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Neighbors Growing Together | Aug 16, 2018

Iowa inventories its conservation practices

By Rod Boshart, The Gazette | Aug 02, 2018

The value of public and private investment in six kinds of conservation practices in Iowa is $6.2 billion in today’s dollars, say coordinators of an effort — now complete — to map the practices.

The mapping is believed by organizers to be the most comprehensive inventory in the nation.

“This mapping effort shows the scale and investment made by farmers, landowners, state and federal agencies, conservation partners and many others over several decades to reduce erosion and protect our natural resources,” Iowa Secretary of Agriculture Mike Naig said Tuesday in a statement.

“While the practices identified are focused on reducing soil erosion and phosphorus loss, seeing the progress that has been made illustrates how we can make similar progress with a long-term focus and investment in proven conservation practices targeted at reducing nitrogen loss,” Naig added.

Additional analysis is underway to use the science of the Iowa Nutrient Reduction Strategy to quantify the impact these practices have on water quality in terms of reducing sediments and phosphorus loads to Iowa streams, Naig said.



Conservation projects aim to reduce nitrates flowing from Iowa farm fields into the Mississippi and Missouri rivers and from there to the Gulf of Mexico, where nitrate and phosphorus are creating an oxygen-deprived dead zone.

A University of Iowa study released this year showed Iowa’s average nitrate contribution to the Mississippi basin was 29 percent, 45 percent to the Upper Mississippi River basin and 55 percent to the Missouri River basin.

The state’s nitrate discharge, the study said, is disproportionate to the amount of water flowing into rivers that border the state, indicating the increase in nitrate share isn’t due to weather.

The study looked at data collected between 1999 and 2016 from 23 Iowa watersheds monitored by the Iowa Department of Natural Resources’ Water Quality Monitoring and Assessment program.

Runoff from 12 states feed into the Mississippi River, leading to the creation of nutrient reduction strategies.


MAPPING project

The new state mapping project includes six conservation practices in 1,711 watersheds: terraces, ponds, grassed waterways, water and sediment control basins, contour strip cropping, and contour buffer strips/prairie strips.

The initial number of practices identified include 114,400 pond dams, 327,900 acres of grassed waterways, 506,100 terraces stretching 88,874 miles, 246,100 water and sediment control basins stretching 12,555 miles, 557,700 acres of contour buffer strips and 109,800 acres of strip cropping, according to researchers.

Iowa DNR officials and researchers at Iowa State University have led the three-year effort to use elevation data and aerial imagery to identify and inventory the conservation practices. The analysis is based on LIDAR data — a laser-based detection system — and imagery that was taken from 2007 to 2010.

Coupling assessments such as the mapping project with the known science of conservation practices “allows us to clearly show the impact of farmer efforts on a statewide scale,” said Shawn Richmond, director of environmental technology for the Iowa Nutrient Research & Education Council.



Officials say Iowa is the first state to analyze every watershed in its borders using LIDAR and aerial imagery to create a detailed assessment of conservation practice implementation. The data allows for a much more detailed and accurate analysis of soil conservation efforts focused on phosphorus reduction because it includes all practices implemented by farmers, even those without government cost sharing.

“This demonstrates that the consistent and persistent effort, year after year, of all the Iowans needed to educate, inform, fund, design, build, and maintain these practices can, practice by practice, change the landscape for the better,” Iowa DNR Acting Director Bruce Trautman said.


BENCHMARK measures

Officials say the completed inventory provides a benchmark for measuring progress. Additional efforts are underway to assess the status of these practices going back to the 1980s and also to assess the recent status of practices from 2016-18.

Once completed, Iowa will have a robust timeline to show the progress that has been made.

Potential project benefits include targeting resources where they are needed most by comparing conservation potential with actual implementation; accurately benchmarking efforts to quantify nutrient reductions and compare with past and future progress; and creating a consistent, scientifically sound data set vetted by both ISU and the DNR, officials say.

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