The soil is rich in biological diversity and complexity that is not immediately visible to the eye. Without a microscope, you wouldn't know that there are millions of organisms in a handful of soil.
Bacteria, algae and fungi play a crucial role in the growth and well-being of the soil and plants. The millions of microbes in the soil can be seen as "workers" of a large recycling plant, mining and refineries. They all have special functions that help make nutrients available to the plants.
Most soil micro-organisms work in a “recycle” role. These are the "decomposers" that absorb and break down dead plant and animal matter. If these “recyclers” didn't do their job, the world would be a pile of useless waste!
Instead, soil microorganisms use the organic matter to release the fundamental components used by plants as food.
The microbes that work in a recycling role use the organic carbon in the organic matter as an energy source (as food). Recycling releases nutrients such as nitrogen, potassium and phosphorus; which are important for plant health. The importance of these “recycle microbes” cannot be overstated; They turn the waste from the soil into the building blocks of life.
The maintenance of plant life is impossible without these organisms.
The soil microorganisms that play the role of “mining microbes” act on nearby minerals, not on organic matter like the “recycle microbes”. “Miner microbes” make a “bacterial gunk”- scientifically named as an exudate.
This gunk has a special pH level and other important properties that bind and extract nutrients such as phosphorus, calcium and potassium. All these minerals are necessary for healthy plants and good crop yield.
A specific group of microorganisms are called mycorrhiza. This is a cohabitation of fungi and plants via roots. Almost all plants interact with fungi underground. For example, these fungi absorb minerals from the soil that they then give to plants, in exchange for which they get sugars back for their own food.
Refining microbes, a class of bacteria called rhizobium, are able to extract nitrogen from the air and process it into a form usable by the plant. These “nitrogen-fixing” bacteria absorb nitrogen gas in the atmosphere (N2 gas) and convert it into vegetable ammonia and other nitrogen-rich organic compounds.
In general, these "refineries" live only in special root forms called "nitrogen root nodules" of legumes. Lucerne and clovers are legumes. They can form this symbiotic relationship with rhizobium.
This special symbiotic relationship, for example, makes clovers a great way to use less fertilizer. The dead tissue of legumes is very rich in nitrogen. This nitrogen-rich plant material can supply nitrogen to neighboring plants such as grasses and herbs.
This means that the livestock farmer can spend less time, money and energy on applying nitrogen fertilizers through the use of clovers.
