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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Nitrogen fertilization of hybrid poplar plantations in Saskatchewan, Canada

Booth, Neil W.H. 31 March 2008
The increasing input costs for traditional agriculture has led land owners and producers in search of alternative opportunities to increase on-farm income. Replacing agricultural crops with short rotation woody species such as hybrid poplar trees is a form of agroforestry. The objectives of this project were to evaluate: 1) a suitable planting stock for hybrid poplar, 2) the effect of nitrogen (N) fertilizer application and pruning on hybrid poplar growth and, 3) the response of four hybrid poplar clones to fertilizer application and their suitability in the boreal transition ecoregion of Saskatchewan. <p>Two trials were established near Meadow Lake, Saskatchewan where three stock types (cuttings, root cuttings and rooted plugs) of Walker poplar were planted into former alfalfa and pasture fields. Trees were pruned each spring to remove multiple leaders and fertilized in year 2 with 100 kg N ha-1. The presence of roots on rooted cutting and plug stock types was beneficial in terms of hybrid poplar growth and survival. Trees grown from planting stock without roots had survival rates between 32-37% whereas, the survival of trees with roots at the time of planting ranged from 62-81% after two years of growth. Trees that were planted as a rooted stock were 3.5 to 4.2 times greater in height and 4.0 to 5.6 times greater in root collar diameter than trees planted as an un-rooted stock type. The application of fertilizer N decreased tree volumes by 31% at the Alfalfa site and had no effect on tree growth at the Pasture site. The total amount of fertilizer N recovered by the hybrid poplar trees ranged from 1-3% at the Alfalfa site and 3-5% at the Pasture site. <p>The second study involved planting four clones of hybrid poplar (Hill, Katepwa, Walker and WP-69) at the same two sites and applying fertilizer at rates of 0, 150 and 300 kg N ha-1 the first two years. Following the second growing season, Katepwa and WP-69 clones had the highest tree volumes of 750 and 1147 cm3 of the four clones evaluated. The Walker clone had the poorest survival rates (52-56%) compared to the other three clones (> 90% survival). Foliar N levels were not correlated with tree height at the Alfalfa (p=0.1326) or the Pasture (p=0.1063) sites. The relationship between foliar P concentration and tree height was more pronounced during July at the Alfalfa site with an r2 value of 0.7102. The N:P ratios for foliar tissue decreased with increasing fertilizer N application during August at the Alfalfa site. Foliar N:P ratios were the same among fertilizer and clone treatments at the Pasture site in August. <p>Results from this study suggest that rooted stock types increase the successful establishment of hybrid poplar plantations. However, application of N fertilizer may not increase growth of trees if soil N is adequate. Other soil nutrients need to be measured prior to fertilization to determine what nutrients may be limiting plant growth.
62

Evaluation of Shortest Path Query Algorithm in Spatial Databases

Lim, Heechul January 2003 (has links)
Many variations of algorithms for finding the shortest path in a large graph have been introduced recently due to the needs of applications like the Geographic Information System (GIS) or Intelligent Transportation System (ITS). The primary subjects of those algorithms are materialization and hierarchical path views. Some studies focus on the materialization and sacrifice the pre-computational costs and storage costs for faster computation of a query. Other studies focus on the shortest-path algorithm, which has less pre-computation and storage but takes more time to compute the shortest path. The main objective of this thesis is to accelerate the computation time for the shortest-path queries while keeping the degree of materialization as low as possible. This thesis explores two different categories: 1) the reduction of the I/O-costs for multiple queries, and 2) the reduction of search spaces in a graph. The thesis proposes two simple algorithms to reduce the I/O-costs, especially for multiple queries. To tackle the problem of reducing search spaces, we give two different levels of materializations, namely, the <i>boundary set distance matrix</i> and <i>x-Hop sketch graph</i>, both of which materialize the shortest-path view of the boundary nodes in a partitioned graph. Our experiments show that a combination of the suggested solutions for 1) and 2) performs better than the original Disk-based SP algorithm [7], on which our work is based, and requires much less storage than <i>HEPV</i> [3].
63

