Water Quality - Nutrient Management and Cropping Systems - Lesson 1 Soil Conservation

Water Quality - Nutrient Management and Cropping Systems - Lesson 1 Soil Conservation

Target Grade Level / Age Range:

Grades 9-12

Time:

Two to three 50-minute class periods

Purpose:

Students will describe the impacts of erosion on soil, water, and air quality and learn about different tactics to reduce soil erosion and then apply the concepts into real life situations while understanding the challenges presented in each conservation tactic.

Materials:

  • Writing Materials
  • Computer or tablet with internet access
  • Soil Erosion Vocab Words.docx
  • Soil Erosion.pptx
  • Soil Erosion Summary Assessment.doc
  • Soil Erosion WS.doc
Activity Materials
  • A stream table box (can be constructed at approximately 16" long by 12" wide by 4" deep or consider purchasing the American Educational Economy Stream Table Kit for $60 found on Amazon.com). This wooden box should be made watertight by either caulking the seams or lining it with materials such as plastic, tin or tar paper. One end of the box should be notched with a V 1.5" deep and a spout attached in the V so that runoff water will flow into your waiting pail.
  • You will also need:
    • A watering can with 1/2 gallon or larger capacity
    • A plastic protractor
    • A pail to catch the excess water
    • Blocks to elevate the stream table
    • 4 inch squares cut out of dressed 2x4s work well and let you raise the elevation in approximately 1.5 inch increments, and a mop or towels to clean up any spills
    • Different soil types will be needed for the various tests and this may create a need for pails and a trowel or small shovel. Various types of mulch such as hay, pine needles, shredded newsprint or paper will also be needed.
    • A supply of small pebbles, mulch, and other materials are needed for the student to construct a dam for the activity
    • NOTE: Larger stream tables are more dramatic, but the volume of materials needed to fill them increases greatly with size

Suggested Companion Resources (books and websites)

Vocabulary

  • Water Erosion—Soil loss resulting from the action of moving water
  • Wind Erosion—Soil loss resulting from the action of the wind.
  • Tillage Erosion—the redistribution of soil through the action of tillage and gravity
  • Sheet Erosion—Gradual removal of soil in thin layers by raindrop impact and shallow surface flow.  Results in loss of the finest soil particles.
  • Rill Erosion—Loss of soil in small but visible tracks that are less than 20 cm deep that can be removed by normal cultivation. Develop when surface water concentrates in depressions or low points.
  • Ephemeral Erosion—small channels eroded by concentrated flow that can be easily filled by normal tillage, only to re-form again in the same location by additional runoff events.
  • Gully Erosion—Loss of soil in large, often impassible trenches or ditches resulting from runoff. Channels are deeper than 30 cm and cannot be removed by normal cultivation.
  • Organic Matter—consisting of plant and animal residues at various stages of decomposition, cells and tissues of soil organisms, and substances synthesized by soil organisms.
  • Top Soil—top layer of soil, and is the most fertile part of the land with the most nutrients for growing crops. It is composed of organic matter.
  • Topography—how the land is arranged by natural and physical features of an area (rolling hills, flat prairie land, deep ravines) and how movement of water flows
  • Soil Cover—refers to vegetation, including crops, and crop residues on the surface of the soil.
  • Land Management—process of managing the use and development (in both urban and rural settings) of land resources.
  • Soil Surface Type—smooth, rough, covered, exposed)
  • Primary Tillage—tillage which inverts, cuts or shatters the soil to a depth of 15-36 cm. Usually leaves the soil rough
  • Secondary Tillage—tillage operations that follow primary tillage. The purpose is to prepare a final seedbed that is suitable for planting, seed germination, and weed control
  • Contour Buffer Strips—Narrow strips of perennial vegetation established across the slope and alternating down the slope with wider cropped strips
  • Contour Farming—Farming sloping land (preparing, planting, and cultivating) on the contour and not up and down the slope.
  • Cover Crops: A green crop including grasses, cereal grains, legumes or forbs seeded in the early fall to protect the soil surface from erosion and reduce sediment and nutrient loss during the winter months between growing seasons.
  • Crop Rotation: Growing different revenue-generating crops in a repeated sequence on the same field. Year 1 = Corn, Year 2 = Soybeans, Year 3 = Corn, Year 4 = Alfalfa, Year 5 = Alfalfa
  • Nutrient Management: Careful management of the amount, source, placement, form and timing of the application of plant nutrients and soil amendments.
  • No-Till Farming: Soil and residue is left undisturbed from harvest to planting. No full-width tillage operations are done.
  • Field Borders: a band or strip of perennial vegetation established on the edge of a cropland field.
  • Grassed Waterways: broad, shallow and typically saucer-shaped channels designed to move surface water across farmland without causing soil erosion.
  • Terraces: Manmade structures that follow the contour of a hillside, breaking a long slope into smaller segments.
  • Windbreaks: Line/row of trees or hedges that provides shelter or protection from the wind.
  • Bioreactors: An underground trench of woodchips at the end of a tile line. Water from the tile flows through the woodchips before entering a stream or river.
  • Highly Erodible Land (HEL): Land which has the potential for long term annual soil losses to exceed the tolerable amount by eight times for a given agricultural field, as defined by USDA Natural Resources Conservation Service

