We recently received the following questions from one of our customers and below are the responses from Dr. Fitzpatrick.
Part of my research is surrounding the soil organic carbon results we attained from microBIOMETER®, and I am wondering if someone from your team could provide more information on what this means relative to total organic carbon (TOC) in a sample and if they are comparable?
The literature shows a strong correlation between available organic carbon and microbial biomass carbon (MBC). Since your compost is not soil, the available organic carbon in your sample would be TOC and would correlate. MBC by microBIOMETER® is even better than that: a big number tells you that you have carbon and all the nutrients needed by microbes and plants.
Since MBC has correlations to TOC is there a formula or percentage to convert MBC to TOC? Or approximately how much MBC makes up a TOC number?
There is no formula to correlate TOC with MBC. TOC includes carbon that we consider stored as well as carbon that is easily available to microbes. Increasing easily available carbon for example by applying compost will increase microbes and eventually increase TOC, but as microbes rarely exceed 1% of TOC, it would have little effect on TOC short term. In long term stable systems we see a correlation but the correlation is not the same for example in forest as in agriculture as the capacity to store TOC is different soils under different conditions. In studying the effect of long term (40 years) different management systems at U. of TN on MBC and TOC, MBC by microBIOMETER® correlated with the TOC demonstrating the effectiveness of sustainable practice on increasing TOC and the positive correlation with MBC levels.
Does a high MBC usually mean a higher F:B ratio? And if so, could we draw any conclusions about carbon sequestration capabilities from that?
Generally as the MBC increases there is an increase in fungi. The soil food web is a balanced community. Some communities are more fungal dominated some less, but similar communities tend to have the same F:B ratio. It is generally believed that fungi, especially mycorrhizal fungi, contribute more to carbon sequestration than bacteria. This may be because glomalin is carbon rich and tends to sequester.
To further my understanding of soil/compost mixtures. I performed two microBIOMETER® tests. One test was on “active compost” which is compost in a medium stage of decomposition, and generates some CO2 and another one “finished compost” which is cured, ready for usage, and low CO2 production. However, I found that they had similar amounts of MBC and F:B ratio. Is this normal?
A study with microBIOMETER® at University showed a higher F:B in finished compost. The higher respiration/MBC indicates that your unfinished compost is still being digested — working microbes make more CO2. Holding MBC stable in your finished product is good.
We were excited to hear from our long-time customer Marcelo Chiappetta of Chiappetta Agricultural Company on how his microBIOMETER® testing has been progressing. Below is what he shared with us.
“Here in southern Brazil the past 5 years we’ve been working with biological agriculture and changing the way we see and manage our farm; more and more like an agricultural organism. Taking care of microorganisms, plants, animals and humans and focusing on producing high quality grains.
Fungal and bacterial ratio is fundamental to know how our soil is related to what crop we grow. And now, after starting to brew compost tea and using compost extract, microBIOMETER® is helping us measure and understand the right recipe of carbon and nitrogen related to the amount of fungi that we want to build in our composts before adding to the soil. We see that good microbial biomass along with organic matter is excellent for our soils.
In practical terms, we see biological flowering in crop fields and this is the proof that we are doing a great job with nature. Our soil is our bioreactor, and we need to feed it with the right nutrients. The Brazilian biome is rich on biodiversity and as farmers and soil guardians we have a responsibility to bring life back to our farm again in a sustainable way of producing food.”
Click here to read more on Marcelo’s soil testing.

