Climate change can feel overwhelming. We hear about melting ice caps and rising temperatures, and it seems like only world leaders can make a real difference. But truthfully, the soil beneath our feet is one of nature’s best tools for fighting climate change. It quietly stores massive amounts of carbon, keeping it out of the atmosphere.
Understanding Soil’s Role in Climate Change
Soil is basically a giant carbon storage system. Scientists have found that healthy soil holds more carbon than all the trees and plants on Earth combined. That’s billions of tons of carbon safely stored underground instead of being released into our atmosphere and warming our planet.
Here’s what happens: plants pull carbon dioxide from the air through photosynthesis. When plants die or drop leaves, the carbon that was stored in plants is released, either through respiration or combustion, and then goes back into the atmosphere or the soil. Soil microbes then break down this material and lock the carbon underground where it can stay for decades or even centuries.
What Makes Soil Healthy?
Healthy soil is alive. It contains billions of tiny organisms working around the clock that form a complex underground ecosystem. Soil microbial biomass refers to all these living organisms combined. They break down dead plant material and animal waste. They build soil structure that holds water during droughts. And most importantly for climate action, they capture and store carbon.
Simple Steps to Improve Your Soil:
Reduce Tilling and Digging
Every time you disturb soil with a tiller or shovel, you could be destroying microbial networks. These organisms build complex underground structures that help them work efficiently. Breaking these structures sets them back to square one.
Add Organic Matter Regularly
Microbes need food to survive and multiply. Organic matter like compost, mulch, or leaf litter provides this food. When you add these materials to your soil, you’re essentially helping to feed billions of organisms.
Plant Cover Crops
Bare soil is a missed opportunity. When ground sits empty between growing seasons, microbes starve and carbon escapes. Cover crops solve this problem by keeping living roots in the soil year-round.
Reduce Chemical Use
Synthetic fertilizers and pesticides can harm beneficial microbes in the long run. While they might boost plant growth in the short term, they often damage the soil ecosystem that supports long-term health causing greater issues down the line.
Why Test Your Soil?
You can’t improve what you don’t measure. Soil testing for climate action gives you concrete data about what’s happening underground. It shows you the current state of your soil’s health and its carbon-capturing ability.
Testing reveals your soil’s microbial biomass levels. High numbers mean your soil is actively storing carbon. Low numbers mean there’s room for improvement. You also learn about the fungal to bacterial ratio, which affects how long carbon stays locked in the ground.
How should you start? Pick one area to focus on first. Maybe it’s your vegetable garden, your front lawn, or a few raised beds. Test that area to establish your baseline numbers.
Choose one or two practices to implement. Don’t try to change everything at once. Start with something simple like adding compost or reducing how often you dig. Small consistent changes produce better results than dramatic overhauls. Track your soil’s biological data over time using the microBIOMETER® and other helpful soil tests.
Remember when you needed expensive equipment just to know what’s happening in your soil? Well now that same device you use to scroll social media and read the news can analyze soil health with lab-quality precision.
The Science Behind Your Pocket Soil Lab
Your smartphone possesses something laboratories have relied on for decades: sophisticated optical sensors and powerful processing capabilities. Modern smartphones can detect color variations, light intensity, and chemical reactions through their cameras and built-in sensors. When paired with the right testing reagents and apps, these everyday devices transform into legitimate soil analysis tools.
The principle is surprisingly straightforward. Soil samples react with specific chemical reagents, producing color changes that correspond to different nutrient levels, pH values, or biological activity. Your phone’s camera captures these color variations, while specialized algorithms interpret the data and provide instant results.
What Your Mobile Soil Lab Can Actually Measure
You might wonder what kind of soil data you can realistically expect from smartphone-based testing. The capabilities are more extensive than you’d think:
Real-Time Results That Actually Matter
The game-changer isn’t just the technology—it’s the speed. Traditional soil testing means collecting samples, shipping them to a lab, and waiting days or weeks for results. And by then, growing conditions and microbial communities may have changed completely. Smartphone-based soil lab technology delivers results in minutes, not days. This real-time capability transforms how you can manage your soil health. And the microBIOMETER® can help you do just that.
Notice your tomatoes looking yellow in mid-July? Test the soil immediately and adjust your fertilization strategy that same afternoon. Planning fall amendments for your lawn in Texas? Test multiple spots across your property in a single morning and create a targeted improvement plan.
Getting Started: Your First Mobile Soil Analysis
Setting up your smartphone as a soil lab is simpler than you might expect. The microBIOMETER® includes testing reagents, measuring tools, and a smartphone app that guide you through the entire process step by step. You’ll collect a representative soil sample, mix it with the provided reagents, and use your smartphone’s camera to capture the resulting color changes. The app then analyzes the images and provides detailed reports about your soil’s condition. The testing process is quick and you can see results in 20 minutes.
The Technology Revolution Happening Now
All-in-one smartphone-based devices are becoming preferable for agricultural soil analysis, enabling users to complete self-assessments about soil quality and receive performance reports with actionable insights.
