Get Started. It's Free
or sign up with your email address
Soil Unit by Mind Map: Soil Unit

1. Horizons

1.1. O Horizon

1.1.1. Organic Layer, Darkest

1.2. A Horizon

1.2.1. Plow layer, Surface Layer, Most fertile, Solum (Most Root Growth)

1.3. E Horizon

1.3.1. Subsurface Layer, Maximum Leaching (Drained away), Not always present

1.4. B Horizon

1.4.1. Subsoil, Illuviation (zone of accumulation), Solum

1.5. C Horizon

1.5.1. Substratum, parent material

1.6. R Horizon

1.6.1. Lowermost layer, Bedrock

2. Texture

2.1. 3 Particales

2.1.1. Sand

2.1.1.1. Largest particle

2.1.2. Silt

2.1.2.1. Medium sized Particle

2.1.3. Clay

2.1.3.1. Smallest Particle

2.2. Soil material makeup

2.2.1. 50% Air/Water

2.2.2. 45% Mineral

2.2.3. 5% Organic

2.3. Erosion

2.3.1. 2.5 Acres lost a year in IL

2.3.2. Erosion control

2.3.2.1. Contour Producing

2.3.2.2. Strip Cropping

2.3.2.3. Terracing

2.3.2.4. No till vs tilling

2.4. Ribbon

2.4.1. Fine Texture- Forms easily, long and flexible

2.4.2. Moderately fine texture- ribbon breaks at about 3/4 to 1 inch

2.4.3. Medium texture- No ribbon, breaks at less than 3/4 of an inch long

2.4.4. Moderately coarse texture- No ribbon, gritty and lacks smoothness

2.4.5. Coarse texture- No ribbon, entirely gritty, leaves no stain

3. Nutrients

3.1. 3 Primary Macronutrients

3.1.1. Nitrogen

3.1.1.1. Deficiency- Yellowing on leaf starting on end and spreading toward stem. Growth is decreased

3.1.1.2. Used- plant growth, development, and photosynthesis

3.1.2. Phospherous

3.1.2.1. Deficiency- dark green/ purple color of leaves

3.1.2.2. Used- root development, production of fruit and flowers

3.1.3. Potassium

3.1.3.1. Deficiency- discoloration and scorching along out rim of leaves. Begins at tip of leaf

3.1.3.2. Used- disease resistance, reproduction

3.2. Secondary Macronutrients

3.2.1. Calcium

3.2.1.1. Deficiency- young leaves die back, delayed emergence of primary leaves

3.2.2. Magnesium

3.2.2.1. Deficiency- Loss of green leaf color starting with bottom leaves, reddish purple from edge inwards

3.2.3. Sulfur

3.2.3.1. Deficiency- young leaves light green with veins being lighter

3.3. Micronutrients

3.3.1. Boron, Copper, Chlorine, Iron, Manganese, Molybdenum, Zinc

4. Soil Orders

4.1. Alfisols- High fertility, northeast Europe and coast of australia

4.2. Andisols- Volcanic activity, high water holding capacity, Caribbean and central mexico

4.3. Ardisols- Dry, low organic material, SW US, N Africa, Middle east, W australia

4.4. Entisols- Mostly A horizon, central africa, central australia

4.5. Gelisols- permafrost, canada, russia, alaska

4.6. Histosols- Mined for horticulture, central canada, russia

4.7. Inceptisols- largest in world, minimal horizon developement, southern alaska, europe, central russia

4.8. Mollisols- very fertile, high ag use, central canada and russia

4.9. Oxisols- tropical regions, low fertility, southern alaska, europe, central russia

4.10. Spodosols- acidic, coarse texture, coniferous forests, NE canada, norway, sweden

4.11. Ultisols- leached clay into subsurface, acidic, low fertility, china, SE US, N South America, Cantral Africa

4.12. Vertisols- High clay particles, shrinks and swells, India, E central africa, NE australia