Improving Tart Cherry Sustainability

View the project final report

• 2016 annual report

Commodities

• Fruits: cherries

Practices

• Crop Production: cropping systems, varieties and cultivars
• Education and Training: demonstration, extension, focus group, on-farm/ranch research, participatory research, workshop
• Farm Business Management: budgets/cost and returns
• Pest Management: integrated pest management
• Sustainable Communities: local and regional food systems, sustainability measures

Utah has a reported 6,700 acres in tree fruit production, with an annual crop value of $25-31 million dollars. Accounting for more than 10% of statewide annual crop receipts, fruit crops are only surpassed by hay and wheat in economic value. Tart cherries are Utah’s most important fruit crop, with 3,300 reported acres and an annual value ranging from $6.07-20.4 million dollars (2009-2013). The value of the 2014 crop has yet to be determined, but statewide yields reached record levels of 49.8 million pounds. Those involved in processing and marketing the crop attribute these record yields to a combination of ideal weather conditions and a relatively high proportion of orchards in the optimum bearing age range.The typical life expectancy of a tart cherry orchard is 25 to 30 years. However, nearly all of the fruit is harvested using mechanical trunk shakers that require the trees to be at least seven to eight years old and in low-density spacings. Trees do not reach their full production potential for 10 to 12 years. Once mechanical harvest begins, trees begin to accumulate repeated trunk injury that eventually results in decline and collapse. Orchard longevity is determined by the care provided by the orchard manager in maintaining tree health, and the skill of the harvester operator in minimizing trunk damage. The optimum productivity typically occurs between years 12 and 16. Productivity then declines with accumulated trunk damage and declining tree health. However, growers typically delay orchard replacement as long as possible because of the 8 to 10 year gap before a new orchard resumes production.Apples, peaches, and sweet cherries are increasingly produced in high density (HD) orchard systems. HD orchards utilize trees on dwarfing rootstocks at close spacing, requiring special training and pruning strategies. One of the primary advantages of HD orchards is precocious fruiting, where fruit production may begin in the second or third season and reach full production potential by year five or six. This much earlier return on investment justifies the higher establishment costs of the HD system. Other perceived advantages are: (1) maximized fruit quality due to improved light distribution; (2) improved efficiency in pest and disease management; (3) maximized efficiency of hand labor for pruning, thinning, and harvesting the fruit; and (4) improved worker safety due to less time on ladders.Tart cherry production has not moved to HD systems due to limitations in (1) appropriate rootstocks, (2) suitable harvest equipment, and (3) appropriate strategies for tree training and pruning. Dwarfing precocious cherry rootstocks are now becoming more readily available, and mechanical berry harvesters could potentially be adapted for harvesting smaller trees, while reducing accumulated trunk damage. This project is to support part of a long-term project to develop a HD tart cherry management system (rootstocks, training and pruning methods, and harvest automation) suitable for climate and soil conditions in the Intermountain West and to determine the sustainability of this approach compared tothe existing low-density system.

1. Determine the optimum combination of rootstock, row spacing, and tree training for consistent high yields and for efficient labor utilization. The three orchards included in this study have a range of rootstocks, tree spacing, initial training, and maintenance pruning strategies included. Data will be collected on input requirements for each system, as well as yields and fruit quality for each treatment.

2. Compare the distribution uniformity of crop protectant applications among the high density training systems, and between the high density and conventional density orchards. From this, determine whether or not application technology could be altered to improve efficiency, and determine susceptibility of each system to non-target exposure resulting from spray drift.

3.  Determine the response of ‘Montmorency’ tart cherry to mechanical summer pruning. Recent work in high-density apples has shown that appropriately-timed summer mechanical pruning (hedging in late June) can induce additional flower bud formation, increasing yields of high-quality fruit in the following season (Robinson, personal communication). Hedging studies will be carried out to determine whether or not tart cherry show a similar response and to determine the optimum timing for hedging.

4.  Determine the relationship between light micro-environment and fruit quality in tart cherry. For most temperate fruit trees, fruit quality (color, flavor, sugar content) is correlated with the amount of light reaching the immediately adjacent leaves. A major advantage to high density plantings in apple, peach, and sweet cherry systems is better light distribution that results in better light exposure to the leaves in proximity to developing fruit. The result is a higher percentage of the total crop load exceeding minimum quality thresholds. An understanding of minimum localized light requirements is needed to devise additional improvements to training and pruning strategies for both high density and conventional density tart cherry management.

5.  Develop enterprise budgets for both conventional and high density systems, based on current conventional tart cherry management and on data from this research project. Construct comparison budget sheets that can be used to determine sensitivity to tree costs, fruit prices, and labor and to set targets for early and total yields. Use techniques such as partial budgets, net present value, and payback to examine the two production systems over
their respective estimated life of the orchard. Analyze the relative risk of each production system based on seasonal yield variability and price volatility.

6.  Provide high-density cherry management experience to several early adopters and establish/maintain high-visibility test planting for observation by commercial growers through organized farm tours sponsored by grower associations and Extension and through informal farm visits.