Long-Term Evidence Shows that Crop-Rotation Diversification Increases Agricultural Resilience to Adverse Growing Conditions in North America

• Published in: One earth (Cambridge, Mass.) Vol. 2; no. 3; pp. 284 - 293
• Main Authors: Bowles, Timothy M., Mooshammer, Maria, Socolar, Yvonne, Calderón, Francisco, Cavigelli, Michel A., Culman, Steve W., Deen, William, Drury, Craig F., Garcia y Garcia, Axel, Gaudin, Amélie C.M., Harkcom, W. Scott, Lehman, R. Michael, Osborne, Shannon L., Robertson, G. Philip, Salerno, Jonathan, Schmer, Marty R., Strock, Jeffrey, Grandy, A. Stuart
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 20.03.2020
• Subjects: climate variability; crop diversity; crop rotation; diversified farming systems; drought; long-term experiment; maize; resilience; diversified farming systems; crop diversity; drought; crop rotation; climate variability; long-term experiment; resilience; maize
• ISSN: 2590-3322; 2590-3322
• DOI: 10.1016/j.oneear.2020.02.007

A grand challenge facing humanity is how to produce food for a growing population in the face of a changing climate and environmental degradation. Although empirical evidence remains sparse, management strategies that increase environmental sustainability, such as increasing agroecosystem diversity through crop rotations, may also increase resilience to weather extremes without sacrificing yields. We used multilevel regression analyses of long-term crop yield datasets across a continental precipitation gradient to assess how temporal crop diversification affects maize yields in intensively managed grain systems. More diverse rotations increased maize yields over time and across all growing conditions (28.1% on average), including in favorable conditions (22.6%). Notably, more diverse rotations also showed positive effects on yield under unfavorable conditions, whereby yield losses were reduced by 14.0%–89.9% in drought years. Systems approaches to environmental sustainability and yield resilience, such as crop-rotation diversification, are a central component of risk-reduction strategies and should inform the enablement of policies. [Display omitted] •347 site-years of yield data from 11 experiments show benefits of diversification•Rotation diversification increased maize yields under putative droughts•More diverse rotations also showed yield benefits across all growing conditions•Diverse rotations accelerated maize yield gains over time A grand challenge facing humanity is how to produce food for a growing population in the face of challenges from climate change while also improving environmental sustainability. Prior research has shown the potential for more biodiversified farming systems to provide substantial environmental benefits, but to what extent they also reduce risks from stressful weather conditions likely to occur more often in the future remains unclear. We use the most comprehensive synthesis to date of crop rotation, or the diversity of crops through time, to show that increasing rotational diversity in maize-based North American cropping systems improves maize yields over time and across all growing conditions, including during droughts. Agricultural systems that increase reliance on biodiversity can reduce risks from climate-change challenges and should be considered an essential component of meeting the grand challenge. Diversifying cropping systems improves environmental health and has the potential to reduce risk from climate-change-related threats, but empirical evidence remains sparse. In this study, we found that maize yields were higher during adverse weather, including droughts, when maize was grown as part of a more diverse rotation. Rotation diversification also increased maize yields over time and under better growing conditions. Policies that support more diversified cropping systems could help reduce risk from increasingly stressful weather.