Course Syllabus

Welcome to Agronomy 502 at Iowa State University!

Agron 502: Chemistry, Physics and Biology of Soils

Instructor: Dan Dobill



Course Overview

Agron 502: Chemistry, Physics & Biology of Soils

Course Description: Soil chemical, physical, and biological properties that control processes within the soil, their influence on plant/soil interactions, and soil classification. Basic concepts in soil science and their applications. Required course for the Master of Science in Agronomy degree program and Agronomy Graduate Certificate program.

Course Prerequisites: AGRON 181 or equivalent, AGRON 182 or equivalent, BIOL 101, CHEM 163, MATH 140. Restricted to graduate students enrolled in MS Agronomy & Agronomy Graduate Certificate online degree programs at ISU. Students from other departments must get permission.

Agron 502 covers the basics of soil science focused primarily for crop production. This involves many factors from climate (i.e. sun, rain, evaporation, temperature) to what the soils are developing from (bedrock or other materials) to living things (vegetation, microorganisms, earthworms) to landscape characteristics (erosion or drainage) to time (weathering). To cover these topics, first we will look at soils in general and then look closer at soil properties as they relate to three areas: soil chemistry, soil physics, and soil biology. Although we will be talking about specific details in soils, we will always try to look at these properties in relation to a bigger picture — crop production and the environment. We realize that many of you have vast experiences with soils in your profession and we would like this course to bring out your experiences through the discussion and assignments.

Soils and some of the factors that influence them.

Soils and some of the factors that influence them.


Agron 502 is one of the first courses in the MS in Agronomy distance education program. It is a course that builds towards other soil courses in the program, Agron 512: Soil-Plant Environment and Agron 532: Soil Management. Agron 512 focuses deeper on soil physical properties, nutrients and their cycles, and plant growth relative to soil properties, whereas Agron 532 focuses on field level management of soils. Agron 502 also builds towards the three capstone courses in the program, Agron 591: Agronomic Systems Analysis, Agron 592: Current Issues in Agronomy, and Agron 594: Workshop in Agronomy (on-campus). These capstone courses encompass all areas of agronomy from individual properties of crops and soils, to field, farm, regional, and global agriculture and the environment. As with any course, the depth and level of details presented do not fully explore any particular concept. The course material is a summary of what we considered to be the most relevant information you need to know in order to support your reasoning when making assessments on agronomic and environmental issues related to or impacted by soils and their management. Consequently, it is important to fully understand the course information at the level of detail presented in order to build your own mental database, which should enable you to be critical about new information in the future.

Course Objectives

  1. To understand that knowledge of soils and their properties is vital to crop production.
  2. To be able to look at individual soil properties and understand how they fit in the larger picture of agriculture, the environment, and the world.
  3. To broaden your understanding of soils to improve your utilization of information for understanding and solving problems.

Course Structure

Module Format

The online course materials in Agronomy 502 consist of 13 modules and four open-book exams.

To accomplish the course objectives, Agronomy 502 modules are categorized into four areas: soil basics, soil chemistry, soil physics, and soil biology. Below is the breakdown of each of these areas by modules. Before the areas, a short introduction to the section is available and the section is concluded with submission of reflections and completion of a take-home exam. At the end of the course, there is a summary activity related to the case study and the soil concept map assignment.

Soil Basics
The following are modules in this area:
- Introduction/Case Study
- Module 1: Soil Development and Classification
- Module 2: Soil Mineralogy and Weathering

Soil Chemistry
The following are modules in this area:
- Module 3: Ion Exchange
- Module 4: Ion Distribution
- Module 5: Ion Activity and Liming
- Module 6: Solubility and Chemical Reactions

Soil Physics
The following are modules in this area:
- Module 7: Soil Solids
- Module 8: Water Flow in Soil
- Module 9: Soil Temperature

Soil Biology
The following are modules in this area:
- Module 10: Soil Organisms
- Module 11: Soil Organism Interactions
- Module 12: Carbon Cycle
- Module 13: Nitrogen Cycle

Click Return to top to view Course Expectations

Instructor Interactions

Office Hours: ​Key activities in Office Hours include answering unclear content from modules, review of key module content, assignment issues/questions, and preparation for exams.

