Soil Science 315

Problem Set 5

Monday, February 20, 2006

Due Friday, March 1, 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.

Answers to the questions below are italic bold. For each question provide a very brief explanation of why the selected answer is correct.

1. A soil used for production of organic vegetables has a texture of clay loam with moderate medium blocky structure. The farmer hires someone to plow the soil. The plow person plows (tills) the soil after a long period of spring rains. The plowing most likely a) changed the soil texture reducing the infiltration b) made the soil massive reducing the infiltration b) changed organic matter content reducing infiltration d) change the plastic limit reducing infiltration.

2. A soil sample is determined to have 49% clay and equal amounts of silt and sand. The textural class of the sample is a) either silty clay, silty clay loam or clay loam b) loam c) sandy clay loam d) clay

3. In Pennsylvania wastewater was applied to soil using spray irrigation in decidueous forests. Because it was advantageous to dispose of as much wastewater as possible water was added at high rates but low enough that that the trees could survive. In about 20 years it was found that the morphology of the soil changed. The most likely change observed is a) weathering of quartz and feldspars to clay minerals b) the change in some color from red to grey c) the leaching of silica d) the formation of a spodic horizon.

4. The soil with the most clay in the control section is a) Coarse-loamy, mixed, mesic Typic Fragiochrept b) Fine, illitic, mesic Aquic Hapludalf c) Fine-loamy, mixed Aquic Eutroboralf d) Loamy-skeletal, mixed Borollic Lithic Haplargid.