Soil and plant microbial communities have a mutualistic relationship where they provide what the other needs to thrive. There are many factors that can influence this relationship, such as soil structure, composition, and humidity, but soil pH has one of the most profound impacts on the growth and survival of plants and microbes.
When we measure pH, we’re actually measuring the local concentration of protons (hydrogen ions, known as H+). When there are too many H+ ions, the soil is acidic, resulting in a low pH. When the proton concentration is low (or a scarcity of H+ ions), the soil is alkaline (or basic) and has a high pH. Soil chemistry largely determines which microbial communities can get established in the soil.
Soil microbes are just as much affected by high pH as they are by low pH. When soil pH is in a neutral range (6.0-7.5, which is close to the pH of water), plants are more easily able to uptake the nutrients they need. For that reason, this is generally their optimal range. However, there are some plants such as blueberries or Rhododendron, that favor a more acidic soils. Not all microbes necessarily favor a neutral pH – fungi actually prefer soils with a lower pH. As acidic soils reduce the availability of certain nutrients, fungi are able to increase access to those limited nutrients for the plant to uptake. Still, challenges can arise for microbial communities when the soil pH deviates from its optimal range. While soil pH will naturally lower in time due to geochemical and metabolic processes, the soil pH can decrease rapidly with the input of certain fertilizers.
For example, when ammonium-based fertilizers are applied to the soil, bacteria use oxygen to convert the ammonium nitrogen (NH4+) to nitrate (NO3–), a more plant-usable form, and H+ ions, through a process called nitrification. Bacteria do this to obtain energy. If a plant needs some potassium, it will exchange one of its positive hydrogen (H+) ions for a potassium cation (K+) in the soil. This exchange helps maintain electrical balance through a natural process called cation exchange. However, this balance can be thrown off by over-application of fertilizers. As plants take up certain nutrients, it leaves a deficit of other nutrients, which can cause a decrease in pH levels.
If more fertilizer is continuously applied, more H+ ions are released, which can cause an imbalance in the soil and lead to soil acidification. The increased amount of H+ ions will directly affect the functionality and structure of the soil microbial communities. A low soil pH can disrupt plant cell membranes – altering enzyme production and limiting cell reproduction. Enzyme production and activity work best in more neutral pH ranges. As well, low soil pH can limit the exchange signals between root bacteria (rhizobia) and plants, which reduces root nodule formation, and alters the symbiosis that allows plants to fix nitrogen.
Overall, maintaining a balanced soil pH is crucial for ensuring nutrient availability and more importantly, microbial diversity in your soil. As deviations in pH can disrupt essential processes like nutrient uptake, enzyme activity, and the communication and functioning of symbiotic relationships between plants and soil microbes.
Amanda Foxon-Hill, a chemist by trade, is working with Mid Lachlan Landcare in the region of NSW, Australia. Mid Lachlan Landcare is a community organization committed to the regeneration of land. Their work includes Regenerative Agriculture, Box Gum Woodland Conservation, Superb Parrot Habitat, Community Gardens, Education & more. Cowra is the main town in their Landcare region which consists of various soil profiles. It is rich in farming land with cropping and grazing.
Amanda designed and performed a soil research project funded by the BCT (Biodiversity Conservation Trust). She took soil samples from farms, conservations and public land across the region to map their soil microbiome. Her goal was to see if she could establish a ’normal’ or ’typical’ range of microbes for each type of landscape and soil.
Amanda looked at grazed vs ungrazed land, mono-cropping vs mixed pasture etc. but that was really secondary to the soil geology and microbe link as there was a short window to complete this round of tests and farm management decisions such as what crop to grow, for instance, requires testing over multiple time points.
As part of the project, Amanda trialed microBIOMETER®. Microbes are essential for soil fertility and almost all plants work cooperatively with microbes to access the nutrients they need to thrive. The relationship between plants and microbes is dynamic; changing with the season, how the land is managed, plant species and life-stage, climate and the soil structure and composition.
“Overall, we feel this project has successfully delivered insights into how the Mid Lachlan region’s soils microbiome functions with respect to landscape features and management decisions although it’s clear there’s still a lot more work to do. Also, after putting the microBIOMETER® through its paces we believe it’s a useful tool for those looking to gain a deeper understanding of their soil. Our advice would be to use the microBIOMETER® or similar microbiology assessment tool/ protocol alongside your existing soil testing tools, at regular intervals to monitor the effect management decisions have on the soil microbiota over time.”
