Soil Lab - Abbreviated

docx

School

Shasta College *

*We aren’t endorsed by this school

Course

Subject

Geology

Date

Feb 20, 2024

Type

docx

Pages

Uploaded by allytilton67

AGNR 61: SOILS LAB Lab Preparation Prior to the laboratory activit y , collec t three soil samples from diversified locations such as a garden, a marsh , an area lacking vegetation, the side of a road, a pond shore, near a creek, etc . Put each collection in a labeled container. You will use portions of this collected soil to complete the following lab exercises. Exercise 1: Soil Color Soils differ in many ways. Soils can have chemical differences that make them acidic, low in nutrients, nutrient-rich, etc. The simplest way to identify different soil types is to examine their physical traits. Color and texture are important physical traits we can easily assess. Soil Type By Color Organic Content Fertility Aeration Dark Soils (Dark Gray, Black, or Brown) High High High Moderately Dark Soils Brown to Yellow-Brown Medium Medium Medium Light-Colored Soils Pale Brown to Yellow or Red Low Low Low Basic Soil Component Color Iron Oxides Red Iron Sulfides Black Specs Calcium Minerals White Organic Matter Black Low Oxygen Gray Name: Alexandria Tilton

Exercise 1: Soil Color (Continued) Munsell Soil Color Charts describe three components of soil color. Soil Color Example: Questions 1. Is a 5R 6/6 more yellow or red? ____Red__ 2. What is the chroma of 5YR 2/4? _Reddish gray 3. Which one of these is darker: 5YR 2/4 or 5YR 8/4? _5YR 2/4 __ Soil Color Observation Chart Soil Describe Color Observed Munsell Color Was this soil well-drained (high oxygen levels) or poorly drained (low oxygen levels)? What types of minerals or substances may be present? 1 Dark brown/Black 10YR 2/2  Well-drained (colors)  Poorly-drained (gray)  Iron oxides  Calcium minerals  Iron sulfides  Organic matter 2 Light brown, black and white specs 10YR 3/1  Well-drained (colors)  Poorly-drained (gray)  Iron oxides  Calcium minerals  Iron sulfides  Organic matter 3 Light brown/cream white 2.5Y 5/3  Well-drained (colors)  Poorly-drained (gray)  Iron oxides  Calcium minerals  Iron sulfides  Organic matter

Exercise 2: Identifying Soil Texture by Measurement Soil texture is determined by the relative proportion of sand, silt and clay present in each sample. Sand is the largest particle in the soil. Its size varies from 0.05 to 2mm. It feels rough to the touch, because it has rough, angular edges and does not "hold" any nutrients. Silt is a soil particle that's size is between that of sand and clay. Silt has a smooth texture. Clay is the smallest of the soil particles, measuring less than 0.002 mm in size. Clay is smooth when dry and sticky when wet and can hold a lot of nutrients, but because it is very compact, it does not allow air or water to pass through it. Any particles that are greater than 2 mm do not contribute to the soil's texture and are considered "gravel". Image: www.nrcs.usda.gov Reading a Soil Textural Triangle A soil texture triangle is used to identify soil texture class of a soil sample. The sides of the soil texture triangle represent percentages of sand, silt, and clay. Percentage of clay is read from left to right across the triangle. Percentage of silt is read from upper right to lower left. Percentage of sand is read from lower right to upper left. The intersection of the three sizes on the triangle give the texture class. The boundaries of the soil texture classes are darker and thicker than the other lines on the triangle. Example: If you have a soil with 20% clay, 60% silt, and 20% sand, it falls in the "silt loam" class.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Materials  3 Clear Vials, Containers, or Jars with Lids  A Few Drops of Dish Soap  Three Soil Samples  Water  Magnifier, Magnifying Glass, Hand Lens, or similar (optional) Procedure Step 1: The composition of soil determines the kind of plants and animals that can exist within i t . Take a small amount of your collected Soil Sample #1 and spread it into a plastic dish to observe its color, texture, and size of its particle s . Using a magnifying glass (if you have one) , tr y to find clay particles, silt, sand , gravel, and organic matter in your soil sample . Describe the appearance of each type of particle. . Step 2: To determine the proportion of the various soil particles present in your soil samples, fill a vial, glass, or jar halfway with e a c h of your soil samples . Add water until it reaches approxi mately 2 cm from the top of the vial. Add a drop of dish soap to your vial. Securely place the cap over the vial and shake the jar vigorously for several minutes, or until all the large particles break apart. Allow the soil mixture to settle (typically takes 6 hours -3 days). Step 3: After the settling period, the soil has separated into layers of floating organic matter, water, settled organic matter, clay , silt, fin e sand, coarse sand, and gravel. Make an illustration on the pre- drawn vials below and identify the various layers observed. Step 4: Using a ruler, m easure the total depth of the soil in each vial. Next, measure the thickness of each layer, calculate percentage of total sample, and record your results in Data Table 1 . Answer Questions relating to each sample. Soil Layers Sketches: Sample 1 Sample 2 Sample 3 ****Please see attached document for drawings***