The implications extend far beyond individual gardeners. Extension services at universities across the United States are incorporating smartphone soil testing into their educational programs. Community gardens in both rural and urban areas are using these tools to optimize their growing strategies and share soil health data among members.
Urban gardening isn’t just about growing tomatoes in a small closet. It’s about understanding the complexity of soil microbes in unconventional spaces and utilizing new methods that make city gardening not only possible, but also incredibly rewarding.
Plants with healthy microbial communities in their root zones tend to grow more vigorously and are better equipped to withstand stressors such as drought, pests, and diseases. In urban environments where plants face challenges like air pollution, heat islands, and limited space, this microbial support system becomes even more crucial.
Urban soil faces unique challenges that rural farmland doesn’t necessarily encounter on a daily basis. You’re dealing with:
Start with Quality Organic Matter
Your soil microbes are essentially composting machines, but they need fuel. Add compost, aged manure, or leaf mold regularly. These organic materials provide the carbon and nutrients that feed your microbial community. In cities like Portland and Seattle, many neighborhoods now offer community composting programs—take advantage of them!
Test and Track Your Progress
Understanding your soil’s microbial health doesn’t have to be guesswork. Modern soil testing technology allows you to monitor microbial biomass and the fungal-to-bacterial ratio right from your balcony or rooftop garden. This data helps you understand whether your soil management practices are actually working.
Minimize Chemical Disruption
Synthetic pesticides and fertilizers can disrupt your carefully cultivated microbial community. Instead, focus on building soil biology through organic amendments and natural pest management strategies. Beneficial soil microbes perform fundamental functions such as nutrient cycling, breaking down crop residues, and stimulating plant growth.
A recent study reported by the NIH reveals an intriguing connection between gardening and human health that goes beyond fresh vegetables and exercise. It found that frequent exposure to environmental microbiota, especially through skin to soil contact, diversifies commensal microbiota, enhances immune modulation, and ultimately lowers the risk of immune-mediated diseases.
As more Americans embrace urban gardening & soil health practices, we’re seeing innovations that make microbial monitoring and management more accessible than ever. Whether you’re growing herbs on a fire escape in Brooklyn or maintaining raised beds in a Phoenix community garden, understanding and nurturing your soil’s microbial community will help you grow healthier plants while potentially benefiting your own well-being.
Successful composting depends on understanding the microbial life within your compost pile. This is where soil testing kits become invaluable tools for gardeners and farmers alike. Modern testing technology allows you to analyze your compost’s biological activity with scientific precision, ensuring you create nutrient-rich amendments for your soil.
Understanding Compost Biology
The foundation of excellent compost lies in its microbial ecosystem. Billions of bacteria, fungi, and other microorganisms work together to break down organic matter into valuable nutrients. These microscopic workers determine whether your compost becomes a powerhouse of plant nutrition or simply decayed organic matter with limited benefits. Bacterial populations typically dominate the early stages of composting, breaking down simple compounds like sugars and proteins. As the process continues, fungal networks develop to tackle more complex materials such as cellulose and lignin. The balance between these microbial communities directly affects the quality and effectiveness of your finished compost.
The Science of Compost Testing
Traditional methods of evaluating compost quality relied heavily on visual inspection, smell tests, and temperature monitoring. While these indicators provide useful information, they cannot reveal the true biological potential of your compost. Modern soil testing kits offer scientific analysis that goes beyond surface observations. Microbial biomass testing measures the total amount of living microorganisms in your compost sample. This measurement indicates the biological activity level and helps predict how effectively the compost will benefit your soil. The fungal-to-bacterial ratio represents another critical measurement that influences how compost affects different types of plants. Vegetables and annual crops typically prefer bacterial-dominated compost, while trees, shrubs, and perennial plants benefit from fungal-dominated amendments. Understanding these ratios helps you tailor your compost for specific garden applications.
microBIOMETER® Technology Advantages
The microBIOMETER® advanced testing platform system brings quality analysis to home composters and small-scale farmers. These tools eliminate guesswork by providing quantitative data about microbial populations in compost samples. The testing process involves extracting microorganisms from compost samples and analyzing the color intensity of the solution using specialized reagents, measurement cards, and the microBIOMETER® app. Results appear within minutes, allowing you to make immediate adjustments to your composting process if needed. This standardized approach ensures reliable results that you can track over time to monitor improvements in your composting methods.
Conclusion
Regular testing throughout the composting process helps identify optimal harvest timing. Compost that appears finished may still contain high levels of bacterial activity, indicating continued decomposition. Investing in soil testing kits transforms composting from an art into a science-based practice. Understanding the microbial life in your compost empowers you to create consistently high-quality amendments that maximize plant health and soil fertility. Modern testing technology makes this level of analysis accessible to gardeners at every skill level, building confidence in composting success.
We first had the pleasure of working with Briana Alfaro and Soul Fire Farm in 2021 when they began testing soil with farmers in their network as part of their SARE research project, Soil Carbon Capture for Diverse Farmers; Black, Latinx, Asian, Indigenous and other farmers and farm workers of color take the lead in testing soil carbon sequestration strategies and measurement protocols and disseminate those findings to the farming community in both English and Spanish.
