In a series of lab tests, Princeton University has discovered that a relatively common soil bacterium has demonstrated its ability to break down the difficult-to-remove class of pollutants called PFAS. Acidimicrobium bacterium A6, removed 60% of PFAS in lab vials over 100 days of observation.
Healthy soil is full of tiny lifeforms – bacteria, fungi, protozoa, nematodes, arthropods and earthworms. A fun way to determine the biology in your soil is by performing the Soil Your Undies Challenge. This challenge consists of burying a pair of 100% cotton undies beneath your soil and digging them up two months later.
Dr. Judith Fitzpatrick, microbiologist and developer of microBIOMETER®, had the pleasure of being interviewed on the Galil Garden Podcast. Some of the important topics discussed include:
Microbes and pesticide use
Microbes affect on erosion
The microbial food chain
Microbial biomass (MB) can be used to determine if you are sequestering carbon, which improves soil and helps combat global warming. In 1989 Anderson and Domsch showed that increasing microbial biomass predicted an increase in soil organic carbon (OC).
Seasonal dynamics are a major driver of soil microbial communities. Much like you and I, microbes are more active during some seasons, and more dormant during others. This can be attributed to the different responses microbes have to nutrient inputs, climatic conditions, and other soil properties. As there are a lot of factors that affect microbial activity, it can be difficult for farmers or researchers to make definitive statements regarding the relationship between their soil microbial communities and seasonal changes. Specifically, temperature, moisture content, and the existence of plant life are considered the most important factors affecting microbial growth and activity within a season.
The presence of plants on the soil has a large impact on microbial life. As plants form, they begin to cultivate microbes surrounding their roots by producing nutrients for the microbes to essentially feed on. As the microbial community grows, they undergo a series of processes allowing them to obtain nitrogen and mineral nutrients from the soil and then provide the nutrients back to the plant to stimulate growth. This is part of the symbiotic relationship between plants and microbes– they support each other through the mining of nutrients from the soil and sun.
Just like plant presence, temperature greatly influences soil microbial properties. During cold seasons, temperature is considered a major limiting factor of microbial activity, whereas water availability could be a limiting factor during the summer season. Soil temperature can affect organic matter decomposition and mineralization rates, thereby impacting microbial biomass and activity levels. Bare soil, or soil without any plants growing, will have lower microbial activity occurring, regardless of season. This is why researchers and land stewards have emphasized the planting of cover crops between growing seasons in regenerative agriculture– as cover crops can alter soil properties and increase the biomass and diversity of microbial communities. In the warmer or hotter seasons, the addition of cover crops can also help to mitigate how much heat the soil is absorbing.
Studies show that microbial activity in agricultural soils increases in the fall when compared to other growing seasons–likely due to an increased level of nutrients and soil organic matter from crop and plant residue post harvest. Throughout the wintertime, or non growing season, microbial activity and composition is thought to be stagnant, but stable. An increase in microbial activity is said to occur after the thawing of frozen soils and can be linked to the freeze-thaw cycle (FTC) that colder climates experience. As snow freezes over soil, it inhibits air diffusion from occurring, creating anaerobic conditions for the microbial communities and therefore altering the soil community structure. In turn, this causes an increase in denitrification, respiration, and production of greenhouse gases, which are being trapped under the frozen layer. Once temperatures begin to rise, the soil begins to thaw, allowing oxygen into the soil. This provides labile carbon and other nutrients to the soil, which increases microbial activity and biomass. However, once thawing occurs, those greenhouse gases that were once trapped, are released into the air. This exact dynamic between microbial activity and the FTC is still being debated due to different soil properties greatly affecting freeze/thaw rates and as researchers use different methodologies, making it difficult to compare results between studies.
But despite the controversy surrounding the exact relationship between microbes and seasonal temperature changes, researchers do agree that microbial biomass and activity are related to seasonal temperature fluctuations. They’ve found that generally, microbial biomass decreases once the temperature increases past a certain point. As temperature increases, there is also an increase in CO2 being released from the soil, which we refer to as respiration. So when more respiration occurs, more carbon is being put into the air. This respiration process is sensitive to temperature change, which is why it’s imperative to have a better understanding of the seasonal dynamics of microbial communities.
As soil microbial life varies naturally by season, it might be hard to differentiate the natural seasonal changes from the changes related to your regenerative growing practices. Understanding the short term seasonal dynamics of microbial communities in various soil conditions is key in furthering our understanding of soil biology. Documenting and analyzing periodic readings with microBIOMETER® can assist you in differentiating between natural and seasonal changes in your soil.
