Q&A with Dan Jaynes, USDA-ARS scientist and ISU collaborating faculty in agronomy, establishing and monitoring saturated buffers

June 30, 2017

Project: Establishment and Monitoring of Saturated Buffers within High–Priority HUC–12 Watersheds

Saturated buffer treesSaturated buffers are a new edge-of-field practice included in the Iowa Nutrient Reduction Strategy. They were developed in Iowa to remove nitrate from water draining out of field tiles before it enters streams and rivers. Dan Jaynes, scientist with the USDA-ARS National Laboratory for Agriculture and the Environment located on the Iowa State University campus, says his study measured the nitrate removal capacity of saturated buffers because only limited data on their effectiveness exists in scientific literature. His team evaluated ten saturated buffers sites across a range of soils and landscapes in Iowa to better understand the effectiveness of this nutrient reduction practice.

Q: What was the main objective of your project?

Jaynes: Our main objective was to measure and document the effectiveness of saturated buffers in removing nitrate from tile drainage water within riparian buffers across Iowa.

Q: Did you find any surprises in your results?

Saturated Buffer fieldJaynes: At all locations, saturated buffers removed nitrate from tile drainage better than we had initially anticipated. But there was substantial variation in nitrate removal among the saturated buffers that we do not fully understand that will require further study before we can accurately predict saturated buffer performance at new locations.

Q: Did you have to overcome any problems/issues while obtaining data for your project?

Jaynes: The saturated buffers we monitored were spread across the state making monitoring and troubleshooting of our monitoring equipment a challenge. As our monitoring equipment is located in riparian buffers, local stream flooding did destroy some of our equipment or caused lost data.

Q: What key message do you want to share about the significance of your project?

Jaynes: We have now measured the performance of saturated buffers over six years and across ten sites within Iowa. At all of these sites, saturated buffers removed substantial nitrate from tile drainage. Saturated buffers appear to be a viable practice for helping improve water quality in streams across Iowa and the Midwest. We are continuing to monitor the ten sites across Iowa to better measure the long-term effectiveness of the practice. All sites are on private land with cooperation from the farmers.

Q: Who collaborated with you on this project?

Jaynes: Tom Isenhart, Department of Natural Resource Ecology and Management, has been involved in all aspects of this project and the development of saturated buffers from the start. Also we could not have conducted this project without the assistance of Kent Heikens, USDA-ARS National Laboratory for Agriculture and the Environment, and many undergraduate students. 

Additional resources on saturated buffers can be found at the Iowa State University Extension Store.