be marketable, inexpensive to raise, efficient at converting feed into fish biomass, and disease resistant.
Methods to Manage Marine Fishing
Eliminate government subsidies for commercial fishing.
Increase the number of marine sanctuaries.
Prevent the importation of fish products from countries that do not adhere to sustainable fishing practices.
Require and enforce labeling of fish products that were raised or caught according to sustainable methods.
Require fishing licenses and open inspections, which limit the number and kind of fish caught per year, and trade sanctions should these limits be exceeded.
Methods to Restore Freshwater Fish Food Webs
Control erosion.
Control invasive species.
Create or restore fish passages.
Enforce laws that protect coastal estuaries and wetlands.
Plant native vegetation on stream banks.
5.9: Mining
Mining: Removing mineral resource from the ground.
Can involve underground mines, drilling, room-and-pillar mining, long-wall mining, open pit, dredging, contour strip mining, and mountaintop removal.
Surface Mining
Contour mining: Removing overburden from the seam in a pattern following the contours along a ridge or around a hillside.
Dredging: A method for mining below the water table and usually associated with gold mining.
Small dredges use suction or scoops to bring the mined material up from the bottom of a body of water.
In situ: Small holes are drilled into the Earth and toxic chemical solvents are injected to extract the resource.
Mountaintop removal: Removal of mountaintops to expose coal seams and disposing of associated mining overburden in adjacent “valley fills”
Open pit: Extracting rock or minerals from the Earth by their removal from an open pit when deposits of commercially useful ore or rocks are found near the surface
Strip mining: Exposes coal by removing the soil above each coal seam
Underground Mining
Blast: Uses explosives to break up the seam, after which the material is loaded onto conveyors and transported to a processing center
Longwall: Uses a rotating drum with “teeth,” which is pulled back and forth across a coal seam—the material then breaks loose and is transported to the surface
Room and pillar: Approximately half of the coal is left in place as pillars to support the roof of the active mining area.
Later, the pillars are removed and the mine collapses.
Environmental Damage from Mining
Acid mine drainage
Disruption of natural habitats
Chemicals from in situ leaching entering the water table
Disruption of soil microorganisms and, consequently, nutrient cycling processes
Dust released during the breakup of materials, causing lung problems and posing other health risks
Land subsidence
Large consumption and release of water
5.10: Impacts of Urbanization
Urbanization
Urbanization: It refers to the movement of people from rural areas to cities and the changes that accompany it.
Areas that are experiencing the greatest growth in urbanization are countries in Asia and Africa.
Pros | Cons |
|---|---|
Better educational delivery system. | Overcrowded schools. |
Better sanitation systems. | Sanitation systems have greater volumes of wastes to deal with. |
Large numbers of people generate high tax revenues. | Large numbers of poor people place strains on social services. |
Mass transit systems decrease reliance on fossil fuels—commuting distances are shorter. | Commuting times are longer because the infrastructure cannot keep with growth. |
Much of the pollution comes from point sources, enabling focused remediation techniques. | Since population densities are high, pollution levels are also high |
Recycling systems are more efficient. | Solid-waste buildup is more pronounced. Landfill space becomes scarce and costly. |
Urban areas attract industry due to the availability of raw materials, distribution networks, customers, and labor pool. | Higher population densities increase crime rates. Population increase may be higher than job growth. |
Urban Sprawl
Urban Sprawl: Also known as suburban, describes the expansion of human populations away from central urban areas into low-density and usually car-dependent communities.
Job sprawl: It has low-density, geographically spread-out employment patterns, with most jobs in a metropolitan area outside the central business district and increasingly in the suburbs.
Agricultural lands, which are/were frequently found immediately surrounding cities, are frequently taken from for urban sprawl.
Most housing is single-family homes on large lots with fewer stories than city homes, farther apart, and separated by lawns, landscaping, or roads.
Single-use development: Separate commercial, residential, institutional, and industrial areas. Thus, people live, work, shop, and play far apart and need a car.
Smart Growth
Smart growth: It promotes compact, transit-oriented, walkable, bicycle-friendly land use, neighborhood schools, and mixed-use development with a variety of housing options to slow urban sprawl and concentrate growth in a compact, walkable "urban villages."
