4 Reasons Why Any 21st Century Gardener Needs to Test for Soil Microbes
Is your cannabis garden lacking nutrient absorption and growing too slowly to your liking?
According to research by the UK Centre for Ecology and Hydrology, a teaspoon of topsoil is said to contain up to 1 billion individual microscopic cells, as well as about 10,000 different species.
Microbes are exceptionally diverse in both form and function, which explains why they are central to every form of life on Earth.
Their tasks are numerous and often include purifying the environment, ensuring crop fertility, regulating the carbon storage stocks, as well as the production and consumption of greenhouse gases (methane and nitrous oxide).
However, despite the vital role of soil microbes in food production and sustainability, very little is known about their functional roles within an ecosystem, biodiversity, the mechanisms altering their population, and their interaction within the ecosystem.
Can this knowledge improve the health of your cannabis garden?
To address your concerns and make up for this lack of knowledge, we will cover the following areas:
- What are microbes?
- Importance of soil microbes
- Why is testing for soil microbes important?
What Are Microbes?
Microbes are the smallest organisms with sizes below 0.1 mm in diameter, and are abundant in soil. Because of their size, they are called microscopic organisms and include bacteria, archaea, viruses, algae, protozoa, nematodes, yeasts, actinomycetes, and fungi.
Where can you find these microbes?
These organisms can exist on top of the soil or in the subsoil, and can be observed using a microscope.
Microbes transform organic matter into plant nutrients that are assimilated by plants. Two main groups are normally found in agricultural soils:
- Mycorrhizal fungi
Bacteria and fungi make up the microbial biomass and are affected by many soil properties.
Many more microbes can exist in the topsoil than the subsoil. In the topsoil, the food sources are more substantial, serving as readily available nutritional sources in places immediately next to plant roots called the rhizosphere, where roots release sloughed-off cells and chemicals.
Importance of Soil Microbes
Microbes represent the main requirement for soil nutrient cycling, playing an important role in the plant's survival. The level of the soil, nutrients, health, and richness depends on the structure and functions of the microbial community and activity in the soil.
Microbes also play an important role in ensuring the mobilization of nutrients and their uptake via the plant roots. They promote healthy plant growth and suppress disease through their various metabolic activities.
Microbes are responsible for the solubilization of chemicals like phosphate and sulfate, plant growth promotion, siderophore production, decomposition of organic matter, nitrogen ﬁxation, denitriﬁcation, immune modulation, removal of harmful chemicals, signal transduction, and pathogen control. These are some of the microbial processes that promote plant growth and protect them from disease.
Let us look at some of the important microbial functions:
- Nitrogen fixer:
Microbes, like bacteria, are responsible for fixing nitrogen in the soil. This means that they transform nitrogen into a form that can be used by the plant in the food chain.
Bacteria do this by converting atmospheric nitrogen into ammonia molecules, nitrate molecules, and nitrite molecules, which are essential for plant growth.
In legumes, the microbe Rhizobium lives in nodules on the roots of the plants in a symbiotic relationship. This means both the Rhizobium microbe and the plant benefits from the association. The plants provide a place in their roots for the microbes to live, while the microbes return the favor by fixing nitrogen that can be utilized by the plants.
The nitrogen-fixing microbes can help the plant by invading the root hairs of host plants, where they multiply and stimulate the production of root nodules, plant cell expansion, and the promotion of bacterial association.
Within the nodules, the microbes then convert free nitrogen to ammonia, nitrate, and nitrite molecules needed by the host plant to grow, ensuring the formation of the required nodule to facilitate maximum growth in plants like alfalfa, beans, clovers, peas, and soybeans.
Their seeds are usually inoculated with the required Rhizobium species, mostly in soils containing poor or inadequate microbes.
- Helps to decompose organic matter:
Microbes are like the housekeepers of soil. Without microbes, all the nutrients the soil needs from dead plants and animals will remain accumulated. Microbes clean up the dead plant and animal remains by breaking it down into smaller particles, which is then returned to the soil as nutrients where it is utilized for growth.
If microbes are damaged or die in the soil, the whole biochemical cycle of the soil is affected. If this should happen on a large scale, all the plants in a particular farm or field could die.
- Removes harmful chemicals:
The process of waste management where living organisms, like microbes, are used to neutralize or remove harmful pollutants from contaminated soil is known as bioremediation. This is a biological process of recycling wastes into another form that can be used and reused by other organisms.
The world as we know is facing so much environmental pollution because of industrialization. Microbes are important in combating this problem. Microbes can survive anywhere in the biosphere due to their complex metabolic activities.
The nutritional capacity of microbes is completely different, making them suitable for bioremediation to solve the problem of environmental pollutants.
Bioremediation involves the degradation, eradication, immobilization, or detoxification of different types of chemical waste and physical hazardous materials from the surroundings with the help of microbes when chemical industries release waste like hydrocarbon, oil, heavy metal, fertilizer, pesticides, and dyes into the soil.
Microbes remove these chemicals via degradation and transformation. This is achieved enzymatically through metabolization, removing harmful chemicals from the soil over time.