References:
Bates, Todd B. (2018, Oct 10). How Plants Harness Microbes to Get Nutrients. Rutgers.edu.
https://www.rutgers.edu/news/how-plants-harness-microbes-get-nutrients
Bizzell, E. (2018, April 16). Plants and the bacteria at the root of it all. ASM.org.
https://asm.org/Articles/2018/April/plants-and-the-bacteria-at-the-root-of-it-all
Gao H, Tian G, Khashi u Rahman M and Wu F (2022) Cover Crop Species Composition Alters the
Soil Bacterial Community in a Continuous Pepper Cropping System. Frontier Microbiology. 12:789034.
Jensen G, Krogstad K, Rezanezhad F and Hug LA (2022) Microbial Community Compositional
Stability in Agricultural Soils During Freeze-Thaw and Fertilizer Stress. Frontier Environmental Science. 10:908568.
McDaniel, M. D. and Grandy, A. S.: Soil microbial biomass and function are altered by 12 years of
crop rotation, SOIL, 2, 583–599, (2016).
onwuka B, Mang B. (2018) Effects of soil temperature on some soil properties and plant growth.
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respiration and bacterial and fungal growth rates. FEMS Microbiology Ecology, 52(1), 49–58.
Simon, E., Canarini, A., Martin, V. et al. Microbial growth and carbon use efficiency show seasonal
responses in a multifactorial climate change experiment. Communicati
Fig Tree Organic Farm produce at the farmer’s market
Adam Jone’s Fig Tree Organic Farm in Queensland, Australia has moved to organic farming. This farm is one of the key producers of foods for the Organic Weekend Sunshine Coast markets, a famous destination for food consumers and tourists. Adam had spent a lot of his time trying a variety of different solutions to grow his crops for market.
Then, Adam met Bronwyn Holm, founder of Earthfood. Arriving on Figtree Organic Farm, Bronwyn and Adam tested the soil with microBIOMETER®; a soil test Bronwyn has been using for some time. The results showed Adam that Australian soil is damaged. This damage is caused by years of hot bush fires, extended lack of rain, overuse of chemicals, topsoil drying out and blowing away, nutrients locked up making soil water-resistant and land surface flooding. This is Australia. It is an ancient land of beauty with extremely damaged farms.
The microBIOMETER® test results also determined the soil was very low on microbes and fungi, and other tests showed it high in acid forming chemicals, probably from the previous owner. Adam was working hard making composting baths and worm juices, yet there was no deep repair due to many years of damage. The microBIOMETER® soil test was evidence that things needed to be done differently.
Bronwyn then explained to Adam the benefits of using Earthfood products which are made by using live microbes, and how they could change his farm’s health, crop yields, and increase his farm’s income. The two filmed a documentary on the farm just after planting. The original crops in the film were up to their knees and the trees to their waist.
Then after using Earthfood for three months, another microBIOMETER® soil test was performed, and they began to see some improvement. The crops seemed settled, and the pumpkin vine which usually has one crop per season had several wheelbarrows of produce. Adam was pleased with the results so far.
Bronwyn and Adam soil testing
At month nine, they ran more soil tests and took another collection of images and were excited about the changes. The soil under the cover crops was cool, and consistently damp when outside the farm boundary the environment was hot and dry. The trees were now two meters above their heads and all bush crops were up to their waist full of produce. The same pumpkin vine produced three crops in the same season and 2.5 tons of produce. The nine-month-old banana trees that were to their waist previously and not doing well were already fruiting and grown way above their heads. It would normally take eighteen months for these trees to grow and fruit. This outcome proved to be very profitable for Adam and he was happy with the results.
Since then, Adam has dove further into the regenerative farming and microbial world. He holds talks and field days, educating the public on the importance of microbes and syntropic farming. He’s found the crowds are getting bigger and bigger each time, which he believes is a result of consumers becoming more aware of their food and the environment in which it is grown.
Earthfood is excited to share their next documentary with us as well which they are currently finishing up. This documentary is on a farm which grows Heritage tomatoes, beans, squash, kale, dragon fruit, papayas, citrus trees, avocados trees, bell peppers, Japanese greens, bananas, and herbs of all kinds.
“Unless you can measure your soil foundations and biology, it is a guessing game on what can be grown to its potential,” Bronwyn said.