Emil Racelis, a 6th grader in McAllen, Texas, utilized microBIOMETER® in his science fair project at IMAS (International Museum of Art & Science) and was awarded 3rd Place in the middle school division!
As a control, Emil tested three different store bought bagged soils with microBIOMETER®; top soil, organic potting soil and commercial potting soil. The top soil had a very low levels of microbes while the organic and commercial potting soils had a high level of microbes. Emil then collected soil samples in his community garden from areas with high plant diversity (five or more species in the sample plot) and areas of low plant diversity (areas with two or less species per sample plot).
His hypothesis was that areas with higher plant diversity would have more microbes, but that is not what he found. There were low/medium levels of microbes in all the plots sampled, therefore, no solid conclusion could be made. Emil believes the results stemmed from drought conditions they were currently experiencing in Texas. The garden was watered sometimes, but not that much. Emil would like to do more microBIOMETER® soil testing in the future during a season with more rain.
“I had a lot of fun using the tests and I got some pretty cool results even though they were not what I expected. I found the process really interesting and the test easy to perform. I hope I get to use microBIOMETER® again some day.” -Emil Racelis
“Emil really got into this project, and was fascinated by what he found, which only leads to more questions! Now he really wants to do more experimenting to see what helps the soil microbes. We have a garden, and he is talking about testing the results of compost tea, and other organic additives, as well as looking at the affect of drought vs rainy season. We may have to save up for more tests! You got us hooked! It was so cool to see him using the tests independently. I love how user-friendly your system is.” – Alison, Emil’s mom
Please click here to view more science fair projects using microBIOMETER®. If you would like to include microBIOMETER® in your next school or science fair project, contact us for details!
PADK is an NGO dedicated to building capacity in regenerative agriculture techniques and soil science research. Their main initiative and focus, the Tropical Agriculture Research and Training Station (TARTS), is in the small village of Ngotto, in the East Region of Cameroon. The company’s objectives are to:
• Produce highly biodynamic and performant soil amendments.
• Restart the microbial activity of tropical soils, increasing nutrient availability, and alleviating the pressures of chemical fertilizers and pesticides.
• Increase local small-holder farmers’ knowledge of soil ecology and provide them with tangible resources to improve and regenerate their farmland.
A variety of logistical factors impeded their workflow while utilizing microscopy in their labs. Sampling was infrequent and irregular, tracking the F: B progression was difficult, and correlating with climate data and environmental parameters was near impossible.
In early 2022, Founder, Mr. Edmond Nader, came across the microBIOMETER®. Since then, they have accelerated their R&D efforts, and their results have benefited from more consistent monitoring. The benefits they have discovered while using microBIOMETER®:
• Process samples, measure the F:B ratio, and record the results using the mobile app’s Data Capture functionality, in about 20 minutes. The data capture has been a very welcome surprise as its simple to follow the evolution of substrates tested with the database and share results.
• Correlate data from other experiments and compare against our microscopy results.
• Accurately track the shift from bacterial dominance (i.e. thermal phase) to fungal dominance in their composting efforts.
“The microBIOMETER® has been an invaluable tool. It has helped our organization to better document results and follow the evolution of our efforts. We have found results to be accurate against most of our microscopy verifications and we trust the results. We are eager to share our experience with this tool with others and promote its use in sub-Saharan Africa, tropical climates, and elsewhere. There are few useful field tests available, especially useful in such rural areas as we work, the microBIOMETER® has been a very welcome addition to our laboratory and field studies.”
The Carbon Sponge Hub at White Feather Farm has been awarded a 2024 Northeast SARE Farmer Grant to lead a network of five small farms in New York’s Hudson Valley region to continue to trial and evaluate white-grain, annual sorghum for yield and changes in soil health while also evaluating a suite of off- the-shelf field monitoring tools, including the microBIOMETER®.
The five farms are: Coming Home Farm, Foxtrot Farm & Flowers, Nimble Roots Farm, Sweet Freedom Farm and White Feather Farm. Sorghum, originally from East Africa, has great potential as both a human food and climate-smart crop capable of helping sequester carbon in soil. Farmers in regions where sorghum has not been widely grown, like the Hudson Valley, can take advantage of the plant’s ability to adapt to a wide range of conditions and provide ecosystem services on farms — especially increasing soil organic carbon — while also generating revenue.
