2013 - 2023: A decade of declining water quality in Iowa

posted by Alicia Vasto on Friday, June 2, 2023

Last week, the Iowa Environmental Council (IEC) launched a new website, decliningdecade.org, to mark the tenth anniversary of the state’s taxpayer-funded nutrient reduction strategy (NRS). We created the site to counter the narrative being pushed by agricultural businesses and organizations that say progress on the NRS is going great and Iowa is taking appropriate action to address nutrient pollution. These groups were very involved in the crafting of the voluntary approach to fertilizer pollution in the NRS, and they are heavily invested in its status quo implementation.  

There are many examples of local initiatives and farmers that are doing the right things: putting conservation practices on the ground and sharing their stories with others to encourage further adoption.

However, focusing on individual stories alone – without shining light on the systemic failures of the voluntary approach and the continuous erosion of state leadership’s support for water quality – circumvents the conversation about policy solutions we need to make actual progress on nutrient pollution reduction.  

Without regulating fertilizer and manure application and requiring basic standards of care, we will never reduce nitrogen and phosphorus pollution anywhere close to what is necessary to protect drinking water here in Iowa or reduce the Gulf hypoxic zone.  

Here’s what we know:  

  • Every scenario in which we reach the 45% nutrient reduction goal of the NRS requires every farmer in Iowa to apply nitrogen fertilizer and manure at rates appropriate for plant uptake, not at rates leading to excess that will leach or runoff into streams and lakes. The original science assessment for the NRS found that applying at this rate (Maximum Return to Nitrogen or MRTN) shows the greatest potential for nitrate reduction. 
  • The average rate of commercial nitrogen applied to corn following soybeans was 174.8 lbs/acre for 2017-2021. For continuous corn, the average was 202.3 lbs/acre.1 
  • With current prices, MRTN is 147 lbs/acre for corn following soybeans and 191 lbs/acre for corn following corn.2 That’s 27.8 lbs/acre and 11.3 lbs/acre less than current average rates, respectively, and doesn’t even include manure application.  
  • Even considering the recent Polk County 'batch and build’ initiative, which was able to install 136 bioreactors and saturated buffers from 2021 to 2022,3 1,200 bioreactors and saturated buffers need to be installed every year across Iowa to reach NRS goals in 100 years.  
  • An estimated 14 million of 24 million cropped acres in Iowa are drained by tile, representing an 11 percent increase from 2012 to 2017.4 The NRS does not account for increasing efficiency of nitrate and dissolved phosphorus export from fields due to tile drainage, and there is no accounting of this countervailing data in NRS progress tracking or measurements.  
  • There are more than 23 million hogs in Iowa at any time, more than seven times the state’s human population.5 Each hog produces 8 to 10 times more fecal matter than a human.6 None of the nutrient contributions of livestock production and manure is addressed by the policies or recommendations of the NRS. 

Until we are able to transform how we address fertilizer pollution through policy and regulation, the NRS will be no more than a cover for 'business-as-usual' conventional agriculture. We invite you to visit decliningdecade.org to view IEC publications, fact sheets, news stories, and blog posts, as well as external reports and articles, all in one place, to get a more complete picture of Iowa’s fertilizer pollution crisis.   


  1. https://www.iowanrec.org/_files/ugd/c03d34_ed7a91982a3f4f5ab2acf1fb4cfac61b.pdf 
  2. Calculated with anhydrous at $0.63/lb and corn at $6.04/bu
  3. https://www.agriculture.com/crops/conservation/batch-and-build-strategy-makes-conservation-more-convenient-in-central-iowa

  4. USDA National Agricultural Statistics Service, 2017 Census of Agriculture. Complete data available at www.nass.usda.gov/AgCensus at Iowa 18, 41.

  5. https://www.nass.usda.gov/Statistics_by_State/Iowa/Publications/Livestock_Report/2022/IA-Hogs-09-22.pdf

  6. https://www.pbsnc.org/blogs/science/exporting-poop-for-profit-could-help-farmers-and-the-environment/#:~:text=In%20fact%2C%20hogs%20leave%20behind,times%20more%20poop%20than%20humans

  1. clean water
  2. drinking water
  3. nitrate pollution
  4. nutrient reduction strategy
  5. phosphorus pollution
  6. water quality
  7. water recreation

About The Author

Alicia joined the Council in 2019. She grew up in Adel, Iowa. She previously worked as the director of the Iowa Conservation Education Coalition, where she supported environmental educators and advanced environmental literacy. Alicia holds a Master of Environmental Management degree from Duke Uni ... read more