Monitoring Belowground Arthropods Associated with Cover Crops in Great Plain High Tunnel Systems

View the project final report

Commodities

• Agronomic: barley, buckwheat, millet, rye, sorghum sudangrass, triticale, wheat
• Vegetables: greens (lettuces), peppers, tomatoes

Practices

• Crop Production: cover crops, cropping systems, crop rotation, fallow, high tunnels or hoop houses, nutrient management
• Education and Training: extension

High tunnels are protected production systems that offer many benefits: disease and pest exclusion, crop season extension, and increase in crop yields and quality. Despite the many benefits high tunnels offer, soils are frequently degraded by intensive production in these systems. This study builds on a current OREI project “A multi-regional approach for sustained soil health in organic high tunnels: nutrient management, economics, and educational programming” that investigates the use of cover crops in high tunnels in regard to agronomic and soils data. We propose to expand this two-year study to include a larger group of cover crop species mixtures in addition to an investigation of belowground arthropods that are involved in high tunnel cover cropping systems. Cover crop plots will be grown in a high tunnel during three growing seasons: over-winter, summer, and fall. Three non-leguminous species will be evaluated with and without hairy vetch (Vicia villosa) or cowepea (Vigna unguiculate). Belowground arthropods (insects and mites) will be isolated using sieve and a lighted berlese funnel system. This work will expand the body of knowledge of high tunnel production and cover cropping by discovering their interplay in affecting belowground arthropod species and abundance.

This study is the first to investigate belowground arthropod abundance in a high tunnel production system and determine the effect of cover crop species. In the study, mites were the most abundant arthropods. In the summer cover crop experiments, more mites were recovered from the buckwheat and cowpea treatment than the other treatments. In the winter cover crop experiments, wheat and vetch, triticale, wheat, and triticale and vetch treatments resulted in fewer mites, indicating that cover crop type may influence mite abundance. In the summer experiment, as soil organic matter increased, mite abundance also increased. However, in the winter experiment, as soil organic matter increased, mite abundance decreased. Therefore, the effects of organic matter on soil arthropod abundance is not clear. As such, more studies are needed to understand why decreases in mite abundance occur with increases in soil organic matter.
Despite studies in open field systems showing a positive correlation between soil water content and arthropod abundance, this was not the case in high tunnels when dry soil conditions occur. Dry soil conditions at the start of the experiments may have resulted in unfavorable conditions for survival. We did not classify belowground arthropod families based on function or measure the impact of arthropods on cover crop decomposition. Therefore, we were not able to assess whether the mites were predators or fungivores, which may have indicated their function in the soil ecosystem. In the study, we did see low diversity of arthropod families in high tunnel systems which may affect soil ecosystem services. This study assessed the relationship between production practices and changes in arthropod abundance. In conclusion, soil management practices in high tunnels can affect arthropod abundance by cover crop type, soil carbon, and organic matter. Understanding how production practices in high tunnels can affect belowground arthropods will help develop best management practices for soil health in high tunnels.

Learning outcomes

This research project seeks to develop adaptable cover cropping methods in high tunnels and increase our understanding of the belowground arthropod communities. Learning outcomes include: -

• Knowledge regarding soil food web community within high tunnel systems
• Flexible and adaptable cover crop recommendations for growers
• Interaction between cover crop species mixtures and below ground arthropods
• Functional high tunnel crop rotations that include cover crops

Action/Behavioral outcomes

This research will influence farmer’s soil nutrient management and production planning in high tunnels in the North Central Region and beyond. Specific behavior changes could include:

• Implementation of season-appropriate cover crops and functional crop rotations in high tunnels
• Adoption of cover crops in high tunnels that promote soil food web activity
• Higher adoption of high tunnels to support local food production using practices that promote soil health
• Extension and other educators provide research-based knowledge to growers that support environmental, social, and economic sustainability