Louisiana Team AgEd
Louisiana Agriscience Education Curriculum
Course: Agriscience I
Unit: Soil Science
Lesson: Soil Properties
LOUISIANA LEARNINGS STANDARDS AND GRADE LEVEL EXPECTATIONS
Learning Standards (LS):
· Strand: Plant Systems
· Standard: AgEd/FFA students will understand the concepts and principles of plant science.
· External environmental factors affecting plant growth and reproduction
· Soil fertility
Grade Level Expectations (GLE):
· Measure the physical properties of different forms of matter in metric system units (e.g., length, mass, volume, temperature) (PS-H-A1).
· Investigate and classify common materials as elements, compounds, or mixtures (heterogeneous or homogeneous) based on their physical and chemical properties (PS-H-C1).
· Classify elements as metals or nonmetals based on their positions in the periodic table (PS-H-C2).
· Classify changes in matter as physical or chemical (PS-H-D1).
· Differentiate between mass and weight (PS-H-E1).
· Draw conclusions and make inferences in oral and written responses about ideas and information in texts, including: nonfiction works, short stories/novels, fiveact plays, poetry/epics, film/visual texts, consumer/instructional materials, and public documents (ELA1H3).
· Explain ways in which ideas and information in a variety of texts (e.g., scientific reports, technical guidelines, business memos, and literary texts) connect to reallife situations and other texts (ELA1H4).
· Demonstrate understanding of information in gradeappropriate texts using a variety of strategies, including: summarizing and paraphrasing information and story elements, comparing and contrasting information in texts, including televised news, news magazines, documentaries, and online information, comparing and contrasting complex literary elements, devices, and ideas within and across texts, examining the sequence of information and procedures in order to critique the logic or development of ideas in texts, making inferences and drawing conclusions, and making predictions and generalizations (ELA7H1).
· Analyze information within and across gradeappropriate texts using various reasoning skills, including: identifying cause-effect relationships, raising questions, reasoning inductively and deductively, generating a theory or hypothesis, and distinguishing facts from opinions and probability (ELA7H4).
· Analyze information found in a variety of complex graphic organizers, including detailed maps, comparative charts, extended tables, graphs, diagrams, cutaways, overlays, and sidebars to determine usefulness for research (ELA5H6).
· Evaluate how location, topography, climate, natural resources, and other physical characteristics affect human activities (e.g., cultural diversity, migration, physical features, historical events, plantation, subsistence farming) or the significance of a place (G-1B-H1).
· Explain how topography, climate, soil, vegetation, and natural resources shape the history of a region (G-1B-H2).
PERFORMANCE-BASED LEARING OBJECTIVES. Instruction in this lesson should result in students being able to:
1. Describe soil by physical, chemical, and biological propertiesl.
2. Distinguish among physical, chemical, and biological properties of the soil.
3. Distinguish between homogenous and heterogeneous mixtures in soil.
LIST OF RESOURCES. Teachers may find the following resources useful in planning and teaching this lesson:
Textbooks:
· Plaster, Edward J., Soil Science & Management 3rd Edition., Albany, New York: Delmar Publishers, 1997.
· Plaster, Edward J., et al., Lab Manual to accompany Soil Science & Management 3rd Edition., Albany, New York: Delmar Publishers, 1997.
Web Sites:
· https://www.soils.org/lessons/plans/lessons/texture.html
· https://www.landjudging.com/a2001/table_of_contents.htm
· https://www.puzzlemaker.com
· http://www.oneplan.org/Water/soil-triangle.shtml
· http://soils.usda.gov/sqi/concepts/soil_biology/images/SBPfoodwebWords.jpg
· http://www.lsuagcenter.com
Other Resources: The following resources will be useful to students and teachers:
· Flynn Scientific Inc.
P.O. Box 219
Batavia, IL 60510
TERMS. The following terms are presented in this lesson:
· Clay
· Sand
· Silt
· Structure
· Texture
· Topsoil
· Subsoil
· Subsoiling
· Tillage pan
· Infiltration
· Percolation
· Mottling
· No-till planting
· Reduced-tillage
· Permeability
· Homogenous mixtures
· Heterogeneous mixtures
· Aerobic
· Algae
· Anaerobic
· Bacteria
· Fungi
· Microorganisms
· Nematodes
· Nitrogen cycle
· Organic matter
· Rodents
· Acid soil
· Alkaline soil
· Ion
· pH
LIST OF EQUIPMENT, TOOLS, SUPPLIES, AND FACILITIES
· Writing Surface
· Computer with PowerPoint
INTEREST APPROACH. Use an interest approach that will prepare students for the lesson. Teachers often develop an approach for their unique class and student situations. A possible approach is included here.
