Written by Steve Holloway from Soil First Farming
Soil microbes are tiny, often invisible to the naked eye. Organisms that play a crucial role in maintaining soil health and enhancing crop productivity.
These microscopic creatures are responsible for numerous functions, including nutrient cycling, decomposition, and the suppression of plant diseases. They also contribute to soil structure, water-holding capacity, and overall fertility. Farmers who manage their soils with an eye towards promoting microbial activity, can benefit from improved crop yields, reduced need for chemical inputs and a more sustainable agricultural system.
Soil is alive – or at least it should be! Including bacteria, fungi, protozoa, to name just a few. Each plays a vital role in the soil’s natural ecosystem. The life in the soil is essential to maintaining soil structure and it’s water-holding capacity. Promoting the growth of healthy plants, which, in turn prevents soil erosion and builds soil resilience to environmental stresses.
Soil microbes can perform a range of critical functions; they decompose organic matter and release essential nutrients such as Nitrogen, Phosphorus, Potassium; control soil-borne pathogens and help maintain soil structure, and aeration. Microbes are also important in plant growth and development, helping to regulate hormone levels and promote root growth, interacting with each other, the crop and soil in complex and diverse ways, determining the health of the soil.
Some microbes form symbiotic relationships, mutually benefitting each other, while others participate in competitive interactions, competing for resources. These complicated interactions create a diverse soil ecosystem that supports healthier plant growth and soil fertility. Changes in their environment both good and bad such as soil pH, temperature, and moisture content, can influence the living soil entities, leading to imbalances.
Studies have shown that soil life helps to protect plants from disease and environmental stress, which makes them essential for sustainable agriculture. Probably the most notable is Mycorrhizal fungi; these form a symbiotic relationship with plant roots, as mentioned previously, enhancing nutrient uptake whilst rhizobia bacteria form nodules on legume roots, where they fix Nitrogen, making it available to the plant; however, although some soil microbes are natural plant defenders, plant pathogens can harm crops and reduce yield.
Today, farmers can easily promote soil microbial health by adopting some cultural practices that enhance soil biodiversity. These include varied crop rotation, which maximises root exploration of the soil, reduced tillage, and cover cropping. This mimics a more natural system, all of which facilitate the building of soil organic matter and reduce soil-borne disease. The bacterial role in soil water retention, is to enhance soil structure by producing polysaccharides, which hold soil particles together, resulting in increased water-holding capacity, so reducing the need for irrigating crops and providing a natural buffer.
These ‘Mega-bacteria’ do what they do best enabling farmers to reduce their reliance on synthetic fertilisers and pesticides by aiding the natural release of nutrients in a form that plants can easily absorb and use. Imagine that you are a plant, all you want to do is grow thrive and survive and that takes energy; you don’t want to waste your resources trying to transform your food into something you can eat. To continue the analogy… when you or I are hungry and fancy some soup, imagine the microbes have already picked the vegetables and blended them up for you ready to eat.
Similarly, certain microbial species can act as natural pest controllers, against harmful insects and pathogens. As previously mentioned, a plant’s natural defences will require maintenance, so the crop must sacrifice resources etc. With an in-built army to protect them, plants can focus on what’s important.
Increasingly over the past few years farmers have begun to use biological inoculants and alternative methods and products much more. Microbial inoculants do offer numerous benefits – improving yields, reducing chemical reliance, enhancing soil health; however, their effectiveness can be variable depending on outside factors such as soil conditions, crop type, and Management practices.
Continuing research has identified specific bacterial strains and their traits, meaning that growers can, with confidence, replace synthetic inputs in exchange for a natural equivalent. For example, it is no surprise that we still see crops testing short of Potash when many soils already have an overabundance of Potassium which is simply unavailable to the growing crop. The conventional solution of putting more K on seems crazy, when you think that there’s already a microbe that can free- up the existing supply that is locked-up.
Bacteria can navigate to and release elements not accessible to crop roots including NPK; knowing and utilising the correct ‘elemental liberator’ can be key to saving £££ when compared to ineffective synthetic inputs. Many have heard of the popular microbe Bacillus Subtillus; these rod-shaped bacteria can tolerate extreme temperatures and are extremely effective in combatting Take-all, Fusarium, and Club root, whilst acting as a soil and nutrient improver.
Often these microbes are put directly into the sprayer in a powder form resembling talcum powder, or perhaps you are brewing your own and making a form of microbial tea and applying them that way. However, Soil Fertility Services prefer to select the various strains subject to the job at hand, cultivate them and then return them to a spore form (put them to sleep), that way they remain more reliably stable for storage.
Once applied the microbial workforce awakens, setting about the task at hand; however, to continue to thrive survive and multiply, they will need to eat, which could be organic matter or sugars from plant root exudates, the latter of which may take some time. Far better to provide the food source at the time of application and send the army to work with a lunch box. SFS prefer a mix that also contains trace elements and carbon foods that support better microbial development.
While Bacterial Management offers substantial benefits, there are several challenges and limitations, such as selecting the appropriate product, ensuring proper application and monitoring its effectiveness. Despite the significant advances in soil microbial ecology, there is still much that is unknown about the complex interactions between soil microbes and their environment. This lack of understanding can make it challenging to predict the effectiveness of microbial management techniques.
Over the last 25 years Soil Fertility Services have seen the tide shift as attitudes and understandings change. We all know of a farmer that got on well one season with a product while the neighbour who did exactly the same saw little change. As an industry, we are slowly realising that no two ecosystems are the same and should be respected accordingly. As we continue to learn more about the role of soil microbes in agriculture, there is great potential for the development of new strategies and technologies for managing soil microbial communities; all hold promise for a more sustainable and productive agricultural system in the future.
If you want to see biological farming in action, why not give SFS a call to see what can be done biologically and equally to the point of what does NOT need to be done.