From a young age, Jamie Herring was intrigued by the dark areas in grass.
“My teacher told me they were fairy rings caused by certain fungi buried in the soil,” he says. “Something interesting was going on that stuck with me.”
What curiosity led the Illinois farmer, who holds a master’s degree in crop sciences, on a path to better understand the soil’s secrets.
“Considering the high variability within each field, I wanted to be able to define the soil’s biology so I know where to push inputs and where to hold off to maximize my profit per acre,” Herring says.
While putting data behind what’s going on in the soil gives him a metric to work from, he found today’s tools expensive, slow, and unreliable. To better quantify his soil’s health, Herring developed a system that defines the soil’s biology on-the-go, in real time, creating a totally new data layer.
A mobile system that measures several volatiles (gases), which are known indicators of soil health, Soil Sense attaches to a coulter that creates a cavity as it moves through the soil. This system pulls out those gases that then go through a set of filters and sensors. A sample is taken every second, and around 300 measurements are run per acre.
As you turn around in the field, the self-cleaning, self-calibrating process takes place. Blowing ambient air back into the tubes to clean out the filters, the system is ready to go on the very next pass.
“Once you’ve cleaned out the tube, you can reset the whole system at normal ambient air positions for the gases. Any change you then measure is relevant,” he says.
The electronics, along with the controls of that alternating measurement via suction and cleaning with forced air, is what creates the system’s unique capability.
To ensure data is reliable, the diameter of the air tubes is critical. “If the tube is too wide or too narrow, you change the parameters of the whole system,” Herring says. “The speed at which the air is aspired is also important, because if the suction is too fast, a lot of junk goes into the filters, and you’ll rapidly choke the system.”
Testing a theory
When Herring started his initiative over two years ago, he had a hunch some volatiles might be relevant in measuring the health of the soil. In 2019, field trials revealed a very high correlation between the levels of these volatiles and yields. Defining how the amount of organic volatiles relates to the rate of nitrogen was the next step.
“If we go through the range of measurements where nitrogen is very low, it pays to increase nitrogen,” he says. “On the other hand, there is a point where adding nitrogen to soil that has a high indicator gas level doesn’t really pay.”
In one trial, specific areas of a field were identified where additional nitrogen could increase the net margin by $79 per acre with higher yields. “There were other areas where the same increase of nitrogen would not pay back in higher yield and would cause a $40 per acre loss,” Herring says.
In addition, data indicated where higher density planting of soybeans would and would not pay off.
Based on what he is learning, Herring is able to find the right combination of management practices and products to help him improve his soil health as quickly as possible.
“Once I could reliably define what was happening in the soil, I could then start to compare that data with other data on my fields to help me make better economic decisions on fertilizer and seeding rates,” he says.
Herring has filed for a patent on his invention. The plan is to have the first commercially available product on the market by 2021.