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Home HortScience Sustainable Strawberries: Summer Cover Crops Effective
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RALEIGH, NC—In the southeastern United States strawberries are a high-value crop marketed to consumers through pick-your-own and roadside stands. With the impending phase-out of methyl bromide, finding innovative and sustainable approaches to pest and soil management is critically important to strawberry operations in the region.

A study from North Carolina State University researchers published in HortScience has yielded important information for strawberry growers, especially those involved in organic production. The research investigated the effectiveness of an alternative, integrated approach to promoting healthy plants and enhancing beneficial soil organisms while reducing pests and diseases. According to lead author Michelle Schroeder-Moreno, the study was the first to evaluate the integrated effects of summer cover crops and inoculation with arbuscular mycorrhizal (AM) fungi on strawberry production in field conditions. "The importance of investigating the effects of cover crops and AM together in field conditions cannot be overemphasized, because soil types, climate, fertility, weed pressures, and other variables can affect the outcome compared with greenhouse conditions where these factors are regulated," Schroeder-Moreno said.

The research team tested and evaluated the combined effects of eight summer cover crop treatments (including a no cover crop control) and two AM inoculants on strawberry growth and yields in a 2-year field experiment. The scientists inoculated strawberry tips with either a native mixture of several AM fungal species or a single species and assessed all treatments for their aboveground biomass and nutrient uptake as well as their impacts on weed abundance and diversity, soil nutrients, and parasitic nematode populations.

Results showed that grass-based cover crop treatments produced the most aboveground biomass. The high biomass producers—pearl millet and sudangrass grown alone and the combination of pearl millet with soybean—reduced weed biomass by more than 98% compared with the control.  In both years, all cover crop treatments reduced summer weed biomass compared with the control (no cover crop).  

Although the ability of cover crops to reduce weeds was one of the main findings in the study, the researchers noted that the treatments did not result in enhanced strawberry total or marketable yields. "It is likely that no overall yield benefit was found among treatments for two reasons: nutrients—especially nitrogen—were not limiting, and the cover crop growth window may have been too short for a significant impact on strawberries over two seasons," they explained.

"Our study results suggest that cover crops can be a viable strategy for reducing summertime weeds and that background, native populations of AM fungi in the soil may be just as effective as a commercially available species," Schroeder-Moreno concluded.


The complete study and abstract are available on the ASHS HortScience electronic journal web site:

Founded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at


Original Article:

Influence of Summer Cover Crops and Mycorrhizal Fungi on Strawberry Production in the Southeastern United States
Benjamin C. Garland, Michelle S. Schroeder-Moreno, Gina E. Fernandez, and Nancy G. Creamer
HortScience 46:985–991. [Abstract][Full Text][PDF]

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