Author: Adam Fitzhenry Date Posted:30 November 2018
They might be small, but microbes are causing a stir in both the farming and gardening worlds! Microbes and a healthy soil biology are believed to improve the quality of produce and some results have even shown plants displaying...
Would you believe us if we told you there are more microbes in a teaspoon of soil than there are people on the earth? We’re not trying to make you feel small, but it’s the truth.
Of late, international interest in soil microbes has skyrocketed. While the science of soil microbes has long been popular among organic farmers and biological farms, it’s a concept that has recently gained significant traction with conventional famers and lawn and garden enthusiasts.
What many think of as ‘just dirt’ is actually a complex combination of rock-derived minerals, plant-derived organic matter, nutrients, gases and interacting organisms.
Microbes and a healthy soil biology are believed to improve the quality of produce and some results have even shown plants displaying resilience to frosts, diseases and weeds.
So, let’s dig a little deeper and see why microbes are taking the farming and gardening worlds by storm!
What are soil microbes?
Microbes have been described as the ‘probiotics’ of the plant world. These microscopic organisms live in healthy soils and are essential to the formation of well-structured soils with high water-holding capacity and high nutrient status.
It would be fair to say healthy soil is like a thriving village - just one handful could contain thousands of microscopic species! These microbes work together, much like a community, forming networks, breaking down complex organic materials and transforming nitrogen from an inert gas into a plant-usable form.
Beneficial soil microbes will often form mutual agreements with plants, with plants exerting up to 30 per cent of their energy to the root area to make food for microbes. In return, those microbes will protect the plant from stress and feed the plant by converting and storing nutrients in the soil.
Why we need to improve our soil
Soil degradation is a real issue and threatens our ability to produce high volumes of healthy produce. Over the past few decades, our soils have been ploughed, tilled and experienced an over use of fertiliser.
Ploughing and tilling has increased the erosion on our agricultural fields by 10 to 100 times the natural rate and loss of soil organic matter has increased our need to rely on fertilisers, pesticides and herbicides.
Functional soil is full of organic matter and soil microbes that work together to hold onto nutrients and convert those nutrients locked in the soil.
In healthy soils, organic matter is protected from decomposition by aggregates, but tilling crushes aggregates, releasing their carbon and allowing microbes and soil fauna to attack it. While this may provide a temporary nourishment for the microbes, it quickly depletes and leaves them without a food supply.
Without a healthy microbial, nutrients fail to recycle, pests can invade and the need for chemicals to replace biological soil functions is increased.
Why do soil microbes matter?
While a lot of modern research has focused on restoring soils with the addition of organic material, new research suggests that by enhancing a functional and active soil microbiome, our soils will experience an accelerated regeneration, beyond those typical rates seen in nature.
University of Minnesota Professor Linda Kinkel is leading international research efforts to learn more about microbes and theorises that if good microbes are strengthened, there will be less need to eradicate the harmful ones.
“We could be reducing inputs of nitrogen, phosphorus, potassium, pesticides for disease control. All of those could be reduced based on optimising microbes,” says Professor Kinkel.
Internally recognised Soil Scientist Cr Christine Jones has also been studying the benefits of microbes and says increasing the diversity of microbes in soil improves the quality of crop.
"If we have sufficient microbes around the roots, they can alter the gene expression of the plant so it is able to defend itself from insects and pathogens" Dr Jones said.
"Furthermore, plants are able to extract, through stimulating specific microbes around their roots, all the nutrients they need."
While scientists are still making progress in understanding soil microbes, there has already been some compelling results - so this is one subject we’ll have to keep a close eye on!