Study Focuses on Eight Watersheds in Four States in the Upper Mississippi River Basin.
September 30, 2020
Washington, D.C. – A new research report on conservation program effectiveness released in September by the Northeast-Midwest Institute provides strong scientific support for the effectiveness of conservation programs, especially the conservation practice of tillage with crop cover, in protecting agricultural land and improving water quality in the Upper Mississippi River Basin. The high level of effectiveness of conservation was confirmed both with historical conditions and with modeled climate change.
Separate research reports document the effectiveness of conservation practices for each of the watersheds studied, including the Upper Sangamon and Vermilion watersheds in Illinois, the Boone and Upper Wapsipinicon watersheds in Iowa, the Cottonwood and Watonwan watersheds in Minnesota, and the Sugar and Trempeleau watersheds in Wisconsin.
The new research reports support policy-making that continues and expands conservation programs, including federal programs to incentivize farmers to implement effective conservation programs. The findings for each of eight watersheds document that policy options promoting conservation tillage with crop cover such as rye grass enhance agricultural productivity in upstream areas and reduce pollution in downstream freshwater systems.
Unique in the new research is that it employs a watershed-specific approach that selected eight watersheds – two in each of four states, the states of Illinois, Iowa, Minnesota, and Wisconsin – evaluating the effectiveness of alternate conservation practices employed by farmers. Each of the eight watersheds studied is in a different Congressional Districts in these four states.
Significant findings in this new watershed conservation research include:
- Crop cover with rye was found to be the most effective conservation practice in reducing nutrient losses in each of the eight watersheds.
- Conservation effectiveness ranged from 6 percent to 43 percent in terms of the reduction in nitrogen loss, and from 7 percent to 31 percent in terms of the reduction in phosphorous loss.
- In modeling the impact of climate change, which in seven of the eight watersheds is predicted to reduce precipitation and therefore water flow in the range of 9 percent to 70 percent, the reduced water flow resulted in a reduction in nutrient leaching in these seven watersheds and improved efficiency of conservation practices in reducing nutrient loss in the face of climate change.
According to the watershed conservation research report for one of the watersheds studied, the Cottonwood watershed in Minnesota, “conservation tillage practices were effective in reducing soil erosion and limiting nutrient loss from the Cottonwood watershed…The most effective intervention to reduce soil erosion and nutrient losses was the conservation tillage with crop cover, both in the historical climate and climate change scenarios.” The study showed that conservation tillage with crop cover in the Cottonwood watershed reduces the long-term average annual sediment yield by 5-10%, total nitrogen loss by 13-26%, and total phosphorus loss by 10-20% at the watershed outlet compared to continuing the current farmers’ (baseline) tillage practice.
In releasing the watershed conservation research report, Northeast-Midwest Institute President and CEO Dr. Michael J. Goff stated “It is imperative to make the strongest case possible for the effectiveness of watershed conservation, because encouraging and incentivizing farmers to utilize the most effective conservation practices both protects their land and protects water quality. This study provides strong evidence yet again that conservation practices work, a message which we hope Congressmen and Senators hear and respond to with future appropriations and policy-making.”
Conducting the hydrological data analysis for the new research report was Dr. Raghaven Srinivasan, Professor of Ecology and Conservation Biology at Texas A&M University, with policy analysis and preparation of the study reports by Dr. Yihun Dile, also of Texas A&M University.
This new watershed conservation effectiveness research report, and the previous research report on this topic, were funded by the Walton Family Foundation’s environmental program.
To see the study, go to www.nemw.org where release of the new research report is featured.
To read the watershed conservation research reports for each of the eight watersheds in specific Congressional Districts, see the following:
Upper Sangamon Watershed, Illinois – Illinois-15.
Vermilion Watershed, Illinois – Illinois-16.
Boone Watershed, Iowa – Iowa-4.
Upper Wapsipinicon, Iowa – Iowa-1.
Cottonwood Watershed, Minnesota – Minnesota-7.
Watonwan Watershed, Minnesota – Minnesota-1.
Sugar Watershed, Wisconsin – Wisconsin-2.
Trempeleau Watershed, Wisconsin – Wisconsin-3.
To read the previous watershed conservation research report on the effectiveness of conservation programs under the Regional Conservation Partnership Program (RCPP), see here.
The Congressional Fact Sheet on Watershed Conservation can be viewed here.