A cluster of strawberries growing at the Gulf Coast Research and Education Center in Balm, Florida. UF/IFAS Photo by Tyler Jones.

UF researchers to study organic strawberry production

By Brad Buck

Researchers at the University of Florida Institute of Food and Agricultural Sciences will address production constraints for organic strawberry producers, thanks to a new $2 million federal grant.

The grant comes from the Organic Research and Extension Initiative (OREI) program, which is administered by the National Institute of Food and Agriculture, a division of the U.S. Department of Agriculture.

The research focuses on strawberry production systems, rather than just one part of the production process, said Mickie Swisher, associate professor of sustainable agriculture in the UF/IFAS Department of Family, Youth and Community Sciences.

“Controlling weeds is a significant cost for all strawberry producers, not just organic producers,” Swisher said. “The project examines the effectiveness of cover crops as a supplementary weed management technique, used in conjunction with plastic mulch.”

Cover crops are grown for the protection and improvement of the soil. Legume cover crops, such as southern peas, can be used as green manure to provide fertility for a subsequent crop.

But the research doesn’t stop with comparing cover crops to other weed management techniques, she said.

The UF/IFAS team also will examine how using cover crops affects other considerations like soil quality, nutrient availability and soil-borne plant pathogenic nematodes.

In addition, a horticulturist will assess how different strawberry cultivars respond to the use of cover crops, searching for the cultivars that will adapt best to the system. An entomologist will focus on the systems’ influence on beneficial insects and on the management of key pests such as spotted wing drosophila and two-spotted spider mites.

Team leader Carlene Chase, UF/IFAS associate professor of horticultural sciences, said farmers need to know how changes in one practice can affect other parts of a system to decide whether a change will work for them. This can make it safer for farmers to try alternatives and be able to adopt money-saving and environmentally sound practices more quickly.

“This is critical in today’s highly competitive marketing system, where international competition continually pressures U.S. producers,” Swisher said.

Part of the key to success is getting good advice from growers — organic and conventional — and acting on their recommendations during the research project, not after it is over, Swisher said.

“Early meetings with Florida producers, before any research was conducted, provided key concepts that are part of this project today,” she said. “That input continued throughout the two years of research funded by the Walmart Foundation. Farmers and technical advisors participated in field assessments of the research plots and made important recommendations for improving both the science and the practicality of the research.”

In the first season of strawberry production (2013-14), farmers who assessed the research plots made two key suggestions. They convinced researchers that the high-tunnel system should focus on colder producing regions. As a result, the high-tunnel work continued only at UF’s partner institution, North Carolina A&T State University in the second year (2014-15). The new OREI grant will allow NCAT to explore the utility of low tunnels and high and low tunnel combinations for organic strawberry production in the cooler regions of the southeastern US.

Due to interest in organic strawberry production among North Florida producers, Florida A&M University will use the results of the previous research in this project to understand if low-cost tunnel systems are a good alternative for areas in Florida with cooler winter temperatures than southwest Florida, where the majority of Florida strawberries are grown.

Growers also recommended adding a treatment that would consist of several cover crops in a “mix.” Their idea was that a mixture of cover crops in the same field might provide more cropping system benefits than a single species. The team adopted this recommendation and will continue to work on it for this project.

The project enjoys the continued support of the Florida Strawberry Growers Association, which is critical to the success of this project, Swisher said. Their members will continue to be important collaborators in the farm trials, which help researchers and farmers who perform the field research assessments see how the different practices hold up under a range of soil types, micro-climatic conditions and pest pressures. Florida Organic Growers and Consumers Inc. will contribute by coordinating outreach activities during the final year of the grant.

Driscoll Strawberry Associates is another strong partner involved with the project’s advisory panel, Swisher said.

“As the largest berry distributor in the nation, their experience and expertise is critical to understanding how the biological factors affect marketability from the distributor’s perspective,” she said. “Their input is particularly important for this project. Consumer preferences for the marketable strawberries that each set of practices creates are, after all, the ultimate test of the quality of the product.”