Soil testing
Modern agriculture practices have led to the systematic degradation of the world’s soil and release of carbon into the environment. The effects are increased need for expensive and environmentally dangerous inputs (fertilizers, pesticides, and herbicides), the loss of fertile top soil, decrease in water holding capacity of soil and dangerously high levels of atmospheric carbon.
Farmers, industry, and environmentalists are looking for cost-effective and reliable ways to measure soil health, to assess impacts of progressive changes on soil and harvest management, and to measure carbon in soil. Before microBIOMETER®, growers have traditionally relied on expensive lab testing of soil. Many current methods are technique and individual lab dependent. Therefore, run-to-run and lab-to-lab variation can greatly affect consistency leading to increased variability. Current methods are performed in labs and the soil is aged and changed from the time of collection. Furthermore, lab tests are difficult to use in developing countries as they can cost upwards of $500 per sample. This makes the test prohibitive to some markets and limits the number of times a grower can test their soil.
Our mission at Prolific Earth Sciences is to enable soil stewards all over the world to use mobile technology and our low-cost soil test to assess regenerative soil practices, to improve soil health, and work towards increased soil carbon sequestration. microBIOMETER® equips growers with the data necessary to make decisions on which practices are the most cost-effective. Inputs such as fertilizers are expensive and changes to practice are risky. Monitoring soil microbial biomass inexpensively, in real time, can help a soil steward quickly assess if an input and practice is improving soil health and worth the investment. In other words, assess before you invest! We also envision microBIOMETER® one day being a powerful tool in the measurement and audit of carbon sequestration programs.
microBIOMETER® has been on the market for over 3 years with direct and distributor sales and currently has customers in over 20 countries.
Ralph Lett, head of product development at Acterra, was kind enough to share his microBIOMETER® experience with us. We love hearing the different ways our customers are using our soil test! Please contact us if you would like to share your soil testing story.
“Thanks for taking an interest in how our company is using microBIOMETER®.
Acterra is a bio stimulant company. We work closely with our sales partner, Bio-Active. Together we capture and solubilize diesel emissions in a fusion tank and then add a beneficial consortium of facultative microbes . This is revolutionary as it allows the farmer to make his own biological fertilizers while he is seeding and/or harvesting.
microBIOMETER® is a handy tool for us to measure the microbial weight of our bio fertilizers when we come in off the fields to refill our tanks . The microbes in our fusion tank reproduce incredibly quickly, much faster than a regular brewing process. If the microbial populations grow too quickly things can get plugged up and can cause problems. This is where microBIOMETER® is incredibly useful. We use it to keep an eye on the populations in our tanks so that if over populations occur we can quickly drain the tank and start over .
We plan to continue working with microBIOMETER® in the future. Our hope is that one day farmers will be able to sit in their tractors and know exactly the microbial bio weight of their biological fertilizers while they are farming their fields.
Never stop innovating !” – Ralph Lett
Last semester Soil Science and Environmental Pedology students under a supervision of Dr. Anna Paltseva [annapaltseva.com] conducted a soil microbial experiment on campus of University of Louisiana at Lafayette. First, each of the group of students collected different samples. Samples were collected from lawn, vegetable containers, around tree pits, and a native plants garden. The soil samples were analyzed in accordance with the provided procedure, which is simple and fast. The microBIOMETER® app tested the samples and gave each of the readings. The readings were in microbial biomass expressed in microbial-carbon per gram of soil (ug/g) and fungal to bacteria ratio F:B, F% and B%.
The vegetable container and samples from the tree pits showed the highest range of 400 – 800 ug/g. This is due to high organic matter content. The low results from the lawns may have been due to limited microbiological diversity due to monoculture of grasses grown. The areas close to the water bodies (culvert, pond, etc.) may have been lower due to organic matter washing away over time. All the samples were predominantly rich in bacterial population over fungal.
“microBIOMETER® is a very efficient and time saving tool. It can be used by scientists, farmers, or a gardener in learning the microbial health of their soil. This testing process is also very non-invasive, and thus having a lesser negative environmental impact compared to traditional testing. One of the students said, It was pretty cool using an app to analyze soil. I want to know how it works since it all felt like magic.” – Dr. Anna Paltseva
Click here to view the student’s video.
Order a microBIOMETER® Academia Kit for soil testing in your classroom!
If you are interested in Dr. Paltseva’s research or would like to learn more about urban soils, please follow her on Instagram.

Microbial Biomass Chart

In the spring and early summer of 2020, the Nutrient Management Spear Program at Cornell University conducted a soil survey of yield-stability based management zones on a New York dairy farm.
Ben Lehman, research assistant in the Nutrient Management Spear Program at Cornell University, completed a study on the Within- Field Variability of Soil Characteristics and Corn Yield Stability on a New York Dairy Farm.
Ben utilized microBIOMETER® in his research to determine the microbial biomass of the soil samples.
This study was presented at the 2020 American Society of Agronomy Annual Meeting.
Source: Cornell Center for Materials Research

Now imagine that I have 600 apartment buildings in NYC that each contain 1 million people, and I decide to check 10 apartments in 10 buildings at 4 p.m. to estimate the number of people actually in the building. Obviously, it would vary because people are not always in their apartment and different apartments have different numbers of inhabitants – the same is true for soil.
Soil contains microscopic aggregates of different sizes and the number and type of inhabitants in each varies on the physical and chemical composition of the space as well as the nutrient, pH and hydration level. Each sample you take is like looking at a number of different apartments in a number of apartment buildings.
For this reason, when conducting research, soil and medical researchers run duplicates or triplicates. Because of cost, soil labs generally do not run duplicates and they see 10- 25% variation. We are recommending running duplicates when using microBIOMETER® unless you are doing academic research. Generally, we see <10% variation for a given sample, and for a field that looks homogeneous. Pastures can have much higher variation because the nutrients level across the area varies tremendously.

