Diverse landscapes but not wildflower plantings increase marketable crop yield

Authors: MCCULLOUGH, CHRISTOPHER - Virginia Tech; GRAB, HEATHER - Cornell University; Angelella, Gina; KARPANTY, SARAH - Virginia Tech; SAMTANI, J - Virginia Tech; OLIMPI, E - Virginia Tech; O'ROURKE, MEGAN - US Department Of Agriculture (USDA)

Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/2022
Publication Date: 11/1/2022
Citation: McCullough, C., Grab, H., Angelella, G.M., Karpanty, S., Samtani, J., Olimpi, E., O'Rourke, M. 2022. Diverse landscapes but not wildflower plantings increase marketable crop yield. Agriculture, Ecosystems and Environment. 339. Article 108120. https://doi.org/10.1016/j.agee.2022.108120.
DOI: https://doi.org/10.1016/j.agee.2022.108120

Interpretive Summary: Farming practices designed to enhance diversity, such as wildflower plantings and the conservation of natural habitat, could help support services such as pollination and biological pest control to boost agricultural production. A researcher at USDA-ARS Wapato in Washington collaborated with scientists from Virginia Tech, Cornell University, and USDA-NIFA to assess how on-farm wildflower plantings and the natural habitat surrounding farms impacted crop yield in collards, tomatoes, strawberries, and winter squash. Both natural habitat and wildflower plantings had some effects on pollination and pest control within the crops, but these effects were inconsistent. However, they found that greater natural habitat surrounding farms consistently led to higher marketable yield in all four crops. Results suggest wildflower plantings provided fewer direct production benefits than natural habitat

Technical Abstract: Biodiversity-friendly farming practices targeting the conservation of wildlife on agricultural land may also support ecosystem services to agriculture, potentially creating a win-win scenario for biodiversity and crop production. Determining the outcome of these biodiversity-focused practices on crop production is therefore critical for informing policies that subsidize conservation practices on agricultural lands. On-farm wildflower plantings and conservation of semi-natural habitat in the surrounding landscape are two such biodiversity-based approaches that focus on the integration of non-crop components into production systems at the local and landscape scale, respectively. Here, we examine the impact of these practices on regulating services including biological control, pollination, as well as the provisioning services of crop yield in collards, tomatoes, strawberries and winter squash. We replicated crop experiments across an agricultural land use gradient on 22 farms in two states and planted small scale wildflower plots on ten of these farms. Both amount of semi-natural habitat and presence of on-farm wildflower plantings influenced pollination and pest control, though not consistently across crops. In contrast, farms surrounded by higher amounts of semi-natural habitat had consistently higher marketable yields for all four crops. Landscape effects on marketable yield were not fully mediated by measured regulating services indicating that semi-natural habitat likely has cumulative effects across multiple regulating services and over entire growing seasons that affect crop productivity. Our findings suggest that on-farm wildflower plantings provide fewer direct production benefits than semi-natural habitat surrounding farms, indicating a need to subsidize or quantify and account for non-production values of this practice