On the Mitchell Farm in eastern Iowa, inefficiency and uncertainty are tolerated about as much as foxtail in corn fields across the Midwest. Once a problem or issue is identified, it becomes an itch that needs to be scratched for Clay Mitchell.
Clay, his father Wade, and great uncle Philip share ownership in this Iowa land and are descendants of a farming family that has farmed since before America was born, but their approach to farming is anything but traditional.
Clay grew up on the farm but is a trained engineer. Returning from Harvard in the late 1990s, he went to work on the family farm reviewing and re-engineering everything that left more to chance than was necessary.
Each season, The Mitchell Farm takes on a number of new projects, but there’s one that stands out as the centerpiece. In 2003, they were working on perfecting a communication network that allows it to control a wide range of farming functions from centralized locations. Last year, Clay focused on spray application efficiency with the addition of automatic boom control using the ZYNX X15 controller from KEE Technologies. Automatically shutting down boom sections to avoid overlapping and spraying too close to waterways resulted in a 30% efficiency gain and a 20% savings in crop protection product.
In 2005, the Mitchells decided that they needed to find a way to deal with the issue of the shifting value of corn in relation to soybeans. It’s an old battleground that growers have been fighting on for decades, one that has largely been at the mercy of basic agronomy and rotation practices.
Still, the Mitchells felt compelled to re-engage the problem. “Back 10 years ago, soybeans were more valuable than corn on a per acre basis, so you saw a lot of farmers going with beans after beans,” explains Clay Mitchell. “Then it became more equitable, and began shifting toward corn. Now farmers want to grow continuous corn, but that’s not a good solution because it creates yield drag and ruins a lot of benefits we get from rotation. We were looking for ways that we could emphasize corn in a given year without sacrificing rotational benefits.”
The Mitchells moved forward in this question by looking back at the ancient practice of intercropping. Simply put, intercropping is placing multiple crops in close proximity to create beneficial interactions. The Mitchells’ practice strip-intercropping by alternating 30-foot swaths of corn and soybeans. What makes it practical and possible in large scale, Iowa-style production farming is technology.
“We feel that the competency we have is to apply appropriate technologies to the current economic context,” says Mitchell. “Automatic steering technology, herbicide tolerant crops, the environmental conditions in corn and soybean country — everything is in place to make intercropping a significant strategic advantage for our farm.”
At the foundation of intercropping is highly accurate, real-time kinematic (RTK) steering. “The rows must be perfect to work,” says Clay Mitchell. “In spring, we plant a 30-foot swath of corn, leave a 30-foot space, then plant another 30-foot swath, and on down the field. Two weeks later, we come back and fill in the soybeans.” The other important consideration is the need for a 22 1/2 inch space between the corn and soybean rows — just enough room for the row divider on the combine header to sit between the rows.
Mitchell uses Trimble Autopilot and Deere’s AutoTrac RTK products because the systems can be used interchangeably. “They use the same mathematical model of the Earth — they will follow the same path,” say Mitchell. “While there are other good systems, these two follow an emerging industry standard. Growers need to be careful about this.” His tractors of choice are a Case MX270 for corn with a 12-row mounted planter, and a Deere 8520 for soybeans, featuring a 24-row, 15-inch seeder.
The other factor about the planting procedure is the implements. Mitchell has modified the trailed air seeder so it is fixed in position and will not drift away from the equipment doing the steering. “If you’re going downhill and the implement drifts a couple of feet on a 7-degree slope, for example, you’ll have beans growing in corn and you’ll ruin any advantage you hoped to gain,” says Mitchell.
At harvest, it’s just the reverse. The soybeans are harvested first, followed by the corn. One cool side-benefit of this process is that there is always an empty row next to the corn being harvested, allowing the corn to be loaded directly into a grain truck for delivery to the elevator.
Seems simple on paper, but there are some key considerations that Mitchell has had to address along the way. Hybrid selection for certain attributes depending on field position is critical. With the corn, the outside row hybrids are selected for root and stalk strength, while taller growing varieties are selected for the inside rows. Soybeans are picked that tend to be bushier and lower growing because they will get less sun.
An unintended consequence of intercropping has been that the corn comes off the field drier than when planted as a monoculture because of the increased airflow across the field. This is a tremendous benefit given that energy costs to dry the crop continue to increase.
Following the harvest, it’s time to fertilize. “We only fertilize the area that is going to corn,” says Mitchell. They use anhydrous ammonia as their nitrogen source.
A tool that continues to be useful in this and other functions is the KEE ZYNX in-cab computer, which runs Microsoft Windows and can control a wide range of functions, from fleet management to e-mail and Internet access. In addition, its wireless capabilities allow it to send data directly to the base computer without needing to transfer a storage device.
That’s certainly a full year, but what about next season? Using corn screenings as fuel instead of propane is on the radar, and who knows what else … next year’s visit should be interesting.
Editor’s note: This article first appeared in the Winter 2005 issue of PrecisionAg Special Reports.