Wallaces Farmer

The project focused on the adoption of practices such as cover crops to reduce the movement of nutrients across the watershed's ag land.

August 19, 2021

5 Min Read
Cover crops
ONGOING EFFORT: Matt Helmers notes there will be continued monitoring and measurement of the watersheds involved in the study to assess longer-term outcomes. courtesy of Iowa Learning Farms

Conservation Learning Labs was a three-year research project designed to observe and measure nutrient losses to waterways from Iowa farm fields at a small watershed scale.

Conducted by Iowa State University’s Conservation Learning Group, the project was conceived as a next step in understanding the effects of in-field and edge-of-field conservation practices to provide further validation of the Iowa Nutrient Reduction Strategy (NRS).

Primarily funded by the Natural Resources Conservation Services and Iowa Department of Agriculture and Land Stewardship (IDALS), CLL focused on small watersheds — between 500 and 1,300 total acres in size — and the adoption of practices such as cover crops to reduce the movement of nitrogen and phosphorus across the watershed’s agricultural land.

The project included two pilot watersheds located in Floyd and Story counties that flowed into established Conservation Reserve Enhancement Program (CREP) wetlands for which baseline water quality monitoring data on nitrogen and phosphorus loads was available.

Matthew Helmers, CLL director and dean's professor in the College of Agriculture and Life Sciences at Iowa State University, took a look back at the project to share some results and a look toward the future.

Why did you consider CLL as the logical next step in understanding practical application of conservation practices?

Helmers: Much of the data utilized to formulate the NRS goals was extrapolated from test-plot studies. While test-plot results were well-documented and valid, it is well understood that many factors play into how water and nutrients move across different landscapes, making it important to study practices at a larger, yet manageable scale. Looking at a small watershed that already feeds an existing CREP wetland provided a deterministic endpoint for measurement, as well as a variety of field conditions.

Was CLL a success, and why is it shutting down after three years?

Helmers: The CLL project was designed as a fixed-term three-year study. We’ve accomplished what we started out to do. While we did not get indisputable proof of our hypothesis regarding significant nutrient runoff reductions, we learned a lot about conservation practices at a watershed scale, the variability and impacts of seasonal weather, and observed what we believe to be many positive outcomes from implementation of practices across more than half the tillable area in the target watersheds.

What factors helped raise awareness and potential for success at the start of the project?

Helmers: One big benefit going into the project was the tremendous support we received from Iowa Agriculture Secretary Bill Northey. He was very invested in the project and joined our meetings with producers in the study watersheds to encourage participation and answer questions about the NRS and the importance of improving water quality for all Iowans.

Backing from NRCS and IDALS helped the program gain quick acceptance and got us in front of most of the farm operators in the study regions. And the availability of cost-share programs and assistance from NRCS offices in navigating these programs was also helpful in gaining participation, particularly since most of the farmers were first-time adopters.

What was the participation level in the study watershed?

Helmers: Of 13 individual farmers across the two study watersheds, seven ultimately agreed to participate. The treated lands made up 49% of the Story County watershed and 77% of the Floyd County study area. The NRS does not require 100% coverage to meet reduction goals, and we felt the levels achieved would provide a good representation of expected statewide participation.

What were the measured outcomes for nutrients in the water?

Helmers: CLL really gave us a classical good news, bad news outcome. The good news is that across the three years, there was no detectable increase in nutrient levels measured in the water. The bad news is that there was also no detectable reduction despite the implementation of practices such as cover crops and reduced tillage. We will continue to study these watersheds to assess whether we see reductions with greater time of practice implementation.

We expected a measurable reduction in levels, and while we were disappointed it was not proven through the data, a lot was accomplished and learned through the study.

What were some of the lessons learned and other benefits of the CLL program?

Helmers: One of the takeaways from CLL is a good profile of the time investment necessary to attract farmers to consider implementing conservation practices, assisting in the preparation of a plan, and supporting funding and implementation when needed. CLL assisted seven farmers in developing and implementing 12 conservation plans.

The typical hands-on time per plan was between 11 and 13 hours. If we expand those numbers to a large watershed [HUC-12] level, the time and labor investment necessary to achieve NRS goals is tremendous — and likely beyond the current agency staffing levels. In time alone, it would take nearly 47 staff-weeks to complete the conservation plans necessary to attain 50% implementation across a typical HUC-12 watershed.

We believe there are other long-term benefits to soil health from these implementations, including improved water infiltration, erosion resistance and biomass buildup, but these were not measured in the CLL study.

One very important resource that relied on the CLL program for information and content is the Whole Farm Conservation Best Practices Manual published by ISU Extension in 2020. The manual provides practical decision tools to help farmers understand the best practices for their lands and provides templates for implementation.

What is the next step?

Helmers: There will be continued monitoring and measurement of the study watersheds to assess longer-term outcomes. There should also be additional studies throughout Iowa on small and large watersheds to continually collect and assess nutrient loss data. This is the clearest path toward understanding methods to attain NRS goals on a large or even statewide scale.

With a conservative estimate that current cover crop implementation is less than 10%, and much greater than that needed, there is more urgency needed in understanding ways to accelerate progress on nutrient reductions through more field studies such as CLL.

Staudt is a water quality specialist with Iowa Learning Farms and director of Water Rocks!

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