Headquartered in Columbus, the Ohio Department of Transportation has offered a precise guidance signal through its Virtual Reference Station network since 2004, which has allowed farmers to farm more efficiently with Global Navigation Satellite Systems.
Real-time corrected GNSS correction services deliver positions that can guide a tractor or spreader to precisely apply a small strip of fertilizer no more than an inch wide. The seeder is guided to the same strip where the seeds are placed, exactly in the right spot to maximize the fertilizer yet not burn the seed. This precision and accuracy are repeatable year after year.
And precision farming is catching on. The past decade has witnessed an explosion of farmers practicing precision across the state. In 2020 alone, farmers accounted for nearly 225,000 hours of Virtual Reference Station use. That total comprises 40% of the Ohio Department of Transportation VRS hours used in the past year.
The Buckeye State has a vanguard of other agricultural service providers. Matt Culler of Ag Info Tech, located in Fredericktown, leverages the ODOT VRS network to provide his farmers with more than just precision seeding.
In the rolling landscape of mid-Ohio, Culler knows a GNSS-connected rig also helps farmers fertilize precisely and design their own surface drainage plans and set drain tile at all the right depths and grades.
What makes VRS tick?
The success of ODOT’s VRS is a combination of components that clicked together about 2009. The foundation of the network is a series of reference stations set up about 20 miles apart throughout the state.
A modern GNSS reference receiver uses multiple satellite constellations, including GPS, GLONASS, Galileo and BeiDou, adding serious horsepower to precise positioning. Running GNSS measurements through the VRS ground network computes a reliable and repeatable datapoint by doubling up on the math.
Behind the scenes and at the heart of ODOT’s VRS is the Trimble Pivot Platform. This software enables a VRS host such as ODOT to securely deliver a reliable correction signal at all times. It also works with all brands of GNSS receivers, provided they are able to connect via NTRIP (Networked Transport of RTCM via Internet Protocol) or IP (Internet Protocol) to the ODOT network.
Making sure the hardware and software are meeting demand and providing high-quality service is ODOT’s VRS network operator, Dave Beiter. He’s also an engineer and a farmer who understands the algebra of precise positioning and crop yield.
Having experience from both sides of the field, Beiter stresses that farmers, who heavily use VRS during peak season, rely on the support they receive from ODOT’s team who are well-respected leaders in the global VRS community.
This team built the first statewide real-time GPS network in 2004, hosted the first statewide dual constellation real-time network in 2008 and became the first GNSS network to be used by the agriculture sector in 2009.
Value in VRS
The real VRS magic for farmers happens in the tractor cab. The same technology that launched social media, streaming video services and mobile banking is now also used as an interface between seeders and satellites when delivered by VRS.
Putting this technology to use, the ODOT VRS interfaces with Trimble’s precision agriculture solutions. The Trimble DCM-300 modem is the gateway to connectivity in the tractor cab. This small box ties satellites to seeding via an Android-based Trimble GFX-350 display and the Trimble NAV-900 guidance controller.
The system easily accommodates 180-degree steering in the headland and pops right back on a row after the turn is completed.
The NAV-900 guidance controller is the brain of the operation. It feeds the precise position to the Trimble Autopilot automated steering system, which is coupled into the tractor hydraulics.
The tractor is held to the row as the autopilot precisely applies the necessary hydraulic pressure to the operative cylinders, removing human overreactions to steering response. Precise control of hydraulics is a key to guaranteeing the seed is going to hit that 1-inch strip of fertilizer every time, year after year.
The Trimble TrueTracker implement steering system puts both the tractor and implement on the same line individually. Because each piece has its own control sensors, the implement is no longer just being dragged behind the tractor, but tightly controlling seeding.
Value in precision
To put a scale on efficiency, take a 1,320-square-foot field of 40 acres. An application rate of 250 pounds per acre with a rotary spreader means the farmer needs 10,000 pounds of mix to cover the entire field conventionally.
Does the whole field really need fertilizer? Row crop farmers have embraced the ODOT VRS and Trimble Precision Ag to answer this question. They have whittled the 40-acre field down to 1-inch-wide rows spaced 20 inches apart, which gives 792 1-inch rows, each being 1,320 feet long.
Subtracting all of the dead space in between rows then nets a total application acreage of 1.92 acres or 480 pounds of fertilizer — a 95% reduction in material.
Stewards of the land
Despite water being on top of every farmer's list of worries, they still can't control the rain. However, Buckeye farmers are striving to be great stewards of the land and have voluntarily adopted environmentally sustainable practices with runoff and stormwater.
In July 2019, the Ohio General Assembly invested $172 million in a multifaceted approach to clean water. “Since announcing the details of my H2Ohio plan in November, we’ve had a great deal of interest from farmers in the Maumee River watershed who want to do their part to improve the health of Lake Erie,” Gov. Mike DeWine said in January.
Ohio Department of Agriculture Director Dorothy Pelanda added, “Ohio farmers want to be part of the solution to water quality concerns in our state.”
The precision agriculture group is at the top of the ODOT VRS user list that includes a large segment of land surveyors and engineers, cities, counties, storm and wastewater agencies, construction and excavating companies, and utility locators along with other users.
Additionally, 21 schools are registered, including Ohio State University, Michigan State University, Michigan Tech, University of Michigan, University of Akron, University of Cincinnati, Case Western Reserve and University of Mount Vernon.
Through H2Ohio, the ODOT VRS is emerging as a utility for farmers, engineers, scientists, biologists and politicians to cooperatively downsize environmental impact. The entire ecosystem can be precisely related by VRS measurements and the data used to analyze the overall impact to the environment.