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Stopping nitrogen escapes

By Staff | Sep 13, 2013

Tim Smith, a Wright County farmer, speaks to Wright County-area producers on Aug. 27 about farming practices that are proven to reduce nitrogen loss from fields into surface waters.

CLARION – Nitrogen leaching and run-off into surface waters is not farming’s best friend.

One in another progression of field days to document farm practices that nitrogen escapes was held Aug. 27 in Wright County.

The event was hosted by Boone River Watershed Partners to present the latest information on preventing nitrogen loss from farm fields.

The field day began at the Wright County Extension office in Clarion. Attending were representatives from Iowa State University Extension, Natural Resources and Conservation Service, Iowa Soybean Association, the Nature Conservancy and Mississippi River Basin Initiative.

Also in attendance were representatives from Coca-Cola and Cargill who were there to learn about what is being done to reduce nitrogen runoff as their companies want to promote sustainability.

Extension agronomist Mark Johnson explained that nitrogen occurs in the soil naturally in many forms and can be added by commercial fertilizer and manure.

Both natural and commercial fertilizer release nitrogen compounds through bacteria conversion by decomposition of organic matter and conversion of commercial fertilizer, Johnson said.

Nitrogen in the form of either ammonium or nitrate is available for plant uptake.

Anhydrous ammonia is quickly converted to ammonium and the ammonium is converted to nitrate when soil temperatures rise above 50 degrees with the conversion rate increasing as temperatures get higher, he said.

In the ammonium form, nitrogen is stable as it attaches itself to soil particles or organic matter, Johnson said. The nitrate gas is not stable and being unattached to soil, moves with water through the soil.

This leaching also occurs by denitrification when there is no oxygen in the soil and the gas escapes into the air, he said.

To assist farmers in applying a rate of nitrogen that is not excessive, a nitrogen rate calculator can be used ,Johnson said.

Farmers indicate on the calculator their state, whether they are rotating corn and soybeans or corn on corn.

Inputs for the price of anhydrous ammonia, nitrogen, and corn are selected and then a nitrogen rate is calculated what will be a maximum return to nitrogen and most profitable, he said.

Emily Funk, of NRCS, presented another computer-based tool available to farmers – the Fieldprint Calculator which measures sustainability in seven areas: land use, soil conservation, soil carbon/organic matter, irrigation water use, energy use, greenhouse gas emissions and water quality index.

To determine a farm’s sustainability, input data will include soil type, crop rotation, planting date, row spacing, manure application, tillage, transportation and drying system.

The software will determine sustainability by crop, giving a farm a value for each area and then compare that number to the state average, Funk said.

The field day attendees drove to the Arliss Nielsen farm near Woolstock where farmer Tim Smith told about his efforts to reduce his nitrogen runoff using numerous conservation practices.

Smith said he started by enrolling 20 acres and has now put his entire farm in the nitrogen reduction program.

Data on Smith’s farm measuring nitrate runoff showed a decrease from January 2011 to July 2012. His July 2013 numbers showed a slight increase in runoff from Smith’s farm when large increases were measured in the Boone River and Eagle Creek from heavy spring rain events.

The field day’s last stop was at the Webster City farm of Larry Haren where advice on using cereal rye as a cover crop and growing it for seed was presented.

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