国家地理儿童百科 · 国家地理儿童百科流利级(高级)
Soil
What is soil? The land is covered with a layer of dirt. This dirt is called soil. Soil can be sandy. Soil can be rocky. Soil can be like clay. Do you know how soil is made?
How is soil made? It takes a very long time for soil to be made. Soil is made from pieces of rock. The pieces of rock are mixed with animalsand plants that have died and rotted.
Some rocks lie on top of the ground. Rain falls on them. Snow and ice cover them. The wind blows them. After a long time, the water, the cold, and the wind help break the rocks into pieces.
These pieces of rock then breakinto smaller and smaller pieces. After thousands of years, the tiny piecesof rock become soil.
Plants and animals also help make soil. Fallen leaves and dead plantslie on the ground. When animals die, their bodiesalso lie on the ground. Hot sun shines on them. Cold rain falls on them. Snow and ice cover them.