Brainstorm how the physical properties of the various soils affect plants and monetary values of these plants. Then, brainstorm how the physical properties of soil can ultimately impact the cost of crops and quality of produce that will be available to consumers in the future. (List ideas on the board as students brainstorm.) How could these factors affect the price of a hamburger? How many hours would you have to work after school to buy a $15 hamburger?
SUMMARY OF CONTENT AND TEACHING STRATEGIES
Objective 1: Describe soil by physical properties.
Anticipated Problem: What are the physical properties of soil and how do they affect productivity?
I. Physical Properties of Soil
A. Terms
1. Clay- The smallest soil particle.
2. Sand - The largest soil particle.
3. Silt - An intermediate sized soil particle.
4. Structure - The way individual soil particles are grouped together.
5. Texture - A physical property of the soil referring to the relative percentages of sand, silt, and clay.
6. Topsoil - The upper part of the soil profile that is normally cultivated.
7. Subsoil - the area in the soil profile below the topsoil which accumulates clay.
8. Subsoiling - A method of breaking up the compacted layers of the soil that restrict air and water movement and root growth using farm machinery.
9. Tillage pan - areas of compacted soil in the plant root zone created by repeated plowing of heavy soils especially when wet. Also called a plow pan.
10. Mottling - Spots of color in the soil that indicates internal drainage and aeration.
B. Content
1. Texture is one of the physical properties of the soil that is considered rather permanent. Texture refers to the relative percentages of the three types of soil particles. It is the varying amount of each portion that gives each soil its texture or feel.
a. Sand, Silt, Clay
b. Determining soil texture
1. Sensing the feel
2. Mechanical analysis
c. The textural triangle is used to obtain a soil textural name for a sample after it has been mechanically analyzed. (Demonstrate the textural triangle)
d. Soils with a sandy or coarse texture are usually referred to as “light soils.” Soils with a clay or fine texture are referred to as “heavy soils.”
Medium textured or loamy soils have more desirable characteristics usually associated with highly productive soils that are easier to manage.
e. When comparing light soils to heavy soils, the light soil will:
1. Require less energy to cultivate.
2. Heat and cool faster.
3. Usually be lighter in color.
4. Wet and dry faster.
5. Usually be subject to greater erosion.
6. Usually be lower in fertility.
2. There are four main types of soil structure.
a. Platy - thin horizontal sheets overlapping each other.
b. Prismatic - long vertical columns without rounded tops.
c. Block like - irregular shaped cubes.
d. Spheroidal - rounded and often referred to as granular or crumb. Usually found in the topsoil.
3. There are two types of structureless soils.
a. Single grained soils like sand.
b. Solid massive condition with no noticeable peds.
4. Internal soil drainage is important for proper plant growth. Permeability can be determined by the color of the subsoil.
a. Poorly drained soils will be grey in color with some red or yellow streaks.
b. As internal drainage improves the subsoil takes a more yellowish - brown or reddish brown color with some grey mottling.
c. Soils with good internal drainage and aeration will have a uniform bright color with few or no grey streaks or mottling.
Objective 2: Distinguish among physical, chemical, and biological properties of the soil.
Anticipated Problem: What are the differences between physical, chemical, and biological properties of soil?
II. Physical, Chemical, and Biological Properties
A. Terms
1. Infiltration - The movement of water into the soil.
2. Percolation - The movement of water through the soil.
3. No-till planting - The planting of a crop into the previous crop stubble or a cover crop, disturbing only the immediate seed zone.
4. Reduced-tillage - The elimination of one or more operational procedures from a conventional system of working the soil.
