Developing sustainable strategies for nutrient and pest management on small-acreage strawberry farms

View the project report

Commodities

• Fruits: berries (strawberries)

Practices

• Crop Production: organic fertilizers
• Education and Training: on-farm/ranch research
• Pest Management: biological control

Local strawberries are in high demand throughout the Intermountain West, but outdoor production to meet demand is risky due to late frosts which threaten yields. Previous research at Utah State University (USU) has shown that high tunnel strawberry production could potentially meet consumer demand and be highly profitable when compared to outdoor or low tunnel production. Despite grower interest, adoption of high tunnel strawberry production in the West is low due to uncertainties over cultivar performance and best management practices for soil fertility and diseases using organic methods. High tunnel growing conditions can promote grey mold (Botrytis cinerea) and powdery mildew (Podosphaera aphanis) epidemics, requiring weekly fungicide application, a practice that is not sustainable for small scale growers using organic or natural growing methods.

Compost is a cost-effective organic fertilizer with potential for enhancing disease suppression but yield response can vary due to challenges associated with predicting nutrient release and plant uptake, which often translates to growers over applying or eschewing the use of compost altogether. Indeed, our preliminary research has shown considerable variability in growth and nitrogen (N) uptake among strawberry cultivars when grown on slow-release organic sources of N like composts. Compost-mediated resistance can also be complemented through use of microbial biological control agents (mBCAs), which can be directly applied by growers or transferred to flowers by pollinators such as bumblebees. While strawberries are self-pollinating, pollinators and their foraging activity can have synergistic effects on grower outcomes through increasing berry size and yields, and by vectoring mBCAs.

This project will improve management options for sustainable strawberry production by harnessing synergies between season extension, cultivar identity, nutrient uptake on compost, and disease suppression by addressing the following objectives: 1) assess strawberry cultivars for nutrient uptake and growth on less readily available organic nutrient sources, 2) assess how mBCA effectiveness, both singly and in mixtures, varies with strawberry cultivar and compost use 3) evaluate use of bumblebee pollinators to enhance biological control and yield 4) assess market value and consumer preference for local strawberries, 5) improve grower and student understanding of high tunnel strawberry production through on-farm trials field days, training events, the development of new online resources and course material. The most promising cultivar/management combinations will be tested and showcased on five commercial farms, with results published in factsheets and videos. This research is unique in that it explores innovative and sustainable ways to solve common production problems. Recent data published by the National Agriculture Statistics Service shows strawberries are among the top selling organic crops. With improved management options, local farms could meet consumer demand, bolster local economies, and improve environmental impacts. The information generated will help growers to potentially transform their production systems, reduce or eliminate reliance on toxic chemicals, improve nutrient management and soil health, and meet market demand for local, sustainably produced strawberries.

The long-term goal of this project is to increase the production of strawberries for local markets, improve soil nutrient and disease management, and reduce reliance on purchased inputs through addressing the following specific, short-term objectives: 1) assess cultivars for nutrient uptake and growth on less readily available organic nutrient sources such as compost, 2) assess how mBCA effectiveness, both singly and in mixtures, varies with strawberry cultivar and compost use 3) explore the use of bee pollinators to enhance biological control and yield and 4) assess market value and customer preferences for local strawberries grown under various production schemes and 5) Improve grower and student understanding of high tunnel strawberry production through on-farm trials, field days, training events, the development of new online resources and course material.  Initial selection of cultivars and mBCAs will occur in the greenhouse and laboratory in year one, with a subset field tested at the USU Student Organic Farm in years one through three. The most promising cultivar and management combinations will be tested and demonstrated on five commercial farms in years two and three. Five commercial growers and one student farm manager will advise the project through twice yearly meetings throughout. Results will be showcased in Utah and five neighboring states through on-farm tours and workshops, and published in factsheets, videos, and peer-reviewed publications