Three years of mechanical harvesting (shake and catch) trials with two freestanding apple (Malus domestica Borkh.) cultivars on a semidwarf rootstock (M.7a) and two training systems (central leader and open center) yielded 64% to 77% overall harvesting efficiency. Mechanically harvested `Bisbee Delicious' apples averaged 70% Extra Fancy and 10% Fancy grade, while two `Golden Delicious' strains (`Smoothee' and `Frazier Goldspur') averaged 40% Extra Fancy and 13% Fancy grade fruit. Mechanically harvesting fresh-market-quality apples from semidwarf freestanding trees was difficult and its potential limited. Cumulative yield of open-center trees was less than that of central-leader trees during the 3 years (sixth through eighth leaf) of our study. `Golden Delicious' trees generally produced higher yields than `Delicious' trees.
D.L. Peterson, S.S. Miller, and J.D. Whitney
Charles A. Mullins and R. Allen Straw
Several pod characteristics were evaluated to select methods for determining optimum maturity for mechanical harvest of flat podded `Roma II' beans (Phaseolus vulgaris L.). The test was conducted over a 3-year period (1993-1995) at Crossville, Tenn. A total length of 3.6 to 4.4 inches (90 to 112 mm) for the center seed from each of 10 of the more mature pods was a rather reliable and rapid field guide for determining optimum maturity for mechanical harvest of `Roma II' bush beans.
Tripti Vashisth, D. Scott NeSmith, and Anish Malladi
plant growth regulator-induced mature fruit abscission occurs at the PPJ ( Vashisth and Malladi, 2013 , 2014 ). Harvesting fruit by hand and the majority of mechanical harvesting in blueberry are typically associated with detachment at the FPJ ( Howell
Rachel Leisso, Bridgid Jarrett, and Zachariah Miller
(10.3% and 9.6%, for ‘Wojteck’ and ‘Brazowa’, respectively) and higher for later harvests (14.1% and 12.6%), which they attributed to higher temperatures later in the season. Importantly, cultivars compatible with a (one-pass) mechanical harvest are a
Lyn A. Gettys, Kyle L. Thayer, and Joseph W. Sigmon
management options such as mechanical harvesting do exist, most have greatly increased costs and reduced efficacy compared with chemical control tools. The need for “softer” products that can be used for aquatic weed control is urgent, and exploration is
Kuo-Tan Li, Jim Syvertsen, and Jackie Burns
Mechanical harvesting using trunk shakers on late-season `Valencia' sweet orange [Citrus sinensis (L.) Osb.] trees can remove young fruit for the next crop and occasionally cause root exposure or severe bark scuffing on the trunk. To evaluate the effects of these physical injuries on fine root growth and lifespan, we installed minirhizotrons in the root zone of 15-year-old fruiting `Valencia' trees on Swingle citrumelo [C. paradise Macf. × Poncirus trifoliate (L.) Raf.] rootstocks. Images of roots against the minirhizotron tubes were captured biweekly with a custom-made video-DVD recorder system. Trees were harvested in early June by hand or with a linear-type trunk shaker in two consecutive years. Bark injury after trunk shaking was mimicked by removing part (42%) of the bark tissue from the main trunk with a sharp knife. Numbers of fine roots, root activity and lifespan as indexed by the color of the root, and the distribution of new fine roots after harvest were analyzed. Although root exposure was common with the normal operations during mechanical harvesting, few disturbances reached the major fine root zone. There was no clear correlation between root growth and trunk shaking with or without bark injury. The root system might benefit from less competition after the loss of young fruit from mechanical harvesting, as a greater availability of carbohydrates or other resources may compensate for any potential damage due to mechanical harvesting.
