Soil Science 315

Problem Set 3

Monday, February 13, 2006

Due Friday, February 17, 2006 at 2:25 PM

Redo due, Wednesday, February 22, 2006 at 2:25 PM

 

Instructions:  You may discuss the problems with anyone but the final work should be done independently. Respond to each question precisely as instructed by the question. For example, if the question says explain one reason only explain one reason even if you know many reasons and if the question asks you to calculate a volume do not give a mass. Be sure to label all numeric answers with the correct units. Use correct English and complete sentences for explanations. Each problem will be marked as accepted or “re-do”. There are no “re-do’s” of “re-do’s”. Re-do’s” are not accepted if an “honest” attempt was not submitted on the original due date. All portions of each problem set must be accepted to receive credit for the entire set. When submitting a problem set be sure to indicate the problem set number and if the submission is a “re-do” in the upper right corner.

 

  1. Select the best answer for the multiple choice question below and then very briefly explain why the answer you selected is the best answer.

 

"Soil erosion, now a threat to food security in some regions, is a natural process and not a danger unless it becomes excessive, surpassing the natural rate of soil formation.  As the pressure to grow more food has intensified, excessive soil erosion has spread, slowly depriving the land of its inherent fertility.  The result, as in a country like Haiti, is deprivation and hunger." (Page 6 of Lester R. Brown, 1996. The Acceleration of History in:  State of the World 1996. W.W. Norton & Company, New York.)  The statement that is true of the rate of soil formation a) soil forms at the rate of 1 inch per year b) soil forms at different rate depending on the processes and factors of soil formation c) naturally soil always forms faster than erosion d) naturally soil always forms slower than erosion.

 

  1. Give the master horizon designations along with the subordinate distinctions of the spodosol profile picture at:

http://soils.usda.gov/technical/classification/orders/spodosols.html

 

  1. A sandy soil has an A horizon from 0 – 31cm, a C horizon from 31 – 94 cm and a 2C below 94 cm. Briefly describe a possible genesis of this soil.