Soil flora – plants in the ground?
The term soil flora usually means the entirety of the plants living in the soil. Actinomycetes, fungi, ray fungi, algae and lichens are mainly attributed to the soil flora. Together they make up about 60-90% of the mass of the entire Edaphon. Since the plants involved are often only a tiny size of <0.2 mm, they are often referred to as microflora.
All living organisms of the soil flora are significantly involved in processes of decomposition, mineralization and humification. The solid soil substance consists mainly of humus. Edaphone, plants and roots only make up about 15-20 percent of the earth’s substance.
Bacteria are also often included in the soil flora in soil science. Not only with them, which are clearly not part of the flora in the biological sense, the term soil flora is problematic. Because all of the groups listed are biologically and systematically non-animal, but in some cases also non-plant organisms.
Especially the mushrooms (Fungi) stand out. They fascinate laypeople as well as professional biologists and, alongside animals (Animalia) and plants (Plantae), form the third great realm of so-called eukaryotic creatures.
Special case of mushrooms
Although fungi are counted as microflora and incorrectly counted as plants by many laypeople, fungi are more similar to animals than to plants. But if you take a closer look at them, you quickly notice that they don’t actually look like the plants at all.
Because you won’t find anything green about them. Neither any things that look like grass, nor leaves or even needles. This is because mushrooms have a completely different metabolism than plants. Plants float with theirs green leaves are known to photosynthesize. The chlorophyll enables them to convert sunlight into energy. In this way, they also build their biomass from the carbon dioxide in the air. Plants can survive with just sunlight, air and a little water.
Mushrooms are different. Like animals and humans, mushrooms also have to “parasitize”, that is to say gain energy by chemically breaking down and metabolizing existing biomass.
On the one hand, they do this by means of dead plant residues that the fungi pull out of the ground. However, fungi often also enter into symbioses – a kind of partnership – with plants by clinging firmly to them. More on that later.
In any case, a mushroom is not a plant. But it is not an animal either, because it does not move from its fixed place in the ground, nor does it have cells that are similar to animals. Here it again looks more like something plant-based. Because in addition to the cell membrane, it also has a solid cell wall. Fungi also reproduce completely differently than animals.
Fungi reproduce via spores, each of which has only one set of chromosomes in its cell nucleus. They germinate in moist soil and form tiny roots, which are also called hyphae – the so-called primary cyclone. As soon as two suitable hyphae are found, they combine and continue to grow as a secondary cyclone. From that point on, they have two nuclei in each cell. In addition, they now have the ability to form fruiting bodies – the beautiful part of the mushroom that we see when walking through the forest or across the meadow.
The research on mushrooms is far from over. The oldest mushroom to date was only discovered in 2005. According to paleontologists, it is around 850 million years old. Almost annually 2000 new species of mushrooms are discovered And researchers are becoming more and more aware of the immense potential of these impressive creatures.
In addition, mushrooms are considered a special delicacy. In addition to their versatility in terms of how they are prepared, they are also extremely healthy. If you want to look for edible mushrooms yourself in the local forest, you should inform yourself thoroughly in advance, as otherwise poisoning can occur.
Special case roots
Subterranean plant organs are not part of the soil flora, but quantitatively important for life underground. Roots and subterranean shoot organs such as bulbs and rhizomes make up around 10 percent of the organic matter in the soil. Especially with regard to the interactions with microorganisms and soil particles, roots are particularly indispensable for life underground.
Trees, in turn, could not live without roots in the ground. So one healthy care is guaranteed, a tree needs the same root volume underground as it has above ground in terms of crown volume. The more oxygen a young tree has in its growth phase and the more access it has to soil areas with proper root conditions, the greater the chance that it will grow and fulfill its full potential in the future.
Incidentally, roots of trees and other plants have not yet been part of the edaphone in soil science. However, they are living parts of plants and bring many benefits to the soil.
- You can consolidate, loosen or compact the soil, depending on your requirements.
- Roots also secrete carbon dioxide (CO2). This combines with water in the soil to form carbonic acid. The carbon dioxide in turn splits into hydrogen carbonate and hydrogen ions. These contribute to the acidification of the soil, which is essential for the life of some plant species.
- Plant roots also emit hydrogen ions and organic acids directly. The secreted acids attack rocks in the ground and ensure that they weather chemically and biologically.
- Roots have a positive effect on a healthy mixed forest. Because they increase soil regeneration in a decisive way.
- Depending on the location of the plants, roots take up basic substances from the unweathered subsoil, which are returned to the topsoil via the falling leaves. This process in turn can counteract the risk of over-acidification of the soil.
As already mentioned, many trees also enter into a symbiosis with fungi through their roots, from which both parties benefit significantly. The mushrooms entwine the roots with many threads and thus receive carbohydrates from the plant. In return, the fine fungal threads take over the task of the root hairs. This helps the trees and other plants to supply their roots with nutrients such as phosphorus, nitrogen and potassium that are sometimes difficult to dissolve. The interrelationship between root and fungus is also called mycorrhiza or simply fungal root.
Soil fauna – animals in the ground
The soil fauna consists of animal protozoa and multicellular organisms, which are differentiated according to their size. A distinction is made between microfauna, mesofauna, macrofauna and megafauna.
- The microfauna includes organisms with a size of <0.2 mm. Well-known representatives are ciliate animals, flagellates, amoebas and small roundworms.
- The mesofauna include organisms with a size of <2 mm. Springtails, rotifers and mites can be found here, for example).
- The macrofauna can be clearly seen with the human eye at the latest. It categorizes animals with a size of> 2 mm. Whether snails, bristle worms, woodlice or insects – all kinds of scurrying and crawling animals can be found here.
- Finally, the megafauna include animals> 20 mm in size. All kinds of vertebrates, such as voles, shrews or even the mole are part of the megafauna.
It is estimated that there are around 1.6 trillion living beings in 0.3 cubic meters of earth – about an area 1 by 1 meter and 30 cm deep. These break down roughly as follows:
- 1.5 trillion microorganisms such as bacteria, fungi and algae.
- 1 million roundworms
- 000 mites
- 000 springtails
- 000 rotifers
- 000 bristle worms
- 100 beetle larvae
- 100 two-winged larvae
- 80 earthworms
- 50 snails
- 50 spiders
- 50 woodlice
Like fungi, for example, bacteria contribute to healthy soil as microorganisms. They usually only consist of a single cell, but ensure that the nutrient turnover in the soil works over the long term. In other words, they decompose dead organisms and, through conversion, provide the plants with new nutrients that, for example, can be used to grow trees healthily.
The burrowing and digging soil animals in turn ensure the loosening, mixing and relocation of soil components. These processes are also called Bioturbation. They improve the ventilation of the soil. In addition, mineral soils are enriched with humus and the ability of the soil to store water is increased.
Earthworms, for example, or snails, also use excretions and mucilage to ensure a stable crumb structure in the topsoil. They and other soil animals always accelerate the breakdown of organic substances, for example by mechanical breaking up of organic substances. They nibble on organic materials with stable covering layers, which ultimately makes it easier for microorganisms to get to the ingredients of cells. Soil fauna and flora work best when they can both interact in a healthy way.
December 01, 2020