APES Soil Labs

1. The Dirt on Soil..... "Dirt is what's under your fingernails, soil is what's under your feet!" APES Soil Labs

2. Soil Labs Instructions • Use eight pages in your journal as follows: • 1. Soil Background Info • - Copy Soil Profile Diagram • - Describe two sources of material that form soil. • - Summarize the descriptions of each soil horizon. • 2&3&4. Soil Texture – Summarize intro paragraph, conduct lab, record data, answer questions (three pages). • 5. Nitrogen Cycle Bacteria – Draw bacteria and answer questions. • 6. Soil Porosity (Upper half of page): Summarize intro paragraph and diagram about soil porosity. • Soil Permeability (Lower half of page): Summarize intro paragraph and diagram about soil permeability. • 7. Soil pH (Upper half of page): Soil pH – Read and answer questions • Soil Nematodes (Lower half of page): Research & describe the niche of soil nematodes (roundworms – focus on soil nematodes, not parasitic or aquatic roundworms!!! • 8. Soil Health and Climate Change – Read article and summarize highlighted sections – include all sections for full credit!!!

3. Soil Studies I: Background Info • · Soil… Required for plants, therefore, required for most terrestrial life, including humans. • · Soil is formed over time by the breakdown and mixing of two sources of material: bedrock from below, and organic matter (mostly decaying parts of plants) from above. • · Mature soils have several layers, called horizons, that can be seen in a soil profile (a cutaway view of soil perpendicular to the ground surface). • · The O horizon (organic layer). Includes decaying leaves, twigs, animal droppings, etc. Loose, barely decayed material on top is called litter, below it is older, partially decayed material called duff (Homer’s favorite layer!). • · The A horizon (aka, topsoil). A mixture of decayed organic material (called humus) and inorganic substances such as clay, silt, and sand. Thick topsoil layers provide nutrients for abundant plantlife. Most organisms that live in soil (worms, arthropods, etc.) are found in the O and A horizons. • · The B horizon (aka, subsoil). Contains a mix of organic and inorganic material. As water percolates down through the soil (known as infilitration), it dissolves minerals out of the O and A horizons and carries them downward (this is called leaching). These minerals are dropped off in the B horizon, a process called accumulation. Most plant roots reach through the O, A, and B horizons. • · The C horizon (parent material). Composed primarily of broken and weathered pieces of the parent bedrock. Very little organic material is found in this horizon.

4. Soil Studies II: Soil Texture The ratio of sand, silt, and clay particles in a soil sample determines the texture of a soil sample. These particles play a major role in determining other soil characteristics, such as porosity and permeability, which in turn influence the water holding capacity of the soil, its percolation rate, and its capillarity. Sand is the largest particle, ranging from 0.05 to 2 mm in diameter. Silt particles are medium-sized, between 0.002 and 0.05 mm in diameter. Clay particles are the smallest, with sizes less than 0.002 mm in diameter (see figure 3 on the soil permeability lab page). • Summarize intro paragraph. • Draw and label sand, silt, and clay particles. Include their size ranges. (See Permeability diagrams for help) Upper half of page: Summarize intro paragraph about soil texture. Include labelled drawings of soil particles.

5. Soil Studies II: Soil Texture Insert four of these charts into your journal. Use it to record the data from the lab. Soil Texture Analysis (x): (source) and (proceure) • Questions: • Insert a soil texture triangle into your journal and label each sample on it to determine the type of soil in the sample. • Compare the soil particles in the two samples. Which particles were most and least common in each sample? How do you explain these differences and / or similarities? • Compare the results of the chemical and physical test procedures. How similar or different were they? Which would you consider more reliable? Why? • Estimate the ratio of organic to inorganic material in each soil sample (hint: floating organics vs. sunken inorganics). Discuss what this indicates about the fertility of each soil sample. • Define these terms in your own words: sand, silt, clay, loam.

6. Soil Texture Triangle Chart Loam: lōm/ noun • a fertile soil of clay and sand containing humus. • a soil with roughly equal proportions of sand, silt, and clay. Example: Soil that is 65% sand, 20% silt, and 15% clay would be classified as “sandy loam” Read chart by finding where particle percentages intersect 6

7. Soil Studies III: Nitrogen Cycle Bacteria • Complete the activity in class where you examine these bacteria in the microscope. • Draw diagrams and answer questions included in the instructions (also repeated on the next slide). • Use the info on the following two slides to help answer questions.

