Successful mechanical harvesting of perennial fruit crops requires efficient, economical harvesting systems that do not reduce trees' production life or diminish fruit quality.
Most of the world's citrus is now harvested manually, but the use of efficient and lower-cost mechanical harvesting techniques is expected to increase in the next few years, especially in the large citrus plantations in Florida and Brazil. The citrus industry is ramping up efforts to extend the harvest season past June, when the following year's crop becomes large enough to be susceptible to mechanical harvesting; discovering techniques that improve late-season harvesting will give growers better tools to minimize damaging impacts on the next year's fruit yield.
Researchers from the University of Florida's Citrus Research and Education Center published a study in a recent issue of HortScience that determined if winter drought stress could successfully delay flowering and fruit development of immature 'Valencia' sweet oranges to avoid young fruit loss during late-season mechanical harvesting.
The researchers hypothesized that if the Florida 'Valencia' bloom period could be delayed by a few weeks using winter drought stress—without negative effects on the quality of the current season's crop—the "fruitlets" from delayed flowering would be too small to be affected by mechanical harvesting late in the current harvest season, thus safely extending the mechanical harvesting period.
The study was designed by Juan Carlos Melgar, Jill M. Dunlop, L. Gene Albrigo, and James P. Syvertsen and conducted at the Citrus Research and Education Center in Lake Alfred. Beginning in December 2006 and continuing for three consecutive seasons, Tyvek® water-resistive barrier material was used as a rain shield groundcover under 13-year-old-trees. The researchers applied three treatments: drought (no irrigation and covered soil), rain only (no irrigation, no cover), and normal irrigation (rain and no cover). Covers were removed in February or March and normal irrigation and fertilization were resumed.
The drought stress did not affect fruit yield, size, percentage juice, or juice quality of the current crop harvested in May and June relative to continuously irrigated trees. Drought stress delayed flowering by 2 to 4 weeks so that the immature fruit for next season's crop were smaller than on continuously irrigated trees during June, but fruit growth caught up by September. During mechanical harvesting, previously drought-stressed trees lost fewer young fruit than continuously irrigated trees.
"The results showed that winter drought stress effectively delayed flowering and avoided young fruit loss during late-season mechanical harvesting without negative impacts on yield or fruit quality", Melgar noted.
The researchers observed that rain-excluding covers were used as an experimental tool, but that the covers may not be a viable commercial option for growers. They added that natural cover crops may help in inducing drought stress, but are yet to be tested as a management tool.
The complete study and abstract are available on the ASHS HortScience electronic journal web site: http://hortsci.ashspublications.org/cgi/content/abstract/45/2/271
Founded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at ashs.org
Michael W. Neff | EurekAlert!
New insight into why Pierce's disease is so deadly to grapevines
11.06.2018 | University of California - Davis
Where are Europe’s last primary forests?
29.05.2018 | Humboldt-Universität zu Berlin
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
22.06.2018 | Materials Sciences
22.06.2018 | Earth Sciences
22.06.2018 | Life Sciences