By Brian Geier
Organic farmers understand that soil health is paramount to our success. More specifically, we know that the living, microbial part of soil, sometimes called the soil microbiome, is something our farming practices can quickly and drastically alter, having serious implications for organic systems that rely on organic processes in the soil. But even though we understand that preserving soil life is good practice, we often do not know how soil life is changing, how farming practices are affecting those changes, and which practices are responsible for increases or decreases in crop or animal health because of those changes.
To address this knowledge gap, researchers at Cornell University are utilizing a novel, farmer-led approach to studying what organic farmers are already doing on their farms and monitoring how the soil microbiome is changing over time. What they find could provide key insights into which organic farming practices might be helping producers promote and maintain soil health through droughts and other climate extremes.
The Human Body and the Soil: An Analogy for Understanding the Soil Microbiome
To help us understand the importance and complexity of the soil microbiome (the living part of the soil that is composed of soil microorganisms), organic researcher Elias Bloom (a member of the Casteel lab at Cornell University) suggests beginning with an analogy. “The human body has more microbiome cells than it does human cells,” Bloom explained at a recent eOrganic webinar. Over 10,000 different species of microorganisms live in and on the human body, and they can have broad implications for human health. Essentially, a healthy human body is driven by a healthy microbiome.
Compare this analogy with the soil: one teaspoon of soil may have over one BILLION microorganisms living in it. And in just one small teaspoon of soil, there are often over 10,000 species of microbes, similar to the number of species found in the human body. Since microbes are involved in everything from water-holding capacity to promoting disease resistance, one begins to see that what a farmer does everyday can have serious effects on current and subsequent crops.
The Importance of the Soil Microbiome
The living portion of the soil is a primary driver of nutrient cycling, a pillar of healthy soil structure, and can enhance resilience to climate change and pests. The microbiome also helps break down pesticides, toxins, and excess nutrients. It is generally understood that high soil microbe diversity promotes pest suppression and that organic land tends to have higher soil diversity than conventional fields. Still, in some cases increases in diversity can mean increases in plant pathogens. For farmers and researchers, understanding which farming practices result in a ‘healthy microbiome’ and translate to positive effects on crop production, is complex.
Organic Farmer Driven Research on the Soil Microbiome at Cornell
To approach this complexity, research projects led at the Casteel lab are utilizing a unique, participatory research approach where organic farmers are providing key insights on soil management practices that could be helping them withstand pests and extreme weather events.
The Organic Microbiome Project is perhaps the largest effort to date that is documenting the soil microbiome on organic farms. Over 80 organic farms are participating. Essentially, organic farmers are sending soil samples in, accompanied with answers about farming practices, and the lab documents changes within the soil microbiome, driving some interesting findings. Rather than deciding what practices to focus on and then involving farmers, the project starts by following practices organic farmers already employ. “We allowed farmers to submit up to two samples from two different fields where they have been using different practices, and we encouraged them to pick comparisons they were interested in,” explained Casteel. In this sense, the project is inherently farmer-led, and evaluates the effects of organic farming practices already being utilized on working farms. While results are still coming in, one thing is clear: when research follows the lead of farmers, it is closely watching how farmers are adapting and building resiliency in real time.
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