Zack Shier, Joseph Tree Service
Effects of Humate and Organic Based Soil Treatments on Urban Soil Characteristics
Zack Shier, Board Certified Master Arborist and Plant Health Care Manager at Joseph Tree Service, is utilizing microBIOMETER® in his study titled Effects of Humate and Organic Based Soil Treatments on Urban Soil Characteristics.
Introduction to the study. Urban soils have long plagued tree care providers with a difficult obstacle to tree health optimization. The very nature of how our urban soils come to be makes it quite challenging to diagnose the major issues with our soils, let alone correct those issues consistently, and with enough efficiency to make it affordable to clients.
When buildings or homes are built in our cities and towns, the natural layout and structure of soils is heavily modified, and often changed in erratic ways. Large holes are dug, bringing soil horizons meant for the deep areas, to the surface; mixing heavily with surface horizons. The top O and A soil horizons are often scraped clean to level surfaces, moving them or completely taking them away. Outside products, like “clean-fill” are often brought in, adding foreign soil or even rock (like quarry, limestone fill) into the surface soil area.
On top of this sub-par growing medium we’ve created, we also plant turf or put asphalt and concrete into most of the area. We then rake up and get rid of all organic litter and material, continually robbing the soil of the reincorporation of organic matter that forests are accustomed to. To add to the problem, urban trees are grown quickly using synthetic fertilizers on tree farms, and then dug up to be planted, cutting anywhere between 50-90% of their roots off, and often planted in different soil than they were grown in.
This entire predicament creates poor chemical, physical, and biological soil characteristics, resulting in poor urban tree growth, increased insect and disease populations, and high rates of nutrient deficiencies. (Read more)
This article was provided to us by Scott Hortop, a retired volunteer and now student of soil, located in the Ottawa Valley, Ontario, Canada. Scott wants to use his retirement to do one important thing for the climate.
At ONfungi we own two microBIOMETER® soil testing kits which we use to determine the fungal to bacterial ratio (F:B) of the Johnson-Su fungal dominant compost (FDC). The ONfungi group makes FDC from tree leaves.
We are excited by the potential of leaf mold to:
• Reduce agricultural dependence on external inputs• Divert leaf organics from landfills• Replenish the inventory of carbon in the soil by drawing down the carbon in the atmosphere• Grow knowledge about working with mother nature to address climate change
Our first FDC bioreactor batch was started in Spring 2018. Since then, we have put up a total of 15 batches; 8 of them in fall 2021.“It took us 3 batches before we faced the fact that we needed to know whether what we were producing was actually what we hoped it was. Our enthusiasm needed to be grounded. What is the fungal bacteria (F:B) ratio in our FDC?,” says Scott Hortop, wizard of compost for the ONfungi group. “This is why we have found the microBIOMETER® to be our most useful tool.”“Dr. David Johnson’s talks have shown us eloquently how the F:B ratio is the most meaningful indicator for soil health”, Hortop explains. “As we share our fungal dominant compost (FDC) with other users, we owe them a solid measure of what they are getting. When we and others share our FDC experiments with each other at the Chico State University Registry of Johnson-Su Bioreactors, the majority of us have been unable to report F:B ratios. This has now changed. With the microBIOMETER® we can confirm that we have the right ratio of ingredients by taking a real measure of the F:B ratio.”Its All Relative – Isn’t it the change and the direction of changes that we really need to know? Of course, it might be nice to think every microbe was identified and counted under a microscope, but that precision comes at a HUGE cost and most likely doesn’t alter the conclusion. The next thing we need to do to strengthen the microbial community.
Immediacy – When you are checking in on living microbes in soil, some of whom are reproducing and dying in a matter of minutes and others taking years, the best timing for a test is here and now. In a world rich with distraction and delay, its awesome to get a result from your testing efforts immediately.
True Cost Per Data Point – For the purpose of our bioreactors, give it a think: the modest variable costs per test, the modest labour to execute a test which is just minutes beyond the time required for sample collection, the VERY efficient and effective recording of results, and the $0 sample shipping cost.
