Enabling factors

Five core factors enable plant growth: sunlight, air, water, decomposition and macro & micro elements.



Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that can be perceived by the human eye.

Sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. This process of photosynthesis provides virtually all the energy used by living things.

Let there be light: In photosynthesis, sunlight is converted into chemical energy in the for of sugars (glucose). In plants, photosynthesis occurs in the chloroplasts in the plant cells. Chlorophyll within the chloroplasts is used to synthesise glucose from water (H2O) and carbon dioxide (CO2) using the energy from sunlight with oxygen (O2) released as a by-product. (Carlos Clarivan, Science Photo Librarary)


Air, or the atmosphere of Earth, contains 78.09% Nitrogen, 20.95% Oxygen, 0.93% Argon, 0.04% Carbon Dioxide and small amounts of other gases. Air is necessary for the respiration and functioning of soil fauna and flora, including plant roots. It also plays an important role in chemical reactions.

In the soil, water and air use the same channels, the pores. Air and water share the same spaces; some air can be dissolved in soil water and some can also be stored in the larger pores not occupied by water, often those resulting from the activities of macrofauna or decay of roots.


Water is vital for all forms of life, even though it doesn’t provide calories or organic nutrients. Photosynthetic cells use the sun’s energy to split off water’s hydrogen from oxygen. Hydrogen is combined with CO2 to form glucose and release oxygen All living cells use such fuels and oxidize the hydrogen and carbon to capture the sun’s energy and reform water and CO2 in the process.

Water in the soil is important for plants and soil life and for soil genesis (weathering, humus, movement of particles, etc.). Soil water is a vehicle for nutrients and is necessary for biological and chemical reactions in the soil, which build in particular the soil fertility.

Organic matter plays an important role in the water cycle as it facilitates infiltration and water storage, structure building for water circulation and production of colloids which retain water. Micro- and macro-organisms also play major role in creating pores and various forms of organic matter.


When plant residues are returned to the soil, various organic compounds undergo decomposition. Decomposition is a biological process that includes the physical breakdown and biochemical transformation of complex organic molecules of dead material into simpler organic and inorganic molecules.

The continual addition of decaying plant residues to the soil surface contributes to the biological activity and the carbon cycling process in the soil. Breakdown of soil organic matter and root growth and decay also contribute to these processes. Carbon cycling is the continuous transformation of organic and inorganic carbon compounds by plants and micro- and macro-organisms between the soil, plants and the atmosphere.

Essential functions performed by different members of soil organisms (FAO, 2020)

Macro or micro elements

Plants must obtain the macro and micro nutrients from their growing medium. Optimizing plant growth means that these macro and micro nutrients must be available for plants on their environment.


Macro nutrients

Micro nutrients

Nitrogen (N) Iron (Fe)
Phosphorus (P) Boron (B)
Potassium (K) Chlorine (Cl)
Calcium (Ca) Manganese (Mn)
Sulfur (S) Zinc (Zn)
Magnesium (Mg) Copper (Cu)
Carbon (C) Molebdenum (Mo)
Oxygen (O) Nickel (Ni)
Hydrogen (H)