In this 2-year study of ‘Brown Snout’ specialty cider apple (Malus ×domestica) grafted onto Malling 27 (M.27) and East Malling/Long Ashton 9, we compared weight of total harvested fruit, labor hours for harvest, tree and fruit damage, and fruit and juice quality characteristics for machine and hand harvest. Machine harvest was with an over-the-row small fruit harvester. There were no significant differences due to rootstock; however, there were differences between years for most measurements. Weight of harvested fruit did not differ because of harvest method; however, harvest efficiency was 68% to 72% for machine pick and 85% to 89% for machine pick + clean-up weight (fruit left on trees and fruit knocked to the ground during harvest) as compared with hand harvest. On average for the 2 years, hand harvest required 23 labor-hours per acre at a total cost of $417, while machine harvest required 5 labor-hours per acre at a cost of $93. There were no differences due to harvest method on damage to spurs (four to eight spurs damaged per tree) or limbs (0.5–0.8 limbs damaged per tree). Although there were also no differences due to harvest method on fruit bruising (100% for both harvest methods in this study), 10% of fruit were sliced and 4% of fruit were cut in half inadvertently with machine harvest, and none were sliced or cut with hand harvest. Harvest method had no effect on fruit quality characteristics, specifically, soluble solids concentration (SSC), pH, specific gravity, titratable acidity (malic acid equivalents), or percent total tannin, when fruit was pressed immediately after harvest or stored for 2, 3, or 4 weeks before pressing. Juice quality characteristics were affected by storage, and SSC increased 11% in 2011 (3 weeks storage), and 12% and 18% in 2012 (2 and 4 weeks storage, respectively). Similarly, specific gravity increased both years after storage, 1% in 2011, and 1% and 2% in 2012 (a 1% increase in juice specific gravity corresponds to a potential 1.3% increase in alcohol by volume after fermentation for cider). Both years, juice pH tended to decline when fruit was stored (0.01 pH units in 2011, 0.06–0.12 pH units in 2012). Overall, cider apple harvest with an over-the-row small fruit machine harvester used four times less labor than hand harvest, yield reached 87% that of hand harvest (when clean-up yield was included), and juice quality characteristics were not negatively affected. These results suggest that machine harvest may be suitable for cider apples if equipment is available and affordable.
Carol A. Miles and Jaqueline King
Fumiomi Takeda and Ann K. Hummell
A new trellis system called the “rotatable cross-arm” (RCA) trellis was developed to ease mechanical fruit harvesting of eastern thornless blackberries. The rotation of the cross-arm following bloom 1) positions all the fruit to one side of the trellis in a plane underneath the cross-arm and 2) permits primocanes to be trained to side without the fruit. To maintain productivity, the number of lateral shoots that arise from primocanes must be maximized. In this study, we examined the growth and development of individual primocanes within plants and the number of lateral canes that developed on them to decide which canes should be retained during the growing season. In `Chester Thornless' blackberry, primocanes trained early in the season produced more laterals per cane, had higher percentage of buds forming laterals, and were much larger in diameter than primocanes trained later in the season. Field observations suggested high sink strength and less light competition probably contributed to the increased productivity of early canes. These results indicated that the canes that become trainable early in the season must be retained for the success of the RCA trellis. Conversely, the primocanes that become trainable later in the season do not develop sufficiently and should be removed.
Fumiomi Takeda, Gerard Krewer, Elvin L. Andrews, Benjamin Mullinix Jr, and Donald L. Peterson
inherent limitation of this study. Mechanical fruit harvesting was not conducted over the entire season. Also, we operated the V45 harvester only at one ground speed and shaker frequency. We did not place machine-harvested fruit in long-term cold storage