Nitrogen fertilization of hybrid poplar plantations in Saskatchewan, Canada

Booth, Neil W.H. 31 March 2008 (has links)
The increasing input costs for traditional agriculture has led land owners and producers in search of alternative opportunities to increase on-farm income. Replacing agricultural crops with short rotation woody species such as hybrid poplar trees is a form of agroforestry. The objectives of this project were to evaluate: 1) a suitable planting stock for hybrid poplar, 2) the effect of nitrogen (N) fertilizer application and pruning on hybrid poplar growth and, 3) the response of four hybrid poplar clones to fertilizer application and their suitability in the boreal transition ecoregion of Saskatchewan. <p>Two trials were established near Meadow Lake, Saskatchewan where three stock types (cuttings, root cuttings and rooted plugs) of Walker poplar were planted into former alfalfa and pasture fields. Trees were pruned each spring to remove multiple leaders and fertilized in year 2 with 100 kg N ha-1. The presence of roots on rooted cutting and plug stock types was beneficial in terms of hybrid poplar growth and survival. Trees grown from planting stock without roots had survival rates between 32-37% whereas, the survival of trees with roots at the time of planting ranged from 62-81% after two years of growth. Trees that were planted as a rooted stock were 3.5 to 4.2 times greater in height and 4.0 to 5.6 times greater in root collar diameter than trees planted as an un-rooted stock type. The application of fertilizer N decreased tree volumes by 31% at the Alfalfa site and had no effect on tree growth at the Pasture site. The total amount of fertilizer N recovered by the hybrid poplar trees ranged from 1-3% at the Alfalfa site and 3-5% at the Pasture site. <p>The second study involved planting four clones of hybrid poplar (Hill, Katepwa, Walker and WP-69) at the same two sites and applying fertilizer at rates of 0, 150 and 300 kg N ha-1 the first two years. Following the second growing season, Katepwa and WP-69 clones had the highest tree volumes of 750 and 1147 cm3 of the four clones evaluated. The Walker clone had the poorest survival rates (52-56%) compared to the other three clones (> 90% survival). Foliar N levels were not correlated with tree height at the Alfalfa (p=0.1326) or the Pasture (p=0.1063) sites. The relationship between foliar P concentration and tree height was more pronounced during July at the Alfalfa site with an r2 value of 0.7102. The N:P ratios for foliar tissue decreased with increasing fertilizer N application during August at the Alfalfa site. Foliar N:P ratios were the same among fertilizer and clone treatments at the Pasture site in August. <p>Results from this study suggest that rooted stock types increase the successful establishment of hybrid poplar plantations. However, application of N fertilizer may not increase growth of trees if soil N is adequate. Other soil nutrients need to be measured prior to fertilization to determine what nutrients may be limiting plant growth.
64

Adequacy Assessment in Power Systems Using Genetic Algorithm and Dynamic Programming

Zhao, Dongbo 2010 December 1900 (has links)
In power system reliability analysis, state space pruning has been investigated to improve the efficiency of the conventional Monte Carlo Simulation (MCS). New algorithms have been proposed to prune the state space so as to make the Monte Carlo Simulation sample a residual state space with a higher density of failure states. This thesis presents a modified Genetic Algorithm (GA) as the state space pruning tool, with higher efficiency and a controllable stopping criterion as well as better parameter selection. This method is tested using the IEEE Reliability Test System (RTS 79 and MRTS), and is compared with the original GA-MCS method. The modified GA shows better efficiency than the previous methods, and it is easier to have its parameters selected. This thesis also presents a Dynamic Programming (DP) algorithm as an alternative state space pruning tool. This method is also tested with the IEEE Reliability Test System and it shows much better efficiency than using Monte Carlo Simulation alone.
65

Nursery Techniques Influence the Growth of Hazelnuts

Wu, Shiman 21 January 2013 (has links)
Since Ferrero SpA established a manufacturing plant in Brantford, Ontario, there has been considerable interest in developing a hazelnut industry locally. One of the issues that needs to be overcome is to supply large numbers of suitable plants rapidly. They can be micropropagated, and then grown in the nursery. Usually, it takes two years to grow suitably sized plants in the nursery. This thesis investigated methods to grow suitably sized plants in one year and evaluated the nursery systems from financial aspect. Hazelnut seedlings were planted in ellepots and plastic pots, and then subjected to three treatments: grown in a retractable roof greenhouse, treated with root pruning technology or grown in outdoor environment. Also, two transplant timings were tested: the fall of 2011 and the spring of 2012. The results showed that pot type did not influence the growth of hazelnut seedlings. The retractable roof greenhouse increased growth and the root pruning technology changed the seedlings root structure but not their growth. Transplant timing did not affect the seedlings growth in the first year in the field. The retractable roof greenhouse has the potential to produce two crops of seedlings in one growing season compared to one crop in the outdoor nursery. The estimated cost per seedling under retractable roof greenhouse was $9.31, which was $1.95 cheaper than outdoor. / Ontario Centres of Excellence and Ontario Ministry of Agriculture, Food and Rural Affairs
66