He visited 28 different farms growing 15 different crops. 14 of these farms are practicing conventional farming, while the other 14 farms are practicing indigenous regenerative farming. Most sites are not receiving irrigation. He tested the soil with microBIOMETER® and ranked the crop health as poor (1), average (2), good (3), excellent (4).
As the graph shows, microbial biomass correlated with crop health under all these different conditions. Samples with microbial biomass lower than 225 were all poor (1) and samples above 400 were all excellent.
The take home lesson is that to improve your plant health and yield, increase your microbial biomass by feeding your microbes with organic amendments.
If you have microBIOMETER® research data you’d like to share with us, please contact us. We would love to share it with our readers!
Contact:. ka*******@***il.com
The effect of various Roundup formulations and microplastics on soil.
Dr. Sharon Pochron and her students at Stonybrook University in New York have been using microBIOMETER® for two years. Dr. Pochron studies the effect of various Roundup formulations and microplastics on soil microbes and soil invertebrates.
Her most recent publication (See Figure 2) shows microbial biomass increasing on day 7 in both the Roundup treated and untreated soils – the 0 line depicts the microbial biomass on day 0. This increase is probably due to the soil microbes responding to rewetting. By day 14 the microbial biomass in the uncontaminated soil is back to baseline, but the Roundup treated soil has dropped well below baseline. By day 21 both soils have returned to baseline. This study shows only total microbial biomass recovery, but there is evidence that Roundup can affect microbial composition.
Prolific Earth Sciences is supporting research at various universities. Feel free to contact us to discuss your project and how we can assist.

Considering the wealth of benefits, it’s no surprise that it is recommended that you do everything you can to maximize the microbial biomass in your soil. While there’s complicated science behind it, nourishing and increasing the amount of microbes in your soil is simple, and can be accomplished with a few tried and true methods. And thanks to the microBIOMETER® soil test, even amateur gardeners can track their microbial biomass levels.
First, let’s detail how you can take care of those important microbes and enhance their numbers. It’ll involve shedding some old gardening habits, along with taking on some new ones, but we promise the end results will be worth it.
What To Avoid
Before you start taking extra steps to care for and increase your microbial biomass, you should ensure you’re avoiding certain tactics that are known to hinder their growth.
While you might think avoiding pesticides wouldn’t enhance plant health, a close look at the ingredients of most pesticides will show you they do far more harm than good. Amongst a variety of issues, one of the most harmful is the fact they decimate microbial populations in the soil. If you want to ensure pests will stay away in the absence of pesticides, try utilizing companion plants instead.
While pesticides are bad, fungicides are even more of a threat. Some of the most vital microbes in your soil, being fungi, would be directly targeted by these treatments. The harshness of these chemicals would also wreak havoc on the non-fungi microbes, all but eliminating any trace of a microbial biomass. Even if you can’t do everything on this list, ensure you at least abide by this particular rule.
Lastly, while many gardeners and farmers consider tilling a standard gardening process, you’ll want to abstain from it if you’re focusing on your soil’s microbes. That, of course, is due to the level of soil disturbance that occurs during the process. The process leads to lost microbes (especially fungi), and any benefits gained from additions made to the soil end up being cancelled out. By avoiding tilling, you’ll allow the delicate environment in your soil to function undisturbed and, in turn, at full capacity.
What To Do
Now that you’ve cut those bad habits out of your gardening routine, you have room for a few that’ll greatly benefit your soil in the long run.
Nothing gets microbes into the soil like a nice big pile of compost! All that food breaking down in one big pile is basically a feast for all the helpful microbes you want around your plants. Once you add it onto your soil, then turn it to make sure air hits every part of it, you’ll be ensuring the microbes have plenty of energy to break down nutrients. To ensure the best compost possible, make sure you add in natural components like grass clippings, fruits, vegetables, wood chips, and straw. There’s no need to exclude other foods, even processed ones, but a healthy blend of green and brown material is a must.
Following the same logic, compost teas can do wonders for the microbes in your soil. All you have to do is take some compost and put it in a water permeable pouch, add some microbe feeding nutrients (perhaps like molasses), and let it brew (bubbling air into it) until the microbes in the compost have multiplied and the tea is full of microbes. Once done, pour it all around the base of your plants. One round will do your plants good, but repeating this process a few times during your growing process will really make a difference.
This last step is actually three steps and if these conditions aren’t met, virtually nothing else on this list will have a noticeable effect. To start, making sure you have adequate moisture is as simple as regularly watering your plants. You may also want to consider purchasing a moisture meter to assure your levels are ideal. Next, the ideal pH range for soil is between 6.0 and 7.0, so you’ll have to test your soil to see where you’re at. If your soil pH is too low try adding limestone and if your pH is too high you can add aluminum sulfate and sulfur to get things balanced. Lastly, mulching is a great way to help your soil maintain an even temperature.
Incorporating these simple tactics into your crop management is an important first step to building the microbial biomass in your soil. Another critical step is testing and quantifying the results of these inputs since decision making without data is like driving blindfolded. microBIOMETER® is a rapid, on-site soil test for microbial biomass. Microbes respond very quickly to any changes in the soil, therefore, you can set a baseline then retest within a week to see if you are heading in the right direction.