Wind Damage of Citrus Fruit in Southern Uruguay: Study and Characterization
Under Uruguayan climatic conditions, peel damage caused by wind is the main reason for discard of citrus fruit for export. In high sensitivity varieties such as Ellendale tangor, the nonmarketable fruit percentage can reach 40% , which represents a significant impact on economic returns. Since current vegetal windbreaks have shown low protection efficiency, the main objectives of this study were; (a) characterizing the climate of winds and its impact on branch and leaf movements that cause fruit damage, and (b) establishing fruit seasonal sensitivity and anatomical shoot aspects in the onset and evolution of damage. In a commercial orchard of Ellendale tangor, located in Kiyu (35° SL), wind speed and turbulence flow were measured with an ultrasonic anemometer. In addition, measurements to characterize the resiliency of different parts of the tree, including branches and leaves, were performed. During three consecutive years in 12 trees without wind protection, 40 fruitlets per plant selected at random were evaluated. In two years, 200 and 400 single leafless flowers were tagged and divided in two groups-, with adult basal leaf (BL) and with adult basal leaf removed (BLR). At the end of petal fall and every 15 days the occurrence of wind damage was quantified. We found three significant turbulence scales. Two of them were linked to fence size as height and length (14m and 300m respectively). The other one was a small scale turbulence tuned to leaf size, with vortices of some centimetres. These vortex ensembles produced damage at different stages of fruit growth. Frequency of scaffold branches was between 0. 65 Hz and 0. 8 Hz. In fruitlets, damage emergence was evident immediately after petal fall and increased until one month after the end of physiological drop. Fruit damage sensitivity was consistently higher in December, 50 to 80 days after full bloom. Percentage of damaged fruits in BL treatment reached 36% and 57% in each year respectively and it diminished to 18% and 41% in BLR treatment. These results indicate that, at low wind scale, mature leaf friction on developing fruitlets explains a major percentage of the fruit damage. These are the first results in order to design an effective wind protection system for the orchards.
Ellendale tangor Peel quality Turbulence
A. Gravina E. Pardo L. Soria G. Gambetta V. Duranona J. Cataldo
Facultad de Agronomia, Universidad de la Republica. Garzon 780, Montevideo 12900, Uruguay Facultad de Ingenierta, Universidad de la Republica. J. Herrera y Reissig 565, Montevideo,Uruguay
国际会议
11th International Citrus Congress(第11届国际柑橘大会)
武汉
英文
754-758
2008-10-01(万方平台首次上网日期,不代表论文的发表时间)