Soils Lab 2: Soil Texture Review ✓ Solved

Soils Lab 2 On Soil Texture Includes A Review Of The Idea Soil Composi

Soils Lab 2 on soil texture includes a review of the idea soil composition, a detailed review of how to calculate soil texture mechanically, and how to calculate soil density and porosity. Assignment activities involve using provided data to determine soil textural class, as well as soil density and porosity. Calculations are reviewed in detail within the lab materials, with review questions incorporating material from lecture topics in 'Soil Architecture and Physical Properties' (Chapter 4). Students are instructed to download the attached laboratory assignment file, thoroughly read and study the information, including equations and review questions, and utilize both lab content as well as lecture notes and textbooks for the completion of the assignment. The assignment requires creating a document containing answers to all questions, with the student's name and exercise number at the top, and submitting it via DropBox labeled 'Soils Lab Assignment 2'. The filename should include the student's last name followed by an underscore and the exercise number (e.g., 'Pope_SoilsLab2.doc' or PDF). Acceptable submission formats are Office documents or PDFs. Points may be deducted for failure to follow these instructions accurately.

Sample Paper For Above instruction

Introduction

Understanding soil texture, density, and porosity is fundamental for soil science, influencing water retention, aeration, fertility, and overall soil health. Accurate determination of soil textural class, density, and porosity allows for better soil management practices and enhances understanding of soil behavior under various environmental conditions. This paper provides a comprehensive analysis of the methodical procedures to calculate soil texture mechanically, as well as how to determine soil density and porosity from experimental data, aligning with the objectives of the laboratory exercise.

Soil Composition and Texture

Soil composition refers to the relative proportions of mineral particles—sand, silt, and clay—that comprise soil. The distribution of these particles defines soil texture, which significantly affects water retention, nutrient availability, and drainage characteristics. Soil texture is traditionally classified into categories such as sand, loam, silt loam, clay, and silty clay, based on specific percentage ranges of particle sizes (Gee & Bauder, 1986). To determine soil texture mechanically, the lab employs the particle size analysis method, which involves sieving for larger particles and sedimentation techniques for finer particles.

Mechanical Soil Texture Determination

The mechanical method divides soil into three different particle size fractions: sand (>0.05mm), silt (0.002mm to 0.05mm), and clay (

Calculating Soil Density and Porosity

Soil bulk density (Bd) is calculated by dividing the oven-dried soil weight by the total volume of soil sample, which includes pore spaces (Hillel, 1998). The formula is Bd = Oven-dried soil weight / Soil volume. Porosity (P) reflects the proportion of pore space within the soil and is derived from bulk density and particle density (Pd) using the formula P = 1 - (Bd / Pd). Particle density is generally assumed to be 2.65 g/cm³ for mineral soils unless laboratory measurements indicate otherwise (Hillel, 1994). Accurate measurements involve collecting a known volume of soil, drying, weighing, and applying the formulas.

Application Using Provided Data

Using the specified data, students determine the percentage of sand, silt, and clay, classify the soil texture accordingly, and compute soil bulk density and porosity. For example, if a soil sample weighs 150 grams, occupies a volume of 100 cm³, and contains 60% sand, 25% silt, and 15% clay, the soil texture class can be identified as loam. Measurements of soil mass and volume allow the calculation of bulk density as 1.5 g/cm³, and assuming a particle density of 2.65 g/cm³, porosity is calculated as approximately 43.4%, indicating a well-drained soil with moderate pore space (Hillel, 1990).

Conclusion

This laboratory exercise demonstrates the importance of accurately determining soil texture, density, and porosity for soil science applications. Mechanical methods for soil textural analysis provide reliable classification, while calculations of density and porosity inform management and conservation strategies. Mastery of these techniques enhances understanding of soil physical properties, which are essential in agriculture, engineering, and environmental sciences.

References

• Gee, G. W., & Bauder, J. W. (1986). Particle size analysis. In A. Klute (Ed.), Methods of Soil Analysis Part 1: Physical and Mineralogical Methods (pp. 383-411). American Society of Agronomy.
• Hillel, D. (1990). Introduction to Soil Physics. Academic Press.
• Hillel, D. (1994). Environmental Soil Physics. Academic Press.
• Hillel, D. (1998). Environmental Soil Physics. Academic Press.
• Raghavan, V., & Ponce, R. (2014). Soil physical properties and their measurement. Journal of Soil Science and Environmental Management, 5(2), 20-30.
• Schoeneberger, P. M., et al. (2012). Field book for describing and sampling soils. Natural Resources Conservation Service, USDA.
• Brady, N. C., & Weil, R. R. (2008). The Nature and Properties of Soils. Pearson.
• Dean, L. W. (1990). Soil structure and porosity. Soil Science Society of America Journal, 54(3), 453-460.
• Blake, G. R., & Hartge, K. H. (1986). Particle density. In A. Klute (Ed.), Methods of Soil Analysis Part 1: Physical and Mineralogical Methods (pp. 377-381). American Society of Agronomy.
• Lehmann, J., & Rillig, M. C. (2018). Soil physics and soil chemistry: An integrated approach. Environmental Science & Technology, 52(4), 1912-1921.