ABOUT EARTHFOOD:
Earthfood is rainforest in a bottle powered by live microbes. Historically handed down in my family since the mid-1880s and used in the Internationally awarded Hermitage Estate Wineries (Dalwood Estate now as one of them) when Eggert Holm, my great-great-grandfather, was their master winemaker using live microbes. With a soil scientist the IP for suspending the microbes to sleep so that the microbial concentrated solution can now be sent globally, and the microbes survive and thrive whether used in a pot-plant or on acres of farming food.
Earthfood has been supplying their liquid microbial concentrate to farms for the past 25 years, in the U.S., Central America, and Australia as well as in trials of vineyard owners in Bordeaux, France, and sugarcane farmers in Fiji, to name a few.
You’ve probably read how important it is for your soil to have a large, diverse microbial population, but how do you know that all those microbes are good?
Well to start, a healthy and optimal microbial population in your soil will always have a mixture of good and bad microbes. Together, these microbes perform important tasks to keep the soil functioning and the plants flourishing. Despite the complex relationship between plant and soil microbes, research suggests that soil microbes play a significant role in nutrient cycling, structuring plant communities, influencing plant performance and growth, and in disease control, which is why it’s so important to have a dense and diverse microbial community.
Thankfully, these soil microbe-plant interactions are self-regulated. And to keep these microbes functioning and plants thriving as they should, there’s a system of checks and balances that occurs within soil. For example, in a healthy, diverse soil mixture, microbes help plants suppress pathogens by inducing natural plant defenses, producing antibiotics, fighting against pathogens, or through the hyperparasitism of the pathogen. However, when there is an influx of pathogens in a not-so-healthy and diverse soil, things will start to function differently.
Once there’s a large enough influx of pathogenic microbes that have colonized within the soil, these microbes will produce chemical signals called autoinducers, which regulate microbial gene expression in a process called quorum sensing. In this example, quorum sensing allows those microbes to communicate with each other and change their genes to become virulent. Soil can become more susceptible to virulent factors if there isn’t adequate microbial diversity, as a diverse microbial community is critical to maintain ecological processes. To mitigate the negative aspects of quorum sensing, it’s imperative to have a diverse vegetation aboveground and a diverse microbial community belowground.
However, despite the good microbes’ best effort, soil conditions change and sometimes pathogens can take control. Depending on the pathogen, different physical signs and symptoms will become evident on the plant. Common signs of pathogenic disease on a plant can include foliage wilting, stunting, browning, and yellowing. Fortunately, because these are all aboveground symptoms, diseases can be easier to identify and potentially treat. Though, there are common belowground pathogens that affect the root systems of plants. These are more difficult to diagnose as they don’t always produce physical signs on the plant. The only way to specifically identify the pathogenic microbial species within your soil is to send your soil’s DNA to a lab for further analysis.
The best method that researchers have found to combat these soil pathogens is by supporting the good microbes, as the best defense is a good offense. Because microbial diversity has an almost linear relationship to microbial biomass, increasing the soil’s microbial biomass will increase its microbial diversity, which is the key to having a functioning and thriving ecosystem.
IngenuityWorx has been working to prove that the application of nanobubble oxygen as an irrigation/fertigation tool can provide low cost, easily applied plant benefits both indoors and outdoors.
It has been known for over 40 years that increased oxygen to plant roots in soil improves nutrient absorption, reduces effects of saline water or sodic soils, and increases plant growth and yields. However, traditional aeration technology prevented its use. Aerated water was limited to very short application duration and limited travel time in an irrigation line with low oxygen transfer efficiency.
The new science of nanobubbles allows us to add high dissolved oxygen concentrations, reaching 30-50 ppm, and the oxygen transfer will continue to take place for weeks. The nanobubbles don’t coalesce and break like macro bubbles, they move within the water using Brownian motion, and upon giving up all their oxygen produce small amounts of reactive oxygen species including hydrogen peroxide. This feature provides a built-in cleaning process that removes biofilm.
The microBIOMETER® analysis here shows that high dissolved oxygen in the irrigation water stimulated the microbial biomass and fungi to increase in number indicating a healthy microbiome in the soil for plant growth.
Additional work is ongoing to measure and understand the effects of the oxygenated water and microbial increases as it relates to soil carbon utilization, and its impact on carbon reserves and available nutrients. For more information, please contact bob@ingenuityworx.com.
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