Acoustic Studies on Wood

Hansen, Helge Johannes January 2006 (has links)
Several acoustic techniques have been used to determine elastic and damping properties of trees, logs and beams. Time of flight (TOF) measurements in the outerwood of 14-year-old Pinus radiata trees showed that pruning operations increased the outerwood stiffness by up to 25% compared with unpruned trees. However, at the most 5% to 10% of the increased stiffness can be explained by the fact that the outerwood of the pruned trees is free of knots, as TOF measurements are little affected by knots. Thus, it is not known what causes the increase of outerwood stiffness in the pruned trees. One possible explanation could be a smaller microfibril angle (MFA) in the S2 layer of the outerwood cells, which would cause a significant increase in stiffness. Thinning operations decreased the outerwood stiffness by up to 8%. In small Eucalyptus nitens and Pinus radiata logs, which had branch nodes and nodal whorls at specific locations, MOE calculations (using the resonance technique) based on different harmonics gave different results. This indicates that defects do interact with acoustic waves. Acoustic tests on laminated beams with artificial defects (holes filled with dowels) at specific locations also had a significant impact on the MOE. Moreover, it was evident that the damping ratio (evaluated from the Q- factor) of the beams increased with increasing diameter of the holes. However, it was found that holes in laminated beams decreased stiffness while branch nodes and nodal whorls increased stiffness. This shows that relatively small defects, occupying a small volume of the beam, have an impact on acoustic measurements. It is not appropriate to base the MOE calculation on a single harmonic, considering that different harmonics investigate different parts of the specimen
67

Pruning and pollination studies on southern highbush blueberries (V. corymbosum L. interspecific hybrids)