It values long-range, regional considerations of sustainability.
Sustainable development strategies include the following:
Adopting mixed-use planning: Combining residential, commercial, cultural, institutional, and/or industrial uses in a specific location
Creating greenbelts and another undeveloped, wild, or agricultural land around cities
Providing property tax incentives to companies that locate in urban centers
Providing subsidies for mass transit systems and riders
Replacing abandoned buildings with green spaces reduces urban blight.
Urban or Planned Development?
Urban development: It is the process of designing and shaping the physical features of cities and towns with the goal of making urban areas more attractive, functional, and sustainable.
Some urban development strategies include the following:
Using recycled materials in waste-minimizing designs
Conserving energy through government and private industry rebates and tax incentives for solar and other clean energy
Improving indoor air quality
Locating buildings near multi-modal public transportation hubs like light rail, subways, and park and rides.
Preserving community history and culture while blending into its natural aesthetics
Using resource-efficient building techniques and materials
Conserving water through the use of xeriscaping
Urban Runoff
Urban runoff: It is surface runoff of rainwater created by urbanization.
This runoff is a major source of urban flooding and water pollution in urban communities worldwide.
Urban runoff results in the following:
Erosion causes runoff sedimentation, which settles to the bottom of water bodies and reservoirs, affecting water quality and storage capacity.
As urban heat transfers to streams and waterways, fish and wildlife suffer.
Runoff with gasoline, motor oil, heavy metals, trash, fertilizers, and pesticides.
Runoff containing gasoline, motor oil, heavy metals, trash, fertilizers, and pesticides
Constructing wetlands to naturally filter water before it enters lakes, rivers, and oceans.
Water retention-infiltration basins—shallow artificial ponds—infiltrate storm water into the groundwater aquifer through permeable soils.
Frequently using street-sweeping vacuums that can reduce the trash and other debris and pollutants that end up in runoff
Expanding urban parks and green spaces to increase natural infiltration
5.11: Ecological Footprints
Ecological Footprint: A measure of human demand on Earth’s ecosystems and is a standardized measure of demand for natural capital that may be contrasted with the planet’s ecological capacity to regenerate.
It represent the amount of biologically productive land and sea area that is necessary to supply the resources a human population consumes, and to assimilate associated waste.
5.12: Sustainability
Sustainability: It refers to the capacity for the biosphere and human civilization to coexist through the balance of resources within their environment.
To ensure that available resources are never depleted faster than those resources can be replaced.
IPAT formula
I = P × A × T
Sustainable agricultural practices, reducing consumption and waste, universal fishing quotas, and collaborative water management is needed to solve environmental issues caused by unsustainable resource use and pollution.
Threats to Sustainability
Earth-System Processes | Control Variable | Boundary Value | Current Value | Boundary Crossed | Preindustrial Value |
|---|---|---|---|---|---|
Biodiversity Loss | Extinction rate | 10 | >100 | yes | 0.1–1 |
Climate change | Atmospheric carbon dioxide concentration | 350 | 400 | yes | 280 |
Freshwater | Global human consumption of water | 4000 | 2600 | no | 415 |
Land use | % land surface converted to cropland | 15 | 11.7 | no | low |
Stratospheric ozone depletion | Dobson units | 276 | 283 | no | 290 |
Sustainable Agriculture
Sustainable agriculture: It emphasizes profitable, environmentally friendly, energy-efficient production and food systems that improve farmers' and the public's quality of life.
It prioritizes long-term solutions over short-term symptoms and land and rural community health.
Examples of sustainable agricultural practices include the following:
Developing ecologically-based pest management programs
Diversifying farms to reduce economic risks
Increasing energy efficiency in production and food distribution
Integrating crop and livestock production
Protecting the water quality
Reducing or eliminating tillage in a manner that is consistent with effective weed control
Rotating crops to enhance yields and facilitate pest management
Using cover crops, green manure, and animal manure to build soil quality and fertility
Using water and nutrients efficiently
Soil Conversion Techniques
Contour plowing: Plowing along the contours of the land in order to minimize soil erosion
No-till agriculture: Soil is left undisturbed by tillage and the residue is left on the soil surface.
