A team of Iowa State University researchers is working on a new solution for fertilizing; specifically, more precise soil sensors to measure how much product to put down throughout a given growing season.

"We started working on nitrogen sensors back in 2018, when we published a manuscript on it," says Dr. Jonathan Claussen, an associate professor at Iowa State University. "Here in Iowa farm country, you're concerned about how to help farmers, so we decided to make these ion-selective nitrogen sensors, and it worked out really well."

The sensors allow for farmers to measure nutrient levels in the soil constantly, rather than pulling soil cores throughout the growing season to see what's needed.

"They’ll take a soil sample and send that back to the laboratory to take a measurement," Claussen says. "That's cumbersome, it's costly to take a one-time measurement. These sensors are measuring continuously; we can take several measurements a day if we want to."

Claussen notes that typically, farmers over fertilize in order to get the best crop yield for the season. The sensors would allow farmers to not only cut back on their costs to fertilize, but also on the amount of fertilizer getting put into groundwater through runoff.

It's a potential game changer in terms of their cost, and also the environment, because we know they’re probably over applying that fertilizer, and that's going prevent that fertilizer from leeching into our waterways and so forth," Claussen says.

Although the sensors are still in the testing stage, the idea is to integrate the probe with current agricultural equipment already on the market. The team at ISU currently has a partnership with Van Wall equipment, a John Deere dealer throughout Iowa.

The sensor, developed in the lab, is one part of the puzzle. The sensors would relay soil nutrient information to the cloud, which would then be applied for the next application of fertilizer.

"That’s why we’re working with these tech companies and John Deere, so that it goes into the existing equipment they’re using, and the electronics and technology they're accustomed to," Claussen says. "It's not an add on, not as much as a learning curve."

The watchful eye over nutrient application is especially important in growing corn, which requires nitrogen-rich fertilizer to be added throughout the season.

"Corn has a lot more high maintenance than beans," says Tom Carman, a third generation corn and soybean farmer in Urbana. "Beans, you just throw in the ground, spray them, kill the weeds and maybe apply a fungicide. Corn, you have to spoon feed the whole time."

Carman adds that this year's corn crop is the priciest he's ever planted.

"This most recent corn crop this year is the most expensive corn crop that we’ve planted," Carman says. "Fertilizer has gone up, nitrogen has skyrocketed. For about an acre of corn this year, you're looking at $1,000 an acre, with rent included."

Carman notes that figure can vary on a number of issues, including the size and rent on a given farm, but the fact remains: costs are high.

Now, the challenge is getting the probes on a production scale and ensuring they can last the growing season.

Dr. Carmen Gomes is an associate professor at ISU working on this project.

We are testing the longevity of the sensors," Gomes says. "We're transferring that information to the cloud and can collect data as frequently as we want."

Gomes adds they're close to getting the devices out of the lab and to mass production.

"Its very much fined tuned. We've proven in the lab that it works, now we're just fine-tuning to really launch," Gomes says.

To farmers like Tom Carman, the probes could be a game changer.

"If you know you’re getting low on nitrogen at certain times, later in the year, that area is going to need more nitrogen, or you lost a lot of that nitrogen," Carman says. "That's where those probes would be good to have."

He adds that heavy rains cause pooling and standing water, which can affect nitrogen levels.

The probes are the latest in a long line of innovations in agriculture technology, with the convergence of technology and farming getting stronger as years pass.

"Everything is getting fine-tuned and going to the technology side," Carman says. "It makes our life a heck of a lot easier, especially when the stuff is working. You can plant all day and not have to stare at the line to make sure your rows are straight, the tracker does it itself. It's amazing what the potential is, and it makes our jobs a lot easier, too."