8. Soil Studies III: Nitrogen Cycle Bacteria • Use the micro-slide viewer to examine photos # 1, 3, 4, & 5. • Draw diagrams of these four images. Diagrams should be 1/8 of a page in size, they should include a title and the amount of magnification, and they should include labels of all identifiable structures (cell wall, cytoplasm, nodule, strep chain, staph cluster, bacillus, coccus, spirillum – see next page for hints). • Read the accompanying information (next two slides) and answer these questions: • Describe the importance of the bacteria of decay and of the nitrogen-fixing bacteria. • Make a Venn Diagram (two partially overlapping circles) that shows the similarities and differences between the habitat and niche of the organisms in images # 3 & 4. • Define legumes and list all examples in the text.

9. Basic Bacteria Descriptions • Bacillus = bacteria with cells shaped like ovals or rods • Coccus = bacteria with cells shaped like spheres or circles • Spirillum = bacteria with spiral-shaped cells, that often are able to swim like a corkscrew • Strep = bacterial colony where several cells grow lined up in a chain • Staph = bacterial colony where several cells grow in a cluster, like grapes • Staphylococcus = combined terms from above, giving a cluster of spherical cells • Streptobacillus = combined terms from above, giving a chain of oval cells

11. Soil Studies IV: Soil Porosity • Different soils have varying amounts of pore spaces in them. These spaces are filled with air, which keeps roots healthy by providing them with oxygen, allows water to move through soil, and stores water. See Figure 2 for more details about pore spaces and the other components of topsoil. Severely compacted soils impair plant growth as well as being more difficult for people to work with when growing plants. • See next slide for figure 2. Summarize intro paragraph and diagram about soil porosity.

12. Soil Studies IV: Soil Porosity Figure 2 Percent Composition of Materials in Typical Soil Summarize intro paragraph and diagram about soil porosity. Include labelled sketch of diagram and important details from descriptions.

13. Soil Studies V: Soil Permeability • Although it might sound synonymous with soil porosity, soil permeability is a separate characteristic. Permeability will be influenced by soil porosity, but it also depends on the particles which compose the soil. These particles are classified as sand, silt, or clay, according to their size. See Figure 3 for more details. • See next slide for Figure 3. Summarize intro paragraph and diagram about soil permeability.

14. Soil Studies V: Soil Permeability Summarize intro paragraph and diagram about soil permeability. Include labelled sketch of diagram and important details from descriptions.

15. Soil Studies VI: Soil pH • The pH of soil is an important factor in determining which plants will grow because it controls which nutrients are available for plants to use. Three primary plant nutrients—nitrogen, phosphorus, and potassium—are required for healthy plant growth. Because plants need them in large quantities, they are called macronutrients. They are the main ingredients of most fertilizers that farmers and gardeners add to their soil. Other nutrients such as iron and manganese are also needed by plants, but only in very small amounts. These nutrients are called micronutrients. See Table 1 below for more details. • The availability of these nutrients depends on the amount of each in the soil, the form that they take (for example, nitrates vs. nitrites vs. ammonium), and the pH of the soil. In general, macronutrients are more available in soil with high pH (basic soils, which are called sweet), while micronutrients are more available in soil with low pH (acidic soils, which are called sour). Conifer forests tend to form sour soils due to the acidity of the trees’ needles. See Table 2 below for more details. • List macro and micronutrients needed for plant growth. • Compare the pH of sweet and sour soils. • Describe which macro & micronutrients would have greater and lesser availability in sweet vs. sour soils. See next slide for diagrams and charts referred to above…

16. Soil Studies VI: Soil pH Figure 1 Map showing pH of US soils Table 1 Comparison of Plant Nutrients in Soils Table 2 Influence of pH on Nutrient Availability in Soils

17. Soil Studies VII: Soil Invertebrates • Do some research to describe the niche of soil nematodes (roundworms) in soil. Include their abundance, diversity, contributions to soil quality, etc. (Focus on SOIL roundworms, not aquatic or parasitic nematodes!!)

18. Soil Studies VIII: Soil Health & Climate Change • Read the highlighted sections of the article on the class website. • Summarize the main points of EACH SECTION. Bullets or outlines are ok, just make sure to include all sections. Pay attention to the subtitles throughout the article, and include them in your notes as needed.

19. Flippin’ dirty Soil!