In March 2020 in San Diego, a small group of farmers decided to activate the “hub” concept and launched Foodshed Small Farm Distro and Resource Hub. Foodshed works directly with farmers, eaters, and entrepreneurs to cultivate an equitable food system in San Diego while addressing the challenges posed by the climate crisis.
Foodshed believes soil health is the key to a thriving local food system, it is the infrastructure from which a myriad of co-benefits can be cultivated. Recognizing healthy soil as vital public infrastructure they’ve uncovered an urgent need to measure the impact of carbon farming for the sake of our own stewardship as well as to communicate effectively with local policymakers. These parallel needs have encouraged them to develop data collection and assessment tools that really work for farmers. They are currently using these tools to gather baseline data and are ready to scale up their use.
For their seasonal soil health assessments, in addition to some of the quantified results from traditional micro and macronutrients soil lab tests, Foodshed integrated Solvita (Basal Soil Respiration) test for measuring soil respiration in fresh soil samples and microBIOMETER®, as microbes are excellent predictors of soil health. microBIOMETER®, a professional lab-grade soil test kit for determination of soil microbial biomass and fungal to bacterial ratio, is an invaluable tool to help them understand their soil’s biology and it’s capacity to integrate nutrients, hold water, increase biodiversity, and strengthen the microbial community.
Using the Soil Mentor Regen Platform as their data management app, they can analyze changes in different soil health indicators from year to year, compare results from farm to farm and in their bioregion. COMET Planner is the evaluation tool that allows them to calculate and validate carbon sequestration potential occurring on their farms by providing estimates of the net greenhouse gas reductions for specific agricultural management conservation practices.
They are dedicated to investing in building soil biology to increase our resilience. Their program demonstrates how we can leverage carbon farming investments to create real equity, and highlights the importance of accessible and affordable tools like the microBIOMETER® to their success in analyzing soil and compost across our farms’ network in an efficient and effective way.
Both microbial biomass and microbial respiration are considered efficient indicators of soil health. Soil respiration is the measure of the carbon dioxide produced by the microbes in a given weight of soil while microbial biomass is the measure of the mass of microbes- both active and dormant. Microbial biomass (MB) is an excellent predictor of soil health because the size of the microbial population correlates with the available nutrients in the soil.
Both microbial biomass and respiration are parameters used to assess soil health. Soil respiration is the measure of the carbon dioxide produced by the microbes in a given weight of soil while microbial biomass is the measure of the mass of microbes- both active and dormant.
Microbial biomass (MB) is an excellent predictor of soil health because the size of the microbial population correlates with the available nutrients in the soil. Interestingly, MB is low in soil treated with high levels of mineral fertilizers. Research has shown that the stimulus for the plant to grow a microbial population is its need for nitrogen and phosphorus. If these nutrients are artificially supplied, the plant is not being stimulated to feed the microbes that usually provide these nutrients to the plant. This can alter plant-microbe interactions and cause an increased need for pesticides in order to protect the plant, as microbes play a fundamental role in the function of the plant’s immune system.
Microbial respiration measures the amount of carbon dioxide (CO2) produced by the microbes in a given weight of soil. The soil is dried and then rewetted and put in an airtight jar that allows measurement of the amount of CO2 produced over 24 hours. The CO2 is produced by the activity of the microbes in the rewetted soil. Between 20% and 70% of the microbes die during drying, but their dead bodies often provide nutrition for the survivors to use and regrow the population to its original level. Respiration reflects the regrowing work that is being done. The respiration level is often mistakenly believed to predict microbial biomass, though it doesn’t.
People often assume a high respiration rate is good because it means there is a lot of microbial activity occurring. However, it doesn’t necessarily mean the soil is healthy. Microbes in a low pH or toxic soil have to work harder, and therefore their respiration rate is higher, just as your respiration rate in the gym is higher than when you are watching TV. High respiration rates can indicate an unstable microbial population, which, for example, can be seen after excessive tillage occurs. Tillage aerates the soil, so right after there is often a boost of microbial respiration. That increased activity however does not always last, as the other damage done by tillage – disruption of microbial life and destruction of existing plants- can lead to a decreased soil microbial population over time.
The use of soil primers stimulates an increase in soil organic matter (SOM) decomposition, which temporarily increases microbial respiration. Excessive decomposition of SOM can cause a loss of stored soil carbon and other mineral nutrients, allowing for the increased production of CO2. Basically, when you stimulate the soil using a fertilizer or biostimulant, it’s an all-you-can-eat buffet for the microbes. It wakes them up and they start growing and reproducing. But whether they can continue to grow depends on the continual supply of existing nutrients and plant life in the soil. It’s very important that there be sufficient food for the microbes after stimulation. For most soils, this requires that the fertilizer have the correct C:N ratio for the soil and crop. A fertilizer with too high a C:N ratio will cause the microbes to harvest some of the stored carbon, nitrogen and other nutrients in the soil, boosting respiration. This means the stored carbon is being depleted and released into the atmosphere as CO2, the microbes won’t be able to nourish the plant and build soil structure as needed. Adoption of less invasive management practices, such as select-till and reduced chemical fertilizers can reduce CO2 emissions from agricultural soils by retaining soil organic matter.