Muller, Jasper Lodewyk 12 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Commercial production of the southern highbush blueberries (SHB) ‘Jewel’, ‘Emerald’, ‘Star’, ‘Snowchaser’ and ‘Bluecrisp’ started recently in the Western Cape. In South Africa, no research has been conducted on pruning and pollination of SHB, and various questions regarding these practices have arisen. Six experiments were conducted to evaluate the self-compatibility and the effect of cross-pollination on berry characteristics of ‘Star’, ‘Emerald’, ‘Jewel’, ‘Bluecrisp’ and ‘Snowchaser’. The effect of cross-pollination on fruit set, berry weight, berry diameter and fruit development period is cultivar dependant. ‘Bluecrisp’ appears self-incompatible and ‘Misty’ or ‘Emerald’ can be recommended as cross-pollinators. ‘Snowchaser’ seems self-compatible and solid block plantings can be recommended. ‘Misty’ and ‘Emerald’ would be recommended as cross-pollinators for ‘Star’ and ‘Jewel’ respectively, even though these cultivars will set an adequate crop when self-pollinated. Although ‘Emerald’ seem self-compatible, the fruit set tends to vary greatly and cross-pollination with ‘Jewel’, ‘Misty’ and ‘Bluecrisp’ is recommended to obtain early maturing berries of the required size. Another season’s data is required before final conclusions can be drawn. In order to establish sustainable summer pruning strategies for South African growing conditions that will maximise yield and berry quality for SHB, two pruning trials were conducted. In the first trial, the severity of pruning of ‘Star’, ‘Emerald’ and ‘Jewel’ was evaluated. We established that summer pruning is a compromise between total yield and desired berry size. All the pruning treatments reduced total vegetative growth and shoot number, but increased individual shoot length. Summer pruning increased berry weight and diameter by reducing total yield, but also by developing better quality bearing wood. Vigorous laterals stimulated by pruning seize growth later thereby delaying reproductive bud initiation and harvest. An increase in the severity of pruning increased the level to which the plants responded. No pruning and ‘light pruning’ gave the highest yields, but one more season’s data will clarify whether successive light pruning is sustainable. “Standard pruning” resulted in a well-balanced plant with an intermediate yield and berry size. Heading of one-year-shoots as part of the pruning strategy is not recommended for any of the cultivars. “Severe pruning” will only be recommended for young, newly established plantings where vegetative growth is the main objective. A second trial was conducted to study the effect of time of summer pruning. At Teeland, delaying pruning resulted in a decrease in total new growth and shoot number thereby reducing yield. This was probably due to progressively more buds that became endodormant. For all three cultivars, pruning as soon as possible after harvest would therefore be recommended. At Lushof, the effect of time of summer pruning was not significant. This could be due to the fact that plants were younger and more vigorous or because the area is warmer and growth continued for longer. One more season’s data is needed before any final conclusions are drawn. / AFRIKAANSE OPSOMMING: Kommersiële verbouing van die “southern highbush” bloubessies (SHB) ‘Jewel’, ‘Emerald’, ‘Star’, ‘Snowchaser’ en ‘Bluecrisp’ is ’n nuwe ontwikkeling in die Wes-Kaap. In Suid-Afrika is nog geen navorsing oor die snoei en bestuiwing van SHB onderneem nie, en verskeie vrae het oor hierdie praktyke ontstaan. Ses eksperimente is gedoen om die self-verenigbaarheid, sowel as die effek van kruisbestuiwing op bessie-eienskappe van ‘Star’, ‘Emerald’, ‘Jewel’, ‘Bluecrisp’ en ‘Snowchaser’ te evalueer. Die effek van kruisbestuiwing op vrugset, bessiegewig, bessiedeursnee en vrugontwikkelingsperiode is kultivar spesifiek. ‘Bluecrisp’ blyk self-onverenigbaar te wees en kruisbestuiwing met ‘Misty’ of ‘Emerald’ word aanbeveel. ‘Snowchaser’ blyk self-verenigbaar te wees en suiwer blok aanplantings kan dus aanbeveel word. ‘Misty’ en ‘Emerald’ word onderskeidelik as kruisbestuiwers vir ‘Star’ en ‘Jewel’ aanbeveel, alhoewel beide kultivars ‘n goeie oes sonder kruisbestuiwing kan lewer. Vir ‘Emerald sal kruisbestuiwing met ‘Jewel’, ‘Misty’ of ‘Bluecrisp’ aanbeveel word, indien vroeë, groot bessies belangrik is. ’n Tweede seisoen se data word benodig om bogenoemde te bevestig voor finale aanbevelings gemaak kan word. Twee snoeiproewe is uitgevoer om volhoubare somersnoei-strategieë te ontwikkel wat die opbrengs en kwaliteit van bessies onder Suid-Afrikaanse groeitoestande sal maksimeer. In die eerste snoeiproef is die intensiteit van snoeisnitte vir ‘Star’, ‘Emerald’ en ‘Jewel’ ondersoek. Daar is vasgestel dat totale opbrengs en bessiegrootte teen mekaar opgeweeg moet word wanneer strafheid van snoei ge-evalueer word. Somersnoei verminder totale vegetatiewe groei en aantal nuwe lote, maar vermeerder lootlengte en bessiegrootte. Somersnoei het ‘n toename in bessiegrootte tot gevolg deur dat die totale opbrengs verminder, maar ook deur die kwaliteit van draende lote te verbeter. Meer groeikragtige lote gestimuleer deur somersnoei, staak verlengingsgroei later in die seisoen wat dan lei tot later bloknopinisiasie en oes. Geen snoei, sowel as “ligte snoei” het gelei tot die grootste opbrengs na die afloop van een seisoen, maar nog ‘n seisoen se data word benodig om vas te stel of dit volhoubaar is. “Standaard snoei’” lei tot ‘n goed gebalanseerde plant met ‘n gemiddelde opbrengs en bessiegrootte. “Harde snoei” sal slegs aanbeveel word vir nuwe aanplantings waar vegetatiewe groei die hoof prioriteit is. Om die tydsbereking van somersnoei aan te spreek, is ‘n tweede snoeiproef uitgevoer. Op Teeland, het ‘n uitstel van somersnoei gelei tot ‘n afname in vegetatiewe groei en aantal lote en dit het dan gelei tot ‘n afname in opbrengs. Hierdie was moontlik die gevolg van meer knoppe wat mettertyd in endodormansie ingegaan het. Op Lushof het die tydsberekening van somersnoei geen betekenisvolle effek gehad nie. Dit kan moontlik toegeskryf word aan die jonger, groeikragtige plante, of aan die langer groeiseisoen weens die warmer klimaat in die area. Nog ‘n seisoen se data word egter benodig voor enige finale gevolgtrekkings gemaak kan word.
68

