Use the right tools on your farm to improve water quality

At a field day near Slater, Iowa, landowners, farmers, and ag experts discuss which tools to implement on the farm that help reduce nitrate leaching.

"We aren't diverting away from corn and soybeans, so as much as we can do in the field to capture and treat left over nitrates, and at the edge to keep them out of the streams, we should," says Chris Hay, senior research scientist with the Iowa Soybean Association.

Two options at the edge of fields that address nutrient concerns in surface water runoff are saturated buffers and woodchip bioreactors.

"Where we have tile drainage in a field, which includes a lot of Iowa farmland, then saturated buffers are fantastic to provide treatment," Hay says.

In a saturated buffer setup, a control structure is placed to intercept the tile line and redirect water through the organic matter of the buffer. The microbes in the buffer process the nitrates and convert them into nitrogen gas.

.

Each state differs in the funding support available to implement edge-of-field conservation practices like saturated buffers. However, if a buffer already exists on the land, the cost reduces significantly. In Iowa, a saturated buffer (with an existing buffer along a stream) costs approximately $3,500 to $5,000.

Woodchip bioreactors, which divert water through an underground trench of woodchips, are more costly at $10,000 to $15,000. Woodchips are projected to last 10 years in a bioreactor trench and at that time need to be replaced, which is an added long-term cost. One benefit they have over saturated buffers, however, is that they can be placed in more locations since they aren't constrained to being stream-side.

Partnerships like the Central Iowa Water Quality Infrastructure Project, though, create new models to fund construction at no cost to the landowners, thanks to multiple funding partners. In 2021, the project has designed and installed 51 saturated buffers and bioreactors in central Iowa.

In addition to these edge-of-field practices, cover crops help fix nitrogen in the soil and Rantizo, a drone spraying platform start-up, is equipped to apply cover crop seed with its swarms of drones.

"The drone specializes in tight areas where the traditional applicator may not be able to get to like a small or awkward-shape field or an area that has been flooded out," Sam Pendleton, director of sales at Rantizo explains.

Pendleton says a drone is not the answer to everything – there will still be areas to ground or air-seed via airplane. But the accuracy of application to the field boundaries, even accounting for wind, is high.

Landowner Lee Tesdell says in the past, seeding cover crops via airplane has crossed over to neighboring fields, so he's most interested in improving the accuracy.

At the field day, Rantizo's three drones seeded a mix of oats, rye, and camelina at 42 pounds per acre. Rantizo charges per hour and specializes in lower-rate cover crop blends.