Soil structure
depends on the formation of stable soil aggregates and occurs through the activity of soil fauna. Earthworm casts, bacterial slime and the hyphae of fungi all help to bind the soil partilcles together into aggregates. This allows the soil to develop a structurce of pores and channels that store air, water and nutrients.

With up to a  billion bacteria present in a teaspoon of soil, modifying soil biology environments is never going to be easy but providing the right conditions for beneficial micro-organisms is where current research is going.

Soil micro-organisms make up only about 2% of SOM (itself a small fraction) yet their presence is essential for soils to function properly. Not only do they produce exudates that bind soil particles together and improve soil structure, they are also assist in retaining soil water, recycling nutrients  and preventing their leaching from the soil.

Soil biology comprises all the organisms living within the soil ranging from soil microbial fungi and bacteria to protozoa and nematodes, earthworms and arthropods. Together they are responsible for the decomposition of organic materials and cycling of nutrients within the soil.

Breakdown begins first with the simple carbohydrates, followed by increasingly resistant cellulose, fats and waxes, lignin and fibre. The different biological factions within the soil can work separately but often together, increasing the synergy of breakdown.

Understanding interactions between plants and soil microbial organisms present some of the biggest challenges to soil science today. Understanding those associations that are beneficial to plant growth presents an opportunity to enhance our farming systems.