Soil Science Objectives: Identify the major soil areas of Alabama. Identify the layers in a soil profile. Determine the texture of different soil samples. Determine the land capability class for a given plot of land. Discuss how to adjust pH.

Soil Profile OM- Organic Matter A- Topsoil B- Subsoil C- Parent Material

OM Horizon OM- Organic Matter- 0-2 inches deep Made of decomposed plant and animal material Rich in nutrients Improves soil structure Increases soil water holding capacity NOT ALWAYS PRESENT

A Horizon A Horizon- Topsoil- Up to 10 inches deep Most important horizon for crop production Must prevent the erosion of this horizon It takes 300-500 years to form 1 inch of topsoil

Topsoil

B Horizon B Horizon- Subsoil- from topsoil up to 48 inches deep or more There is usually a definite line between the topsoil and subsoil Subsoil needs to be at least 36 inches deep to support the roots of crops.

Subsoil

C Horizon C Horizon- Parent Material- below the subsoil The rock the soil came from The parent material of a soil determines many of the soils characteristics

Parent Material and Bedrock All horizons are clear C horizon is the peach colored Bedrock at the bottom is actually called the R horizon

Soil Texture Sand Silt Clay

Sand Course texture, large particles Low water holding capacity Drains too quickly

Sand

Silt Medium texture, medium particles Good water holding capacity Good drainage

Silt

Clay Fine texture, small particles High water holding capacity Drains too slow Can be red or black

Clay

Soil State Soil of Alabama Bama sandy loam Mix is best

Primary Succession

Soil Areas of Alabama Coastal Plains Black land Prairie Piedmont Plateau Limestone Valleys Appalachian Plateau

pH pH-stands for percent Hydrogen Defined as a measure of acidity Scale is from 0-14, 7 is neutral

pH scale 0-6.9 is Acidic 7.1-14 is Alkaline 7 is neutral

pH pH determines nutrient availability for plants If pH is too high or low the nutrients in the soil are not available to the plants

Soil Test Test in a zigzag pattern Test determines pH and fertility 15-20 samples in 20 acres

Correcting pH Lime raises pH if acidic Apply Lime if 5.7 or below Sulfur lowers pH in alkaline soils