Questions: Sample 1: 1. Which soil particle made up the greatest portion of your soil sample? The organic matter makes up the greatest portion of this soil sample 2. How do you think the soil’s particle type might affect plant growth ? I think it could affect it in positive way because the amount of organic matter would provide a plant with many nutrients, but it may also affect it negatively by being so dense is nutrients, it cannot adequately distribute growth especially when watering. When it’s wet, it stays wet for a long time even with proper drainage. 3. Knowing the source of your soil sample, what do you find interesting or noteworthy regarding its composition? Why? I find interesting that I didn’t know this soil needed to be mixed in with soil that doesn’t have all the plenty of organic material and nutrients in it. And it’s probably not best to use it by itself. Sample 2: 1. Which soil particle made up the greatest portion of your soil sample? The sand made up the greatest portion of this soil sample. 2. How do you think the soil’s particle type might affect plant growth ? I think it might keep a plant alive but may need extra attention to make sure if it needs nutrients added. It looked scarce of organic matter and looked dark brown/whiteish/grey when extremely dry. 3. Knowing the source of your soil sample, what do you find interesting or noteworthy regarding its composition? Why? I found it interesting how much chunkier organic matter it had, that was likely pulling away nutrients or water from the plants, and affecting the drainage or absorption of it all. Sample 3: 1. Which soil particle made up the greatest portion of your soil sample? Sand made up the greatest portion of this soil sample. 2. How do you think the soil’s particle type might affect plant growth ? I think the soils particle type would affect plant growth because there is no density, or organic matter to provide. When wet, this soil falls apart easy, and wouldn’t hold up, so I don’t think all plants fragile systems would be able to handle much movement with this soil in and around a plant. 3. Knowing the source of your soil sample, what do you find interesting or noteworthy regarding its composition? Why?

I originally always see this soil as light brown and tan in color, but when I collected it, it had been raining slightly, so it was thicker and stickier than I anticipated. It was very hard and compacted in the ground. I can see how this type of soil may hard from constant activity or nature has built itself a strong surface, knowing that it can be weaker if not as “compact”.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Table 1: Soil Layers Soil Total Soil Depth Thickness of Each Soil Type (in mm) Percentage of Sample (type thickness / total thickness) x 100 = % Soil Type (Refer to Textural Triangle) Sand course + fine Silt Clay Sand Silt Clay 1 9 mm 8 mm 1 mm 0 mm ( 8 / 9 ) x 100 = 88.9 % ( 1 / 9 ) x 100 = 11.1 % ( 0 / 9 ) x 100 = 0 % Loamy sand 2 9 mm 8 mm 1 mm 0 mm ( 8 / 9 ) x 100 = 88.9 % ( 1 / 9 ) x 100 = 11.1 % ( 0 / 9 ) x 100 = 0 % Loamy Sand 3 12 mm 5 mm 2 mm 5 mm ( 5 / 12 ) x 100 = 41.6 % ( 2 / 12 ) x 100 = 16.7 % ( 5 / 12) x 100 = 41.6 % Sandy Clay

Soil Lab - Abbreviated

Related Documents