Donald L. Peterson
Hand-harvesting fruit crops is labor-intensive, and the supply of dependable, skilled labor is a concern of the fruit industry. Only a small portion of all fruit crops is harvested mechanically, primarily for processing. Public funding of mechanical harvesting research on fruit crops has reached a low level. However, there is renewed interest in mechanical harvesting research due to the potential scarcity of hand-harvest labor and new federal laws that may deplete further the labor pool. Much of the research expertise in mechanical harvesting of fruit crops has been lost, since most projects have been discontinued. Considerable lead time will be required to develop facilities, personnel, and projects if the decision is made to initiate publicly funded harvest mechanization research. More time will be required before commercially acceptable techniques and methods will be available. A majority of the research described in this paper was conducted outside the United States. The United States will not remain competitive in the world market for fruit crops with the present lack of mechanical harvesting research.
Jorge E. Arboleya, Joseph G. Masabni, Michael G. Particka, and Bernard H. Zandstra
Dry bulb onion (Allium cepa) leaves may not dry down normally and bulbs may not attain dormancy during adverse growing seasons. An effective method of artificial leaf desiccation is needed to complement mechanical harvesting and onion conditioning for storage. Desiccants were tested in 1993, 1994, 1995, 2001, 2002, 2003 on onion leaves prior to harvest, and bulb quality was evaluated after 5 months or more of storage. Carfentrazone, diquat, and paraquat desiccated onion foliage well but increased bulb rot and reduced the percentage of marketable bulbs after storage. Bromoxynil and endothall desiccated onion foliage significantly without inducing rot or reducing the percentage of marketable bulbs. Copper sulfate and pelargonic acid increased desiccation of onion foliage but were not sufficiently effective for field use. Neither reduced the percentage of marketable bulbs. If bromoxynil or endothall were labelled for onion desiccation, they could be applied 10-14 days before harvest to enhance natural leaf senescence and facilitate mechanical harvest.
Deciduous tree fruit crops such as apple (Malus domestica), peach (Prunus persica), and sweet cherry (Prunus avium) are not mechanically harvested for the fresh market. Attempts to mechanically harvest these fruits by mass removal techniques have not been successful due to excessive fruit damage caused during detachment, fall through the canopy, and collection. Robotic harvesters have not been commercially accepted due to insufficient fruit recovery. A U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) harvesting concept shows promise for harvesting both fresh market quality apples and sweet cherries. Successful mechanical harvesting of fresh market quality deciduous tree fruit will only occur when plant characteristics and machine designs are integrated into a compatible system. Cultivar characteristics that would facilitate machine harvesting are uniform fruit maturity at harvest, firm fruit that are resistant to mechanical damage, and compact growth habit that produces fruit in narrow canopies and on short/stiff limbs. Engineers must develop new detachment principles that minimize the energy input to effect fruit detachment, and develop durable energy-absorbing catching surfaces/conveyors to eliminate damage during collection of the fruit. As technology advances, sorting and sizing systems might be developed that can be operating on the harvester to eliminate culls in the field and deliver only fresh market quality fruit to the packers.
A.R. Gonzalez, D.E. Smith, A. Mauromoustakos, and M. Davis
A study was conducted to evaluate the possibility of producing and processing immature cowpea (Vigna unguiculata) green pods by using the same technology used for green beans (Phaseolus vulgaris). The cowpea cultivar Bettersnap developed for green pod production and the green bean cultivars Benton and OSU-5402 were produced under the same cultural conditions. `Bettersnap' yielded less than 0.5 ton/ha, while `Benton' and `OSU-5402' produced about 2.5 ton/ha in once-over simulated mechanical harvest. `Bettersnap' had long vines and dense foliage, which resulted in plants with more width and less erectness than `Benton', the predominant green bean cultivar. Uneven pod setting and long pods (23.8 cm) in `Bettersnap' constitute potential problem for mechanical harvest. Canned cowpea pods of sieves 2 and 3 had darker green color, smaller seeds, and higher shear value, fiber content, and sloughing than green bean pods. Our study indicates that there is a need to develop cultivars with high yield potential and concentrated pod setting adapted to mechanical harvest with pods containing less fiber and less tendency to sloughing.