| A | B |
|---|
| soil | material on the surface of the land in which plants can grow |
| weathering | breaking rocks into fragments by the action of rain or changing temperature |
| erosion | the process of transporting away fragments of weathered rock |
| deposition | the leaving behind of rock fragments by wind and water; helps make soil and rocks |
| humus | partially decayed organic material found in soil |
| silt | a sedimentary material made of very fine particles in size between sand and clay |
| soil particles | the small lumps that make up soil |
| lime | the compound calcium hydroxide, Ca(OH)2, an alkaline substance that is commonly used by farmers to make the pH of the soil higher |
| calcium carbonate | compound made of calcium, carbon and oxygen; a.k.a. chalk |
| manure | animal droppings used to fertilize land on which plants are grown |
| *pioneer plants | the first plants to grow in areas of land damaged by fire or volcanic activity |
| *leaching | the process by which minerals are removed from the top layers of soil by a high flow of water |
| *aeration | the process of exposing to air |
| *permeabililty | the rate of flow of a liquid, e.g. water, through a porous substance |
| *waterlogging | to saturate with water and make soggy or unusable |
| *buffer | a substance that resists changes in pH when an acid or alkali is added to it |
