Mechanical Thinning (mechanical + thinning)

Distribution by Scientific Domains


Selected Abstracts


Mechanical flower thinning improves the fruit quality of apples

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2010
Alexey A Solomakhin
Abstract BACKGROUND: Apple ,Golden Delicious Reinders' and ,Gala Mondial' trees were mechanically blossom-thinned with 30,77 × g (300,480 rpm rotation) and 5 or 7.5 km h,1 vehicle speed to improve fruit quality, minimise leaf damage, reduce hand and chemical thinning and to prevent or overcome alternate bearing; adjacent untreated or manually thinned apple trees served as controls. RESULTS: Mechanical thinning (43 × g, 360 rpm, 5,7.5 km h,1) had a positive effect on fruit size (15% larger), firmness (8.4 in Gala vs. 7.6 kg cm,2 in the unthinned control), sweetness (124 vs. 117 g kg,1 sugar in the control), contained the largest malic acid content (4 g kg,1 vs. 3.4 g kg,1 in the control) and 17% more anthocyanin (normalised anthocyanin index = 0.8 in Gala vs. 0.7 in the control); fruit of Golden and Gala showed additionally advanced starch breakdown and ripened earlier. CONCLUSIONS: Since increases in rotor speed, viz. centrifugal force, versus increases in the vehicle speed resulted in opposing effects, an integrated coefficient of thinning (ICT) was devised with optimum values of 10,40 (at 43 × g, 5,7.5 km h,1), where an ICT > 50 led to tree damage and ICT < 8 led to sub-optimum thinning efficacy. Copyright © 2010 Society of Chemical Industry [source]


Crop thinning (hand versus mechanical), grape maturity and anthocyanin concentration: outcomes from irrigated Cabernet Sauvignon (Vitis vinifera L.) in a warm climate

AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2006
PAUL R. PETRIE
Abstract Crop thinning subsequent to fruit set can help regulate yield and improve fruit composition at harvest. Accordingly, an experiment was established in two vineyards (Site 1 Riverland District of South Australia; Site 2 Sunraysia District of Victoria) to investigate effects of crop removal after fruit set (when berries were pea size) using a machine harvester. Specific zones of the canopy were targeted for thinning to remove a predetermined percentage of the fruit and avoid over-thinning. Cropping responses to mechanical thinning were compared with control (un-thinned) vines, and with hand thinned vines (where fruit was removed from a similar portion of the canopy as for mechanical thinning). In a fourth treatment, bunches damaged by mechanical thinning were removed by hand. Inclusion of hand thinning treatments enabled us to distinguish between the potential benefits of reduced yield and the potential damage caused by the mechanical harvester to foliage and/or remaining fruit. Both the mechanical and the hand thinning treatments reduced bunch number as well as yield by a similar amount (approximately 24% on Site 1 and approximately 45% on Site 2) and advanced fruit maturity (soluble solids accumulation at harvest), relative to un-thinned controls, by approximately 1.6 % and 1.7% respectively. Soluble solids accumulated at a similar rate for all treatments at sites, despite differences in yield, implying that the impact of thinning treatments originated prior to veraison. Berry weight was increased by hand thinning at Site1, and by all thinning treatments at Site 2. Anthocyanin concentration (berry fresh weight basis) was higher in fruit from the mechanically thinned vines compared to controls (un-thinned). Mechanical thinning successfully reduced crop level to the target yield, and improved fruit quality. Mechanical thinning, via modified use of a machine harvester, thus offers some potential to regulate yield over large and minimally pruned vineyards, in a timely and cost-effective fashion. [source]


Pressure dependence of photoluminescence spectra of self-assembled InAs/GaAs quantum dots

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2003
F.J. Manjón
Abstract Photoluminescence (PL) measurements have been performed in InAs/GaAs self-assembled quantum dots (QDs) under high excitation conditions at low temperatures and under high hydrostatic pressures up to 10 GPa. Mechanically polished samples for high pressure experiments exhibited PL emission from the QD ground state but not from the excited states. Instead, a new broad band is observed in the energy range of the first excited state, which is tentatively attributed to emission from smaller dots formed during the mechanical thinning of the sample. With increasing pressure we found a similar blue shift for the PL maxima of the QD ground state (65 meV/GPa) and of the new broad band (69 meV/GPa). These pressure coefficients are 20% and 40% lower than those reported for dots of less than half the height as in our case and for the wetting layer, respectively. Our results point to a systematic reduction of the pressure coefficient of the InAs QDs with the increase of the dot height. [source]


Crop thinning (hand versus mechanical), grape maturity and anthocyanin concentration: outcomes from irrigated Cabernet Sauvignon (Vitis vinifera L.) in a warm climate

AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2006
PAUL R. PETRIE
Abstract Crop thinning subsequent to fruit set can help regulate yield and improve fruit composition at harvest. Accordingly, an experiment was established in two vineyards (Site 1 Riverland District of South Australia; Site 2 Sunraysia District of Victoria) to investigate effects of crop removal after fruit set (when berries were pea size) using a machine harvester. Specific zones of the canopy were targeted for thinning to remove a predetermined percentage of the fruit and avoid over-thinning. Cropping responses to mechanical thinning were compared with control (un-thinned) vines, and with hand thinned vines (where fruit was removed from a similar portion of the canopy as for mechanical thinning). In a fourth treatment, bunches damaged by mechanical thinning were removed by hand. Inclusion of hand thinning treatments enabled us to distinguish between the potential benefits of reduced yield and the potential damage caused by the mechanical harvester to foliage and/or remaining fruit. Both the mechanical and the hand thinning treatments reduced bunch number as well as yield by a similar amount (approximately 24% on Site 1 and approximately 45% on Site 2) and advanced fruit maturity (soluble solids accumulation at harvest), relative to un-thinned controls, by approximately 1.6 % and 1.7% respectively. Soluble solids accumulated at a similar rate for all treatments at sites, despite differences in yield, implying that the impact of thinning treatments originated prior to veraison. Berry weight was increased by hand thinning at Site1, and by all thinning treatments at Site 2. Anthocyanin concentration (berry fresh weight basis) was higher in fruit from the mechanically thinned vines compared to controls (un-thinned). Mechanical thinning successfully reduced crop level to the target yield, and improved fruit quality. Mechanical thinning, via modified use of a machine harvester, thus offers some potential to regulate yield over large and minimally pruned vineyards, in a timely and cost-effective fashion. [source]