Avaliação de cultivares e épocas de poda para o pessegueiro na região de Botucatu/SP

Ferraz, Rafael Augusto [UNESP] 01 August 2013 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-08-01Bitstream added on 2014-06-13T19:34:20Z : No. of bitstreams: 1 ferraz_ra_me_botfca.pdf: 388233 bytes, checksum: fbbfcde57ff8206969370389519d439a (MD5) / O pessegueiro (Prunus persica L. Bastch) é uma fruteira de clima temperado, pertencente à família das rosáceas. É uma planta de origem chinesa, sendo hoje cultivada em diversos países, inclusive em áreas subtropicais. Destacam-se como grandes produtores mundiais desta frutífera a China, EUA, Itália e Espanha. O pessegueiro, assim como outras frutíferas, necessita de tratos culturais importantes como a poda e o uso de técnicas para a quebra da dormência em cultivares utilizados em regiões subtropicais, já que nessas regiões, a planta não tem suas exigências em frio totalmente satisfeitas. Neste contexto, o presente trabalho teve como objetivo avaliar o desempenho agronômico e a qualidade dos frutos de 3 cultivares de pessegueiro, submetidas à diferentes épocas de poda de frutificação. O experimento foi realizado na Fazenda Experimental Lageado, da Faculdade de Ciências Agronômicas da UNESP de Botucatu/SP, localizada nas seguintes coordenadas geográficas: 22° 51‟ 55” S e 48° 26‟ 22” O e a 810 m de altitude, onde foram avaliados pessegueiros com 2 anos de idade, cultivados no espaçamento de 6,0 x 4,0 m. O delineamento foi em parcelas subdivididas com 4 blocos, onde as parcelas corresponderam aos tratamentos cultivares (Douradão, BRS Kampai e BRS Rubimel) e as subparcelas às épocas de poda (maio, junho, julho e agosto). Foram empregadas 10 plantas por parcela experimental, onde as 4 centrais foram consideradas úteis e as demais serviram como bordadura. As épocas de poda em junho e julho apresentaram os melhores resultados para porcentagem de fixação de frutos, com melhor resultado para „BRS Rubimel‟ podado em junho, com 44,96 %. A cultivar BRS Rubimel podada em julho, obteve a maior produção, 18,70 kg planta-1. A poda realizada em maio antecipou a colheita da cultivar BRS Rubimel em 13 dias, e, a poda... / The peach tree (Prunus persica L. Bastch) is a temperate zone fruit, belonging to the family Rosaceae. Is a plant of Chinese origin, being now cultivated in many countries, including in subtropical zone. Stand out as major world producers of peach China, USA, Italy and Spain. The peach tree, as others fruits, require cultural practices such as pruning and using techniques to break dormancy in cultivars in subtropical regions, since these regions, the peach tree not has its demands in cold fully satisfied. In this context, the present study aimed to evaluate the agronomic performance and fruit quality of three cultivars, submitted to different pruning times production. The experiment was conducted at the Experimental Farm Lageado of Faculty of Agricultural Sciences of UNESP at Botucatu/SP, located at the following coordinates: 22° 51‟ 55” S e 48° 26‟ 22” O e a 810 m height, where peach trees were evaluated with 2 years old, grown at a spacing of 6.0 x 4.0 meters. The experimental design was a split plot design with four blocks, where the plots corresponded to treatments cultivars (Douradão, BRS Kampai and BRS Rubimel) and subplots to pruning times (May, June, July and August). Were used 10 plants per plot, where the 4 central were considered useful and others served as margin. The pruning times in June and July showed the best results for percentage fruit set, with best results for „BRS Rubimel‟ pruned in June, with 44,96 %. The cultivar BRS Rubimel pruned in July, had the highest production, 18,7 kg plant-1. The pruning in may anticipated harvest cultivar BRS Rubimel in 13 days, and pruning carried out in july and August, provided a late harvest for cultivars Douradão and BRS Kampai for the state of São Paulo. The cultivar BRS Rubimel presented the highest values of average mass, diameter and lengh of th... (Complete abstract click electronic access below)
69

