SWS 3022 Exam 2 Questions with Answers
Know that primary minerals dominate the sand and silt fractions, while secondary minerals dominate the clay fraction. Also, know the basic difference in reactivity of primary vs. secondary minerals. - Answer-Primary= less reactive
Know how texture generall...
Know that primary minerals dominate the sand and silt fractions, while secondary
minerals dominate the clay fraction. Also, know the basic difference in reactivity of
primary vs. secondary minerals. - Answer-Primary= less reactive
Know how texture generally affects overall porosity and pore size distribution. - Answer-
Larger particles-> large pores, low porosity
Clay- high water retention
Know generally how texture affects water and gas movement in soils. - Answer-Course
texture- easier path, less contact time
Fine texture- more convoluted path, more contact time
Be able to use the soil textural triangle. Know the number of textural classes,
Understand the general trends in the triangle. - Answer-12 textural classes
Clay at top takes up most, sand to left, silt to right
Understand the relationship between soil texture and specific surface area; why is it
important? - Answer-Finer soils have higher specific surface area
Sand SSA- 444
Silt- 100,000
Clat- 7,000,000
Understand what Stokes' Law indicates and how it is used in the hydrometer method to
assess soil texture. - Answer-Stokes law allows determination of the
time required for different particle size
separates to settle from a suspension
Understand the hydrometer method and how to calculate % sand, silt, and clay given
appropriate measurements. - Answer-Hydrometer measures in g/L
Know the numerical value for soil particle density. - Answer-2.65 g/cm cubed
Know how to compute soil bulk density and what it is. - Answer-Mass oven dried soil
divided by volume of soil
Density of soil including the
particles and the pore spaces
, Know the range in bulk densities for a typical mineral soil containing approximately 1-
5% organic matter. - Answer-1-1.6 g/cm cubed
Know how organic matter, aggregation, compaction, and depth in profile affect porosity
and bulk density. - Answer-Organic soils have a lower bulk density, high porosity
Aggregation- low bulk density, increases porosity
Compaction- decreases porosity, increases bulk density
Depth- compacted, low organic matter, fewer roots, high bulk density, decrease porosity
Know the conceptual and quantitative relationship between BD and porosity. - Answer-
When porosity declines, BD increases because there is a greater mass of soil particles
for a given volume.
Quantitative- Porosity= 1-BD/PD= Volume of pores/Volume of soils
Understand the difference between total porosity and pore size distribution. - Answer-
Total porosity indicates the maximum volume
of water and gases a soil can hold
Pore size distribution- diameters of pore
macro pores- >/08 mm
Meso pores- .08-.03mm
Micropores -.03-.005 mm
Understand basically how differences in density and texture impact water and gas
movement and chemical properties of soils. - Answer-Lower diameter, slower water
movement
Know what soil structure is and how it affects soil porosity and pore size distribution. -
Answer-Arrangement of grouping of individual soil particles into secondary units.
(aggregates)
Interaggregate- porosity btwn aggregates, larger diameters, drains rapidly
Intraaggregate- within aggregate, small diameters, strong capillary forces, retain water
well
Know the boiling and freezing point of water. - Answer-100 degrees Celsius and 0
degrees Celsius
Know the dimensions of the earth. - Answer-Diameter: 8,000 mi
Circumference: 25,000 mi
Understand that definitions of soil depend strongly on the concerns of those making the
definitions - Answer-
Know the parameters related to soil composition for an idealized surface soil. - Answer-
Reactive and porous
45% mineral particles
5% organic matter
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Perfectscorer. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.89. You're not tied to anything after your purchase.