Background – Agricultural Connections (what would a teacher need to know to be able to teach this content)

A big part in understanding soil erosion is understanding how environmental factors affect the soil and how certain management goals are focused on controlling the effects of erosion while also controlling plant yield and growth.

  • Introduction to Soil Erosion
    • Naturally occurring process that affects all landforms. In agriculture, soil erosion refers to the wearing away of a field’s topsoil by the natural physical forces of water and wind and the forces associated the farming activities such as tillage.
  • Types of Soil Erosion
  • Water Erosion- soil loss resulting from the action of moving water
    • Factors influencing water erosion
      • Excess rainfall
      • Gravity
      • Topography- how the land is arranged by natural and physical features of an area (rolling hills, flat prairie land, deep ravines) and how movement of water flows
  • Wind Erosion - Soil loss resulting from the action of the wind.
    • Factors Influencing wind erosion
      • Soil cover
      • Land management
      • Soil surface type (smooth, rough, covered, exposed)
  • Tillage Erosion- the redistribution of soil through the action of tillage and gravity
    • Refers to the manual or mechanical soil stirring actions and the types and sequences of tillage operations used for the proper establishment and growth of crops
    • Tillage has been a main part of crop production since the beginning of agriculture
      • Role of tillage is important to all people because tillage may have one of the largest environmental impacts on our landscape.
  • Types and forms of tillage vary among different farmers, environments, and geographical areas
Types of tillage
  • Primary tillage- tillage which inverts, cuts or shatters the soil to a depth of 15-36 cm. Usually leaves the soil rough
    • Moldboard plows, disk plows, chisel plows, sweep plows, powered rotary tillers, listers/bedders
  • Secondary Tillage- tillage operations that follow primary tillage. The purpose is to prepare a final seedbed that is suitable for planting, seed germination, and weed control
    • Disk harrows, field cultivators, powered rotary tillers, roller packers, bed shaping equipment and weed control equipment
  • Types of erosion that are effects of water, wind, and tillage erosion
    • Sheet Erosion—Gradual removal of soil in thin layers by raindrop impact and shallow surface flow.  Results in loss of the finest soil particles.
    • Rill Erosion—Loss of soil in small but visible tracks that are less than 20 cm deep that can be removed by normal cultivation. Develop when surface water concentrates in depressions or low points.
    • Ephemeral Erosion—small channels eroded by concentrated flow that can be easily filled by normal tillage, only to re-form again in the same location by additional runoff events.
    • Gully Erosion—Loss of soil in large, often impassible trenches or ditches resulting from runoff. Channels are deeper than 30 cm and cannot be removed by normal cultivation.
Impacts of Erosion on Soil Quality
  • Organic matter is a small fraction (2% to 4%) of soil mainly present on the soil surface.
  • Organic matter contributes to productivity through its effect on the physical, chemical, and biological properties of the soil.
  • Erosion gradually depletes organic matter and decreases soil productivity
Soil Management Goals
  • To sustain and protect soil and enhance its performance, so farmers can farm profitably and preserve environmental quality for decades to come.
  • Ways to Reduce Soil Erosion
    • Conservation Practices- https://www.extension.iastate.edu/agdm/crops/html/a1-41.html this link gives a detailed description of each of these practices along with pictures and a cost example
      • Contour Buffer Strips: Narrow strips of perennial vegetation established across the slope and alternating down the slope with wider cropped strips
      • Contour Farming: Farming sloping land (preparing, planting, and cultivating) on the contour and not up and down the slope.
      • Cover Crops: A green crop including grasses, cereal grains, legumes or forbs seeded in the early fall to protect the soil surface from erosion and reduce sediment and nutrient loss during the winter months between growing seasons.
      • Crop Rotation: Growing different revenue-generating crops in a repeated sequence on the same field. Year 1 = Corn, Year 2 = Soybeans, Year 3 = Corn, Year 4 = Alfalfa, Year 5 = Alfalfa
      • Nutrient Management: Careful management of the amount, source, placement, form and timing of the application of plant nutrients and soil amendments.
      • No-Till Farming: Soil and residue is left undisturbed from harvest to planting. No full-width tillage operations are done.
      • Field Borders: a band or strip of perennial vegetation established on the edge of a cropland field.
      • Grassed Waterways: broad, shallow and typically saucer-shaped channels designed to move surface water across farmland without causing soil erosion.
        • The vegetative cover in the waterway slows the water flow and protects the channel surface from the eroding forces of runoff water.
      • Terraces: Manmade structures that follow the contour of a hillside, breaking a long slope into smaller segments.
      • Windbreaks: Line/row of trees or hedges that provides shelter or protection from the wind.
      • Bioreactors: An underground trench of woodchips at the end of a tile line. Water from the tile flows through the woodchips before entering a stream or river.
      • Link: Iowa State University research Farms Utilize conservation Practices for Science, Stewardship   https://www.cals.iastate.edu/news/releases/iowa-state-university-research-farms-utilize-conservation-practices-science
      • Link: Reducing Nutrient Loss: Science Shows What Works- https://store.extension.iastate.edu/Product/Reducing-Nutrient-Loss-Science-Shows-What-Works

