When we first visited Iowa farmer Clay Mitchell in 2004, his precision technology experimentation was already well past what many farmers are willing to try today. He had three seasons of using automatic steering already under his belt, which he used to take his strip-till practices to the next level. He was also broadcasting the Internet wirelessly across his fields, providing him access to the Web and e-mail virtually anywhere.
Over subsequent years, Mitchell implemented a wide range of agronomy and efficiency-improving technologies, including application and seeding control at the nozzle and clutch level, RTK-based implement steering, and corn and soybean intercropping to name a few.
This season, Mitchell took his work in an entirely new and more dramatic direction — he set out to improve land use methods beyond the ordinary. If it were a TV show you could call it “Extreme Makeover, Farm Edition.”
Mitchell’s work is focused on trying to get an answer to a pretty simple question: Can you take really good soil from one part of the field, transport it to a poor performing area and increase yield in the historically yield-challenged zone?
He set out to get answers to his questions this season, as he embarked on a plan that would involve moving available or excess topsoil and placing it in the poor performing areas in order to grow a better crop. “Agronomists know the value of top soil,” says Mitchell. “It does no additional good to have 10 feet of top soil in an area of the field below what’s needed to grow a crop, but it does a lot of good if you can put, say, 2 feet of top soil on a sandy knoll where the top soil is very thin.”
As a first-year program, Mitchell began implementing new practices in bite-sized pieces.
“We took a ‘do no harm’ approach this first season,” says Mitchell. “We did not want to do anything that would degrade a field and make it impossible for us to bring it back to the way it was. The changes in topsoil depth and other soil qualities tend to be smooth changes over broad areas, but after pulling soil around with a scraper we can get sharp discontinuities if we don’t do a good job. It’s real easy to mess things up.”
Talking about moving soil is getting ahead of the story a bit, because it took some substantial planning and a bit of technology implementation to make it go. Mitchell has plenty historic field data to go on, so identifying poor performing areas was not the challenge. Identifying and locating the good, movable soil was key.
For this first season he went for the low-hanging fruit, the soil that’s eroded into grassed waterways. “This is required work in all fields,” says Mitchell, “but that soil is usually just deposited near the sides of the waterways. We took the soil out to the fields where the poor soil anomalies were distinct.” By “distinct” he means clearly poor performing — this delivers more response than attempting this on a mid-range performing piece of ground.
It was assumed, but not taken for granted, that the eroded soil would be excellent. “The top layer is what has the highest organic matter and highest fertility, and that’s what erodes and gets deposited,” says Mitchell. “Still, we did extensive soil testing to confirm our expectation. We also tested within the areas that we knew were bad. We tested both texture as well as chemical properties.”
Technology Kicks In
Once the fields are identified, then the heavy lifting — literally — begins in earnest. A technology that is helping this along is RTK controls that are based on elevation. Soils can be leveled with much less time and labor than the old-fashioned way. “Using lasers and surveying equipment, it would take a dozen people to do what I am doing by myself with RTK GPS technology,” says Mitchell. Another important factor is the availability of high-horsepower tractors which allow scrapers to move soil with relative ease.
Finally, compaction was an important consideration with all of the traffic that was necessary to move the soil around. “We try to consolidate traffic lanes for the earth moving equipment, which is a good thing because they showed up in aerial photos,” says Mitchell.
This winter, the main measuring stick will be the yield map, he notes. “Yield maps are how deposit areas are targeted, and they are how verification is done after the work.” How the plan panned out is yet to be seen, but Mitchell is optimistic.