Using the assigned readings for Week Four, write a 50- to 75-word response to each of the following questions. Your responses will be assessed according to the accuracy of the content.
1. How do minerals affect society?
The extraction, processing, and disposal of minerals clearly harm the environment. Mining disturbs and damages the land, and the processing and disposal of minerals pollute the air, soil, and water. Although pollution can be controlled and damaged lands can be restored, these remedies are costly. Mining has contaminated thousands of kilometers of streams and rivers in the United States. Rocks rich in minerals often contain high concentrations of heavy metals such as arsenic and lead.
2. What is the difference between metallic and nonmetallic minerals? Provide two examples from each category and discuss their uses.
Metallic mineral are those minerals which can be melted to obtain new products and are good conductors of heat and electricity. Examples of metallic minerals are iron, aluminum, and copper. Non-metallic minerals are those which do not yield new products on melting. Examples of non-metallic minerals are sand, stone, salt, and phosphates.
1. How are minerals extracted from the Earth and processed?
The depth of a particular mineral deposit determines whether surface or subsurface
mining will be used. In surface mining, minerals are extracted near the surface. Subsurface mining extracts minerals too deep in the ground to be removed by surface mining. Subsurface mining may be done with underground shaft mines or slope mines. Processing minerals often involves smelting.
2. What are the different ways minerals can be mined? Provide a brief description of at least three types of mining.
There are two kinds of surface mining, open-pit surface mining and strip mining. Open-pit surface mining, in which a giant hole, called a quarry, is dug in the ground to extract the minerals. In strip mining, a trench is dug to extract the minerals, then a new trench is dug parallel to the old one, and the overburden from the new trench is put into the old one, creating a hill of loose rock called a spoil bank. In a shaft mine, a hole is dug straight through the overburden to the ore, which is removed up through the shaft in buckets.
3. What effect does extracting minerals have on the environment?
Surface mining destroys vegetation across large areas, increasing erosion. Open-pit mining uses huge quantities of water. Mining also affects water quality. Acid mine drainage is pollution caused when dissolved toxic materials wash from mines into nearby lakes and streams. Rainwater seeping through the sulfide minerals in mine waste produces sulfuric acid, which dissolves the heavy metals and other toxic substances in the spoil banks. These acids, called acid mine drainage, are highly toxic and are washed into soil and water, including groundwater, by precipitation runoff.
1. What is your definition of soil? What is soil composed of? Why is soil important to the environment?
The relatively thin surface layer of Earth’s crust is soil, which consists of mineral and organic matter modified by the natural actions of agents such as weather, wind, water, and organisms. Soil is composed of four distinct parts: mineral particles, organic matter, water, and air. Vast numbers and kinds of organisms, mainly microorganisms, inhabit soil and depend on it for shelter, food, and water. Plants anchor themselves in soil, and from it they receive essential minerals and water. Terrestrial plants could not survive without soil, and because we depend on plants for our food, humans could not exist without soil either.
2. What types of organisms are found in soil? Determine the relationship between soil and organisms
The diversity of life in fertile soil includes plants, algae, fungi, earthworms, flatworms, roundworms, insects, spiders and mites, bacteria, and burrowing animals such as moles and groundhogs. The relationship between soil and organisms is that soil organisms provide several essential ecosystem services, such as maintaining soil fertility, preventing soil erosion, breaking down toxic materials, and cleansing water.
3. What is soil erosion? How can soil become polluted? What effect does soil erosion and pollution have on the environment?
Water, wind, ice, and other agents promote soil erosion, a natural process often accelerated by human activities. Water and wind are particularly effective in moving soil from one place to another. Rainfall loosens soil particles, which are transported by moving water. Wind loosens soil and blows it away, particularly if the soil is barren and dry. Soil erosion reduces fertility because essential minerals and organic matter are removed. Erosion causes sediments and pesticide and fertilizer residues to pollute nearby waterways.
4. What is the purpose of soil reclamation?
Badly eroded land can be reclaimed by (1) preventing further erosion and (2) restoring soil fertility. To prevent further erosion, the bare ground is seeded with plants; they eventually grow to cover the soil, stabilizing it and holding it in place. The plants start to improve the quality of the soil almost immediately, as dead material decays into humus. The humus holds nutrient minerals in place, releasing them a little at a time; it also improves the water-holding capacity of the soil.
Forestry and Rangeland Resources and Management Strategies
1. Differentiate between government-owned lands and public lands. Which government agencies are involved with government-owned lands? What is the purpose of government-owned lands?
