While state officials and others in Iowa celebrated the five-year anniversary of the state’s voluntary nutrient reduction strategy this past week, a study from the University of Iowa shows the pace of nutrient runoff from the state contributing to hypoxia in the Gulf of Mexico has increased since 1999 and continues to be a large portion of total runoff to the Gulf.
In 2013, Iowa announced its strategy that includes stepping up conservation efforts to reduce non-point sources of pollution. More than 80% of nutrient runoff in the state comes from agriculture sources.
A recent study funded by the Iowa Nutrient Research Center, however, found nitrate-nitrogen runoff in the state to the Upper Mississippi River Basin, the Missouri River Basin and the Mississippi-Atchafalaya Basin has increased since 1999.
Discharge data collected from 1999 to 2016 at 23 Iowa streams shows Iowa’s long-term runoff accounts for an average of 29% of the runoff into the Gulf of Mexico via the Mississippi-Atchafalaya Basin, 45% of the runoff via the Upper Mississippi River Basin, and 55% via the Missouri River Basin.
State and agriculture leaders in Iowa have maintained the voluntary reduction strategy is a long-term effort to reverse what is largely legacy nutrients from decades of over-application.
“Since 1999, nitrate loads in the Iowa inclusive basins have increased and these increases do not appear to be driven by changes in discharge and cropping intensity unique to Iowa,” the study said.
“The five-year running annual average of Iowa nitrate loading has been above the 2003 level for 10 consecutive years, implying that Gulf hypoxic areal goals, also based on a five-year running annual average, will be very difficult to achieve if nitrate retention cannot be improved in Iowa.
“An opportunity exists for land managers, policy makers and conservationists to manifest a positive effect on water quality by targeting and implementing nitrate reducing-practices in areas like Iowa while avoiding areas that are less likely to affect Gulf of Mexico hypoxia.”
According to the state’s latest annual progress report on the strategy, Iowa farmers have modestly stepped up conservation efforts, and the level of government and private funding for conservation programs has increased.
Public funding for conservation programs in Iowa increased from $11.9 million in 2016 to about $19.4 million in 2017, according to the latest report. In addition, Iowa farmer and landowner investment in conservation also increased from about $23.4 million in 2016 to about $27.8 million in 2017. Also, USDA Conservation Reserve Program rental payments in Iowa increased from $225 million in 2016 to about $243.7 million in 2017.
The state clean water revolving fund has financed a cumulative total of $2.9 billion in conservation projects, including about $205 million in 2017.
Iowa farmers have made progress in expanding the use of cover crops. According to the annual progress report, from 2011 to 2016, cost-share programs have resulted in nearly annual increases in the amount of cover crop acres planted and reductions in nitrogen losses.
In 2011, cover crops acres installed annually using state and federal cost-share money stood at 14,683 acres, with nitrogen loss reductions of 67.5 tons. By 2016, the rate of installation using cost-share funds increased to 302,136 acres and 1,375.4 tons reduced.
According to information from the Iowa Nutrient Research Center, a total of $420 million in private and public sector funding was spent on water quality efforts in 2017. That was an increase of $32 million from 2016.
Overall, about 760,000 acres of cover crops were planted in Iowa in 2017. That represents a 22% increase from the year before. Fewer than 10,000 acres were planted with cost share in 2009.
During the past five years, 8,000 farmers, including nearly 4,600 first-time users, signed up to use water-quality-focused practices. Those farmers invested more than $17 million in cover crops, no-till, strip-till or a nitrification inhibitor on their land.
On Thursday, EPA Administrator Scott Pruitt announced Iowa received a $1 million grant from the agency’s Gulf of Mexico Program to support the water quality efforts underway in the state. The grant funds will be targeted to the Des Moines River Basin to support the construction of 20 saturated buffers, 10 bioreactors, four targeted wetlands, three drainage water recycling systems and two drainage water management systems.
According to a news release from the Iowa Department of Agriculture and Land Stewardship, the practices are estimated to benefit 2,800 acres and reduce nitrogen loading by 33% to 52% percent on average.
In November 2012, then-Iowa Gov. Terry Branstad unveiled the state’s voluntary nutrient reduction program.
Previous plans to reduce nutrient releases into Iowa waters have failed several times. That’s because those efforts focused either on point source or non-point sources, but not both. The plan came about after the EPA ordered Iowa in 2008 to develop a plan to reduce nutrient runoff.
The plan said any policy involving agriculture “must be different” from any plans to reduce nutrient discharges from Iowa’s 130 major cities and industries.
“The target load reductions for non-point sources is 41% of statewide total nitrogen and 29% of the total phosphorous to meet the Gulf Hypoxia Action Plan goal,” the plan said.
“Iowa has nutrient-rich landscapes, and significant progress towards these large nutrient reduction targets will take considerable time, effort and funding sources.”
Yet, it would take a dramatic increase in overall conservation practices to achieve significant reductions in nitrogen loads.
If cover crops were used on all corn-soybean rotations, it would reduce nitrogen runoff 28% and phosphorus by 50%, according to an analysis conducted by Iowa State University.
The possible nutrient reduction practices identified include nitrogen and phosphorous management, erosion control and land use, and edge of field. Management practices include nutrient application rates, timing and method, plus the use of cover crops and living mulches.
Land-use practices include perennial energy crops, extended rotations, tillage methods, grazed pastures, land retirement and terraces. Edge of field involves drainage water management, wetlands, bioreactors, buffers and sediment control.
The plan includes steps to prioritize watersheds and the state’s resources, to improve the effectiveness of current state programs, and to increase voluntary conservation and other efforts to reduce nutrient loading, ultimately into the Gulf of Mexico.
Read the latest study here.
Read the progress report here.
Todd Neeley can be reached at firstname.lastname@example.org
Follow him on Twitter @toddneeleyDTN