Unit 4 Soil Science

Importance of Soil What is soil? Holds water and nutrients for plants Natural filter Stores and recycles nutrients Fertile soil = higher yields Erosion

Soil Formation 5 Factors – Parent material – Climate – Biological factors – Topography – Time

Soil Profile O = organic matter or humus A = organic and inorganic E = little organic matter due to eluviation B = leached or washed materials C = parent material

Organic and Inorganic Soils Organic Soils Composed mostly of decayed plant and animal matter Inorganic Soils Composed mostly of minerals

Soil Types and Texture

Soil pH Affects how nutrients and chemical are absorbed by plants Some plants like more acidic soil Others prefer a more basic soil How is soil pH changed?

Water and Nutrients in the Soil Sand Silt Clay Large pore spaces allow water and nutrients to move quickly Small pore spaces tightly hold onto water and nutrients

Soil Erosion Topsoil Nutrients are lost Water erosion Wind erosion Management – Crop rotation – Cover crops – Rotational grazing – Tillage practices

Soil Ecosystems Plants Burrowing Mammals Arthropods Earthworms Microorganisms