Skip to main content
Engineering LibreTexts

6: Soils as a Key Resource for Food Systems

  • Page ID
    47131
  • Introduction

    Interactions Between Soil Nutrients, Nutrient Cycling, and Food Production Systems

    Along with water, sunlight, and the earth's atmosphere, the soil is one of the key resources underlying food production by humans. In terms of the coupled human-natural systems we use as a way to understand food systems, we can say that human systems organize landscapes and manage soils, along with agricultural biodiversity and other parts of natural systems, to produce food. Soils exert an influence on this coupled system because they vary in terms of properties such as depth and nutrient content, which alters their response to human management. Soils also have great importance as the site of many nutrient and carbon transformations within the biosphere. They are a storehouse of beneficial soil organic matter that benefits the earth system in many ways. Also, by understanding soils and the earth surface and ecological processes that occur there, human management is able to maintain and improve them, as well as overcome initial limitations or past degradation.

    The purpose of this module is to give you as a learner a basic grounding in the nature of soils and soil nutrients. Module 5.1 provides the foundation for understanding soils, soil nutrients and their connection to food. We will also focus on ways that soils are vulnerable to degradation that impairs their role in food production. In module 5.2 we will deepen understanding of how soil management can protect soils in their role of supplying nutrients to crops and protecting other valuable resources such as surface water. To accomplish this we will focus on nitrogen (N) and phosphorus (P) as key nutrients for food production in module 5.2.

    Goals

    • Identify soil nutrients and soil function as key resources in need of protection for food production and food systems.
    • Describe spatial and geographic variation in soil resources and soil fertility.
    • Distinguish between preexisting aspects of biogeochemical cycling and human-induced processes that affect biogeochemical cycling.
    • Attribute different soil fertility outcomes in food systems to the coupled natural and human factors and feedbacks that produce them.

    Learning Objectives

    After completing this module, students will be able to:

    • Describe the basic properties of soil that distinguish it from mere "dirt".
    • Explain how soil serves as a medium for plant growth.
    • Explain how the five soil-forming factors interact to produce soils.
    • Explain the term "biogeochemical cycling".
    • Explain common limiting factors to plant growth that limits food production around the world.
    • Explain how nutrient and carbon depletion from soils and soil erosion create conditions of low food productivity.
    • Assess how farming practices affect soil fertility.
    • Analyze modern fertilizer use as the emergence of a strong human system impact on nutrients in soils that replenishes soil nutrients but can create nutrient pollution.
    • Analyze how natural/human system feedbacks operate to limit the actions of poorer food producers around the world.
    • Incorporate sustainability challenges related to soil nutrient management into an analysis of food systems.

    Assignments

    PrintPrint

    Module 5 Assignments Roadmap

    Detailed instructions for completing the Summative Assessment will be provided in each module.

    Module 5 Roadmap
    Action Assignment Location
    To Read
    1. Materials on the course website.
    2. Chapter 2, pp. 9-17 in Building Soils for Better Crops (USDA Sustainable Agriculture Research and Education), available as a free e-book. You can download the entire book since future modules will also use this source.
    1. You are on the course website now.
    2. Building Soils for Better Crops
    To Do
    1. Formative Assessment: Mapping Trends in Soil Properties
    2. Summative Assessment: N and P Balances
    3. Participate in the Discussion
    4. Take Module Quiz
    1. In course content: Formative Assessment; then take quiz in Canvas
    2. In course content: Summative Assessment; then take quiz in Canvas
    3. In Canvas
    4. In Canvas

    Questions?

    If you prefer to use email:

    If you have any questions, please send them through Canvas e-mail. We will check daily to respond. If your question is one that is relevant to the entire class, we may respond to the entire class rather than individually.

    If you prefer to use the discussion forums:

    If you have any questions, please post them to the discussion forum in Canvas. We will check that discussion forum daily to respond. While you are there, feel free to post your own responses if you, too, are able to help out a classmate.

    • Was this article helpful?