Just as looking at a cast of actors does not tell you what their play is about, looking at soil organisms in their individual groupings does not tell you about the significance of their presence and activities.
Ecosystem services are defined as are the benefits people obtain from ecosystems- according to the Millennium Ecosystem Assessment
(If you want to know more about ecosystem services (hint, hint), see https://dedide.info/ecosystemservices/)
Table of Contents
ToggleExplanation of soil services
The soil ecosystem is often overlooked, but the services it provides are essential to the continuation of life on the planet.
In order to provide for the plants that give us food, fibre and fuel, soils must be fertile.
Soil fertility - chemical
Soil organisms clear away and degrade organic debris such as dead plants, animals and dung and use it as a source of food and nutrients, and in the process, release chemical elements (nutrients) into the soil solution so that living plants may re-use them. This process sustains soil chemical fertility. For crop plants, fertile soil means nutritious food.
Table of plant nutrient requirements (Atomic symbol in brackets)
Soil fertility - physical
Soil organisms are also responsible for soil physical fertility as well. They help the formation of good soil structure. The microbiota is intricately linked with soil structure, such as aggregation and pore connectivity, which regulates the flow of water, oxygen and nutrients through the system.
Soil biota drive key functions in agroecosystems, determining soil fertility, crop productivity and stress tolerance.
Local agricultural management practices can induce structural alterations to the soil, thereby changing the microbial processes occurring at the microscale. These changes may also have large-scale consequences, such as soil erosion, reduced soil fertility and increased greenhouse gas emissions.
Brief case study - bamboo 
Species of bamboo are used as food, spun into fibre and used for both building and furniture, It provides valuable services to humans.
There are of course differences from species to species, but as useful generalisation, bamboo is rich in
- Potassium
- Calcium
- Manganese
- Zinc
- Chromium
- Copper
- Iron
- Thiamine
- Niacin
- Vitamin A
- Vitamin B6
- Vitamin E
All of these substances are derived from the soil it is growing in and made available to the plant by the actions of the biota in the soil.
Soil related hunger in humans
Soils which are deficient in certain nutrients can lead to disease and malnutrition in humans.
Carbon sequestration is the placement of carbon into a depository in such way that it remains stored and not released back to the atmosphere. It is an important global phenomenon that plays a significant role in maintaining a balanced global carbon cycle and sustainable crop production.
Soils can act as either a source or a sink of atmospheric carbon. Globally, soils contain a vast amount of organic carbon (~ 1 550 thousand million tonnes), which is more than the total carbon contained in vegetation and the atmosphere combined. An additional 750 thousand million tonnes of carbon is contained in inorganic forms in soils. These soil carbon stocks are not static, but dynamic over time, with accumulation occurring through plant and animal inputs, and losses via decomposition of soil organic carbon (SOC) leading to the release of CO2 into the atmosphere. Not all soils have the same carbon sequestration capabilities.
Globally, soils contain more than three times as much carbon as the atmosphere and four and a half times more carbon than the world’s biota (Lal 2004); therefore, even small changes in soil carbon stocks could lead to large changes in the atmospheric concentration of carbon dioxide (CO2).
A variety of soil animals and microbes can process plant litter that contributes to a pool of unprotected particulate organic matter (OM) with a relatively short turnover time. Alternatively, soil microbes also can process this litter into more stabilized forms such as aggregates or mineral-protected OM with relatively long turnover times. In this carbon pool, belowground litter appears to be preferentially stabilized, partly because of its proximity to both microbes and minerals. Root exudates may contribute to microbial carbon pools or to priming (i.e., the loss of mineral-protected soil carbon). Respiratory losses—occurring at all stages of biotic processing—can be affected by microbial carbon use efficiency and by conditions in the natural environment or those arising from land use. Not only can land use significantly affect both the quality and quantity of plant residues delivered to soils and their processing, it also can affect erosional losses and deposition. Climate change, especially in northern latitudes, may cause significant losses of soil carbon.
https://carbon2018.globalchange.gov/downloads/SOCCR2_Ch12_Soils.pdf
According to a recent study published in the journal Nature, microbes are the key drivers behind carbon storage in soil, surpassing other soil processes by a factor of four.
Carbon cycling
The transfer of carbon (C), in its many forms, between the atmosphere, living organisms (biosphere), oceans and soils (pedosphere) is described as the carbon cycle. In the atmosphere, carbon can be found in two main forms: CO2, carbon dioxide; CH4, methane. Carbon dioxide (CO2) moves from the atmosphere to the terrestrial biosphere through photosynthesis (process used by plants and other organisms (such as bacteria) to convert light energy and CO2 into chemical energy, in the form of carbohydrates (sugars). Carbon leaves the terrestrial biosphere in several ways, including through the combustion of fossil fuels and metabolic respiration by plant and soil organisms.
Carbon dioxide is a greenhouse gas which means it traps heat in the atmosphere. Without it and other greenhouse gases, Earth would be a frozen world. There has been a recent sharp increase in amounts of greenhouse gases such as carbon dioxide due to humans burning fossil fuels and this is having a significant impact on the warming of our planet. So soils acting as receptacles for captured carbon are intimately tied to climate regulation.
Methane is another greenhouse gas. Soils contain bacteria which "eat" methane, and also bacteria which can produce methane as part of the process of decomposing organic matter. Many of these bacteria can only function in the absence of oxygen O2 so methane storage is most likely to be found in waterlogged soils e.g. rice paddies.
All soil organisms, from bacteria to the largest of the invertebrates, are part of complex interactions that lead to the decomposition of organic matter. As decomposition is the main process that recycles nutrients (e.g. carbon, nitrogen, phosphorus) back into the soil, soil biota is crucial to nutrient cycles and, consequently, to the regulation of the atmospheric composition and climate.
