Arthropod Response to Cover Crop-Based Reduced-Tillage Organic Cropping Systems
Open Access
- Author:
- Regan, Karly
- Graduate Program:
- Entomology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 26, 2019
- Committee Members:
- Mary Ellen Barbercheck, Dissertation Advisor/Co-Advisor
Mary Ellen Barbercheck, Committee Chair/Co-Chair
John Frazier Tooker, Committee Member
Kelli Hoover, Committee Member
Armen R. Kemanian, Outside Member
William Curran, Outside Member - Keywords:
- agroecology
biological control
cover crops
tillage
organic agriculture
arthropod community composition
conservation biological control
pest management
Carabidae
Araneae
Opiliones
Staphylinidae
Delia
Lepidoptera
interseeding
intercropping - Abstract:
- Although all farmers face potential trade-offs between management tactics such as chemical usage, tillage, crop rotation, and other aspects of their production system, these trade-offs can be especially challenging to balance for organic producers. Conservation of natural enemies can be one of the most important tactics for managing invertebrate pests that is available to organic producers (NOP 2005). Through this dissertation, I investigated the response of arthropod pests and predators to organic cropping systems incorporating cover crops and reducing tillage, as well as reviewing broader effects of tillage on pests and predators. My dissertation addresses multiple objectives through five chapters. Chapter 1 is a general introduction that reviews organic field crop production, tillage as a soil management practice, the use of winter cover crops, and how these agricultural practices influence arthropod pest and predator populations. Chapter 2 assesses the effects of tillage on arthropod populations, particularly predator populations, through a review and meta-analysis conducted in collaboration with Elizabeth Rowen. In addition to comparing the effects of conventionally managed systems with frequent and/or intensive tillage to no-till systems, the meta-analysis examines the effects of reduced or conservation tillage practices on arthropod communities in these systems. Chapter 3 investigates the effects of winter cover crop species, tillage, and interseeding of cover crops into standing corn on the soil-dwelling arthropod community, with a focus on arthropod predators, in an organic agronomic crop rotation. Characterizing the soil-associated invertebrate community allows us to understand the effects of these practices on arthropod abundance, diversity, and community composition, and the roles that invertebrates play in these systems. I examine the relationship between different predator groups and the response of the predator community to four organic cropping systems that vary in the frequency, intensity, and timing of disturbance. I also quantify predation exerted by the predator community in the same four cover crop-based, reduced-tillage cropping systems using sentinel prey assays to evaluate the effects of these cropping systems and their associated management practices on the conservation of beneficial predators and enhancement of predation. Chapter 4 investigates the effects of cropping systems that vary in disturbance on damage from common early and late season invertebrate pests of corn in the Mid-Atlantic US. Through assessment of pest damage, I evaluate risks that producers face when implementing cover crops or reducing tillage in an organic cropping system. Chapter 5 examines the effects of tillage and cover crop management on a pest of large-seeded crops, Delia platura (Diptera: Anthomyiidae), through 6 years of management in an organic cropping system. Lastly, Chapter 6 serves as a conclusion, in which I summarize the results presented throughout the dissertation and their relevance to agronomic production in Pennsylvania, the surrounding region, and in organic systems more broadly. I also propose suggestions for future research directions.