Numbers matter for Iowa’s Nutrient Reduction Strategy

Sports fans know that at the end of a game, the only numbers that count are the scores: who put up the most points; who fell short.

It’s similar in science. Experiments may succeed or fail, and researchers often learn more from unsuccessful trials than they do from ones that work. But a failed experiment still is a failed experiment. Metrics matter.

So it was interesting to see Mike Naig, the Iowa agriculture secretary, essentially say giving water quality the old college try is more important than actually reducing pollution.

In a May 30 Des Moines Register article, Naig bragged about the Nutrient Reduction Strategy’s 10 years of supposed success in cutting fertilizer runoff, but downplayed the importance of water quality monitoring to truly measure results. Counting the number of farms using cover crops, buffer strips or bioreactors is “a more holistic, and frankly more realistic way, to actually measure progress” than quantifying pollutant levels, he said.

Using Naig’s logic, if the Iowa Hawkeyes gain 100 yards in one game and 110 in the next, that’s a win, even if they fail to score and lose the game. Progress on the field matters more, Naig would say.

Unfortunately, the Nutrient Reduction Strategy fails on both progress and results. For example, a glossy website touting the program’s “defining decade” cites 3 million acres of planted cover crops but doesn’t mention that it’s just 13 percent of the 23 million acres Iowa farmers put into corn and soybeans in 2022. It says bioreactors and saturated buffer use has increased an average of 650 percent year over year but doesn’t provide the supporting numbers. Going from one bioreactor to seven is a more than 650 percent increase, but it’s insignificant compared to the need.

And the need outstrips the strategy. Since it was introduced, total phosphorus and nitrogen losses have barely changed from baseline measurements. The five-year average phosphorus load in Iowa waterways is down a measly 0.9 percent, while it increased 0.2 percent for nitrogen — and that includes drought in 2020-21, when less runoff produced less pollution.

With numbers like those, it’s clear why Naig and ag businesses wave away questions about the data.

The Nutrient Reduction Strategy is a failed experiment. What will Iowans and Iowa policymakers learn from it? Science Iowa’s more than 400 members demand an evidence-based policy that produces clean water, not feel-good websites.

The Science Iowa Board includes President Dan Chibnall, West Des Moines, Treasurer Ruth Henderson, West Des Moines, Secretary Thomas R. O’Donnell, Keosauqua, Laurie Neuerburg, Iowa City, and Nathan Steimel, West Des Moines. Science Iowa is a nonpartisan nonprofit organization that advocates for science in the public interest, publicly supported research and evidence-based policy.