Research farm is leading water quality research

NASHUA, Iowa — Some of the longest running research on tile drainage and nutrient runoff comes from the Northeast Research and Demonstration Farm at Nashua.

ISU Northeast Research Farm superintendent Ken Pecinovsky takes a water sample at the bioreactor at the Nashua research farm.

NASHUA, Iowa — Some of the longest running research on tile drainage and nutrient runoff comes from the Northeast Research and Demonstration Farm at Nashua.

Matt Helmers, Iowa State University Extension agricultural engineer, summarized some of the drainage water quality work at Nashua and other research sites during the recent Northeast Iowa Agricultural Experiment Station annual meeting.

"This has been really instrumental in the Iowa Nutrient Reduction Strategy," Helmers said. "The work done on this farm has really helped inform what we can do about nutrients leaving our fields and getting into downstream waters. As we make science-based decisions, we want good data and data from Iowa."

Many of the practices listed in the Iowa Nutrient Reduction Strategy have been studied on the farm. Research farm superintendent Ken Pecinovsky and farm technician Ralph White deserve credit for maintaining the equipment and carrying out the studies.

Concern about local and regional waters is increasing at the same time there is substantial demand for agricultural products, Helmers said. A 2008 Hypoxia Action Plan called for implementation of nitrogen and phosphorus reduction strategies in the Mississippi/Atchafalaya River Basin.


The Des Moines Waterworks filed a lawsuit a year ago against drainage districts in three northwest Iowa counties over high nitrate levels in the Raccoon and Des Moines rivers. That suit is set to go to trial in August.

Iowa's goal is to reduce nitrate and phosphorus loading by 45 percent.

ISU has five drainage water quality research sites that replicate subsurface drainage plots to evaluate the performance of various in field management practices. Sites at Nashua and Gilmore City have been running for more than 25 years.

"We've looked at nitrogen sources, timing and now cover crops," Helmers said.

A drainage water quality research site at the Northwest Research Farm at Sutherland was established in 2013. Researchers are looking at fall applied anhydrous ammonia, spring anhydrous, a side dress application and a plot with no nitrogen.

The Comparison of Biofuels Systems research site at Ames is examining prairie grass, corn and soybeans and continuous corn. The Southeast Research Farm at Crawfordsville is focused on different drainage designs, depth and spacing of drains or controlled drainage.

"Iowa is a leader in its drainage water quality research across the Corn Belt," Helmers said.

This research has shown that there is variability in drainage, nitrate concentration and nitrate loss depending on the year. Dry years bring very little nitrate loss followed by spikes in very wet years. There was almost similar nitrate loss in the soybean year as in the corn year.


"This illustrates the challenge with nitrogen management and how it can vary," Helmers said.

While it is important to manage nitrogen, pushing really low nitrogen rates won't solve the problem, Helmers said. Cover crops have been shown to reduce nitrate loss spikes.

Nashua researchers looked at six management systems in 2015 — spring UAN application at 150 pounds N per acre in a corn-soybean rotation with chisel plow and field cultivation and fall applied liquid swine manure at 150 pounds N in a corn-soybean rotation with tillage. There was a fall manure application with tillage at 150 pounds N for corn and 100 pounds with soybeans.

The fourth plot looked at fall manure application at 200 pounds N in continuous corn with tillage, with and without stover removal. The fifth treatment was 150 pounds UAN spring-applied with a rye cover crop in a corn/soybean rotation. The sixth treatment was fall-applied manure on no-till corn and soybeans at 150 pounds N per acre.

The plots with cover crops had the lowest nitrate concentrations in the combined phase as well as the corn phase.

"We're in the infancy of learning about how cover crops work, how they help soil and what cover crops are best for our environment," Helmers said.

The rate of soil nitrate production from native soil organic matter occurs early in spring when there generally isn't crop to use it, Helmers said. As a result, some nitrate is lost to waterways. Most nitrate used by corn and soybeans comes from soil nitrate production. Corn gets the difference from fertilizer while soybeans get the difference from legume fixation of atmospheric nitrogen. Even with no nitrogen application, research results show 7 parts per million nitrate in tile water.

A study at Gilmore City showed a 25 percent reduction in nitrate nitrogen concentration with a winter cereal rye cover crop in row crop systems. Research from the COBS site shows little nitrate leaching in prairie and fertilized prairie.


Starting in 2016, a Nashua manure management and water quality study will look at treatments involving fertilizer, manure, manure applied early in the fall with and without an inhibitor, manure applied in the spring, manure applied in fall with gypsum, early fall manure application with a cover crop and late fall manure application with tillage and no-till.

"We're trying to answer some pretty important questions that may be coming up in the future," Helmers said.

Water monitoring equipment at the ISU Northeast Research Farm at Nashua can take automatic samples.

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