Research finds fluctuating commitment to cover crop adoption among Iowa farmers

AMES — A new study led by researchers at Iowa State University sheds light on the dynamic nature of cover crop adoption among Iowa farmers, further challenging assumptions that conservation practice adoption is a one-time, permanent decision.

Planting cover crops, like ryegrass, after fall harvest is a key conservation practice that can reduce soil erosion and improve water quality and soil health, especially when consistently implemented over time. They can also boost soil organic matter and reduce weeds.

The new research, published in the Journal of Soil and Water Conservation, found that Iowa farmers’ use of cover crops often lacks long-term consistency, with significant implications for agricultural sustainability and policy design.

“We researchers have generally focused on factors that predict adoption,” said co-author J. Arbuckle, professor of sociology and criminal justice. “Our results suggest that we need a paradigm shift in research focus from initial adoption to an integrated emphasis on both initial and continued adoption.”

Key findings

The study analyzed responses from 519 Iowa farmers who participated in the Iowa Farm and Rural Life Poll in 2014, 2016 and 2018. The same farmers participate in this longitudinal panel survey each year, allowing researchers to track individual farmers’ use of cover crops over five years from 2013 to 2017.

“Most adoption studies use one year of data, so they’re only a snapshot of behavior,” said lead author Zhushan Du, a doctoral student in economics who is now an assistant professor at Jinhua University of Vocational Technology, Jinhua, China. “Having three years of data provided a unique opportunity to examine cover crop use over time.”

Three adoption groups were identified:

• Continuous adopters (6.6%) who were more likely to raise livestock, farm highly erodible land and perceive greater benefits from cover crops.

• Intermittent adopters (28.9%) who alternated between using and not using cover crops were four times as common as continuous adopters. They had larger farms and higher overall sales but planted fewer cover crop acres and received less cost-share support.

• Continuous nonadopters (64.5%) reported the least knowledge and interest in cover crops.

Intermittent adopters expressed strong interest in learning more about cover crops, while also reporting moderate perceptions of benefits and barriers. Nonadopters perceived more barriers and were least interested in learning more.

High levels of intermittent use led to lower-than-expected growth in practice use. While the percentage of cover crop adopters among the farmers rose from 17.7% to 22.9% during the period studied, frequent dis-adoption and intermittent use meant this net increase was much smaller than cumulative gains that would have been realized without dis-adoption.

Policy and outreach implications

The study’s findings highlight the need for policies and programs that spur initial adoption and help farmers maintain conservation practices over time. The researchers’ paper calls for a shift in conservation policy and research focus — from simply encouraging initial adoption to putting greater emphasis on supporting sustained, long-term use of conservation practices.

“Our results suggest that we need to change the way we support farmers’ adoption of cover crops and similar conservation practices,” said co-author Hongli Feng, assistant professor, economics. “To keep generating the benefits of these practices, it appears that more technical and/or financial assistance is needed.”

Recommendations from the research:

• Provide longer-term incentives such as extended financial and technical support to encourage continued use of cover crops.

• Tailor outreach toward intermittent adopters, responding to their interest in learning more about cover crops and addressing their heightened perceived risks.

• Shift research and extension focus to recognize that farmers’ decisions about cover crops often change based on conditions, including weather and crop economics.

This work was partially supported by the Iowa Agriculture and Home Economics Experiment Station, Iowa State University and the Iowa Nutrient Research Center.