- Produce a growth-stimulating product:
Microbes produce siderophores that stimulate plant growth. Siderophores are low-molecular-weight secondary metabolites produced by microbes. This product is important when there is iron deficiency in the soil. Plants that are deficient in iron can obtain it from microbe-producing siderophores.
- Suppress disease organism:
Pathogens are responsible for plant diseases. With the presence of microbes in the soil, the pathogen may not be able to establish itself. If it does establish itself it may fail to cause disease.
In extreme cases, it can establish itself and even cause disease initially, which then declines with a continuous monoculture of the host crop. The microbiological makeup and activity of the soil play an important role during this process.
The soil is a host to many important microbes. Plants whose roots are enriched with these microbes can withstand certain plant diseases because these microbes help to improve plant health.
Certain soils can protect plants from specific diseases due to the presence of microbes. These soil microbes are referred to as disease suppressive soil microbes, and protect plants from the effects of pathogens causing plant disease.
Recent advancements in DNA sequencing technologies and data analyses have enabled scientists to identify certain soil microbes that can contribute to disease suppression by improving the immunity of plants.
Why Is Testing Soil Microbes Important?
Research shows that between 1ooo to 2000 times more microbes are found near active live roots than in tilled soil. The active roots are responsible for supplying between 25% to 45% of the total root carbohydrates required to feed the microbes.
But do you really need to test soil microbes? Is it necessary or negligible?
Testing soil microbes is important for the following reasons:
- Some microbes are not important to the soil:
There are five different types of soil microbes:
Each of these has a different role in either boosting soil and plant health or harming soil nutrients and plant immunity.
Actinomycetes are important microbes but since some are pathogenic, they will harm the plant.
The potato scab disease is known to be caused by a type of Actinomycetes called Streptomyces scabies. It attacks various underground vegetables, producing a phytotoxin called thaxtomin that causes necrotic lesions in potato plants.
The nematode is another microbe that can be predatory, and are worms that live around or inside the plant. Actinomycetes and nematodes can only be detected via testing to determine their harmful potential.
- Several conditions determine the population of soil microbes:
You have seen how the presence of microbes in the soil affects plants. It is important to note that all soils do not have the same number of microbes. For microbes to grow successfully there must be a supply of water, this is very important because microbes cannot survive in dry areas.
The soil should contain a good amount of carbon. Virtually all chemical substances in microbes contain carbon in the form of proteins, fats, carbohydrates, or lipids.
Carbon can be obtained from organic materials in the environment, or it may be derived from carbon dioxide in the atmosphere. Other soil requirements for microbial survival include substances like mineral elements, growth factors, phosphorus, nitrogen, and gas, such as oxygen.
Not all types of soil meet the above requirements, and we know without them microbes cannot multiply. If microbes cannot multiply, plants cannot grow. So, it's important to carry out a soil test, which is the most reliable way to identify the microbial activities in the soil.
- Helps to reduce waste while addressing soil challenges:
The first thing farmers do when they discover that their plants are not doing well, is apply chemicals. However, there is a process before proceeding with chemical testing.
When you apply a chemical, such as fertilizer to the soil, it draws out the moisture from the plant and then forces its way into the plant through a very interesting and complex process. The fertilizer should not build up in the soil. Using salt-based fertilizers inactivates the microbes, even killing them in extreme cases.
A USDA publication reported that 20% to 80% of all fertilizers applied to plants are never used up, what a waste. What farm owner would accept that? Testing helps to manage the soil’s particular challenges, whether its salinity, compaction, low organic matter, or low water holding capacity.
With testing, you can determine the holding capacity of the soil, and reduce fertilizer inputs, which kills microbes and makes it more efficient. Soil microbes are easily disrupted by tillage, fertilizer, pesticide salts, and compaction, disturbing the soil’s natural processes.
Testing for biological activity helps you to get back on track, allowing the organisms to work for you rather than waste a huge amount of money on buying chemicals to improve plant growth.
- Different plants have their preferred microbial communities:
Plants are very selective with the microbial communities they associate with. Testing soil microbes will help determine the balance of different microbes present in the soil. This information will be useful when deciding to plant.
Any type of plant you are trying to grow has certain kinds of microbes it likes to exchange nutrients and minerals with.
How do you know if your soil and plant communities are well-matched?
The most effective way is through testing. Testing helps to reveal the microbial balance in your soil allowing you to determine the type of support to give your plant while growing.
So, Are You Ready To Get The Most Out Of Your Soil?
Understanding how soil microbes work and are distributed can help to improve your understanding of vital interactions between soils and the ecosystem. This knowledge has the potential to impact food security, water security, and climate change.
Do you want to enrich your soil, improve your crop health and yield, use less fertilizer, use less water, and have fewer pesticides to deal with?
Are you worried about how to revive your poorly-performing garden?
At Plant Revolution Inc., we want to empower successful gardeners like you, educate you on how to improve the health of your soil, and show you how gardening can heal you, the ecosystem, and the planet.