Comparing Vesicular-Arbuscular Mycorrhizal Colonization in Conventional versus Organic Strawberry Production Systems

Comparing Vesicular-Arbuscular Mycorrhizal Colonization in Conventional versus Organic Strawberry Production Systems

Summary

An on-farm comparison showed no differences in arbuscular mycorrhizal fungal (AMF) colonization between conventional and organic strawberry management strategies. However, the high variability of on-farm systems may make small differences difficult to detect. A research plot study comparing simulated conventional and organic strawberry management strategies found that fungicide and insecticide sprays did not affect levels of AMF colonization. However, organic mulch materials in the establishment year translated to higher levels of AMF colonization and root biomass than herbicide or hand-weeded groundcover management strategies.

Objectives/Performance Targets

1. Compare effects of various strawberry management strategies on AMF

   Increase grower awareness of soil system and its biotic components, focusing on AMF

   Facilitate grower discussions

Accomplishments/Milestones

All required plant material has been collected and evaluated for mycorrhizal colonization. Statistical analyses have been completed. Two articles have been written and submitted for publication in scholarly journals. A final report will be written and results consolidated into a 1-2 page online University of Minnesota Extension document.

The growers participating in the study received substantial information packets regarding AMF ecology and the symbiosis between plants and AMF, in addition to verbal information through conversations with the researchers. The growers who participated in the study also attended one grower feed back session where they were able to view microscope slides of the mycorrhizal organisms on their particular farms. Non-participating growers have been updated on the project via newsletters. An educational seminar and preliminary results were presented at the Minnesota Fruit and Vegetable Growers Association meeting in February 2004.

The grower feedback session allowed participating farmers to view preliminary results and discuss implications in terms of farming methods, economic returns, feasibility, etc. Additional follow-up sessions at the completion of the project provided an opportunity for discussion of final results and future research needs.

Impacts and Contributions/Outcomes

Implementation of, and results from this project provided strawberry growers with more insight into the soil ecosystem and how it is affected by agricultural practices. Through the example of AMF in strawberries, the project’s educational components highlighted the presence and importance of the soil community, which many growers may not have considered in overall farm management plans. Although the information was focused on AMF in strawberry systems its applicability to other production systems was emphasized.

While new management strategies may take infinite forms based on individual farms, some examples might include reduced tillage and subsequent reduced erosion and compaction; increased mulch applications or cover cropping; or reduced pesticide use. These changes will benefit the farmer in terms of reduced costs and potential higher returns. In addition, the environmental benefits will serve both consumers and the farming community.

This research contributes to the body of knowledge related to the community of soil organisms in agricultural settings. Further research and outreach in this area, using this study as a starting point, will provide farmers with more insight into this ‘unseen’ yet very important component of the agroecosystem.

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