Soil research using microBIOMETER®

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

Variance in soil samples explained

Often, we are asked about variance – different results when you test the same sample. Our answer is that nature produces most of this variance. To explain, when you measure out 0.5 cc of soil, you have on average about 0.6 grams of soil. If your microBIOMETER® results read 300ugMBC/gram of soil, that means you have 600ug of microbial biomass – we divide the number we get by ½ because the literature tells us that 50% of the dried MB is carbon. As dried bacteria is estimated to weigh 1pg, if this were all bacteria, it constitutes 600,000,000pg or 600 million bacteria.

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.

Research shows microBIOMETER® correlates with crop health

Katharhy G. is an agroecosystem and ethnoscience researcher who traveled to Ecuador to investigate the relationship between microbial biomass and crop health, as well as to study the local indigenous agriculture practices.

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:. katharhyg@gmail.com

microBIOMETER® collaborates with university soil study

Earthworms recover from Roundup exposure

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.

Source: Earthworms (Eisenia fetida) recover from Roundup® exposure. Pochron et al., 2021 Applied Soil Ecology. 158: 103793.

Prolific Earth Sciences is supporting research at various universities. Feel free to contact us to discuss your project and how we can assist.

Simple ways to increase the microbial biomass in your soil

Healthy soil is brimming with beneficial microbes, and those microbes are one of the important keys to ensuring the health of your plants. Along with breaking down key nutrients for your plants, they’ll aerate the soil so nutrients are evenly distributed, and fend off parasitic microbes so your garden can grow in peace.

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.

  • Pesticides

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.

  • Fungicides

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. 

  • Tilling

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.

  • Composting

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. 

  • Compost Teas

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.

  • Optimize soil moisture, pH, and temperature

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.

 

Soil Health Improvement Tracking

Microbial biomass (MB) is the best single indicator of soil health (Doran, 2000). Microbes feed and protect plants, build soil structure which prevents erosion, increase water holding capacity, and build soil organic matter (SOM). MB is low in any situation that is harmful to plant growth (and vice versa) and protects against pathogens, thereby reducing the need for pesticides. MB can predict success before plant outcome. The Fungal:Bacterial ratio (F:B) of the MB provides crucial information regarding colonization by Arbuscular Mycorrhizal Fungi (AMF), and the recycling metabolic processes of saprophytic fungi (SpF).

Soil stewards all over the world are seeking to understand the microbial levels in their soil and the ratio of fungal to bacterial life. The higher the microbial biomass, the more nutrients will be available to plants naturally, decreasing or eliminating the need for chemical fertilizers. Higher fungal to bacterial ratios are critical for building soil structure that prevents erosion and runoff off of pollutant chemicals while building moisture holding capacity of the soil and sequestering carbon.

Soil health is fast becoming one of the most important factors in agriculture and in the growing efforts to improve the earth’s stock of agricultural land. Farmers, industry, and environmentalists are looking for cost-effective and reliable ways to measure soil health and to assess impacts of progressive changes to soil and harvest management.

Testing soil in homogeneous sections at similar stages of the growth cycle can set a baseline for microbial biomass and fungal to bacterial ratio. That baseline can be used to assess how different stewardship practices are impacting the soil and allow for refinement to soil management plans and show soil health improvement over time. While every soil steward’s situation is unique, microBIOMETER® can help measure, follow, and assess efficacy of improvement to soil health.

Why is microBIOMETER® the best test for soil health?

soil health testUntil now tests for microbial biomass were expensive and time consuming. microBIOMETER® costs $13.50 or less and takes 20 minutes with results read by your cell phone.

* Only microBIOMETER® identified soil health in a U. of Tennessee study of soil health test methods including Cornell, USDA, Alabama and other soil health panels costing ten times as much.

* There are >2 million academic articles that use microbial biomass laboratory tests as proof of soil health. However, lab tests cost $100 – $500. microBIOMETER® takes 20 minutes at an average of $10/test.

