What Makes Topsoil So Dark?

Soil Components

• Topsoil is composed of minerals, water, air and organic matter. As plants and animals die on the earth's surface, their remains break down into humus, which is brown or black and binds the soil particles together.

Soil Formation

• Many factors play roles in soil formation, which can take hundreds of years. In addition to the formation of the dark humus, a sublayer of minerals, called parent material, waits its turn while rain does its job of dissolving and dispersing nutrients and air promotes the bacterial action necessary for the breakdown of the organic materials.

Significance

• Like other natural resources that renew themselves very slowly, topsoil must be effectively managed, protected and maintained for it to continue to support the plant life that is crucial to human survival.