October 2, 2019

How to Determine the Composition of Soil

What is the composition of soil?
Soil contains both organic and non-organic materials, both of which are necessary for good root growth and plant development. Depending on the type of plants being planted in the soil, some may have better adaptations to certain components than others. Through in-field testing (such as rolling soil together to determine how well the soil sticks together) or through lab testing for properties such as pH levels, chemical composition, and other factors, the composition of soil can be easily determined.

What are some of the types of soil and their main components? 
  • Sand: Not a very nutrient-rich soil, sand does allow for drainage due to its large particles. Comprised mainly of silicon-dioxide, it is very stable chemically (very similar in composition to glass, which is a refined form of silicon-dioxide and other elements). In combination with silt and clay, sand is necessary in the composition of loam, an ideal state of soil for fertility and growth in plants.
  • Silt: Individual particles are angular at a microscopic level and can pack tightly together under pressure and moisture. Silt, when dry, can become very dusty and can even be carried off by the wind, and in flood conditions, this moderately fertile soil can be taken away downstream.
  • Clay: Individual clay particles are microscopic, but generally lie flat and group up well with other flat clay particles. This explains why clay is so useful in forming ceramics, since the clay particles align when wet and pack together, but once the moisture is removed through firing or heat, the clay particles form very strong physical bonds. In soil, that can mean that the soil can be very hard for water, air, and organic material (including nutrients) to penetrate.
  • Peat: This component of many types of soil is extremely high in organic material, particularly carbon. Made from organic materials that have been in contact with water and low oxygen, they can compress into a material which holds moisture and nutrients extremely well, especially nitrogen-fixing bacteria. In some parts of the world, peat is valued for its ability to burn, making it very similar to coal.
  • Salt: Soluble salts can affect electrical conductivity in plants at the molecular level – think of how acids or alkalines are used in batteries. Slow growth due to electrical conductivity can lead to root disease, so salts must be analyzed and controlled in order to propagate good root growth.
  • Humus: Composed mostly of organic material, but different in composition compared to peat. Humus might include decaying plant or fungus material, cellulose, such as wood pulp, straw, or other composted ingredients.
  • Minerals: From iron to potassium, manganese, alkalines and other soluble salts, the mineral content of soil is important, especially in growth and fertility. pH factors are beneficial to all plants, yet in particular, acidity or basic levels affect different plants in different ways. Excessive amounts of iron and manganese can prove to be toxic to certain plants, and limestone may have to be added in order to “iron out” the soil to acceptable levels.
  • Water: Moisture is retained by organic and non-organic components alike, such as clay or peat. A soil’s ability to retain water makes it a more or less hospitable growing medium, depending on the needs of the plants being grown.


Why is soil testing important?

The more information you have, the better, which is why soil testing is so crucial. Essel Environmental provides soil testing so that the composition, acidity, chemical trace elements, and physical workability can be better assessed. Soil is not only important for agricultural purposes, but also for building and the assessment of an area’s ability to withstand the pressure of infrastructure and allow buildings to settle and construction to be possible in some conditions.

An area with soil that is extremely difficult to pack together may be ideal for planting, landscaping, or agriculture, whereas it might be a nightmare for commercial or residential development. Some soil composition can lead to erosion or sliding of certain types of buildings. Other types of soil might be ideal for retention of water; however these conditions may not be suitable for buildings which are partially built underground, or near the water table.

Essel Environmental provides comprehensive soil testing so that you are informed in the type(s) of soil of the potential property before committing to a decision in purchasing or building. Contact us today for more information regarding how we can keep you informed in your new property purchase.
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