Draining water away from fields to make them more productive is nothing new. But with the advent of new technology and rising concerns about runoff, drainage systems are capturing more attention nowadays.
Ron Heck farms near Perry, IA. Over time, he has been developing the most efficient combination of drainage systems to maximize profits on his land.
”We came to realize that tile alone wasn't really enough to restore the soil quality to what it needed to be to raise crops, particularly soybeans,” he says. ”We've learned how easy it is to farm right through shallow drainage ditches. You don't really lose any crop, but you do gain yield.”
The Iowa corn and soybean grower acknowledges that there are some bits of fields that it might not pay to improve, but through yield mapping, he identified areas where he was losing a lot of yield in extremely fertile soil — it just happened to be at the bottom of prairie potholes. Part of the yield loss was due to drainage, but Heck also attributes some to nematodes, high pH soils and possible pooling of atrazine. Heck estimates that by using all the technology available to him to manage water flow, he's increasing soybean yields as much as 30-40 bu./acre in some areas.
He explains that the real ”aha” moment for him was when he saw his first yield maps in 1994. ”For the first time we got a report, foot by foot, on how a field was doing. I'm sure every farmer realized how much yield they were losing in some spots when they looked at those first yield maps,” he says. ”The plants looked fairly healthy, but they didn't produce as well. This certainly renewed our interest in trying to figure out whatever it was that was causing harm in particular areas.”
As for how to solve drainage problems, Heck says the solutions vary from field to field.
”Sometimes diverting water to stop it from going into the low areas to start with is the best thing to do. But there are other times when it's best to let the water go into that low area and drain it from there,” he says.
Heck notes that in some cases he has agreements with neighboring landowners to divert water through several tracts of land. ”You do have to respect the rights of other property owners,” he adds.
What has really helped him take the guessing out of the process is another layer of technology — topography maps that show the field elevations alongside the yield maps make the design of drainage systems much simpler, Heck says. ”Those two tools are more than 90% accurate, but like all things you do at your desk that look reasonable, you still have to go stand out in the field and get a surveyor to work with you.” He credits his cousin Don Heck of Heck's Dozer Service in Ogden, IA, for his skill in putting in drainage ditches that are just the right depth to be effective, yet shallow enough to drive across with farm equipment.
The economic benefit of such improvements is tough to pencil out, but Heck says he knows his fields are more productive than they were before.
”We're using the same inputs and getting more yield out of it. That's a net gain,” he says. ”I know that when there's a big storm, the drainage systems we have in place allow the land to drain and dry out, and enables crops to use moisture more efficiently.”
Tracy Blackmer, research director for the Iowa Soybean Association, says there are several reasons why growers might consider taking a closer look at drainage issues on their land.
In most of Iowa, he says drown-outs are common. Early spring rains create ponding and cause nutrient loss. ”It's safe to say most fields in Iowa would benefit from better managing water flow through fields. By doing this you can also reduce the environmental consequences,” he says. ”Drainage can also be managed in such a way that erosion is minimized.”
Blackmer says remote sensing measures the topography, enabling a landowner to see a three-dimensional view of their land. The elevation mapping can help quantify how much earth needs to be moved to improve the flow of water on the land.
In Heck's case, Blackmer says they flew over his fields after a 4 in. rain event and there was very little standing water compared to the land surrounding them. ”When you consider the impact of having standing water in your fields for days, making sure your fields properly drain can be a significant benefit,” says Blackmer.