Raccoon River nitrate levels show significant, steady decline.

An analysis of recent water data show long-term declining levels of nitrates in the Raccoon River, despite the weather-induced spike seen this spring.

“While values did spike this spring, overall, the long-term daily nitrate levels have been declining, even when including this spring’s weather-induced spike,” says Iowa Farm Bureau Environmental Policy Advisor Rick Robinson.   “According to all available daily nitrate values reported by the Des Moines Water Works on their website for the Raccoon River, the data yield a statistically significant negative linear downward trend line in nitrates for 2006-2013.  There were record high levels of nitrate levels out of the Raccoon for a short duration this spring and we can clearly see why that happened; it was a ‘perfect storm’ which started with last year’s drought, followed by a spring of cooler temperatures and record rainfall.  In fact, rainfall this past April and May broke records that stood for 141 years,” says Robinson. Rainfall statistically correlates the most with the higher nitrates, he says.

Additionally, according to Des Moines Water Works website posted measurements, 80 percent of the daily nitrate values since 2006 are less than the drinking water standard of 10 parts per million (ppm).   “The fact that there’s been a steady decline in nitrates in the Raccoon River should not be interpreted that farmers are somehow shirking their responsibility for their share of the nitrate load. In fact, ag groups are stepping up to the plate, embracing the new Iowa Nutrient Reduction Strategy and encouraging all farmers to do the same. Farmers are considering additional steps they can take to help make further reductions,” says IFBF president Craig Hill.

This trend analysis follows a recent study, featured in the Journal of Environmental Quality, 2012, which confirmed that for 1992-2008, rainfall and temperature contribute more to nitrate variations in the Raccoon River, than modern farming practices. “While conservation work is never finished, it is worth noting that farmers have embraced conservation on 23 million acres of crop land, land which is constantly affected by our increasingly volatile weather.  The Iowa Nutrient Reduction Strategy is all about sharing information with farmers, to help them find the practices that best fit their farm and landscape,” says Robinson.

The Nutrient Reduction Strategy is one of the nation’s first ‘in the field,’ science-based assessments, which analyzes a varied menu of conservation practice scenarios.  The goal is to get the most nutrient reduction, while allowing the nation’s farmers to keep pace with growing population and energy needs.  “Voluntary approaches aren’t about doing what we’ve always been doing; it’s about doing more, embracing new methods.  When it comes to conservation, everyone needs to do their part,” says Hill, a crop and livestock family farmer from Milo.  

In the last 30 years, voluntary conservation measures have reduced soil erosion in the U.S. by 43 percent, according to the USDA’s National Resources Inventory report.  Iowa’s erosion rate was down 33 percent, due in part to a combination of practices being put in place, such as buffer strips, terraces, no-till, cover crops, restoring wetlands, installing bio-filters and grassy waterways in fields.

IFBF invites all Iowans to learn more about the latest conservation measures, by checking out ‘Conservation Counts’ at http://programs.iowafarmbureau.com/conservationcounts/