Soils in the Environment: Unit Review

Bits of rock (minerals), humus, water and air.

Topsoil, subsoil, bedrock.

Water in cracks freezes and expands, pushing the cracks wider until pieces break off (weathering).

Living: worm, mushroom. Non-living: sand, air.

They break down dead plants and animals into humus and nutrients.

Any three: dark, crumbly, smells earthy, many living things, water soaks in, air spaces, plants grow well, no garbage or chemicals.

Sand has the biggest bits. Clay holds the most water.

55 mL. 100 − 45 = 55.

It holds enough water but lets extra drain, so roots get water and air.

Dark muck soil made from rotted plants.

Beans add nitrogen. Squash leaves shade the soil, keep it damp and block weeds. (Corn holds up the beans.)

The soil is thin and rocky over bedrock.

Any two: plants grow in it, habitat, holds water, filters water, recycles nutrients, stores carbon.

Bread is made from flour, flour from wheat, and wheat grows in soil.

Bricks, pottery, flower pots or dishes.

Any three: water, wind, ice, gravity, people and animals.

Weathering breaks, erosion takes (moves).

Roots hold the soil, and leaves and stems soften rain and slow water and wind.

Helpful: mulch, compost. Harmful: road salt, spilled oil.

Extra washes into lakes and makes algae grow too much, harming fish.

The kind of water (plain or salty).

Soil pressed down so air spaces are squeezed out. Caused by heavy machines, cars and many feet.

They reduced pollution, spread crushed limestone, and planted grass and millions of trees.

8 minutes longer. 10 − 2 = 8.

To cover and protect the soil (roots hold soil, adds humus).

Any two: cover crops, crop rotation, no-till, windbreaks, grassy strips by streams, adding manure or compost, testing soil, keeping machines off wet fields.

Plan, build, test, improve (after understanding the problem and brainstorming).

Greens, browns, water, air.

Dry leaves: brown. Banana peel: green.

Soil: adds humus and nutrients (or helps hold water, feeds soil life). Environment: less garbage in landfills (or less gas that warms the planet).