Black Soil

Soil Health

 

Soil is teeming with life!

Soil is arguably the planet's most important natural resource. It is home to billions of microorganisms, invertebrates, plants and animals; all of which play an important roll in ecosystems, and cycles of nutrients, carbon, and water. Soil is also the life source for terrestrial vegetation. Without it, there would be no food, no clean air to breath, no filtration of water. Protecting our soils and restoring damaged soil is today's priority. 

The soil beneath your feet today began to form thousands, if not millions of years ago. Since soil takes so long to form, farmers and environmentalists often list soil erosion as one of the highest areas of concern. Once soil is gone, it's gone. 

Soil is not just dirt - it is a highly complex, living entity. In essence, soil is a mixture of four main ingredients; minerals, organic matter, water, and air.  When soil loses one of these components, it loses its ability to support life. So, lets break down the soil recipe even further. 

Minerals

Soil is formed in part by the erosion of bedrock, the solid earth layers buried under the soft soil layers. Over the course of many years, exposed bedrock gets worn down by elements like rain, wind, heat and chemical weathering. This erosion and weathering creates soil particles of various sizes; sand, clay, or silt. Each grain of soil contains specific minerals based on the type of bedrock the particle came from. Chemical and biological processes allow plant life to use the minerals available in the soil. 

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Organic Layer

Bedrock

Parent Material

Sub Soil

Top Soil

Organic Material

Organic Material is any decomposing plant or animal residue. Organic matter plays a variety of rolls in soil. It helps with maintaining soil structure, moisture permeability, and nutrient availability.  Farmers are encouraged to leave plant residue on their farms after harvest, and use cover crops to help increase the amount of organic material in their soil and aid in nutrient recycling. When organic matter begins to decompose, it provides living plants with nitrogen, phosphorus, potassium and host of other required nutrients. This decreases the amount of nutrients a farmer needs to apply to their fields - which, in turn, reduces costs for farmers, decreases nutrient leeching, and increases crop yields. Once organic material is decomposed, it becomes hummus. Hummus provides long lasting benefits in terms of maintaining soil structure, moisture permeability, and a home for beneficial soil microbes. 

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Photo courtesy of Hendrikus Organics 

Air and Water

The rolls air and water play in terms of sustaining life on earth are obvious. Depending on soil quality, the presence of air and water can become imbalanced - creating soils that are inhospitable for plant life. If a soil is too compact, or if it doesn't hold its structure, soil will not be able to properly store air and water. By increasing organic matter in a soil, more pockets for air and water to pass become available. These pockets of air and water then become available for plants and beneficial microorganisms.

Soil Texture

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Photos courtesy of Soils Science Society of America

A soil texture triangle is used to classify soil types and mixtures. Soils types are classified based on the percentage of sand, silt or clay in a sample. Image (a) Texture Triangle (b) an example of how a soil containing 33% clay, 33% silt and 34% sand is classified as a Clay Loam. 

Soil texture plays an important roll in the behavior of soil. Some soils' behavior are perfect for croplands, while others are great for wetlands or deserts. Soil texture is largely dependent on geographical location and the history of the landscape. Learning what type of soil is available on a piece of land can can help landowners conserve the soil, and help the soil meet demands of the property. Soil tests are available to get the most accurate information on soil type and quality. 

 

There are three main sizes of grain in a soil: sand, silt, and clay. Soil can contain any combination of one or more of these grain sizes to create a unique mixture. Soils can be classified based on the amount of sand, silt and clay they contain. A soil that contains a mixture of all three soil types is called a loam. Each soil type has its pros and cons, and each soil type is perfect for sustaining a unique niche of plant and microbial life.

Characteristics of Soil Types

Sand

- water drains quickly

- difficult to compact, doesn't hold         shape

- roots are able to establish quickly

- easy to work with and manipulate

- does not hold nutrients very well

Silt

- holds nutrients well

- slow to drain water

- when dried, it forms a hardened          crust 

Clay

- holds water, poor drainage

- easily compacted

- clumps together, holds shape

- roots have difficulty establishing          themselves. 

How can you protect soils?

Keeping soils covered and protected from the elements year round is one of the most effective ways to retain soil quality. If you are a farmer or landowner, consider planting cover crops, or native plant species. If you are a farmer, consider implementing a no-tillage, or reduced-tillage system. Minimally disturbed soils allows organic matter to decompose, prevents soil compaction, and decreases nutrient and sediment runoff from farmland into watersheds. 

 

Learn more about Conservation Practices 

Contact our

Soil Conservation Technicians

 

Jenna Rasmusson

jenna.rasmusson@macd.org

Bonne Matheson

bonne.matheson@macd.org