Every two years the Soul Fire Farm team takes a closer look at the soil ecosystem and assesses how healthy their soil is. They do this by performing a series of in-field tests. Long before the western study of soil science, Indigenous communities practiced–and still practice–methods of evaluating soil health using characteristics such as color or the presence of specific plants or insects that tell us something about the system as a whole. On their soil testing days, they count the number of earthworms, perform a slake test to observe aggregate stability, look at soil color as an indicator of organic matter, and use the microBIOMETER® field kit to assess soil biology.
You can learn more in their Guide to In-Field Soil Health Measurement Protocols: How Alive is My Soil (English) & ¿Qué tan vivo está mi suelo? (Español), and by watching their Liberation on Land skill share videos: Soil Carbon part 1, Soil Carbon part 2 & Investigating Soil with an Auger.
Your soil is a unique mixture of sand, silt, clay, and organic matter. The particular make-up of your soil determines its color, texture, and nutrient storage capacity. Knowing your soil’s texture and nutrient storage capacity is important when deciding how much and how often to feed and water your plants. Some nutrients are more easily stored and attached to soil particles compared to others due to the strength of their electrostatic bond. As the famous saying goes, opposites attract – and this holds true in soil as well.
Mineral nutrients such as calcium, potassium, ammonium, and magnesium are called cations because they have positively charged ions. The ability to attract and hold onto these positive cations comes from negatively charged soil particles, called colloids, found in organic matter and clay. It’s important for these nutrient cations to attach to the soil colloids so that they can be supplied to the plant when needed. If the nutrient cations don’t attach, they’ll easily leach out during a time of rain.
However, like in most fair economic systems, the plant can’t just take these nutrients from the soil without giving something in return. For example, if a plant needs some potassium, it will have to exchange one of its cations for the soil’s potassium cation. Thankfully, plants produce hydrogen cations that they can use for this exchange. The soil accepts these hydrogen cations because they’ll be used in photosynthesis and respiration.
This exchange is easier than others because both hydrogen and potassium have a positive charge of +1. Calcium, on the other hand, has a positive charge of +2 and therefore requires two hydrogen cations for its exchange, making the process a bit harder. The higher the positive charge on the cation, the harder it becomes to exchange between the soil and plant. However, the bond between the higher charged cations and the soil is stronger than that of the lower charged cations. This exchange process occurs on the plant’s root hairs, which is why it’s important to have a strong, healthy root system for your plants. The amount of cations that can be retained within the soil is called Cation Exchange Capacity (CEC) Source: Jagdish Patel.
Understanding the CEC of your soil is important due to its strong influence on nutrient and water retention and availability, soil structure stability, and soil pH and fertility. Adding organic matter to your soil is one of the most effective ways of increasing your soil’s CEC and increasing the amount of exchange sites. The more exchange sites, the greater the ability for nutrients to be retained within the soil. Having a high CEC not only reduces leaching of nutrients, but also helps buffer your soil against pH changes.
While it’s very beneficial to have a high CEC in your soil, soils with a low CEC can still be managed successfully – they just have different requirements than soils with a high CEC. Low CEC soils need small, but frequent intakes of nutrients and water, rather than large, infrequent intakes due to their fewer exchange sites. Less exchange sites means less space to hold onto the incoming nutrients. And as microbes are actively involved in transforming nutrients to plant-available forms, it’s imperative to maintain suitable soil conditions for optimal microbial activity.
Many soil testing labs will provide you with your CEC levels which are reported in units of milli-equivalents per 100 grams of soil (meq/100 g). Average levels range from less than 10 for sandy soils and 50-100 for organic rich soils. Pure organic matter has a level of 200-400. Generally, 1-10 is considered low while 10-50 is considered moderate to high.
Chiappetta Agricultural Company
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.
We receive this question often and the answer is no.
How do we know this? microBIOMETER® shows that soil removed from the earth and plants lose microbial biomass every day which we have confirmed with microscopic studies. The literature also confirms this.
Why is there confusion? Most of the microbes in soil are in the “dormant” state, they only wake up when stimulated by the plant or some other stimulus. For a long time people thought dormant microbes were dead. Now we know they have lost as much water as possible and encased themselves in a tough cocoon that can allow them to survive for up to thousands of years. microBIOMETER® measures these earth-colored dormant microbes.
What microbes are dormant? All soil microbes have the ability to go dormant. This allows them to survive drought, freezing, starvation, etc. Bacteria and fungi build tough spore walls to protect themselves. microBIOMETER® measures those spores.
In the winter when it is below freezing in New York, if we microscopically examine the microbes that are separated from soil using microBIOMETER® we see very few fungi but plenty of spores. In spring the arbuscular mycorrhizal fungi spores will germinate and find a plant to colonize. In the Fall when roots are dying and decaying organic matter is present in the soil, we see a profusion of the saprophytic fungi that break down the tough vegetable matter. Bacteria can sporulate but even the bacteria that do not sporulate manage to wrap themselves in a tough outer coat by collecting clay and minerals in their gluey outer biofilm.
For more information on fungal spores, please visit mycorrhizas.info.
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