Interest Approach or Motivator

Have students make small discussion groups. Have each group assign a writer and a speaker of each group. Ask the groups to discuss these questions and then have each group report what they know to the rest of the class.

  1. What is soil erosion?
  2. Name as many types of erosion you know of.
  3. What are some ways to reduce soil erosion?
  4. What questions do you have about soil erosion?

Procedures

  1. Have students make discussion groups or assign groups (no more than 4 per group). Ask discussion questions and have students report out.
    • Make a list of questions students have about soil erosion to make sure they are answered by the end of presentation.
  2. Walk through PowerPoint presentation (attached) with students. Ask questions throughout and monitor students for understanding of material.
  3. When the power point is over, go through any other questions that the students may have and answer any of the questions that students had at the beginning of the presentation.
  4. Introduce erosion activity.
    • Objective: students will observe soil erosion by the force of water. They will then use the information of different soil conservation practices to create a solution to controlling water-induced topsoil erosion with different soil types.
    • Allow 45 minutes or more for activity.
      • Set the stream table at an elevated height that erosion takes place (can be determined by trial and error).
      • Fill the stream table with different types of erodible soil (sand, clay/loam, loam, silt loam).
      • Note: Water is added to the upper end of the stream table and flows downhill. This will create erosion and runoff so make sure there is a pail at the end of the stream table to catch excess flow.
      • Depending on the different erodible soils used will determine the types of erosion created. Sheet, rill, and gully erosion can be studied by the flow of water down the table.
      • Have students observe the types of erosion taking place and take notes of observations on Soil Erosion WS (attached)
      • Have the class share observations and then break into pairs or groups of three. Each group’s task is to create a solution to the soil erosion observed in the experiment as well as learned about in the presentation.
        • First have the group draw out a plan of their proposed idea to reduce soil erosion. Have them research the practice used and have them calculate the cost of implementing the practice into an operation. They can use the internet to search or provide them this link, https://www.extension.iastate.edu/agdm/crops/html/a1-41.html
        • This link gives a detailed description of each of the conservation practices along with pictures and a cost examples of the practice)
      • After they have a written plan of their concept, provide them with resources to create their concept and test it on the stream table.
  5. To end class, have a “ticket out” or a “ticket in” to the beginning of the next class.
    • Have the students reflect on their concept and how it held up in the stream table test. Have them reflect on what went well in their concept and what needs improvement. Have them explain what they found interesting or disappointing in the experiment. And lastly any questions they still might have about soil erosion.

