GOAL:

To develop an understanding of the interdependence of all organisms and the need for conserving natural resources

An adequate and continuous supply of soil, water, air, and energy are essential to the survival of living things.

Ecology O1.00 To understand how the actions of man affect the quality and quantity of the soil

1.01 List the causes and results of erosion.

1.02 Describe the procedures necessary to minimize erosion in harvesting timber, strip mining, conventional agricultural tillage.

1.03 List ways sail may be rendered useless.

I. Causes of loss of usable soil
A. Agriculture
1. Tilling soil before planting
2. Cultivation after planting
3. Improper irrigation
B. Deforestation
C. Changing of an ecosystem
1. Drought
2. Frost
3. Heat epidemic
4. Wind
D. Improper mining
II. Results
A. Results of excessive run-off
1. Clogs rivers
2. Decreases reservoir capacity
3. Increased sediment
a. natural (eutrophication)
b. chemical form pesticides
4. Increase coat of farming
III. Minimizing Erosion
A. Harvesting timber
1. Selective cutting
2. Clear cutting with replanting and ground cover
B. Strip Mining
1. Preplanning
2. Stabilization
a. Quick growing plants
b. Permanent ground cover
c. Replanting
3. Storm water control
4. Water quality control
C. Conventional agricultural tillage
1. Crop rotation
2. Cover crops
3. Wind breaks
4. Fallowing
5. Terracing
6. Conservation types of tillage
a. No till
b. Mulch till
c. Ridge till
d. Strip till
IV. Ways soil can be rendered useless
A. Poor agricultural practices
B. Strip mining
C. Harvesting of timber
D. Building of highways, parking lots, and buildings
E. Sterilization of soil by agricultural chemicals and industrial by-products
V. Farming practices
A. Crop rotation
B. Cover crops
C. Wind breaks
D. Fallowing
E. Terracing
F. Conservation types of tillage
1. No till
2. Mulch till
3. Ridge till
4. Strip till
G. Shelter belts H. Better Management of irrigation systems
1. Prevent salt build-up
2. Water logging
3. Siltation of canals
I. Increasing inorganic fertilizer

TN COMPONENT OF SCIENCE: Science in Society

GOAL:

To enable students to demonstrate positive attitudes toward science in solving problems and making personal decisions about issues affecting the individual, society and the environment.

4.4 SOCIETAL NEEDS - Science establishes the basis for applying technology to needs within a society.

4.4d - Basic research contributes to the body of scientific knowledge and may have unexpected results.

BENCHMARK: The value of basic research, recording predicted and unexpected results, is essential to the scientific process.

TIME REQUIRED:

Two instructional periods

Newspaper and magazine articles, pamphlets from soil conservation service

This classroom connector addresses Instructional Objective 1.01.

Erosion, strip mining

Everyone knows what soil is. What do we use soil for? (grow food, grass, trees, flowers) Why do we need soil? (to grow food) What happens to the soil when there is a great amount of rainfall? (washes away into ditches, etc.) What is it called when a large amount of soil is washed away? (erosion) Today we are going to talk about the causes and results of soil erosion.

List on board the three things that may happen to rain when it hits the ground (1. may evaporate, 2. sink into the ground, 3. flow over the land surface as runoff). Runoff is the major cause of erosion. Whether runoff is detrimental or not depends on the plant growth in an area. Plant roots hold soil particles in place. The shape of the land also affects the amount of runoff.

Let's look at ways agricultural practices cause excessive run-off. When farmers till the land before planting, they destroy all plant growth. At this point the soil is particularly vulnerable to erosion. A drought could cause the wind to dry the soil and blow it away, or a heavy rain could wash soil away before plant growth occurs. Even after crops begin to grow, farmers cultivate rows by plowing between the rows to prevent weeds from growing, thus leaving a part of the soil exposed to the elements. Any activity that causes plant cover to be lost, leaves soil vulnerable. When a farmer cuts down trees to till the soil or when industry cuts trees for land use or when logging itself occurs, land is left unprotected and subject to erosion. Plant life can also be lost to factors such as drought, frost, pest epidemics, wind, and improper methods of irrigation which cause plants to die of salination (waste evaporates and leaves too many minerals which cause plants to die) and water logging (too much water accumulating). Another man-caused loss of plants is due to mining. When water is allowed to flow over unprotected soil, sediments are picked up and carried with it to rivers, lakes, and reservoirs. Here the sediments filter out and cause navigation problems, decrease water holding capacity and if nutrients are in the sediment the process of eutrophication will begin. Accelerated soil erosion and the dumping of wastes that are rich in plant nutrients will speed up the filling-in process in lakes and ponds. (You may want to go into more detailed explanation of eutrophication).

Sediment from farms that have used harmful pesticides and herbicides also run into these rivers and lakes. These pollutants destroy fish spawning areas, stimulate weed growth, pollute drinking water, and make water unsafe for boating, swimming, and fishing.

The annual price tag for erosion damage is estimated to be in the billions of dollars. On-farm damage from erosion includes lower yields of crops, higher fertilizer requirements, more difficult tillage, and higher bills for farm maintenance.

(Invite a farmer or soil conservation district supervisor to class to discuss erosion procedures used in your area)

Today we learned how the actions of man affect the soil by increasing the causes of erosion and the results of these practices. List causes of erosion; List results of erosion.

