In our previous article, we talked about the importance of soils – their diversity and vulnerability. Now, we take a look at the microbial organisms that are the soul of soil.
We refer to the community of soil-dwelling bacteria as the microbiome. It is a species-rich and diverse community in which bacteria are in constant interaction with each other and with the organic and inorganic components of the soil and other organisms. It is safe to say that without a complex and healthy soil microbiome, life cannot exist on the planet.
From an agricultural point of view, the presence of soil bacteria is one of the prerequisites for soil to be suitable for any kind of plant life. There is a well-documented correlation between the sparse vegetation of microbiologically poor soils and the rich vegetation of soils with a rich microbiology. In this respect, strong, well-developed and abundant crops can only be expected if the soil is rich in soil bacteria.
Types of soil bacteria
Unfortunately, the equation is not that simple; a large number of soil bacteria does not automatically mean rich and healthy soil. You can find bacteria that are useful for agriculture as well as those that are harmful or parasitic. Crop production can be successful in soils with a predominance of bacteria that help nutrient uptake and fixation, and bacteria that control pests.
Useful bacteria
Decomposer bacteria: These organisms are able to break down organic matter, plant and animal residues in the soil. Their metabolic processes result in nutrients, trace elements and minerals in the soil in forms that are available for plants.
Nitrogen fixing bacteria: Some species are symbiotic, i.e. they colonise the root system of plants, living in symbiosis with the plants. Other species live freely in the soil. The third type is endophytic nitrogen fixing bacteria, which live inside the plant’s body. Examples of such bacteria are Rhizobium or Azotobacter species.
Pest-parasitic bacteria: Some bacterial species specifically live as parasites inside agricultural pests. The most well-known representative is Bacillus thuringiensis, which is present in several bacterial preparations used in organic farming. When present in large enough quantities, these bacteria prevent pests from appearing and proliferating in the crop. Bacillus subtilis has shown promising results, and according to the experiments, it can be effective against both Sclerotinia and Fusarium diseases.
Bacteria posing a risk
About 20 percent of plant diseases are caused by bacteria. All horticultural crops and ornamentals have bacterial pathogens. It is therefore advisable to be prepared to control bacterial diseases in both crop and ornamental plant production. The so-called plant pathogenic bacteria that cause plant diseases are usually active in the soil and find their way to the host plant in response to chemical stimuli. In addition, they can easily enter the host plant through inadequately disinfected tools.
Improper plant care, any open wounds left untreated, insect bites, or hail damage all increase the risk of bacterial diseases. The wounds caused by these damages serve as excellent entry points for bacteria into the plant’s system. Examples of important bacterial pests are Clavibacter michiganensis subsp. sepedonicus, which causes the wilting of potatoes and tomatoes, Erwinia amylovora, which causes needle blight, and Ralstonia solanacearum, which causes potato tuber rot.
Let’s help the bacteria
A farmer’s goal is to promote the presence of as many beneficial bacteria as possible, while minimizing the impact of harmful bacteria on the plantation. One of the biggest challenges of our time is sustainable, chemical-free crop production, which can be based on the proper balance of bacteria.
Conventional agriculture has significantly reduced soil bacteria numbers over the long term. Fertilisation, pesticides (especially copper-based products) and soil compaction have a negative effect on soil bacteria. According to some studies, the number of soil bacteria in areas with intensive tillage is often only a fraction of the optimal level.
It is important to know that intensive cultivation and fertilisation result in the loss of proportionally more beneficial soil bacteria than pests. In intensively cultivated soils, as beneficial bacteria disappear, much more resilient pathogenic bacteria can easily proliferate.
The proliferation of beneficial soil bacteria can be encouraged by a range of agricultural practices. In particular, it is advisable to apply organic fertilisers and green manures instead of fertilisers.
This provides nutrients for the decomposing bacteria that can break down this large amount of organic matter into nutrients that plants can absorb. It is also a good idea to seed your soil with butterfly crops such as peas and beans from time to time. The root system of these plants are rich in nitrogen-fixing bacteria described above. After harvesting the butterfly crop, a lot of useful nitrogen-fixing bacteria remain in the soil. It is also important to know that bacteria will not thrive in compacted, airless soil, therefore, it is advisable to loosen the soil.
Humic acid and earthworm humus
If there are two basic tools for soil improvement, they are almost certainly humic acid and worm humus.
Humic acid, also known as potassium humate, is a complex compound derived from plant and animal remains that have undergone humification processes.
Along with fulvic acids, humic acid is the building block of soil humus formation. Humic acid treatment is one of the best tools for revitalising degraded soils.
Biomit Genesis is an aqueous suspension with a high concentration of humic acid. This makes it easy to apply and work it into the soil. Both soil organisms and plants respond very well to humic acid added to the soil. After treatment, the soil-dwelling bacteria begin to proliferate explosively, which in itself improves soil life. Seeds that are sown or seedlings that are planted are placed in an optimal microbial medium.
The use of worm castings is recommended to counteract the effects of conventional agriculture. Optimally, millions of worms would live in a hectare of soil. However, chemical inputs, and heavy metals from most pesticide carriers in particular, have significantly depleted worm numbers. Biomit Terra worm castings are an effective way to make up for this deficit.
Its application is quick and easy thanks to its dissolved form. It is recommended to apply 100-200 litres of Biomit Terra per hectare, with a minimum of 300 litres of water. The dissolved worm humus fills the capillaries and provides an optimal medium for soil bacteria and beneficial fungi. The use of worm castings will result in better rooting and stronger, more resistant crops.
Soil spraying
The quickest and simplest way to improve soil is to apply live bacteria directly as a bacterial fertiliser. This usually involves live bacterial strains in an aqueous suspension. When sprayed onto the soil or mulch, the bacteria will begin to proliferate. However, soil inoculation is not a panacea, it is also necessary to provide the right conditions for the bacterial preparation, such as optimum temperature, pH range, moisture and oxygen. If the soil is in a completely degraded state, it is not advisable to inoculate it with a bacterial preparation immediately. Instead, it is recommended to improve the soil condition first.
This can be done by applying compost, humic acid, green manure, or by sowing a green mulch mixture that loosens and replenishes the soil with organic matter. Bacteria applied to the prepared area will easily and quickly multiply and feed. The microbes applied have a special property called microbial self-defense. In this process, the micro-organisms protect themselves, their habitat and their food source from harmful organisms in the soil. A well-established method of defense is the production of secondary metabolites that inhibit the proliferation of other bacteria.