In an ONfungi citizen science trial last summer by one of our volunteers in White Lake, Ontario, 2 sunflower seeds were planted in late June into moderately degraded farmland (microBIOMETER® F:B 0.7:1; 464 µg C/g).The control seed (left) received no soil amendments. The 2nd seed (right) was planted with 50 grams (a small handful) of Johnson-Su fungal dominant compost (microBIOMETER® F:B 1.7:1; 700 µg C/g) surrounding the seed. For 8 weeks both plants received identical, adequate watering. The 8-week photo below shows the control sunflower on the left suffering from an invasion of cucumber beetles with less than ½ the height and 1/3 the stalk width compared to the sunflower on the right with FDC at its root zone. Although beetles were observed on the FDC sunflower, some disease resistance was evident.One of ONfungi’s targets this year is to do monthly tests on completed FDC material to chart the staying power and degradation curve of finished FDC, not yet put to use and in several storage modes. We are also using the microBIOMETER® to look at carbon sequestration in lawn soils.About ONfungi; ONfungi is a happy conglomeration of active volunteer folks. Their goal is to explore, through citizen science, the use of Johnson-Su fungal dominant compost (FDC) in improving soil, storing carbon, and enhancing plant health and nutrition. Learn more at ONfungi.net
microBIOMETER® can tell you if you are increasing the nutrient value and disease resistance of your crop.
A Rodale study showed greatly increased levels of the vitamins and minerals in sustainably farmed soils as opposed to mineral fertilized crops. And at Rodale, the sustainable practice yields are the same as the paired fields farmed with mineral fertilizers – and in bad weather, and disease years significantly better. Rodale is only one of many studies showing the increased nutrient value of organically and sustainably grown food.
Now Dr. Montgomery of the University of Washington’s team in a similar study has shown that if you are increasing your microbial biomass you are increasing the nutrient level of your crop: “soil health is a more pertinent metric for assessing the impact of farming practices on the nutrient composition of crops”.
Biklé, A. and Montgomery, D.R., 2021. Soil health and nutrient density: beyond organic vs. conventional farming. Frontiers in Sustainable Food Systems.
Hepperly, P.R., Omondi, E. and Seidel, R., 2018. Soil regeneration increases crop nutrients, antioxidants and adaptive responses. MOJ Food Process Technol, 6(2), pp.196-203.
University study demonstrates legumes are more efficient at improving soil MBC than grasses
Under the direction of Assistant Professor Denise Finney, Kylie Cherneskie, biology student at Ursinus College, conducted an experiment on the impacts of nitrogen fertilizer addition on soil microbial communities. Kylie measured microbial responses using microBIOMETER®.
Click here to view the finished poster presentation. If you would like to incorporate microBIOMETER® into your classroom studies/academic research, we offer a selection of Academia Classroom Kits.
Calibration of microBIOMETER® to units of µg microbial carbon / gram soil
The gold standard of laboratory soil microbial biomass testing is Chloroform Fumigation and Extraction (CFE). The multiple steps, time, and labor involved with CFE require pricing at up to $500 per sample. CFE works by comparing the difference of chemically extractable carbon between two portions of a soil sample: One that has been treated to break open microbial cell membranes and expose the carbon-containing biological molecules to extraction, and one that has not. The difference in carbon for the two portions is reported as microbial biomass carbon (MBC), in units of µg C / g soil.
microBIOMETER® is calibrated to the same units by a different method. Estimates of bacterial dry mass converge at around one trillionth (1×10-12) of a gram (1 pg) for a 1 µm bacterium. We measured the area of microbes in known volumes of microBIOMETER® extract (both by manual counting on a hemocytometer and by digital analysis of micrographs) and calculated total microbial mass, which was then converted to µg / g for the whole 0.5 ml sample of soil in the extract. We found that on average, 0.5 ml of soil weighs 0.6 g when fully dried, independent of starting moisture content. The 1 pg dry mass per bacterium is 50% carbon, so we also had to account for that in our calibration.
Here’s an example of the conversion.
Let’s say that in 1×10-8 liter (10 nl) of microBIOMETER® extract we measured 240 µm2 of microbes. 240 µm2 = 240 bacteria equivalents (BE). 240 BE x 1×10-12 g per BE = 240×10-12 g of dry microbes. The volume of original extract is 10 ml (1 x 10-2 liter), and 10 nl of microscopically examined extract represents 1×10-8/1×10-2 = 1×10-6 of the total mass of the microbes in the extract. So 240×10-12 g microbes / 1×10-6 = 240 x 10-6 g microbes in the whole extract. 50% of the 240 x 10-6 g of microbes is carbon, so we have 120 x 10-6 g microbial carbon. We started with 0.5 ml = 0.6 grams of dried soil in the extraction process, therefore 120 x 10-6 g microbial carbon / 0.6 g soil = 200 x 10-6 g microbial carbon / gram soil, or 200 µg microbial carbon / gram soil.
While we arrived at µg microbial carbon / gram soil through a different method than CFE, it turns out our methods are on par with the CFE test. We compared measurements of µg carbon / gram soil via CFE and microBIOMETER® from 28 soils from across the U.S.
The slope of ~1 of the regression line indicates our units are on par with CFE, and the 94% correlation indicates that users can be confident that the $13.50 or less microBIOMETER® test gives results as accurate and informative as one priced $500.
