Soil health and microbes

What do we need to know about soil to determine its productivity? How can we be better stewards of soil health?
Soil is an ecosystem, full of both living organisms and nonliving factors. These factors interact within the ecosystem to support one another. Find out what methods are used by soil scientists and microbiologists to measure the diversity of life in soil. Students will be given a scenario and led through this series of activities to determine the healthiest soils. See teacher background →


# Soil sampling and texture testing

Students will collect soil samples to determine the texture of their local soil(s) and look for diversity within the soil. Background information about soil may be found in the GrowNextGen soil e-learning course.


# Soil biology

Students examine soil samples and begin to identify the organisms present using a microscope.


# Soil microbes

Students will follow a procedure to dilute soil samples and identify bacteria using the Gram staining method.


Teacher background

Soil is the basis of all commodity farming; if the soil is not healthy, the crops will not grow and produce. Soil testing gives growers important information about the nutrients and pH of the soil. However, the nutrients in soil are only part of the story. The living things in soil, including plant roots, give a more complete picture of how productive soil may be.

If soil is growing the same crop year after year with no change, nutrients are removed and not replaced. Pests for that crop continue to have ample food supplies and may reproduce at a rapid rate. Weeds may also become a bigger problem, if they are able to out compete the crop. Microbes may become less diverse, which changes the nutrients that are available to plants. The best management practices for soil health in a farm field include: crop rotation between grass crops (corn and wheat) and legumes (soybean and alfalfa); cover crops including a mix of different types; and no-till or strip till practices so soil remains covered most of the year. Soil microbes help prevent disease and reduce plant stress, as well as cycle nutrients.

More and more research is being done to determine how best to protect or increase soil health, including bioprospecting for groups of microbes that are especially efficient at forming new soil and recycling nutrients, as well as research into which crop traits support microbiomes that help enhance soil health.

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Next gen science standards

Science and engineering practices

  • Asking questions (for science) and defining problems (for engineering)
  • Planning and carrying out investigations
  • Analyzing and interpreting data
  • Engaging in argument from evidence
  • Obtaining, evaluating, and communicating information

Crosscutting concepts

  • Cause and effect
  • Scale, proportion, and quantity
  • Systems and system models

Disciplinary core ideas/content

  • ESS2A Earth materials and systems
  • ESS3A Natural resources
  • ESS3C Human impacts on Earth systems
  • LS1A Structure and Function
  • LS1C Organization for matter and energy flow in organisms
  • LS2A Interdependent relationships in ecosystems
  • LS2B Cycles of matter and energy transfer in ecosystems
  • LS2C Ecosystem dynamics, functioning and resilience

Curriculum authors