Email: Feel free to message the instructor at or via the Canvas Inbox if you have any questions or concerns.

Discussions: The instructor leads the Intro and Module 1 discussions. After that, leaders are assigned per week by the instructor. The instructor regularly monitors the interaction and questions for clarification as needed.

Graded Feedback: All graded assessments will be returned with feedback within 7 days of the due date. Exams will be returned within 14 days. Be sure to check your graded submissions for comments regarding your work.

Grading Procedures

The graded portions of the course are divided into assignments/reflections, discussions, exams, and a case study.

Course Grading System
Assignments 20%
Discussion Topics 30%
Soil Basics Exam 10%
Soil Chemistry Exam 10%
Soil Physics Exam 10%
Soil Biology Exam 10%
Case Study 10%
Total 100%


Descriptions of Expectations

  • Assignments are worth ~20% of the points in the class. Assignments are intended to tie module concepts to the case study. For the assignments, they generally are at the end of the module.

    Module Reflections for the four course sections are also considered assignments in the course. These include top 10 items an Agronomist should know, unclear module content, and learning strategies used.
  • Discussion Topics are worth ~30% of the points in the class. This includes general module posting as well as being discussion leaders.
    • General Posting - All students are required to contribute at least one original posting and reply to two or more other postings on the discussion topic. Discussion grading will involve quality of postings and active participation in the discussion forum. You are expected to post and reply to messages several times over several days during the time frame of each module.
    • Discussion Leader - The class will be divided into several discussion groups based on class size. During the semester, 1-3 students per module in each group will be assigned to be discussion leaders. This means that 2 times a semester you will be asked to be the discussion leader for your group. On the weeks that you are discussion leader, you are responsible for the postings in the discussion forum daily (initiating the discussion and facilitating further discussion). At the end of the discussion period, you and your fellow leader(s) are responsible for posting a summary of the discussion that the entire class can see (If there are three discussion groups in the course, there should be three summaries). 
  • Exams - In total, the exams are worth ~40% of your points in the class. Exams will be open-book examinations consisting of a mix of subjective questions (explanation/essay) and objective questions (e.g., calculations) that require you to apply content to questions of importance to agronomists. You will have one week to complete each examination. 
  • Case Study - The case study is worth ~10% of the points in the class. The Case Study is introduced in the introductory module and researched/discussed throughout the course.  There will be a summary project at the end of the course that will involve a role-playing discussion and a written submission. Most assignments and a few discussions during the course relate to the case so you will be working with the case most weeks that builds to this final project.
  • Final Grades will be assigned on a +/- scale.
    Letter Grade Percent
    A 94+
    A- 90 to <94
    B+ 87 to <90
    B 84 to <87
    B- 80 to <84
    C+ 77 to <80
    C 74 to <77
    C- 70 to <74
  • Bonus Discussion Topics - Extra credit will be given for contributions to 4 Bonus Discussion Topics throughout the course. These are available in the summary section pages of the course and ask about your experiences related to the concepts covered. You can post to these anytime in the course, whether we are on the topic or not. These are not required but are a valuable addition to the content of this course because others can learn from your experiences. Also, if your course grade is marginal between values (e.g. between B+ and A-), satisfactory contributions to these topics will increase your course grade to the higher value.


Communication Policy

All communication within the course should adhere to university standards of Netiquette at ISU. Specifically, communication should be scholarly, respectful, professional, and polite. You are encouraged to disagree with other students, but such disagreements need to be based upon facts and documentation. It is the instructor’s goal to promote an atmosphere of mutual respect in our interactions. Please contact the instructor if you have suggestions for improving the interactions in this course.

Please contact me by email: I will primarily use your ISU email to communicate important course information on a timely basis.

General announcements will be posted to the Announcements section of the Learning Management System (Canvas).

Be sure to properly configure your Notification settings or commit yourself to checking Canvas daily for new communication.

Additional guidelines apply to communication within your discussion groups. Please review the Discussion Topic rubric shown above.

Feedback Policy

All graded assessments will be returned with feedback within 7 days of the due date. Exams will be returned within 14 days. Be sure to check your graded submissions for comments regarding your work.


All deadlines are posted on the Course Calendar in Canvas.