Essential Files (maps, charts, pictures, or documents)

Did you know? (Ag facts)

  • Anywhere that fast moving water moves across soil, erosion can occur. If the water is moving fast enough, water can pick up and move rock.
  • Places where there are no roots from vegetation holding the soil in place require less water speed to cause erosion.
  • More than 90 percent of Iowa’s land, or 26 million acres, is used to produce agricultural crops.
  • Of the millions of acres used to grow crops in Iowa, about 90 percent is farmed using some type of “soil conservation” practice.
  • It can take 1,000 years to form one inch of soil.
  • Accelerated erosion is caused by the activities of human beings.
  • The “Dust Bowl” of the 1930s is an extreme example of wind erosion.
  • From 1982 to 1992, it is estimated that Iowa farmers applied conservation practices to save 100 million more tons of topsoil than in 1982. That’s enough to fill a convoy of dump trucks 105 wide, parked bumper-to-bumper, on Interstate 80 from Council Bluffs to Davenport.
  • Soil erosion can never be stopped. It only can be controlled.
  • A 90-percent reduction in soil erosion can be expected when using no-till versus an intensive tillage system.
  • Contour farming can reduce soil erosion by as much as 50 percent.
  • Because of CRP, today about 30 million acres of fragile cropland across the United States is seeded to grass or planted to trees and is not being farmed.
  • https://www.extension.iastate.edu/4h/sites/www.extension.iastate.edu/files/4h/connecting/ag_issues_soil_conservation.pdf

Extension Activities (how students can carry this beyond the classroom)

  • Using the information and the results of the water erosion activity along with the student’s concept idea, have students write a proposal to their legislators on soil erosion and water quality.
  • Have students calculate the slope of hill and how fast erosion can take place if no conservation practices have been applied to it.

Sources/Credits

Lesson plan development was funded by the Resource Enhancement and Protection Conservation Education Program (REAP CEP). Resource Enhancement and Protection Program (REAP): Invest in Iowa our outdoors, our heritage, our people. REAP is supported by the state of Iowa, providing funding to public and private partners for natural and cultural resources projects, including water quality, wildlife habitat, soil conservation, parks, trails, historic preservation and more.

Author

Hannah Pagel

Organization Affiliation

Iowa Agriculture Literacy Foundation

National Agriculture Literacy Outcomes

  • T1.9-12.a. Describe how wildlife habitats are created and maintained by farmers/ranchers and why these habitats are important (e.g., promoting pollinator habitat, insect refuges, creating buffer zones for nutrient management, etc.)
  • T1.9-12.b. Describe resource and conservation management practices used in agricultural systems (e.g., riparian management, rotational grazing, no till farming, crop and variety selection, wildlife management, timber harvesting techniques)
  • T2.9-12.d. Evaluate evidence for differing points of view on topics related to agricultural production, processing, and marketing (e.g., grazing; genetic variation and crop production; use of fertilizers and pesticides; open space; farmland preservation; animal welfare practices; world hunger)
  • T4.9-12.e. Identify current and emerging scientific discoveries and technologies and their possible use in agriculture (e.g., biotechnology, bio-chemical, mechanical, etc.)

Iowa Core Standards

  • HS-PS2-1. Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration. (surface water movement over fields and things like terraces to reduce the speed and force of water)
  • HS-LS2-6. Evaluate the claims, evidence, and reasoning that the complex interactions in ecosystems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem. (soil structure, water cycle, nitrogen cycle)
  • HS-ETS1-2. Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering. (manage watersheds is complex, planting cover crops is actionable)

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