Alongside field testing, Carbon Sponge will send samples to two professional labs and work with soil scientists to analyze results. The goal is to endorse specific tests and carbon targets for farmers. Carbon Sponge is interested in changing the profile of sorghum in the U.S., including where it is grown, how it is grown and what it is used for. A final report featuring the five farm case studies and recommendations for how to incorporate annual sorghum as a cash crop on a small farm and priorities for future research and investments will be published in 2025.
During the 2024 season, Carbon Sponge will host public workshops and community volunteer days to share research, like during Soil Fest at White Feather Farm on July 27.
Our customer Living Water has been utilizing microBIOMETER® to enhance their approach to sustainable farming and to refine their microbial treatments, ensuring they meet the specific needs of each farm.
Their innovative system integrates with the existing irrigation setup to distribute beneficial microbes effectively. With the help of microBIOMETER®’s soil testing, they are able to analyze microbial biomass and adjust the microbial mixes they provide each month, ensuring optimal soil health.
Sales rep Brent taking a soil sample at one of the farms in West Texas
Leveraging microBIOMETER® for Increased Soil Health
Our customer Living Water has been utilizing microBIOMETER® to enhance their approach to sustainable farming and to refine their microbial treatments, ensuring they meet the specific needs of each farm.
Their innovative system integrates with the existing irrigation setup to distribute beneficial microbes effectively. With the help of microBIOMETER®’s soil testing, they are able to analyze microbial biomass and adjust the microbial mixes they provide each month, ensuring optimal soil health.
Key Benefits:
Living Water and microBIOMETER®’s collaboration is the result of their shared passion for soil health and their quest to transform farming with data-driven microbial management.
About Living Water: Living Water is a visionary agricultural technology company with a mission to redefine the way farmers approach soil health. Their flagship product is a subscription-based automated microbe bioreactor that seamlessly infuses essential nutrients into every irrigation cycle. Designed to deliver maximum efficiency with minimal labor, this innovative system eliminates the need for labor-intensive hauling, mixing, or application processes. Learn more at WeSaveSoil.
Soil testing in Mexico
In the Pacific region of Mexico (state of Sinaloa), many vegetables are grown mainly for export to the United States and Canada. The soils in these crops have been greatly affected by the intensity of their management, which has unfortunately caused a considerable loss in their fertility and microbial biodiversity. In lieu of this, the use of biotechnologies based on microbial complexes is currently being highly promoted in order to inoculate the soils and recover part of the natural fertility. This is being performed alongside the use of other organic tools such as algae extracts, humic/fulvic acids, and liquid composts.
Mydagro LLC is using microBIOMETER® on vegetable plots where their biotechnology E-Microzyme (mix of beneficial bacteria) is inoculated into the soil. Their results have shown an increase in microorganisms and yield compared with the check plots. With the use of the microBIOMETER® soil test to measure the microbial increase quickly, it is now possible to better understand the behavior of microbiology and the positive effects of this type of horticultural crop.
“microBIOMETER® has proven that the use of biological and organic technologies can substantially help with the renewal of worn-out soils and gradually revitalize them to boost the productivity and health of the crops.” Fernando Cantu Galindo- Technical advisor Mydagro LLC Mexico
The image here shows an example of before (control) and 4 weeks after application.
Worm Power, a world leader in organic vermicompost products, helps growers improve crop yield and plant performance through increased root development and plant nutrient uptake. Worm Power’s Vermicompost Liquid Extract is shelf-stable soil amendment from liquid worm castings that have hundreds of diverse bacteria species.
The company currently utilizes the microBIOMETER® test to evaluate field trials on how their product is impacting the soil when compared to an untreated control. They like having the ability to show growers that the product is functioning as intended for increasing microbes in the soil.
Many specialty crops sterilize the soil to avoid pathogens. The addition of Worm Power’s products strives to bring soil back to a healthy and functional microbiome. microBIOMETER® provides the grower a visual measurement of the microbial community over time and the improvements gained with each application of their product. Healthy soils promote healthy plants and having a diverse microbe population is critical to this process and the microBIOMETER® provides a great tool to support their efforts.
“microBIOMETER® lets us see immediate results rather than waiting to see the increase in yield at the end of the season.”
Holganix utilizes the microBIOMETER® test as a baseline for their customers to see the fungi and bacteria levels present in their soil. These results act as a starting point. Most of the soil initially tested is bacteria dominant. That is what the company is trying to change. The Holganix product used to amend the soil is fungal and protozoa dominant. By increasing these levels, they are increasing the soil health on their customer’s farms.