Planting perennial crops: Perennials live for several years; e.g., fruit trees.
Strip cropping: Cultivation in which different crops are sown in alternate strips
Terracing: Make or form (sloping land) into a number of level flat areas resembling a series of steps
Windbreaks: Rows of trees that provide shelter or protection from the wind
Chapter 5: Land and Water Use
5.1: The Tragedy of the Commons
Garrett Hardin wrote “The Tragedy of the Commons” in 1968.
The essay parallels what is happening worldwide in regards to resource depletion and pollution.
The seas, air, water, animals, and minerals are all “the commons” and are for humans to use, but those who exploit them become rich.
The following environmental issues echo "The Tragedy of the Commons" sustainability issues:
Air pollution
Burning of fossil fuels and consequential global warming
Frontier logging of old-growth forests and the practice of “slash and burn”
Habitat destruction and poaching
Over-extraction of groundwater and wastewater due to excessive irrigation
Overfishing
Overpopulation
Limits to “The Tragedy of the Commons” include the following:
Dividing a "commons" into privately owned parcels fragments its policies.
Different standards and practices on one parcel may or may not affect all parcels. Environmental decisions are long-term, while economic decisions are short-term.
Investors would be encouraged to pay a short-term price for a long-term gain by including discount rates in resource valuation.
Market pressure affects privately owned land.
Controlling some "commons" is easier than others. Air and the open oceans are harder to control than land, lakes, rangeland, deserts, and forests.
5.2: Clear-Cutting
Clear-cutting: It occurs is when all of the trees in an area are cut at the same time.
Environmental impacts of clear-cutting include the following:
Habitat loss reduces biodiversity.
Allows sunlight to reach the ground, making it warmer and drier, unsuitable for many forest plants.
Temporary wood availability followed by long periods without wood Reduction in long-term and short-term carbon sinks, which increases atmospheric CO2
Runoff increases soil erosion.
Edge Effect: It refers to how the local environment changes along some type of boundary or edge.
Forest edges: These are created when trees are harvested, particularly when they are clear-cut.
Tree canopies: It provide the ground below with shade and maintain a cooler and moister environment below.
Deforestation: It is the conversion of forested areas to non-forested areas, which are then used for grain and grass fields mining, petroleum extraction, fuel wood cutting, commercial logging, tree plantations, or urban development.
Impacts of deforestation include the following:
Runoff into aquatic ecosystems, climate change, and erosion decrease soil fertility.
Without shade, forest soils dry out quickly.
Degrading environment(s) with decreased biodiversity and ecological services.
Forests house 80% of land animals and plants.
Increasing habitat fragmentation and CO2 emissions from burning and tree decay.
Reducing migratory bird and butterfly habitats
Endangering niche-specialized species.
Deforestation Mitigation
Adopting uneven-aged forest management practices.
Educating farmers about sustainable forest practices and their advantages.
Monitoring and enforcing timber-harvesting laws.
Growing timber on longer rotations.
Reducing fragmentation in remaining large forests.
Reducing road building in forests.
Reducing or eliminating the practice of clear-cutting.
Relying on more sustainable tree-cutting methods.
5.3: The Agricultural and Green Revolutions
Agricultural Revolutions
First Agricultural Revolution (2000+ B.C.E.)
People went from hunting and gathering to the domestication of plants and animals, which allowed people to settle in areas and create cities.
Settled communities permitted people to observe and experiment with plants to learn how they grow and develop.
Second Agricultural Revolution (1700–1900 C.E.)
Occurred at the same time as the Industrial Revolution—mechanization had a major role in this revolution and changed the way people farmed.
Advances were made in breeding livestock.
Increased agricultural output made it possible to feed large, urban populations.
Methods of soil preparation, fertilization, crop care, and harvesting improved.
New banking and lending practices helped farmers afford new equipment and seed.
New crops came into Europe from trade with the Americas.
Railroads allowed distribution of products.