Need extra time to meet a deadline? Explain the situation to your instructor IN ADVANCE and accommodation can be made. The explanation doesn't need to be extensive. The important factor is to attempt to notify the instructor ahead of time.

Click Return to top to view Study Tips

Study Tips

  • Know the course format and make certain your computer is set up adequately.
  • Know the Agron 502 Course Calendar in Canvas. The calendar provides all of the start and due dates for required submissions in the course. If changes to the course schedule are made during the semester, the changes will be identified in the course calendar.
  • Do not fall behind schedule! Work ahead when you know that you will be out-of-town or unable to do a module during its designated week. If an unforeseen absence from the course occurs, please notify the instructor at your earliest convenience so we can work together to get you caught up as quickly as possible.
  • Complete one Module each week. Allow at least 8 hours per module (4 hours to do the module + 2 hours to do assignments and participate in discussions + 2 hours for text readings). Depending on your knowledge of the subject, you may spend less time or more time on a particular module.
  • Do each Activity as you come across it in the module. For example, the Web Soil Survey and Official Soil Series websites are important throughout the entire course, especially assignments, so complete them as you encounter them.  Other activities like study questions are designed to enhance your learning, to provide opportunities to apply the information presented, and to let you evaluate your understanding of the material. They often expand on the concepts, so don't skip any.
  • Be sure to submit all Assignments and Discussion Topics on time. Discussion on topics with the class are not effective if the entire class doesn't participate in a timely manner. Assignments and Discussion Topics may be completed as they appear or after you finish the module and readings.  Refer to the assignment and discussion rubrics for further details and expectations.
  • Interact with your classmates and instructor. Visit the discussion board often! Discussions need not be limited to the assigned topics. Use the General Discussion, In the News and Course Question forums in the discussion board to ask questions, answer questions, share an interesting article or observation, or comment on current and relevant events. When you work ahead, be sure to go back and post your comments and responses to classmates during that module's scheduled week.
  • Do the text readings. Readings from the texts supplement the material presented in the module and are required unless stated otherwise. The online course materials are not intended to be complete by themselves. The text provides more detailed information in some areas and is to be considered as important as the online modules.
  • Get to know your classmates. The introduction discussion is a great way to get to know each other further.  Leverage this information to benefit perspective by revisiting throughout the course.
  • Something unclear? Consult with your instructor and/or classmates through the discussion board or email. Don't be afraid to post your question in the discussion board unless it is of a personal nature. All can benefit from the response in the discussion board but not via email.

Click Return to top to view Support


Category Description Action

Course Content Support

Questions related to course content or grading should be directed to the course instructor. Instructor via Canvas Inbox

Student Support

The Center for Excellence in Learning and Teaching is an organization dedicated to supporting, promoting, and enhancing teaching effectiveness and student learning at ISU.

Self-guided orientation which you may find useful.

CELT: Online Learner Support

Self-Guided Orientation

Canvas Technical Support

If you experience any technical issues while using Canvas, contact the Solution Center. The Solution Center's hours are posted on their website.

Solution Center

Technology support

If you have any technical issues while using the University Library's Course Reserves system, please refer to the Library's FAQ page.

For all other technical issues, contact Agron DevLab Support. The Agronomy Development Lab staff is guaranteed to respond to requests within 24 hours during regular business hours. All requests made during the weekend will be addressed first thing Monday morning.

Course Reserves FAQ


Agron DevLab Support

Writing Support

The MS Agronomy program has built a Writing Guide to help answer some of the questions you may have while working on your courses.

One-on-one writing help - Ms. Amy Pollpeter is available for one-on-one consultations and can assist you with any part of the writing process. Schedule an appointment with Amy through the CELT's website or via email.

Writing Guide

CELT's website or via email.

Library and research support

Anita Kay is the liaison librarian to the Department of Agronomy and has built a really useful Agronomy Research Guide (Links to an external site.).

ISU Distance Learning Library Support - This guide provides information about how material from the library can be accessed remotely. Includes FAQs and live chat with a helpful librarian.

email: Anita Kay
Agronomy Research Guide (Links to an external site.)

ISU Library phone

Department Contact

Contact Dr. Mary Wiedenhoeft, Associate Chair for Academics in Agronomy, if issues persist after working with the support systems listed above. Dr. Mary Wiedenhoeft

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Course Summary:

Date Details Due