Organic matter decomposition in our every day life

From the dumps we take daily to the kitchen wastes we dispose of, organic matter decomposition is a subject that concerns every human on earth. Without organic matter decomposing, humans will be living in a world stockpiled with waste; that is even largely based on the assumption that life can exist at all without it.

Let me explain more.

Organic matter decomposition has to do with the decomposition of chemical materials that make up life. It is the brain behind the cycling of important nutrient elements that help to sustain life. For example, humans need carbon and nitrogen to form important biomolecules that help build tissues, act as important components of physiological processes, and much more. How do we obtain these elements for these vital functions? From the foods we consume.

We consume foods that are rich in carbon (carbohydrates) and nitrogen (proteins). The foods are either derived from plants or meats derived from animals. Plants get these nutrients directly from the soil while animals get theirs either by feeding on plants or by consuming their fellow animals. How do these nutrients get into soils?

This is where organic matter decomposition comes in. A significant portion of the soil-based nutrients come from organic matter decomposition. When plants and animals die, they eventually decompose and become integral parts of soils. The same thing is applicable to plants and animal-derived products.

^{Fate of buried organic matter. Credit: GRID-Arendal on flickr}

When these materials decompose, all the nutrients locked up in them go into the soil and the cycle is repeated.

Factors that determine the decomposition rate

Recently I got involved in a project that has to do with establishing a burial ground. The area to be used for this project is about 4 plots. based on the average size of each tomb, I estimate that the entire land area may be able to accommodate a few hundred bodies. What then happens afterward? Does the burial ground become just a monument and new bodies are buried somewhere else?

As far as I'm concerned, tombs in burial grounds can be reused once the bodies have completely decomposed to nothing. When everything has become soil. This is exactly what is practiced in some parts of the world. However, since the rate of decomposition of organic matters depends on some factors which have to be put into consideration when burial grounds are to be sited. The faster the decomposition rate, the more suitable a site would be for locating a burial ground.

The factors that influence organic matter decomposition rate include:

• Soil texture
• Soil aeration
• Clay mineralogy
• Soil pH
• climatic factors
• litter quality
• Inorganic chemicals

Decomposition requires oxygen as most decomposing microbes are aerobic in nature. Hence, the more aerated a soil is, the faster the decomposition rate with all other things being equal. The texture and clay mineralogy of soil affects the level of aeration in soils.

Microbes also require nutrients for their metabolism and the availability of nutrients in soils depends largely on the pH of the soil. Some nutrients become available at a specific pH range while others become bound to soil. An optimal pH would be one in which the majority of the nutrients become available in the soil.

Climatic factors such as moisture, temperature, etc., also affect the decomposition rate. According to findings, the availability of moisture and warm temperatures are optimal for the growth of microbes while cold temperature limits their growth. In other words, decomposition rates are faster in warm and humid climates than in cold, dry climates.

Litter quality refers to the structure and composition of decaying substances. In this case, the size, structure, and composition of bodies will come into play.

All these factors work in synergy to dictate the rate of decomposition of organic matter in the soil. They are the reason why when you dig up over a thousand-year-old tomb, parts of the buried body can still be found in some soils and just some years after burial, all the tissues of the buried have completely dissolved in some soils.

How these factors work in synergy remains an active area of research and findings will go a long way in locating landfills, and burial grounds, among other processes that rely on organic matter decomposition.

What do you think?