Key Players (Microorganisms)
This group of single-celled organisms reproduces rapidly and plays a major role in breaking down simple organic compounds.
What are bacteria?
Compost is created through this biological process that breaks down organic materials under controlled aerobic conditions.
What is decomposition?
Name the two forms of nitrogen that plants can take up directly.
What are ammonium (NH₄⁺) and nitrate (NO₃⁻)?
Adding this soil amendment boosts microbial activity by supplying organic matter and nutrients.
What is compost?
These thread-like organisms decompose complex materials like lignin and help form soil aggregates.
What are fungi?
Name one of the four essential components of quality compost.
What is organic material, moisture, aeration, or temperature?
This nitrogen process converts NH₄⁺ to NO₃⁻ and is performed by aerobic bacteria.
What is nitrification?
This practice minimizes soil disturbance and helps protect fungal networks and aggregates.
What is reduced tillage?
These tiny soil predators feed on bacteria and release plant-available nutrients in the process.
What are protozoa?
At what temperature range (°C) does the thermophilic stage occur to kill pathogens and weed seeds?
What is 55–65°C?
In the nitrogen cycle, which process returns nitrogen gas (N₂) to the atmosphere?
What is denitrification?
These plants grown between cash crops add diversity, feed soil microbes, and protect against erosion.
What are cover crops?
This group includes both plant-parasitic and beneficial species that regulate microbial populations in the soil food web.
What are nematodes?
If a compost pile becomes anaerobic and smells bad, which factor is most likely out of balance?
What is aeration or moisture?
When microbes use available nitrogen to build their own biomass, making it temporarily unavailable to plants, this process occurs.
What is immobilization?
Name one negative impact of excessive nitrogen or phosphorus in the environment.
What is eutrophication, algal blooms, or groundwater contamination?
This group of soil animals mixes organic matter with mineral soil, improving structure and drainage; they’re often classified as epigeic, endogeic, or anecic.
What are earthworms?
During composting, microbes go through three main stages of activity: name them in order.
What are mesophilic → thermophilic → curing (or cooling)?
Explain the difference between mineralization and immobilization.
Mineralization converts organic N to inorganic (plant-available); immobilization converts inorganic N to organic (microbial biomass).
List three management practices that promote healthy and diverse soil microbial communities.
What are adding organic matter or compost, reducing tillage, and planting cover crops or diverse rotations?