* Soil microbes quickly die when removed from the soil. microBIOMETER® reveals the microbial biomass of your soil as it exists. Lab tests use dried soil and we have demonstrated that 80% of microbes die upon drying.

* The low cost and simplicity of microBIOMETER® means you can use it to monitor what is happening in time to make necessary corrections.

* microBIOMETER® can tell you if you are increasing your soil organic carbon. For instance, an increase in microbial biomass of 100 ug MBC/g per acre of agricultural land is equal to an elephant’s weight in microbial biomass, which is about 400 lbs of microbial carbon or >1450 lbs of CO2 equivalents. This can be accomplished by switching from heavy chemical fertilizer use to regenerative practices.

What is a good level of soil microbial biomass?

Understanding Soil Organic Matter and its impact on soil health and microbial biomass.

We are often asked what is a good level of microbial biomass (MB). There is no one answer. The level of MB you can reach is dependent on soil organic matter (SOM.) Soil organic carbon (SOC) is a large part of soil organic matter but SOM is a mixture of Carbon (C), Nitrogen (N), Phosphorus (P), Sulfur (S) and all the other minerals that microbes and plants need.

There are 2 types of SOM: Stable SOM, often referred to as humic matter; and Fresh SOM. Fresh SOM is composed of SOM material recently released from Stable SOM and any fertilizers, amendments or litter. You can compensate for low stable SOM by providing lots of fresh SOM. The key to the efficacy of fresh SOM is that it needs to be nutrient balanced*, i.e. it needs the correct balance of C,N,P, and S. That is where understanding soil chemistry and using the right additives comes in.

Think of SOM as your credit reserve. In spring, the plant starts to grow and puts out exudates that stimulate the microbes to multiply. But these multiplying microbes need more than the sugars that the plant supplies, they need the N, P, S and micro nutrients that are in SOM.

Agronomists often cultivate soil for intensive organic agriculture and those soils contain lots of fresh organic matter. The microbial biomass of these mixtures can read as high as 2000 ug MBC/gram of dry soil. As the microbes and plants in this rich soil die, they become fresh SOM. The amount of stable SOM that soil can store depends to a large degree on the type of soil because storage requires mineral surfaces for attachment and aggregates for protection. If your soil is inherently poor at storing SOM, you will need to rely on fresh SOM to feed your microbes and plants.

We highly recommend that you read the review referenced below to better understand SOM.

Coonan, E.C., Kirkby, C.A., Kirkegaard, J.A. et al. Microorganisms and nutrient stoichiometry as mediators of soil organic matter dynamics. Nutr Cycl Agroecosyst 117, 273–298 (2020). https://doi.org/10.1007/s10705-020-10076-8

A Day on the Farm in Brazil

The Sítio Escola Portão Grande is a Brazilian NGO, nonprofit organization which was founded in October 2012.

Sítio Escola Portão Grande hosted students from the Mentoring and Language Acquisition Program (MLAB) for a full day immersion at the farm in Brazil which featured soil testing with microBIOMETER®. MLAB is a mentoring and language acquisition program for Harvard students and Brazilian high school students, with low income and high performance. In addition to mentoring, the program brings foreign students to an immersion in Brazil, exploring themes that motivate them.

The students were delighted to observe the use of microBIOMETER® to assess fertility based on the measurement of soil microbial biomass. It was explained to the students that microBIOMETER® is used monthly to assess the evolution of fertility due to the different inputs applied to the soil, the crops and harvests carried out, as well as throughout the seasons. Therefore, providing a database of great importance to make future decisions. In addition, due to its ease of use, microBIOMETER® also proved to be an good tool to assess the quality of the inputs we produce on the farm, such as bokashi and compost tea, allowing the tuning of the culture media we use for them.

A big thank you to Antonio Feres Neto for sharing this story with us! We love hearing how our customers are using microBIOMETER®.