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Nitrogen runoff from fertilizer diminishes the quality of Iowa waterways and drinking water. The runoff spurs toxic algae growth that can turn water green and ultimately kill fish.
Green Valley Lake in Creston is one of those waterways with nutrient enrichment issues, and state park officials often have to issue beach advisory warnings because of it. But Connor Travis said he and other farmers he knows in the Creston area are doing what they can to mitigate the problem.
“A lot of people are using dry fertilizer and the dry fertilizer form of nitrogen is what they call urea. So the way dry fertilizer works is that you can spread it out across the top of the field. When the rain hits it, it gets incorporated down into the soil. We experience nitrogen runoff when people do not have well drained fields,” Travis said. “So if we just go out there and we spread urea on top of the field and we experience heavy rain where we actually have erosion, like water running off the field, that’s when we experience a very significant amount of nitrogen runoff.”
He said drain tiling helps prevent runoff.
“What we’ve done to stop that is we put in drain tile in all our fields so that way it’s taking that moisture or that rain, and soaking it through the soil. And that nitrogen grabs on to solar molecules as it’s getting soaked down,” he said. “So when we go to put in tile line we put it four to six feet deep, whatever it needs to be, in the ground. So that way it has plenty of time for that water to sift through the soil and release that nitrogen into the actual soil profile, not with our water. So then it’s kind of a natural process of refining that water to make sure it has less nitrogen in it as it leaves.”
He said farmers are usually careful to avoid spreading dry fertilizer before a heavy rain.
“Typically farmers nowadays are gauging that. They are looking at the weather and making decisions based off of common sense, for lack of a better term, and understanding some fields are going to runoff. Some fields are going to drain better,” he said. “So if I’ve got an 80 [acre farm] that doesn’t have drain tile and we got four inches of rain coming, I’m obviously not going to be spreading some over top of that.”
He emphasized farmers have a financial incentive to avoid nitrogen runoff.
“It’s hurting us too. I mean, us farmers want that nitrogen. Our goal is not to let it runoff into the water,” he said. “That doesn’t make financial sense to us.”
Travis said most farmers in the Creston area use anhydrous ammonia fertilizer.
“That’s a form of gas, anhydrous ammonia, and we hook it up to a toolbar that has shakes. They’re spaced out on 30 inch rows where we can use that nitrogen more efficiently. We pull that across our field and we inject nitrogen, anhydrous ammonia, into the soil and then cover it up with dirt,” he said. “So that way it’s almost like it’s trapped in there. But then since it doesn’t have oxygen, it’s still in liquid form and it attaches to the soil profile and attaches to microbials in the soil. So that’s more prevalent around here.”
He said technology has improved to a degree that he has greater control to ensure that no area gets covered twice.
“We’ve got to the point where we can shut off seven feet at a time on those big 40 foot toolbars and we’re not putting anhydrous where there already is anhydrous,” he said.
He said cover crops are another effective defense against nitrogen runoff that can also boost soybean yields and prevent erosion. He typically plants rye.
“Cover crops do help, especially with erosion. But it can also take some of that leftover nitrogen in the soil and put it toward good use of growing a crop. Rather than just having it sit in the ground and potentially being run off, instead it becomes useful.” he said. “With cover crops we can hold that top layer of soil better to prevent wind erosion in the winter time when we have wind and snow blowing across the ridges.”
Travis said he’s an outdoorsman and does what can to prevent damage to waterways.
“I love fishing. The last thing I would want to do is kill fish. We’re trying to provide for the earth, we’re not trying to ruin it,” he said. “We’re trying to be good stewards of the land.”
Adam Schneiders, a Water Quality Resource coordinator with the Iowa Department of Natural Resources, said they have programs in place to mitigate the effects of nitrogen runoff.
“We do have a water restoration program, where we look at restoring lakes,” he said. “And when they do a restoration, they’ll look at and determine if there’s nutrient impacts. And they’ll implement practices within the watershed feeding into that basin that’s collecting all the rainwater.”
He said there are many joint efforts with agricultural departments to address the issue.
“Farmers and landowners have access to NRCS [National Resources Conservation Services] and Department of Agriculture Land Stewardship cost share programs to put in practice a variety of conservation measures in the field and at the edge of the field to reduce nutrients and prevent soil loss,” Schneiders said.