The Iowa Farm Bureau unleashed its public relations machine after release of the 2018-19 Nutrient Reduction Strategy (NRS) Report July 2, heralding what it called "clear and significant strides" on reducing nitrogen and phosphorus leaching from farms fields into state streams, rivers and lakes.
Problem is the farm bureau either failed to read the report statistics on nitrogen and phosphorus runoff, or simply chose to ignore the research results and spin the findings.
The NRS reports two methods in analyzing nitrogen loads leaving Iowa farm fields: one based on actual monitors on Iowa's 23 watersheds; the second based on an annual nitrogen load average over the past 18 years with adjustments made each year reflecting land usage and ag practices that can boost or lower nitrogen loads.
Statistics for both nitrogen and phosphorus loads show 2018 clearly wasn't a year of "clear and significant strides."
In fact, the report's nutrient analysis of farm runoff monitored across the state shows nitrogen loads flowing into waterways in 2018 totaled 426,416 tons – 34 per cent more than during 2017.
That's 23.7 pounds of nitrogen/nitrate exported from each of Iowa's 33 million acres of farm land and is up substantially from 2017 when 318,111 tons – 636 million pounds – were deposited in state waterways.
However, ag researchers don't like to rely solely on the water monitors because nitrogen loads typically are higher in wet years and lower in dry years when there is less runoff.
That's why the researchers took 18 years of nitrogen loads (2000 through 2018) and determined the average annual nitrogen runoff was 292,022 tons, or 584 million pounds.
Using that as the baseline, the NRS researchers looked at factors which increased or decreased nitrogen loads to come up with an estimated average each year.
In 2018, the use of cover crops, bioreactors, saturated buffers and additional wetland creation lowered nitrogen loads by 4,620 tons (9.2 million pounds), according to the NRS report. But more corn and soybean acres, and fewer acres in pasture/grass/hay and land set aside in Conservation Reserve Programs (CRP) increased nitrogen loads by 16,358 tons (32.7 million pounds).
The net result was an increase in nitrogen runoff of 11,738 tons, or 23.5 million pounds, in 2018, according to the just released NRS analysis.
For phosphorus runoff, no-till practices, cover crops and conservation tillage was sufficient to offset the loss of pasture/grass/hay and CRP set-aside acres, the report states.
The result was a slight decline – 519 tons (1 million pounds) – of phosphorus leaving farm fields in 2018. But that's a small slice – less than 2 percent – of the estimated 28,822 tons (57.6 million pounds) of phosphorus that leaches off farm land each year in Iowa, according to the NRS report.
Not surprisingly, Iowa's Secretary of Agriculture and Land Stewardship Michael Naig claimed progress in lowering run-off of nutrients that eventually end up fouling lakes, streams and rivers.
“Here’s why I know we can be successful with nitrogen, nitrates and water quality overall; we’ve done it before,” Naig crowed in the public relation material sent out by the farm bureau and posted on social media. “We’re doing it now, with phosphorus and soil conservation.”
Naig and Iowa farm industry officials point to a 22 percent drop in phosphorus contaminating state waterways as if the decline occurred in recent years after unveiling of the Nutrient Reduction Strategy in 2013.
However, that 22 percent "reduction" reflects a 30-year timeframe, the difference between phosphorus loads estimated by Iowa State University researchers for the years 1980-1996 versus 2006-2010.
The phosphorus reductions were "primarily due to fewer acres under intensive tillage, and a significant increase in no-till acreage from the 1980-96 time period," according to NRS researchers.
So why not just use the most recent period, 2006-2010, as the baseline for calculating the effectiveness of the NRS rather than going back 40 years when much different farm practices were used?
Part of the answer may lie with the 2008 Gulf Hypoxia Action Plan, which calls for states within the Mississippi River watershed to reduce phosphorus amounts by 25 percent and nitrogen loads by 45 percent.
The hypoxia reduction plan specifically states goals would "be measured against the average load over the 1980-1996 time period. . ." Using more recent numbers would make it much more difficult for the state's farm operators to reach those goals.
By using the older data set as a baseline also means the farm bureau and farm operators can say they're already at 22 percent of the group's 25 percent goal in reducing phosphorus going into state waterways.
The goal of both the NRS and hypoxia task has been to reduce nutrients flowing into the Missouri and Mississippi Rivers and down to the Gulf of Mexico where they create a "dead zone" in which marine life cannot live.
In the Upper Mississippi River Basin, Iowa contributes 21 percent of the water, comprises 21 percent of the land area, but is responsible for nearly half – 45 percent – of nitrate-nitrogen pollution that flows into the Mississippi River, according to research by IIHR — Hydroscience & Engineering at the University of Iowa and the Iowa Geological Survey.
In the Missouri River Basin, Iowa contributes 12 percent of the water, comprises only 3.3 percent of the watershed land area, yet is responsible for more than half – 55 percent – of the nitrate-nitrogen polluting the Missouri River, researcher have determined.
