Soils, Fertilizers, and Soil Amendments



References

Colorado State University Extension

Fertilizers

CMG GardenNotes

CE Fact Sheets

Soil Amendments

CMG GardenNotes

CE Fact Sheets

Soil Management

CMG GardenNotes

CE Fact Sheets

Books

  • Urban Soil Primer by the Natural Resources Conservation Service, USDA. 2005.  Available on-line at http://soils.usda.gov/use/urban/primer.htm
  • Urban Soils: Applications and Practices by Phillip J Craul.  John Wiley & Sons Publishing. 1999.  ISBN: 0471189030

Soils, Fertilizes, and Soil Amendments curriculum developed by David Whiting, Adrian Card, and Carl Wilson; CSU Extension.

David E Whiting
Extension Consumer Horticulture Specialist
Department of Horticulture and LA
Colorado State University
Phone: 970-491-7030
Fax: 970-491-7745
E-mail: david.whiting@colostate.edu


o Colorado Master Gardener training is made possible, in part, by a grant from the Colorado Garden Show, Inc.
o Colorado State University, U.S. Department of Agriculture and Colorado counties cooperating.
o Extension programs are available to all without discrimination.
o No endorsement of products mentioned is intended nor is criticism implied of products not mentioned.
o Copyright © 2003-2006. Colorado Master Gardener Program, Colorado State University Extension. All Rights Reserved. Training packet may not be reproduced without written permission of David Whiting. Revised December 2006

Review Questions

Note: Class time does not permit the instructor to cover all the topics.  Please take time to read and review study materials.

The Living Soil

  1. How does a gardener enhance the “living soil”?
  2. What are mycorrhizae?  How are they important to plant growth?  What soil conditions support mycorrhizal activity?  How can a gardener promote mycorrhizal activity?
  3. Describe the role of earthworms in enhancing the garden soil?  How can the gardener encourage earthworm activity?

Managing Soil Tilth

  1. A textbook soil is ___% mineral, ___% air, ___% water, and ___% organic matter.  What is the typical organic matter content of Colorado native soils?  What is the ideal organic matter content for a garden soil?
  2. Compared to an agricultural or field crop setting, list the unique characteristics of an urban soil?
  3. Define the terms soil texture, soil structure, and soil profile.  Explain how they are interrelated. 
  4. Define the following
    1. Coarse-textured, sandy soil
    2. Loamy soil
    3. Fine-textured, clayey soil
  5. Compare the characters of fine-textured and coarse-textured soils as they relate to plant growth.
  6. Explain what is significant about large pore spaces and small pore spaces? 
  7. Describe how water moves through small pore spaces and large pore spaces.
  8. In relation to root growth and water movement, what happens when the soil has an abrupt change in soil texture (actually pores space)?
  9. Explain management of fine-textured, clayey soils and coarse-textured, sandy soils.
  10. In terms of pore space, water movement, and air infiltration, describe soil compaction.
  11. List techniques to prevent soil compaction.  List techniques to reduce soil compaction.
  12. In relation to root growth and water movement, what happens when “black dirt” or top soil is added over compacted soil?
  13. In terms of pore space, explain what actually happens when sand is added to clayey soils.
  14. What is gypsum?  Under what situations is it used to improve soil?  Will it break up a clayey soil?
  15. Describe the special landscape design and maintenance issues associated with an expanding clay soil.

Soil Drainage Problems

  1. Describe drainage problems as related to pore space, surface runoff, and leaching.
  2. Why is it so important to identify the causes of a drainage problem before attempting corrections? 
  3. List common causes of surface drainage problems with possible corrective action.  List common causes of sub-surface drainage problems with possible corrective actions.

Soil Tests

  1. List situations when a soil test will be helpful.  List examples of plant growth problems for which a soil test will NOT be helpful.
  2. Describe the steps to a soil test.
  3. Where does one find a list of soil testing labs?

pH and Iron Chlorosis

  1. What does soil pH measure?  What is an acceptable range for most plants?  What are the implications for gardening in Colorado?
  2. Describe the management strategy for alkaline soils?
  3. Describe the symptoms of iron chlorosis?  What other situations can be confused with iron chlorosis?  How can you tell them apart?
  4. List factors that contribute to iron chlorosis.  Explain how to manage spring irrigation and soil compaction to minimize iron chlorosis.
  5. Give examples of common plants prone to iron chlorosis.
  6. What simple method identifies soils prone to iron chlorosis problems?
  7. Describe the limitations and application criteria for the following iron treatments.
    • Soil applications of sulfur
    • Soil applications of iron sulfate plus sulfur
    • Soil applications of iron chelates
    • Foliar sprays
    • Trunk injections

Saline Soils

  1. Describe plant problems associated with excess soil salt levels.
  2. List sources/causes of high soil salts.
  3. Describe the leaching process for salty soils.  What about situations when excess salts can’t be leached out?
  4. Describe other management strategies for salty soils.

Plant Nutrition

  1. Define plant nutrition and fertilizer.
  2. Will addition of nitrogen fertilizer help plant growth when soil compaction is the limiting factor?  Explain.
  3. What does Cation Exchange Capacity disclose about a soil?
  4. What are the typical symptoms of nitrogen deficiency?  What are the problems associated with excessive nitrogen fertilization?
  5. In Colorado soils, under what situations will phosphorus levels likely be adequate and deficient?  How does one determine the need for phosphate fertilizer?
  6. In Colorado soils, under what situations will potassium levels likely be adequate and deficient?  How does one determine the need for potash fertilizers?

Fertilizers

  1. Define the following terms: fertilizer, organic fertilizer, certified organic fertilizer, and soil amendment.
  2. What does grade or analysis indicate about a fertilizer?  What is a fertilizer ratio? 
  3. What is a fertilizer formulation?  What is a complete fertilizer?  When applying a complete fertilizer, what is the application rate always based upon?
  4. What is the routine application rate for nitrogen fertilizer?  How does it change based on soil organic matter?  What is the routine application rate when using a) ammonium sulfate, 21-0-0, b) ammonium nitrate, 34-0-0, and c) urea, 45-0-0 fertilizers?
  5. In relation to phosphorus water pollution, what happens to phosphate fertilizers applied to a) a lawn or garden area, and b) over-spread onto the street, sidewalk, or driveway?  According to the research base, what is the major source of phosphate water pollution from the landscape setting?

Soil Amendments

  1. Define the following terms:
    • Soil amendment
    • Mulch
    • Compost
  2. Explain how organic soil amendments improve soil structure and rooting depth on a clayey and/or compacted soil.
  3. Describe the visual evaluation of soil amendment materials. 
  4. What is the routine application rate for soil amendments?  What is the precaution about adding additional amounts?
  5. Describe the application and limitations on using biosolids and worm castings.
  6. Explain the use and limitations on using manure and compost in the home garden as it relates to:
    • E. coli
    • Nitrogen release rates
    • Salt
    • Weed seeds
  7. What are cover crops and green manure crops?  List benefits of cover cropping and green manuring. 
  8. Describe the basic recipe for a fall planted cover crop to be plowed into the garden in the spring.
  9. List common organic and inorganic soil amendments.  Describe the characteristics of each.  Which are best for a sandy soil?  Which are best for a clayey soil?

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Updated Monday September 24 2007, David Whiting