Nutrient Cycling in Thin Soil · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Rainforest Soil: Rich Jungle, Poor Ground

Science · Rainforests · ages 9-11
Name ______________________   Date ____________

  1. Most of a rainforest's nutrients are stored in the soil.

    Circle one:   True   False

  2. What is true about rainforest soil?

    • It is thick and rich in nutrients
    • It is thin and poor in nutrients
    • It has no soil at all

  3. In a rainforest, what happens to a dead leaf almost right away?

    • It gets buried and stays whole for years
    • Decomposers break it down quickly
    • It blows away and is lost

  4. Look at the cycle. Which step comes right after 'Decomposed'?

    Leaf fallsDecomposedReleasedAbsorbed
    • Leaf falls
    • Released
    • Absorbed

  5. A dead leaf falls to the rainforest floor. What happens next in the cycle?

    • Decomposers break it down and roots soak up the nutrients right away
    • The leaf sits unchanged for years, slowly turning to soil
    • The nutrients drain deep underground where roots cannot reach them

  6. Why can a rainforest keep growing so much even though the soil is poor?

    • Because nutrients cycle quickly between dead material and living roots
    • Because rainforest soil is actually very deep and rich underground
    • Because plants do not need nutrients to grow

  7. Mia says, 'Rainforest soil must be the richest soil in the world because so many plants grow there.' What is wrong with her reasoning?

    • Rainforests do not have any soil
    • Nothing, she is right
    • She is confusing lush growth above ground with rich soil below ground

  8. A farmer clears a rainforest and plants crops. They grow well for one year but get weaker every year after. What is the best explanation?

    • The soil was rich all along and just needed clearing
    • Without trees and fungi to catch nutrients, they wash away instead of recycling
    • Crops always get weaker no matter where they are planted
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Rainforest Soil: Rich Jungle, Poor Ground W1-mt_JcfP1hWKa_-s1

  1. False · Most nutrients are locked inside living plants, animals, and fungi, not the ground.
  2. It is thin and poor in nutrients · Even though rainforests look lush, the soil itself holds very few nutrients.
  3. Decomposers break it down quickly · Warm, wet conditions make decomposers work fast, breaking the leaf down quickly.
  4. Released · After decomposers finish, the nutrients are released for a short moment before roots take them up.
  5. Decomposers break it down and roots soak up the nutrients right away · Decomposers work fast, and roots and fungi grab the nutrients as soon as they are released.
  6. Because nutrients cycle quickly between dead material and living roots · The fast recycling loop keeps nutrients moving from dead material straight back into living plants.
  7. She is confusing lush growth above ground with rich soil below ground · The lush growth comes from fast nutrient cycling among living things, not from rich soil.
  8. Without trees and fungi to catch nutrients, they wash away instead of recycling · Once the living plants are gone, nothing quickly reuses the nutrients, so rain carries them away.
Worksheet · LightMySky