The invention of the seed drill allowed farmers to avoid wasting seeds and to plant in rows.
The invention of the tractor, combined with other farm machinery, improved efficiency on farms.
Third Agricultural Revolution (1900 C.E.–present)
Mechanization such as tractors and combines requires less labor and makes food prices more affordable.
Scientific farming methods such as biotechnology, genetic engineering, and the use of pesticides are now beginning to focus on more sustainable methods.
Green Revolutions
First Green Revolution (1940s–1980s)
The introduction of inorganic fertilizers, synthetic pesticides, new irrigation methods, and disease-resistant, high-yielding crop seeds.
Second Agricultural Revolution (1980s–Present)
In the mid-1980s, new engineering techniques and free-trade agreements involving food production property rights shaped agricultural policies and food production and distribution systems worldwide.
This revolution saw the development and spread of genetically modified organisms (GMOs)—animals, plants, and microorganisms—with genes that don't exist in nature.
BT corn and Golden Rice, modified with daffodil genes to produce more beta-carotene (converts to Vitamin A), are examples (corn modified with a bacterial insecticide gene that produces insect toxins within the cells of the corn).
5.4: Agricultural Practices
Agricultural productivity: It implies greater output with less input.
As farms become more efficient, they are able to produce more products at a lower cost, which tends to stabilize food prices and make more food available to more people, which is vital for developing countries.
Desertification: It is the conversion of marginal rangeland or cropland to a more desert-like land type.
Overgrazing: A plant is considered overgrazed when it is re-grazed before the roots recover, which can reduce root growth by up to 90%.
Fertilizers: These provide plants with the nutrients needed to grow healthy and strong.
Inorganic Fertilizers: A fertilizer mined from mineral deposits or manufactured from synthetic compounds.
Organic Fertilizers: Any Any fertilizer that originates from an organic source, such as bone meal, compost, fish extracts, manure, or seaweed.
Genetically modified foods: These are foods produced from organisms both animal and plant) that have had changes introduced into their DNA.
Genetic engineering techniques: These allow for the introduction of new traits as well as greater control over traits when compared to previous methods.
Rangelands: These are native grasslands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals.
These are managed through livestock grazing and prescribed fire rather than more intensive agricultural practices of seeding, irrigation, and the use of fertilizers.
Slash-and-Burn Agriculture: It is a widely used method of growing food or clearing land in which wild or forested land is clear-cut and any remaining vegetation is burned.
Soil Erosion: It is the movement of weathered rock or soil components from one place to another and is caused by flowing water, wind, and human activity.
Soil degradation: It is the decline in soil condition caused by its improper use or poor management, usually for agricultural, industrial, or urban purposes.
Desertification: Productive potential of arid or semiarid land falls by at least 10% due to human activity and/or climate change.
Salinization: Water that is not absorbed into the soil evaporates, leaving behind dissolved salts in topsoil.
Waterlogging: Saturation of soil with water, resulting in a rise in the water table.
Tillage: An agricultural method in which the surface is plowed and broken up to expose the soil, which is then smoothed and planted.
5.5: Irrigation Methods
Irrigation: The application of controlled amounts of water to plants at needed intervals and has been a necessary component of agriculture for over 5,000 years.
Ditch: Dug and seedlings are planted in rows.
The plantings are watered by placing canals or furrows in between the rows of plants.
Siphon tubes are used to move the water from the main ditch to the canals.
Drip: Water is delivered at the root zone of a plant through small tubes that drip water at a measured rate.
Flood: Water is pumped or brought to the fields and is allowed to flow along the ground among the crops.
Being simple and inexpensive, it is the method most widely used in less-developed countries.
Furrow (Channel): Small parallel channels are dug along the field length in the direction of the predominant slope.
Water is applied to the top of each furrow and flows down the field under gravity, infiltrating the ground more at the beginning and less at the end.
Spray: Uses overhead sprinklers, sprays or guns to spray water onto crops.
5.6: Pest-Control Methods
Pesticides: These can be used to control pests, but their use has drawbacks.
Integrated Pest Management (IPM): It is an ecologically based approach to control pests.
Types of Pesticides
Biological Pesticides: Living organisms used to control pests.