Class will divide into three groups. Group I will prepare a simulated area of soil at a slight incline with no growth. (a square foil pie pan propped on a block of wood) Group II will prepare a similar area of soil with minimal vegetation (Small patches of grass and weeds transplanted to simulate bushes and trees). Group III will prepare soil with dense cover. (fast growing grass seed or prepared sod) With the three pans of soil titled, pour water at the top of each and observe what happens to the soil. (A large pan at the bottom to catch water will be needed.)

This classroom connector addresses Instructional Objective 1.02.

Name some things you use that come from wood. (List these on board.) Wood is a valuable commodity. Name some uses for coal, sand and gravel, stone, clay, copper, iron ore. (List these on board.) These rocks and minerals are very useful and valuable. Everyone likes to eat. Where does our food come from? (farms)

Wood, rocks and minerals, and food come from the soil. Harvesting these can cause problems if not properly done. Today we will learn ways that minimize erosion while obtaining these resources.

Wood is a valuable resource. In 1970, domestic timber was growing faster than it was being removed, but since then the gap between supply and demand has been closing. As more and more wood is needed, the questions about modern logging practices arise. In the U.S., timber crews often clear-cut patches of about 40 acres leaving alternate patches of timber. Young seedlings are then planted in the clear-cut areas. Clear-cut patches are not particularly disruptive to wildlife; in fact, many animals thrive on the lush new growth that sprouts up. However, there is serious debate over how much soil is lost when vegetation is removed and logging roads are built. Clear cutting can only be done successfully in areas where the danger of erosion is minimal.

Selective cutting happens when loggers harvest only those mature trees and leave the rest of the forest untouched. This approach minimizes ecological disruption. If loggers move into an area and cut selectively every twenty years or so, the most valuable commercial timber can be harvested and at the same time the quality of the natural system be preserved. However, in many cases, this technique is most expensive. Approximately 90WA of the rock and mineral resources that are consumed in the U.S. and more than 60% of the nation's coal output are extracted by methods of surface mining. Strip mining is the method that disrupts landscape most extensively. To dig a strip mine, the surface layer of topsoil and rock are first scooped off by huge power shovels. This exposes the underlying minerals. If the land is not reclaimed, strip mines leave vast holes and huge piles of rubble. The dirt piles erode and cause pollution. The Surface Mining Control and Reclamation Act passed in 1977 required that mining companies:

1. prove the land can be restored before starting

2. must use best available technology to minimize water pollution and disruption of streams, lakes, and flow of ground water

3. must restore the land so that it is useful for the same purpose for which it was used before mining

4. pay tax; money used to reclaim land that was destroyed before law was put into effect

There are many methods farmers can use to help stop erosion. Soil erosion can be reduced and soil fertility can be maintained by planting two or more different kinds of crops in a single area. This process is known as rotation. There are two basic types of rotation. Alternate year rotation involves planting crops that require nitrogen, such as corn, one year and then planting nitrogen-fixing crops in the same field the next year. Another type of rotation scheme involves the use of alternate bands of different crops in a single year. Certain crops such as hay, alfalfa, and many cereals are generally grown as cover crops in bands between row crops. Fallowing is a method of leaving a field unplanted - resting - every few years. This helps the moisture and nutrient content of the field. Farmers are very reluctant to use this method. A method that helps prevent soil erosion on hillsides is terracing. This involves building terraces and layering on the hillside. Even if farmers are reluctant to do this, most all resort to plowing along the contours of the land so each furrow becomes its own small dam or terrace. There are several different types of tillage that help control erosion.

Conservation tillage refers to any tillage and planting system that is designed to reduce soil erosion by wind and water. One type of conservation tillage is no-till, which leaves the soil undisturbed prior to planting. Planting undisturbed prior to planting. Planting is completed in a narrow seedbed created by a planter. Weeds are controlled primarily with herbicides. Other types involve minimal tillage, where the farmer uses disks, chisels, and row cleaner to turn some of the leftover plant growth into the ground but does not allow the bare soil to be exposed to the elements.

This would seem to be the answer but farmers argue that no-till causes increased peat infestation and lower yields.

List two methods of harvesting timber that would minimize erosion. Tell how strip mining must be done in order to leave a healthy environment. List at least three conservation agricultural practices.

Today we learned how to minimize erosion while harvesting timber, strip mining and farming. List two methods of harvesting timber. List three things strip miners should do to preserve land. List five agriculture methods of sail conservation.

This classroom connector addresses Instructional Objective 1.03.

Does anyone have places in their yard where grass doesn't grow? Why do you think grass doesn't grow in these areas? We have been talking about soil erosion, but now we will see what happens when the soil is useless and how it got that way.

Usually the reason things won't grow even if there is soil, has to do with the nutrients in the soil. If farmers have let their top soil erode, and strip miners have pushed top soil away, and no ground cover was planted after trees were cut and top soil washed away, then the soil that is left cannot support any kind of substantial growth unless nutrients are added. Farmers also cause soil to become sterile when run-off water containing chemicals that were used in the field is left deposited and allowed to build up. Industrial by-products and pollution from mining also found in run-off water, carried and deposited, can cause sterilization. Another thing to think about is that when soil is covered with highways, parking lots, and buildings, it can't be used again.

List some ways soil may be rendered useless.

Investigate destruction caused by mining at Copper Basin (Duck Town) Tennessee

This is the time this file has been accessed since 11/01/02.

The University of Tennessee at Martin is not responsible for the information or views expressed here.

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