Priming can be a good way to understand the difference between and uses of respiration data and microbial biomass data. Testing for both initial respiration and long term microbial biomass population can tell you if the priming worked and if the increase in microbial activity led to increased soil microbial biomass and therefore increased soil health and fertility.
Long time customer Jesse Wiser recently presented at the annual American Community Gardening Association (ACGA) conference in New Orleans. His presentation centered on methods small growers can use to improve the soil ecosystem.
During the presentation, Jesse demonstrated microBIOMETER® as a user-friendly, cost-effective tool to measure microbial health. The demonstration to an audience of small scale, mostly urban gardeners featured trial microBIOMETER® readings. These readings confirmed an increase in microbial biomass and fungal to bacterial ratio with the application of vermicompost extract, correlating with impressive plant growth and vegetable production.
Bio-Extractor
Over the past decades, scientific awareness and appreciation of soil microbiology in agricultural systems has dramatically expanded. Flourishing microbial communities interacting with plant root networks play a direct role in plant growth, crop nutrition, disease and pest resistance, and soil aggregate structure, leading to increased soil oxygen flow and water holding capacity. Unfortunately, many agricultural soils have depleted functioning microbial ecosystems through decades of physical and chemical disturbance. Regenerating these microbial ecosystems is crucial to refocusing agricultural production on soil, human, and environmental health.
One extremely promising method of regenerating soil biology is through the production and application of liquid compost extract. Microbially-rich compost can be produced on-farm from locally-sourced and inexpensive organic materials, through systems such as the Johnson-Su bioreactor process and / or vermicomposting. Vermicompost also includes many naturally-produced bio-stimulants, such as humic and fulvic acids. These compost products, while valuable in solid form, can be extracted into a powerful liquid biological amendment to increase their efficiency and soil infiltration, inoculating beneficial microbes directly into root zones or onto the surfaces of leaves.
In addition to being both biologically beneficial and cost-effective to produce, liquid compost extract is also extremely versatile. Microbial foods, such as blackstrap molasses, kelp, and fish hydrolysate can be added for additional stimulation. Injecting oxygen into the liquid prior to application will activate the microbes and multiply the population (this is often referred to as “compost tea”). Application systems can be tailored to desired effects, including fertigation, soil drenches, soil injections, seed soaking, and foliar sprays. Improving soil biology not only benefits crop production, but also pastures, lawns, and turf, including athletic fields. Here’s a sample operation in New York’s Hudson Valley that uses compost extract for all of the above.
At Hiwassee Products, the goal is to help make this potentially transformative process both scalable and adaptable to a wide array of situations by designing and manufacturing innovative equipment solutions. The Bio-Extractor, released for production in 2022, is the only commercially available continuous-flow compost extractor to date, able to extract at 700 gallons per hour to meet any target volume, large or small. The company will continue to release equipment in the upcoming year, focusing on continuous-flow-through (CFT) vermicomposting systems and biologically-friendly spray systems, which differ from high-pressure chemical applicators. These equipment items can be combined into one closed-loop system (potentially including a pre-composting system to make vermicomposting more efficient), or be used as components of other soil biological management systems.
According to experts, more than half of the world’s agricultural soil has already been degraded. Attempting to improve matters, revolutionary Indian guru – Sadhguru is continuing to lead a global campaign called SaveSoil, which pushes to improve soil health around the world.
We know there are several causes for soil degradation – from overgrazing, to only growing one crop time after time, and excessive use of weed killers.
The rise of global carbon dioxide levels has called on governments and businesses to limit how much carbon emissions they produce over the succeeding years. There have been several international agreements which address this issue, specifically, the Paris Agreement has been the most notable, as it established international compliance through carbon markets.
Created and performed by microBIOMETER® intern, Leanna Ramus, environmental science student at Siena College, this sample experiment is appropriate for high school and advanced middle schoolers.
The research project is designed to help students study soil health and understand the impact of soil biology on soil health and plant growth. Supplies are minimal cost and nothing recommended is dangerous or controlled. We expect students to use this as a guide to develop their own experiment.
We love supporting young minds with a passion for soil science. They are the future of soil health! If you are an educator that would like to bring microBIOMETER® soil testing into the classroom, we have three Academia Kits available for purchase. We are also happy to cater supplies to your specific needs. Please contact us for more information!
Our soil scientist, Marisa, had the pleasure of attending Generation Fest hosted by Thought For Food and the NYC Agriculture Collective in Brooklyn, NY.
Regenerative ag community members, executives, organizations, and creative artists and innovators from around the world filled the room, eager to learn and share ideas.
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