Soils NOT Just Dirt By: Rebekah Triolo

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Defining Soil “a natural body consisting of layers (horizons) of mineral and/or organic constituents of variable thickness, which differ from parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics” – Birkeland, 1999; Joffe 1949

Why not Dirt? Soil is a living environment Has nutrients Earthworms and insects Diverse Bacteria Layers

Soil Importance Medium for plant growth Water purifier Facilitates waste decomposition

Plant Growth

Water Purification Natural filtration Chemical absorption and adsorption Living organisms Human interaction and manipulation of soils can interrupt the process of natural water purification.

How Soils Form There are multiple processes happening at the same time to allow soil to form. Pedogenic regimes Soil succession Clay factories Complexity Energy

Average Soil Sample Contains

Soil Horizons Basics O – Organic: leaf litter and humus A – Topsoil: seeds germinate and plant roots grow, made of humus and mineral B – Subsoil: clay and mineral deposits C – Regolith: slightly broken up bed rock, plant roots cannot break through

Categorizing Soil Color Texture Structure Porosity Density Temperature Moisture

Color Munsell System quantitatively measures differences in color characteristics It measures – Hue: yellow, red, blue, green – Value: high value= light colored, low value = dark colored – Chroma: purity of color, high chroma = pure color, low chroma = less pure

Texture Evaluating particle size

Too Much Sand Soils with lots of sand have to much space between particles. This makes it hard for them to hold water or any nutrients. Plant’s roots cannot hold well.

Too much Silt Soils with too much silt is very light. Commonly found in flood plains and is the components of soil that makes mud. Lots of silt makes excellent farmland, but increase erosion. This is that part of soil that blows away in sand storms

Too Much Clay Soil with too much clay is heavy and dense. There is almost no space between the particles. Bacteria and microorganisms in the soil cannot get oxygen. Plant roots cannot push through.

That’s Just Right LOAM Perfect soil for plants has about equal parts sand and silt with less clay. There is large enough space between particles for air, water, and nutrients. There should be enough clay to help stick together.

Structure Effected By: Chemicals Biological activity Soil use Water content Overburden

Structure vs. Texture

Porosity Fraction of void space in the material Can contain water or air

Density Less dense More Dense

Temperature Becomes important with seed germination and crop growth – Minimum temperature – Optimum range of temperature – Optimum temperature – Maximum temperature Measured with thermometer placed 3 to 4 inches into the ground

Moisture

Chemicals in Soils pH measures the acidity or alkalinity of soil – Neural = 7.0 – Acidic < 7.0 – Alkaline > 7.0 Effects solubility of plant nutrients Soils normally range from pH Most cultivated plants like slightly acidic soil