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