Selected examples
Water cycle
The typical terrestrial plant, absorbs water from the soil through its roots. That water is then used for metabolic and physiologic functions. The water eventually is released to the atmosphere as vapor via the plant's stomata — tiny, closeable, pore-like structures on the surfaces of leaves. Overall, this uptake of water at the roots, transport of water through plant tissues, and release of vapor by leaves is known as transpiration. Water also evaporates directly into the atmosphere from soil in the vicinity of the plant. Any dew or droplets of water present on stems and leaves of the plant eventually evaporates as well. Scientists refer to the combination of evaporation and transpiration as evapotranspiration.
Nitrogen cycle
Most of the nitrogen on Earth is in the atmosphere. Approximately 80% of the molecules in Earth's atmosphere are made of two nitrogen atoms bonded together (N2). All plants and animals need nitrogen to make amino acids, proteins and DNA, but the nitrogen in the atmosphere is not in a form that they can use. The molecules of nitrogen in the atmosphere can become usable for living things when they are broken apart during lightning strikes or fires, by certain types of bacteria, or by bacteria associated with legume plants. Other plants get the nitrogen they need from the soils or water in which they live mostly in the form of inorganic nitrate (NO3-). Nitrogen is a limiting factor for plant growth. Animals get the nitrogen they need by consuming plants or other animals that contain organic molecules composed partially of nitrogen. When organisms die, their bodies decompose bringing the nitrogen into soil on land or into the oceans. As dead plants and animals decompose, nitrogen is converted into inorganic forms such as ammonium salts (NH4+) by a process called mineralization. The ammonium salts are absorbed onto clay in the soil and then chemically altered by bacteria into nitrite (NO2-) and then nitrate (NO3-). Nitrate is the form commonly used by plants. It is easily dissolved in water and leached from the soil system. Dissolved nitrate can be returned to the atmosphere by certain bacteria through a process called denitrification.
More information about nitrogen recycling can be found at What is nitrogen pollution? - a page of information on the delicate balancing act between too much and too little nitrogen.
Phosphorus cycle
The Phosphorus cycle in another important example of the soil's involvement in nutrient recycling.
This diagram describes the flow of phosphorus through the soil. Soil P chemistry is very complex, with more than 200 possible forms of P compounds being affected by a variety of biological, physical and chemical factors.
More detail about nutrient cycling can be found at the Microrrhazal fungi page and also at pages 102 to 106 of the recommended download Global Soil Biodiversity Atlas. Also https://youtu.be/njzFtvMPJ3A is useful.
How we benefit from soil and water interaction
Soil detoxification and water ‘filtration’ are essential for maintaining the quality of soil and, consequently, that of our surface and groundwater resources.
Only soils with diverse and abundant soil life and high biodiversity can act as efficient filters to produce clean drinking water. Soil organisms, both fauna and flora, facilitate water infiltration and drainage due to the creation of macro- and micro channels created by digging and also by changing soil aggregate adhesion. In addition, a greater accumulation of organic matter in the soil by biota increases the water holding capacity of the soil. Soil organisms thereby improve soil aeration and water infiltration.
In addition to the above process, contaminants (such as metals, pesticides and solvents) are removed from soil through the actions of certain bacteria and fungi.
For more detailed information, see the following videos
https://youtu.be/vmo0FRAVgkM Water Movement in Soil
https://youtu.be/ZwQeTJEeedk Soils Clean and Capture Water
As stated previously, soil is home to a significant portion of the earth's biodiversity. Due to its dynamic and heterogeneous nature, there are many microhabitats e.g. different pore sizes, different levels of light penetration, variations in temperature fluctuations, that support a high level of biodiversity.
There is constant interaction between the biota of the soil and the non-living components, so that soil is dynamic and constant changing as organisms take what they need to live their lives and perform services which maintain the soil as a favourable habitat.
Traditional remedies
- In some cultures, mud is applied to open wounds to relieve pain and seal the wound off from sources of infection.
- Clay is swallowed by animals, and in some cultures by humans, to soak up and neutralise poisonous substances in the intestines.
Modern technologies
As stated previously, soil is a major reservoir of species biodiversity. It is not well studied and so many organisms, particularly in the microbiota grouping are not even named by humans due to insufficient time and funding to do this work.
A study, in 2018, examined the equivalent of 1 teaspoon of soil, and turned up hundreds of genes for complex and potentially useful molecules that would not have been found otherwise because the microbes cannot be grown in a petri dish.
The genes, many from previously unknown groups of bacteria, likely produce antibiotics or antifungals that the microbes make to defend themselves and which may also be able to combat bacterial or fungal infections in humans.
Actinomycetes, a versatile microbial soil dwelling group, are well known for producing antibiotic compounds and other important substances. They have been useful in diverse applications in the food, medical, pharmaceutical, and bioremediation industries.
Build in it, on it, with it
Products from Soil
- Egyptians used soils for paint, as did Native Americans.
- Other cultures used soils as dyes for their cloth.
- Some make up and skin preparations include soil components
- Porcelain china for household goods
Soil as part of the landscape
- Bush walking
- Mountain biking
- Aesthetic appreciation
- Health benefits
- Enjoyment from gardening activities
Cultural significance of soils
- Burial ceremonies
- Visiting sacred sites
- Listening to songs and reading books which feature soil and landscape
Enjoyment
Video overviews
Go to Explore my understanding of Soil Health
Click on the following link to visit the page - Explore my understanding of Soil Services (will open in a new window or tab)