Soil is described as a natural body which consist series of layers (the soil horizons) of mineral particles of changeable thicknesses, which are different from the parent materials in their morphological, physical, chemical, and mineralogical characteristics. It is located at the top layer of the Earth’s crust.
Made Of
Soil is made up of organic substance, minerals and living organisms. Organic substance is decaying material such as rotting plants and dead animals. Minerals are crushed rocks or bedrock, formed through geological processes that has a characteristic chemical composition. Living organisms include insects, moles, worms and beetles, which churn through the earth as well as essential bacteria that help to break down organic matter. In addition, the soil nutrients are boron (B), calcium (Ca), carbon (C), chlorine (Cl), copper (Cu), hydrogen (H), iron (Fe), magnesium (Mg), manganese (Mn), molypdenum (Mo), nitrogen (N), oxygen (O), phosphorus (P), potassium (K), sulphur (S), and zinc (Zn).
The Soil Living Organisms
Formation
The formation of soil happens over a very long period of time and it took 1,000 years and beyond. Soil is formed from the weathering process of rocks and minerals. The surface rocks break down into smaller pieces through a process of weathering and is then mixed with moss and organic matter. Over these times it would create a thin layer of soil. Plants help the development of the soil by attracting animals, and when the animals die, their bodies would decompose. Decaying matter makes the soil thick and rich. This cycle continues until the soil is fully formed and may supports many species of plants.
Importance
Soil is more than just the brown dirt under our feet. It is a home for many living organisms and it provides nutrients and stability for plants to grow and produce food. Without soil, the plants which produced food necessary for people and animals to survive could not exist.
By caring for our soil properly, we can make sure the longevity existence of both animals and people. The use of crop rotation, limiting harsh chemicals and composting will help to keep up a healthy balance of nutrients, living organisms and minerals in the soil. It is important to remember that the fresh foods on which we feast have an affect upon our health.
pH
Soil pH Chart
The pH level of the soil directly affects the soil life and the availability of essential nutrients for plant growth. Whether you’re planting for commercial or recreational reasons, knowing the pH of your soil can help you choose the right mix of plants and allow the right treatment for your soil.
Soil life refers to the living organisms that live in soil and break organic materials down into simpler forms. Soil bacteria, a microscopic soil occupant responsible for the decomposition of organic material into simpler nutrient forms that become food for plants, thrives at about 6.3 to 6.8 pH. While soil life plays an important part in fertilizing soil, the pH of your soil determines the form nutrients will take, as well as their availability for plant absorption.
Types
Cohesive soils
Cohesive soils have the smallest particles. Clay has a particle size range of 0.00004″ to 0.002″. Silt ranges from 0.0002″ to 0.003″. Clay is used in embankment fills and retaining pond beds.
Characteristics: Cohesive soils are dense and tightly bound together by molecular attraction. They are plastic when wet and can be molded, but become very hard when dry. Proper water content, evenly distributed, is critical for proper compaction. Cohesive soils usually need a force such as impact or pressure. Silt has a noticeably lower cohesion than clay. However, silt is still heavily reliant on water content.
Granular or Cohesionless soils
Granular soils range in particle size from 0.003″ to 0.08″ (sand) and 0.08″ to 1.0″ (fine to medium gravel). Granular soils are known for their water-draining properties.
Characteristics: Sand and gravel obtain maximum density in either a fully dry or saturated state. Testing curves are relatively flat so density can be obtained regardless of water content
Colours
A soil profile is the side view of soil, from the uppermost layer to the bottom layer. There are six layers that exist in a soil profile. They are as follows:
- The top-most layer of the soil is composed mainly of fresh soil and decaying organic matter; the color ranges from brown to black.
- The second layer of the soil consists of highly decomposing organic matter; the color ranges from brown to gray.
- The third layer of soil is composed of sand and silt. It has lost most of its nutrients; the color of this layer is light brown.
- The fourth layer consists of clay and large rocks and bedrock; the color ranges from rust to tan.
- The fifth layer of soil is bedrock; the color is gray.
- The sixth layer of soil is comprised of rock; the color is gray.
Textures
Soil texture is an important soil characteristic that drives crop production and field management. The textural class of a soil is determined by the percentage of sand, silt, and clay. Soils can be classified as one of four major textural classes: (1) sands; (2) silts; (3) loams; and (4) clays. In this fact sheet, we will discuss the importance of the soil texture, different methods to determine soil texture, and the impact of texture on management decisions.
Importance of Soil Texture
Soil texture determines the rate at which water drains through a saturated soil; water moves more freely through sandy soils than it does through clayey soils. Once field capacity is reached, soil texture also influences how much water is available to the plant; clay soils have a greater water holding capacity than sandy soils. A clay soil is referred to as a fine-textured soil whereas a sandy soil is a coarse textured soil.
Soil Textural Classes
The combined portions of sand, silt, and clay in a soil determine its textural classification. Sand particles range in size from 0.05–2.0 mm, silt ranges from 0.002–0.05 mm, and the clay fraction is made up of particles less than 0.002 mm in diameter. Gravel or rocks greater than 2 mm in diameter are not considered when determining texture. Once the sand, silt, and clay percentages of a soil are known, the textural class can be read from the textural triangle. For example, a soil with 40% sand, 40% silt and 20% clay would be classified as a loam.
The Soil Textural Triangle
The Soil Textural Triangle is used to determine soil textural class from the percentages of sand, silt, and clay in the soil. Clay percentages are read from left to right across the triangle (dashed lines). Silt is read from the upper right to lower left (light, dotted lines). Sand from lower right towards the upper left portion of the triangle (bold, solid lines). The boundaries of the soil texture classes are highlighted in blue. The intersection of the three sizes on the triangle give the texture class. For instance, if you have a soil with 20% clay, 60% silt, and 20% sand it falls in the “silt loam” class.
There you have it, approximately 7 things that you should know about the most precious material, the soil. This for an additional info and cheers to our Mother Earth…
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