Humus
What is Humus?
Humus is made of dead plants and animals that have decomposed.
Which soil particle is the smallest?
Clay
What does fertile mean?
Good for growing plants.
What tool helps scientists look closely at soil?
A hand lens.
What does retain mean?
to hold or keep.
How is humus different from sand and clay?
Humus comes from once-living things. Sand and clay are minerals.
Which soil particle is the largest?
Sand
What happens when soil becomes more fertile?
Plants grow better.
What does the word retain mean?
To hold or keep.
What does decompose mean?
To break down over time.
Name one way humus helps plants.
It adds nutrients to soil OR helps soil hold water.
Put these soil particles in order from smallest to largest: loam, sand, clay.
Clay → Loam → Sand
Why do plants grow better in soil with humus?
Humus provides nutrients and helps hold water.
What could a scientist add to soil to test how much water it can hold?
Water.
What does fertile mean?
Rich in nutrients and good for growing plants.
A soil sample contains lots of humus. What will most likely happen to the plants growing in it?
The plants will grow better.
Which particle is larger than clay but smaller than sand?
Loam
Which soil is better for growing plants: soil with humus or soil without humus?
Soil with humus.
A scientist slowly adds water to soil and records results. What is being tested?
Water retention.
What is a mineral?
A natural, nonliving substance found in rocks.
Why is humus important for healthy soil?
It provides nutrients and helps the soil retain water.
A student lists soil particles as sand, clay, loam. How should they correct their list?
Clay → Loam → Sand
Name two things soil provides for plants.
Water, nutrients, and/or support for roots.
Why would a scientist use a hand lens when studying soil?
To observe small particles and details more closely.
What are the four main things found in soil?
Minerals, air, water, and organic matter.