Government-owned land encompasses all types of ecosystems, and includes land that contains important resources such as minerals and fossil fuels, land that possesses historical or cultural significance, and land that provides critical biological habitat. Public lands are important for their recreational value, providing places for hiking, swimming, boating, rafting, sport hunting, and fishing.
Federal land is managed primarily by four agencies, three in the U.S. Department of the Interior—the Bureau of Land Management (BLM), the Fish and Wildlife Service (FWS), and the National Park Service (NPS)—and one in the Department of Agriculture—the U.S. Forest Service.
Government-owned lands provide vital ecosystem services that benefit humans and these services include wildlife habitat, flood and erosion control, groundwater recharge, and the breakdown of pollutants.
2. Why is the forest an important ecosystem?
Forests, important ecosystems that provide many goods and services to support human society, occupy less than one-third of Earth’s total land area. Timber harvested from forests is used for fuel, construction materials, and paper products. Forests supply nuts, mushrooms, fruits, and medicines. Forests provide employment for millions of people worldwide and offer recreation and spiritual sustenance in an increasingly crowded world.
3. What is your definition of forest management? What is its purpose? Describe the concept of sustainable forestry.
Management for timber production disrupts a forest’s natural condition and alters its species composition and other characteristics. Traditional forest management often results in low-diversity forests. Forest management plantations supplement harvesting of trees in wild forests to provide the United States with the timber it requires.
Sustainable forestry also attempts to sustain biological diversity by providing improved habitats for a variety of species, prevent soil erosion and improve soil conditions, and preserve watersheds that produce clean water.
4. What effect does the harvesting of trees and deforestation have on forests and the environment? Is there a preferred method for harvesting trees? Explain.
Deforestation results in decreased soil fertility, as the essential mineral nutrients found in most forest soils leach away rapidly without trees to absorb them. Uncontrolled soil erosion, particularly on steep deforested slopes. Deforestation contributes to the extinction of many species.
The preferred method for harvesting trees would be selective cutting, the older, mature trees are selectively harvested from time to time, and the forest regenerates itself naturally. Shelterwood cutting, less desirable and dead trees are harvested. As younger trees mature, they produce seedlings, which continue to grow as the now-mature trees are harvested.
5. What is a rangeland? Describe rangeland degradation and desertification. What effect does degradation and desertification have on the environment?
Rangelands are grasslands, in both temperate and tropical climates, that serve as important areas of food production for humans by providing fodder for livestock such as cattle, sheep, and goats.
Land degradation is a natural or human-induced process that decreases the future ability of the land to support crops or livestock. The progressive degradation which induces unproductive desert-like conditions on formerly productive rangeland (or tropical dry forest), is called desertification. It reduces the agricultural productivity of economically valuable land, forces many organisms out, and threatens endangered species.
6. What is overgrazing? What effect does this have on rangelands?
Overgrazing is the destruction of vegetation caused by too many grazing animals consuming the plants in a particular area, leaving them unable to recover. Overgrazing accelerates land degradation, which decreases the future ability of the land to support crops or livestock. Several studies have reported that moderate levels of grazing encourage greater plant diversity.
7. What strategies can be employed for the management and conservation of forests and rangelands?
Rangeland management includes seeding in places where plant cover is sparse or absent, conducting controlled burns to suppress shrubby plants, constructing fences to allow rotational grazing, controlling invasive weeds, and protecting habitats of endangered species. Most livestock operators use public rangelands in a way that results in their overall improvement.
1. What is the difference between industrialized agriculture and subsistence agriculture? What effect do these methods of agriculture have on the environment?
Industrialized agriculture produces high yields, which allows forests and other natural areas to remain wild instead of being converted to agricultural land. Industrialized agriculture uses modern methods requiring large capital input and less land and labor than traditional methods.
Subsistence agriculture requires labor and a large amount of land to produce enough food to feed a family. Industrialized agriculture comes with costs, such as soil degradation and increased pesticide resistance in agricultural pests.
2. What is one agricultural challenge, other than soil erosion, that society faces? Explain your answer.
There is considerable concern that much of the nation’s prime agricultural land is falling victim to urbanization and suburban sprawl by being converted to parking lots, housing developments, and shopping malls. The reduction of agricultural land is cause a decrease in crops and will cause prices to increase of certain products.
3. How would you describe sustainable agriculture? How does it affect the environment? In regards to agriculture, what are the advantages and disadvantages involved with genetic engineering?
Sustainable agriculture uses methods that maintain soil productivity and a healthy ecological balance while minimizing long-term impacts. Genetic engineering, the manipulation of genes to produce a particular trait, can produce more nutritious crops or crop plants that are resistant to pests, diseases, or drought. Concerns about genetic engineering include unknown environmental effects.