Carbamates: Also known as urethanes, affect the nervous system of pests, which results in the swelling of tissue in the pest.
Fumigants: These are used to sterilize soil and prevent pest infestation of stored grain.
Inorganic pesticides: These are broad-based pesticides that include arsenic, copper, lead, and mercury. They are highly toxic and accumulate in the environment.
Organic pesticides: These are natural poisons derived from plants such as tobacco or chrysanthemum.
Organophosphates: These are extremely toxic but remain in the environment for only a brief time.
Persistent Organic Pollutants (POPS)
Persistent organic pollutants (POPS): These organic compounds can pass through and accumulate in living organisms' fatty tissues because they don't break down chemically or biologically.
They also biomagnify food pyramids.
The Pesticide Treadmill
Pesticide resistance: It describes the decreased susceptibility of a pest population to a pesticide that was previously effective at controlling the pest.
Pest species: They evolve pesticide resistance via natural selection.
In response to resistance, farmers may increase pesticide quantities and/or the frequency of pesticide applications, which magnifies the problem.
Pesticide Treadmill: Also known as pest traps; farmers are forced to use more and more toxic chemicals to control pesticide-resistant insects and weeds.
Integrated Pest Management (IPM)
IPM: It is an ecological pest-control strategy that uses a combination of biological, chemical, and physical methods together or in succession and requires an understanding of the ecology and life cycle of pests.
Methods used in IPM include the following:
Construction of mechanical controls.
Developing genetically modified crops that are more pest-resistant.
Intercropping: A farming method that involves planting or growing more than one crop at the same time and on the same piece of land.
Natural insect predators
Planting pest-repellant crops
Polyculture: The simultaneous cultivation or raising of several crops or types of animals
Regular monitoring through visual inspection and traps followed by record keeping
Releasing sterilized insects
Rotating crops often to disrupt insect cycles
Using mulch to control weeds
Using pheromones or hormone interrupters
Using pyrethroids or naturally occurring microorganisms
When used effectively, IPM can reduce the following:
Bioaccumulation and biomagnification of pesticides
Pests’ becoming resistant to a particular pesticide
Genetic resistance: An inherited change in the genetic makeup of the pests that confers a selective survival advantage.
The destruction of beneficial and non-targeted organisms.
5.7: Meat Production Methods
Concentrated Animal Feeding Operations (CAFOs)
CAFO: It is an intensive animal feeding operation in which large numbers of animals are confined in feeding pens for over 45 days a year.
The large amounts of animal waste from CAFOs present a risk to water quality and aquatic ecosystems.
States with high concentrations of CAFOs experience on average 20 to 30 serious water-quality problems per year as a result of manure management issues.
Manure discharge from CAFOs can negatively impact water quality.
The two main contributors to water pollution caused by CAFOs are
soluble nitrogen compounds
phosphorus
Water pollution from CAFOs can affect both sources if one or the other is contaminated.
CAFOs release several types of gas emissions—ammonia, hydrogen sulfide, methane, and particulate matter.
The primary cause of gas emissions from CAFOs is the decomposition of animal manure being stored in large quantities.
5.8: Overfishing
Fishing is an important industry that is under pressure from growing demand and falling supply.
Marine life, including fisheries, as well as terrestrial life, depends upon primary producers.
Aquatic plants require sunlight and are therefore largely restricted to shallow coastal waters, which make up less than 10% of the world’s ocean area yet contain 90% of all marine species.
Aquaculture: Mariculture or fish farming. It includes the commercial growing of aquatic organisms for food and involves stocking, feeding, protecting from predators, and harvesting.
For aquaculture to be profitable, the species must be marketable, inexpensive to raise, efficient at converting feed into fish biomass, and disease resistant.
Methods to Manage Marine Fishing
Eliminate government subsidies for commercial fishing.
Increase the number of marine sanctuaries.
Prevent the importation of fish products from countries that do not adhere to sustainable fishing practices.
Require and enforce labeling of fish products that were raised or caught according to sustainable methods.
Require fishing licenses and open inspections, which limit the number and kind of fish caught per year, and trade sanctions should these limits be exceeded.
