A fertile soil is humus, bacteria and minerals .It also has enough water and a good texture. The rock beneath the soil is important. Permeable rocks, such as sandstone , make the soil light and dry. Very limey (alkaline ) soils are bad for some plants .Broken- down rock fragments provide the minerals which plants need. Climate and natural vegetation are also important. Plants need organic matter, called humus. This contains nutrients plants need for growth.
