| A | B |
|---|
| HUMUS | Decayed plant &animal remains |
| SUBSOIL | Soil layer made of clay & particles |
| DECOMPOSERS | Organisms that break down organic waste. |
| BEDROCK | Layer of rock beneath the soil |
| TOPSOIL | Dark brown soil mix of humus,clay&minerals. |
| LOAM | Soil from clay sand and silt. |
| SOIL HORIZON | soil layer that differs from the layers around it. |
| SOIL | the surface material in which plants can grow; one of Earth's most valuable resources. |
| LITTER | Leaves or other plant material on top of the soil. |
| A HORIZON | The top layer of soil, where humus and eroded rock are mixed, forming "Top soil" |
| B HORIZON | Develops as rainwater washes clay and minerals from A horizon to B horizon. |
| C HORIZON | Bedrock (parent rock) weathers and breaks into soil particles. |
| SOIL TEXTURE | Ranges for Gravel to sand to sitl and finally clay. |
| SOIL COMPOSITION | H2O 25%, Air 25%, Silt 18%, Sand 18%, Clay 9%, and Organic matter 5%. |
| DESERTIFICATION | the advance of desert-like conditions onto areas that were once fertile. |
| SOD | Thick mass of tough roots at the surface of soil that helps to keep soil in place and hold moisture |
| DUST BOWL | Southern Plains States that lost their topsoil from 1930 -1938 due to drought |
| SOIL CONSERVATION | The management of soil to prevent its loss or destruction |
| CONTOUR PLOWING | Slows runoff and erosion by plowing along the curves of hills |
| CONSERVATION PLOWING | disturbs the soil and plant cover as little as possible |
| CROP ROTATION | Improves the fertility of soil by groving different crops and sometimes leaving the land fallow (unplanted) |
| LAND RECLAMATION | restoring lands for agriculture, lands from mining, or habitats for wildlife |