Methods to Restore Freshwater Fish Food Webs
Control erosion.
Control invasive species.
Create or restore fish passages.
Enforce laws that protect coastal estuaries and wetlands.
Plant native vegetation on stream banks.
5.9: Mining
Mining: Removing mineral resource from the ground.
Can involve underground mines, drilling, room-and-pillar mining, long-wall mining, open pit, dredging, contour strip mining, and mountaintop removal.
Surface Mining
Contour mining: Removing overburden from the seam in a pattern following the contours along a ridge or around a hillside.
Dredging: A method for mining below the water table and usually associated with gold mining.
Small dredges use suction or scoops to bring the mined material up from the bottom of a body of water.
In situ: Small holes are drilled into the Earth and toxic chemical solvents are injected to extract the resource.
Mountaintop removal: Removal of mountaintops to expose coal seams and disposing of associated mining overburden in adjacent “valley fills”
Open pit: Extracting rock or minerals from the Earth by their removal from an open pit when deposits of commercially useful ore or rocks are found near the surface
Strip mining: Exposes coal by removing the soil above each coal seam
Underground Mining
Blast: Uses explosives to break up the seam, after which the material is loaded onto conveyors and transported to a processing center
Longwall: Uses a rotating drum with “teeth,” which is pulled back and forth across a coal seam—the material then breaks loose and is transported to the surface
Room and pillar: Approximately half of the coal is left in place as pillars to support the roof of the active mining area.
Later, the pillars are removed and the mine collapses.
Environmental Damage from Mining
Acid mine drainage
Disruption of natural habitats
Chemicals from in situ leaching entering the water table
Disruption of soil microorganisms and, consequently, nutrient cycling processes
Dust released during the breakup of materials, causing lung problems and posing other health risks
Land subsidence
Large consumption and release of water
5.10: Impacts of Urbanization
Urbanization
Urbanization: It refers to the movement of people from rural areas to cities and the changes that accompany it.
Areas that are experiencing the greatest growth in urbanization are countries in Asia and Africa.
Pros | Cons |
|---|---|
Better educational delivery system. | Overcrowded schools. |
Better sanitation systems. | Sanitation systems have greater volumes of wastes to deal with. |
Large numbers of people generate high tax revenues. | Large numbers of poor people place strains on social services. |
Mass transit systems decrease reliance on fossil fuels—commuting distances are shorter. | Commuting times are longer because the infrastructure cannot keep with growth. |
Much of the pollution comes from point sources, enabling focused remediation techniques. | Since population densities are high, pollution levels are also high |
Recycling systems are more efficient. | Solid-waste buildup is more pronounced. Landfill space becomes scarce and costly. |
Urban areas attract industry due to the availability of raw materials, distribution networks, customers, and labor pool. | Higher population densities increase crime rates. Population increase may be higher than job growth. |
Urban Sprawl
Urban Sprawl: Also known as suburban, describes the expansion of human populations away from central urban areas into low-density and usually car-dependent communities.
Job sprawl: It has low-density, geographically spread-out employment patterns, with most jobs in a metropolitan area outside the central business district and increasingly in the suburbs.
Agricultural lands, which are/were frequently found immediately surrounding cities, are frequently taken from for urban sprawl.
Most housing is single-family homes on large lots with fewer stories than city homes, farther apart, and separated by lawns, landscaping, or roads.
Single-use development: Separate commercial, residential, institutional, and industrial areas. Thus, people live, work, shop, and play far apart and need a car.
Smart Growth
Smart growth: It promotes compact, transit-oriented, walkable, bicycle-friendly land use, neighborhood schools, and mixed-use development with a variety of housing options to slow urban sprawl and concentrate growth in a compact, walkable "urban villages."
It values long-range, regional considerations of sustainability.
Sustainable development strategies include the following:
Adopting mixed-use planning: Combining residential, commercial, cultural, institutional, and/or industrial uses in a specific location
Creating greenbelts and another undeveloped, wild, or agricultural land around cities
Providing property tax incentives to companies that locate in urban centers
Providing subsidies for mass transit systems and riders
Replacing abandoned buildings with green spaces reduces urban blight.