Different methods measure different fungal and bacterial populations. The chart below, adapted from Wang et al review of 192 different F:B ratios, illustrates how three different methods came up with three different F:B ratios for Forest, Farmland and Grassland. Note that microBIOMETER® correlates well with the gold standard, microscopy. By plate culture, forest F:B is about 1/3 that of farmland, whereas PLFA forest F:B is slightly higher, and microscopy and microBIOMETER® forest F:B are 10 times higher than farmland.
Informal science education is a key for community engagement and healthy gardening. Community gardening brings numerous benefits such as fresh produce, therapy, physical exercise, reduction in grocery bills, improvement of mood among many others.
“Last weekend I had the privilege to teach community gardeners on the importance of soil testing side by side with my very first student at NYBG Adult Education program (class 2015). Dr. Joan Basile is a clinical psychologist who has developed her own horticulture therapy program incorporating soil knowledge brining therapy & soil science & gardening together.” – Dr. Anna Paltseva, soil_expert.
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“While the microBIOMETER® results showed there is room for improvement, the result from last year’s beds also proved that composting and mulching practices are paying off in increased soil life. This means that sandy soil will gradually be able to hold nutrients better and better!” – Dr. Basile
The Biospheres, working through the CDA*, accompanies and trains farmers/agricultural companies in the agroecological transition based on a soil conservation approach. The group is also working on applied research projects and therefore on trials under real farming conditions in which they evaluate the impact of certain changes in practices on different indicators (biological, chemical, physical, economic).
“One of our primary objectives is that farmers succeed in putting biology back into their soils to ensure their natural fertility. We are therefore very interested in everything that lives in the soil, from earthworms and microarthropods to microorganisms (bacteria, fungi, nematodes). For us, microbial biomass is one of the most important indicators that help us understand soil biology. Fungal to bacterial ratio, which is a less documented indicator for the moment, remains interesting to observe in certain situations and is the object of real research by our R&D team to understand how best to interpret it.
We have been using microBIOMETER® for 8 months now to test the soil in different projects in our panel of biological indicators. microBIOMETER® provides us with quick and easy results on microbial biomass and F:B ratio which is a real plus for us. We can perform tests directly in the field and present the results to the farmers. Moreover, the affordable price of the analysis allows us to perform soil biology tests in projects where we had no affordable way to do so before.”
*CDA, Centre de Développement de l’Agroécologie, are affiliates dedicated to R&D and advisory.
Ariel White; Post-Wildfire Forest Reboot Kit
Ariel White, a ninth grader at Pretty River Academy in Ontario, Canada, utilized microBIOMETER® in their science fair project titled Post Wildfire Forest Reboot Kit.
The project was awarded first place at their high school and chosen to compete at the Simcoe County Regional Science Fair. At the regional fair, Ariel was awarded a gold medal, Best of Earth and Environmental Sciences, Best of Fair, The Dufferin Simcoe Land Stewardship Network Award, and was one of seven students selected to represent their county in the Canada Wide Science Fair where they won a silver medal!
About the project: Forest fires have increased due to climate change, causing forests to burn down at an unbelievable rate. Now we need forests more than ever, yet they have been taking years if at all to regrow. This project explores the question “how can we boost the speed of forest regrowth after forest fires?”. For phase one of this experiment, each plant was graded for performance using tests such as success-rate, growth-rate, compost-value, and self-propagation. For the second phase, it was seen what effect this plant had on the soil microbiome; which is key to healthy, speedy plant growth and isn’t evident after fires. It was concluded that the morning glory substantially increased the microbiome health from inevident to healthy, and had an almost perfect performance score. These results are very important to our world’s future as they could help to deter climate change and repair our forests and their diverse ecosystems.
Graham Mackie, Golf Course Manager at Edzell Golf Course in the U.K., has been using microBIOMETER® to monitor the health of the soil on the greens. Here is what he had to say about our soil test.
“I really like microBIOMETER®. It is simple to use and for the first time I can get baseline readings to see what is effective and what is not in influencing soil biology. As a golf course manager I believe that swinging the F: B ratio in favor of the fungi will allow the dominant grasses to be the desirable perennials.
I took microBIOMETER® readings of the main 18- hole course as well as the small 9-hole course and the readings correlated with what I expected. The 9-hole greens have more poa annua, therefore, were more bacterial dominant. I also took a reading of an area of untouched fescue rough which was very fungal dominant, as expected. It was great to have this theory confirmed. I am now looking forward to see if and how I can swing the balance to more fungal dominance on the greens.”
A BIG thank you to Graham for sharing his testing experience with us!
