Living Understories in Apple Orchards for Improved Quality of Fruit, Cider, and Rural Life

Commodities

Practices

Diversified perennial cropping systems are an essential part of the transition to more sustainable, equitable, and resilient food production. Perennial systems allow for long-term improvements in soil health and the establishment of diverse, multi-strata biotic communities that self-regulate through competitive and multi-trophic interactions. Yet, research on regenerative practices in perennials has lagged behind research in annuals, and the industry often lacks evidence-based alternatives to unsustainable practices. In apple orchards, current industry standards for ground management are to maintain the within-row spaces as bare ground with herbicides. We aim to conduct ecological and economic research that will advance the development of living understory alternatives. We will add novel perspectives to past research on cover crops or living mulch by: 1) examining how living understories affect fruit quality, in particular polyphenols and nutrients that are important for the growing craft cider industry, and 2) examining how the competitive effects between trees and understory plants (shown to reduce yield in past studies) may be alleviated with nutrient management based on plant sap analysis.    

Specifically, we will address four objectives. First, we will conduct five case studies with Virginia growers that maintain orchards with living understories. All of our grower-collaborators focus on the production of high-quality fruit for the growing craft cider industry, which represents an important value-added market that can connect growers directly to consumers. We will work with growers to understand the links among their management practices, plant diversity in the understory, soil health and microbial diversity, and fruit quality, including nutrient and polyphenol composition. Second, we will conduct an experiment in our research orchard at Virginia Tech that will examine the interactive effects of living understories and nutrient management on soil health, microbial composition, and fruit yield and quality. We will test the hypothesis that increased biodiversity in the understory will increase soil health and ultimately fruit quality, with limited consequences for yield when plant nutrient status is monitored and deficiencies corrected. Third, we will conduct economic research to understand how fruit quality is perceived and valued by both consumers and cidermakers that purchase fruit for fermentation. We will work with grower-collaborators, cooperating institutions, and extension professionals to recruit a diversity of participants and gain a broad perspective that can directly inform grower practices and marketing. Finally, our fourth objective focuses on education and communication of results to the farming community, the cider community, and the general public. This will involve a combination of presentations at scientific and industry meetings, non-technical publications and videos, and demonstrations at our research orchard. Throughout the project, we will also train a diverse cohort of graduate and undergraduate students in systems agricultural research.

Overall, the project will advance sustainability by: 1) providing new evidence on the systems-level consequences of living understories, 2) increasing opportunities for small farmers to differentiate and engage with local communities through a focus on fruit quality, and 3) training the next generation of agroecology practitioners in interdisciplinary systems research.

Our project will address four specific objectives, each of which will involve multiple project PIs, cooperators, and participants (Table 2). The first three objectives are focused on research activities, while the fourth objective (described under Outreach Plan, below) is focused on engagement with diverse stakeholders, co-design of living understory recommendations, and the development of educational materials with long shelf-lives and multiple delivery formats.   

Table 2: Project objectives and summary of leads and participants