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Farm’s field day is serious business

By Staff | Jul 18, 2015

JOEL DEJONG, an ISU field agronomist, displays the sole example of corn blight he could find after a 45-minute search in the crop on the Northwest Iowa Research Farm’s test plots. He advised that it would not be cost-effec- tive to spray, given the low in- cidence, but told farmers to “keep an eye on it.”

fiddelke@longlines.com

SUTHERLAND – Feeding corn plants the nitrogen they need while keeping nutrient run-off out of waterways was the hot topic at a recent field day in Sutherland.

Matt Helmers, an Iowa State University biosystems engineer, spoke to 123 people at the ISU experimental farm about how to best care for the plants while also keeping the run-off out of waterways, the water table and wells.

Helmers made reference to cities where the water supplies – rivers, wells and underground aquifers – are being affected by fertilizer run-off and are protesting or taking legal action.

Helmers said experiments to rein in that chemical run-off are in progress now at the research farm.

The research seeks to learn more, including how to keep that nitrogen from flowing downstream where it can infiltrate communities’ water supplies, or even contribute to hypoxia – the lack of oxygen – that created the Gulf of Mexico’s dead zone.

According to research by the Louisiana Universities Marine Consortium, in the past 30 years, 5,300 square miles of the Gulf’s ecosystem has become a dead zone, containing little oxygen for marine life.

What to do?

Helmers said his research is still in early days. The study focuses on the side-effects of nitrogen-based fertilizer run-off and how it might be mitigated by changing the timing of application, or taking other actions, without sacrificing yields.

The study involves 32 plots of cropland, each planted with corn and tiled to direct any excess water to one of 16 separate sumps.

Run-off from 24 of the plots is divided evenly and sent to eight of the 16 sumps.

The run-off from each one of the remaining eight plots is channeled into its own sump.

If the crop is not using all the nitrogen, it will show up in one or more of the water samples, telling researchers that there is room to reduce the amount of fertilizer – and chemical run-off.

Each protective sump house has a gauge that measure the inflow.

Josh Sievers and Chad Huffman, the farm’s superintendent and ag specialist, respectively, take samples from the sumps – about 125 milliliters from each – and send them in special packaging to Ames, where the well samples are analyzed.

The first samples were collected on July 7 and 10, and will continue to be gathered and shipped twice a week.

No results have been reported yet.

Corn growing options

Four nutrient management models are being tested at Sutherland – no nitrogen, fall-applied anhydrous with stabilizers, spring-applied anhydrous only, and fall/spring split application with a third added at planting, and two-thirds applied at V-10.

From these plots, Helmers said researchers hope to learn how much nitrogen and total phosphorus is in the run-off, which fields retain the most nitrogen and which fields shed the most nitrogen.

Helmers said they want to know if nitrate loss depends on the type of nitrogen applied, and if more N is lost through fall application with stabilizers effective versus spring with no stabilizer; and ways to reduce losses through more timely application practices.

In the end, Helmers said, the study should give producers more direction about using – and the corn retaining – only the necessary amount of nitrogen, thus eliminating or reducing nitrogen run-off.

Time to act

The research is nothing if not timely.

Communities downriver from farming operations are demanding a reduction of nitrates in rivers and wells used for public water supplies.

Hypoxia is fueled partially by nitrate run-off, no matter its sources. It also contaminates the underground water table , according to Helmers.

Helmers said healthy soil will contain nitrogen and organic matter, which will be used up by the crop.

He said no one knows the best way to retain all the nitrogen needed to maximize production while reducing, or eliminating, the amount of nitrates that wash away unused.

But he had a few suggestions. These include:

  • Think about soil health; better soil retains more moisture.
  • Apply nitrogen close to the time the corn will be able to use it, in late June, and July, not in April or May, when typically heavier rains can wash it away unused.
  • Plant cover crops such as hay, which grows well in northern Iowa and is a natural supplier of nitrogen that won’t wash downstream.

‘We’re making headway’

Helmers said that in the 1950s, before the demand for soybeans became primary, farmers planted grassy crops, which he noted “is not a challenge in Northwest Iowa.”

He said that today, rye could be planted before the beans go in and that oats would be good to grow in fields that will be planted with corn.

A farmer in the audience questioned what the market for those grains would be if everyone began growing them.

“We do have a lot to learn to put that into practice,” Helmers said.

He noted that grazing livestock would be another way to benefit from grassy crops.

Several farmers shared their own experiences in using cover crops.

One said he plants barley in the fall.

“The frost kills it so I don’t need to use any herbicide,” he said.

Another farmer said he rolls over his rye to plant his corn and gets far fewer weeds in his corn field than he did without the rye.

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