5. Permeability - the characteristics of a soil which permits variations in the speed of air and water movement.
6. Homogenous mixtures – soil mixtures that contain the same type of soil particles
7. Heterogeneous mixtures – soil mixtures that contain different types of soil particles
8. Aerobic – occurring only in the presence of free oxygen
9. Algae – soil plant microorganisms capable of photosynthesis
10. Anaerobic – growing or occurring in the absence of free oxygen
11. Bacteria – single-celled soil plant microorganisms, some of which are responsible for organic matter decomposition, while others are responsible for nitrogen fixation
12. Fungi – soil plant microorganisms responsible for organic matter decomposition, especially the cellulose, lignin and gum
13. Microorganisms – life forms too small to be seen with the unaided eye or barely visible
14. Nematodes - soil animal microorganisms that are responsible for the decomposition of organic mater, consumption of other animal microorganisms and parasitism on the roots of certain higher plants
15. Nitrogen cycle – the biochemical changes undergone by this atmospheric gas from its use by living organisms to decomposition and conversion back to the atmosphere
16. Organic matter – soil materials including plant and animal residues at various stages of decomposition
17. Rodents – small gnawing animals such as rats and mice
18. Acid soil – one having a pH below 7.0 on a scale from 0 to 14
19. Alkaline soil – one having a pH below 7.0 on a scale from 0 to 14
20. Ion – charged atoms or groups of charged atoms
21. pH – a numerical measure of the degree of acidity or alkalinity of the soil solution
B. Content
1. Soil types influence crop selection.
a. Oats, peanuts, and beets do best in light textured soil.
b. The majority of our crops grow best in a loamy textured soil.
c. Flooded rice requires a heavy fine textured soil to prevent loss of surface water. Sugarcane is also grown in heavy clay soils.
2. The soil structure is determined by the way the particles of sand silt and clay are grouped together in aggregates.
a. Peds are naturally formed groups of soil particles.
b. Clods are artificially formed groups of soil particles.
3. A structured soil is more desirable because it:
a. Is easier to cultivate.
b. Allows more water intake.
c. Does not restrict root growth.
d. Encourages better drainage within pore spaces.
e. Allows entry of oxygen into the pore spaces after the water has drained.
f. Facilitates organic matter decomposition and the release of plant nutrients.
4. Soil structure can be destroyed by :
a. Working the soil when it is wet.
b. Repeated movement of equipment or livestock.
c. Repeated use of equipment at the same depth in the soil.
d. Continual flooding of the soil.
5. Soils with poor soil structure can be improved by:
a. Leaving it alone, in time it will repair itself.
b. Planting a green manure crop.
c. Incorporating plant residue into the soil.
6. Soil structure influences infiltration and percolation rates.
a. Rapid - spheroidal structure and single grained structureless soils.
b. Moderate - blocky and prismatic structure.
c. Slow - platy structure or massive structureless soil.
7. Tillage pans are areas of compacted soil in the plant root zone caused by repeated plowing at the same depth.
8. Both tillage and traffic pans are serious problems in many parts of the country because the area of root restriction is generally in the topsoil. This reduces the movement of air, water, and roots and therefore limits crop yields.
9. Fragipans (silt pans) and clay pans can occur naturally in or near the subsoil. A fragipan is the result of too much silt in or near the B horizon, and is not the result of mans actions.
10. Methods for alleviating traffic or tillage pans.
a. Subsoiling breaks up or shatters compacted layers using deep plowing equipment.
b. Reduced or minimum tillage means less movement over the soil which results in less compaction of the soil. Deep Subsoiling should precede reduced or minimum till operations.
c. No till reduces the formation of traffic pans because planting is done directly in the stubble of the previous crop.
11. The biological properties of soil refer to the living organisms found in the soil. This includes both the micro and macro plants and animals.
a. Plants
1. Micro
a. Bacteria
b. Fungi
c. Actinomycetes
2. Macro – roots of higher plants
b. Animals
1. Micro
a. Nematodes
b. Protozoa
2. Macro
a. Earthworms
b. Rodents (prairie dogs, moles, gophers, etc.)
c. Arthropods (mites, insects, spiders, etc.)
d. Gastropods (slugs, snails, etc.)
12. The ability of soil to provide the essential elements needed for plant growth includes not only the availability of these elements, but also other chemical properties such as clay minerals present, humus content, cation exchange, and soil reaction (pH).
Objective 3: Distinguish between homogenous and heterogeneous mixtures in soil.
Anticipated Problem: How do homogenous and heterogeneous mixtures differ?
III. Homogenous and Heterogeneous Mixures in Soil
A. Terms
1. Homogenous mixtures – contain the same type of soil particles
2. Heterogeneous mixtures – contain different types of soil particles
B. Content
1. Homogenous mixtures in soil
a. Sand
b. Silt
c. Clay
2. Heterogeneous mixtures in soil
a. Any combination and proportion of sand, silt, or clay
(Additional information on homogenous and heterogeneous soils can be found at https://www.soils.org/lessons/plans/lessons/texture.html )
REVIEW/SUMMARY. Use the student learning objectives as the basis for review and summary. Use unit objectives to review using question/answer format in order to determine student comprehension. Re-teach those concepts that students have not demonstrated achievement of a competent knowledge level.