Urban or Planned Development?
Urban development: It is the process of designing and shaping the physical features of cities and towns with the goal of making urban areas more attractive, functional, and sustainable.
Some urban development strategies include the following:
Using recycled materials in waste-minimizing designs
Conserving energy through government and private industry rebates and tax incentives for solar and other clean energy
Improving indoor air quality
Locating buildings near multi-modal public transportation hubs like light rail, subways, and park and rides.
Preserving community history and culture while blending into its natural aesthetics
Using resource-efficient building techniques and materials
Conserving water through the use of xeriscaping
Urban Runoff
Urban runoff: It is surface runoff of rainwater created by urbanization.
This runoff is a major source of urban flooding and water pollution in urban communities worldwide.
Urban runoff results in the following:
Erosion causes runoff sedimentation, which settles to the bottom of water bodies and reservoirs, affecting water quality and storage capacity.
As urban heat transfers to streams and waterways, fish and wildlife suffer.
Runoff with gasoline, motor oil, heavy metals, trash, fertilizers, and pesticides.
Runoff containing gasoline, motor oil, heavy metals, trash, fertilizers, and pesticides
Constructing wetlands to naturally filter water before it enters lakes, rivers, and oceans.
Water retention-infiltration basins—shallow artificial ponds—infiltrate storm water into the groundwater aquifer through permeable soils.
Frequently using street-sweeping vacuums that can reduce the trash and other debris and pollutants that end up in runoff
Expanding urban parks and green spaces to increase natural infiltration
5.11: Ecological Footprints
Ecological Footprint: A measure of human demand on Earth’s ecosystems and is a standardized measure of demand for natural capital that may be contrasted with the planet’s ecological capacity to regenerate.
It represent the amount of biologically productive land and sea area that is necessary to supply the resources a human population consumes, and to assimilate associated waste.
5.12: Sustainability
Sustainability: It refers to the capacity for the biosphere and human civilization to coexist through the balance of resources within their environment.
To ensure that available resources are never depleted faster than those resources can be replaced.
IPAT formula
I = P × A × T
Sustainable agricultural practices, reducing consumption and waste, universal fishing quotas, and collaborative water management is needed to solve environmental issues caused by unsustainable resource use and pollution.
Threats to Sustainability
Earth-System Processes | Control Variable | Boundary Value | Current Value | Boundary Crossed | Preindustrial Value |
|---|---|---|---|---|---|
Biodiversity Loss | Extinction rate | 10 | >100 | yes | 0.1–1 |
Climate change | Atmospheric carbon dioxide concentration | 350 | 400 | yes | 280 |
Freshwater | Global human consumption of water | 4000 | 2600 | no | 415 |
Land use | % land surface converted to cropland | 15 | 11.7 | no | low |
Stratospheric ozone depletion | Dobson units | 276 | 283 | no | 290 |
Sustainable Agriculture
Sustainable agriculture: It emphasizes profitable, environmentally friendly, energy-efficient production and food systems that improve farmers' and the public's quality of life.
It prioritizes long-term solutions over short-term symptoms and land and rural community health.
Examples of sustainable agricultural practices include the following:
Developing ecologically-based pest management programs
Diversifying farms to reduce economic risks
Increasing energy efficiency in production and food distribution
Integrating crop and livestock production
Protecting the water quality
Reducing or eliminating tillage in a manner that is consistent with effective weed control
Rotating crops to enhance yields and facilitate pest management
Using cover crops, green manure, and animal manure to build soil quality and fertility
Using water and nutrients efficiently
Soil Conversion Techniques
Contour plowing: Plowing along the contours of the land in order to minimize soil erosion
No-till agriculture: Soil is left undisturbed by tillage and the residue is left on the soil surface.
Planting perennial crops: Perennials live for several years; e.g., fruit trees.
Strip cropping: Cultivation in which different crops are sown in alternate strips
Terracing: Make or form (sloping land) into a number of level flat areas resembling a series of steps
Windbreaks: Rows of trees that provide shelter or protection from the wind
