Robotic soil sampler is slow but consistent

The autonomous SmartCore is not just another agricultural robot — it should also be considered an agronomic tool

Try pulling six-inch cores from 100,000 acres on 2.5-acre grids with just four machines. It happened this fall, thanks to the autonomous SmartCore robot that samples 110 acres per hour.

The machine was developed by two Purdue University engineering students, Troy Fiechter and Drew Schumacher. Once out of college, they turned their engineering project into a start-up company called Rogo Ag. They are now booking acres to have their four SmartCore robots collect spring soil samples in Ohio, Illinois and Indiana.

At this point in their business plan, Rogo Ag is more interested in providing a better soil sampling service than in selling robots, Fiechter said.

Their motivation in developing SmartCore was not to build and sell robots, but rather to pull more consistent soil samples, thus providing an improved agronomic service to farmers, he added. Extracting all the cores a farmer wants in a short season is a challenge many years. That’s why high performance became one of their main criteria.

“With an average 110 acres per hour on a 2.5 acre grid with eight cores, SmartCore is almost triple the performance of any human operated sampling machine. It doesn’t travel very fast. It just doesn’t stop for coffee or lunch breaks,” he said.

“The entire reason Rogo Ag exists is fertility management. That’s what we’re interested in.…

“SmartCore is just a tool. We made SmartCore autonomous, not because we wanted to play with robots but because we needed it to return to the exact same spot for every core year after year.

“We developed a high-speed auger because we knew we needed accurate depth. We found that 30 percent of our lime had been going to different spots in the field simply based on bad sampling practices. Half the problem was core depth inconsistency. The other half of the problem was core spot repeatability. The SmartCore is accurate within an eighth of an inch 100 percent of the time.”

Conventional samples can be inconsistent by as much as 20 percent using traditional methods. What does 20 percent cost you? Plenty, according to Fiechter who has run cost analysis on his own 2,500 acres on the east side of Indiana. He said there were problems managing his fertility program because of erratic soil sample data.

The highly accurate SmartCore allowed Fiechter to lower his sample discrepancy from 20 percent to five percent. A more accurate soil sample lets a farmer cut fertilizer where it’s not needed and add fertilizer where it is needed to boost yields, and thus the bottom line.

“We started this SmartCore project because we weren’t getting good sample information for our own farm. We found that 30 percent of our lime was going to the wrong spot in the field, just based on how it was sampled. So we knew we needed more accurate data.

“For example, lets plug in $85 an acre for MAP, potash and lime. A 20 percent error in the sample costs you $22 an acre, either by over-fertilizing or under-fertilizing. If we use a five percent error, the reps were repeatable within $8 an acre using the SmartCore.

“We’re putting precision into so many implements, like our planter and sprayer and combine, but our soil sampling program did not have that kind of precision. There was no accountability.”

Fiechter said the SmartCore is fresh technology — they designed and built the components themselves. Other than the Bobcat and guidance system, he added, there’s very little off the shelf stuff that can be sourced anywhere. The Bobcat autonomously navigates via LiDAR sensors and boundary algorithms using a real-time kinematic GPS. The compartment on the Bobcat once occupied by a driver now holds all the SmartCore equipment. They added a standup driver platform at the rear of the machine so the operator can load and unload from a trailer. SmartCore holds 250 samples.

“We developed all the unique technology. For example, nobody has ever packaged and labeled soil samples on the go. We developed that system. We’re the first company to come out with a high-speed auger to clean out the bottom of the holes in fine textured soils. It’s self-cleaning, so there’s no cross contamination between samples. It extracts the entire core every time regardless of soil type or soil condition.”

Although they are up to Version Five of the SmartCore, they still want to keep one of their engineers working directly with each machine to troubleshoot mechanical and computer glitches immediately when they occur. Fiechter said Version Five is faster. It has a suspension system, so much of the bounce gone, and the electronics are easier to diagnose. However, they’re in no rush to sell machines.

“In terms of viability, we can put more acres through a machine per year by having five customers tied to one robot. That makes more sense to us than selling robots to people who aren’t engineers.”

Rogo Ag was still running fall samples with four machines and is taking orders for spring sampling. Cost is competitive with market rates at US$3.50 to $4.50 per acre based on a 2.5 acre grid system.

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