Época e técnica de poda verde de pessegueiro na obtenção dos frutos de qualidade

Dotto, Marcelo 28 February 2013 (has links)
Um dos aspectos que devem ser considerados no mercado de frutas frescas de pessegueiro é a qualidade de seus frutos. Considera-se a aparência como fator importante, sendo a coloração da epiderme relevante, pois se associa com a maturação e o sabor dos frutos. Uma das técnicas de manejo que visam melhorar a qualidade dos frutos é a poda verde, que tem como intuito principal de aumentar a penetração da luz no interior da copa e consequentemente favorecer a pigmentação, bem como, melhorar o sabor dos frutos. Porém, esta técnica pode apresentar resultados variáveis, de acordo com a época e a forma em que a mesma é realizada. O objetivo deste trabalho foi de determinar o período e a forma de execução da poda verde para melhorar a qualidade dos frutos de pessegueiros. O trabalho foi conduzido em pomar comercial no município de Dois Vizinhos (PR), nos ciclos produtivos 2009/2010,2010/2011 e 2011/2012. Foi utilizados pêssegos dos cultivares Charme e Maciel. Foi utilizado delineamento experimental inteiramente casualizados, em esquema fatorial 3 x 3 (época da poda verde x técnica de manejo da poda verde), com 4 repetições, constituindo-se cada parcela de 2 plantas. As épocas de realização da poda verde foram na terceira, quarta e quinta semanas antes da colheita. As técnicas de manejo foram primeiro, baseadas na retirada dos ramos ladrões no interior e na base dos ramos, ramos quebrados e mal posicionados e, segundo no dobramento destes, permanecendo-os ligados a planta. A campo foi avaliado a capacidade produtiva das plantas e análises fisiológicas nos ciclos 2010/2011 e 2011/2012, e em laboratório foram analisadas as características físico-química e bioquímica dos frutos. Conclui se ao final deste trabalho que o uso da poda verde em plantas de pessegueiro Charme e Maciel a cinco e quatro semanas antes da colheita, com a técnica de corte e de dobramento dos ramos proporcionou melhorias na qualidade de seus frutos. / One of the aspects that it should be considered in the fresh fruit market peach is the fruit quality. The visual aspect is the most important factor, it being the skin color relevant because it is associated with the fruit maturation and flavor. One of cultural techniques to improve the fruit quality is summer pruning, which has as main purpose to increase light penetration within the canopy tree and consequently it to promote the pigmentation, as well as improvements in the fruit flavor. However, this technique can to present results variable according to the time and manner in which it was realized. The aim of this work was evaluate the time and management type for summer pruning to obtain peach quality. The work was carried out at commercial orchard from Dois Vizinhos city, Paraná State, Brazil, in 2009/2010, 2010/2011 and 2011/2012 cycle. It was used Charme and Maciel peach varieties. The experimental design was completely randomized, in factorial 3. x 3 (summer pruning time x summer pruning management type), with 4 replications of two plants by plot. The summer pruning time were in the third, fourth and fifth week before harvest. First the cultural practices were realized removal vigorous vertical shoot inside and in the base of crown, break shoots and bad shoots position in the tree. The second in the bending shoots in the tree. The yield and physiology characteristics tree on orchard in 2010/2011 and 2011/2012 cycle and fruit physical-chemical- biochemistry variables were evaluated on Plant Physiology Laboratory. It was concluded that the summer pruning use in Charme and Maciel peach tree during four and five weeks before harvest, with the pruning and beding shoot increased the fruit quality.
70

Época e técnica de poda verde de pessegueiro na obtenção dos frutos de qualidade

Dotto, Marcelo 28 February 2013 (has links)
Um dos aspectos que devem ser considerados no mercado de frutas frescas de pessegueiro é a qualidade de seus frutos. Considera-se a aparência como fator importante, sendo a coloração da epiderme relevante, pois se associa com a maturação e o sabor dos frutos. Uma das técnicas de manejo que visam melhorar a qualidade dos frutos é a poda verde, que tem como intuito principal de aumentar a penetração da luz no interior da copa e consequentemente favorecer a pigmentação, bem como, melhorar o sabor dos frutos. Porém, esta técnica pode apresentar resultados variáveis, de acordo com a época e a forma em que a mesma é realizada. O objetivo deste trabalho foi de determinar o período e a forma de execução da poda verde para melhorar a qualidade dos frutos de pessegueiros. O trabalho foi conduzido em pomar comercial no município de Dois Vizinhos (PR), nos ciclos produtivos 2009/2010,2010/2011 e 2011/2012. Foi utilizados pêssegos dos cultivares Charme e Maciel. Foi utilizado delineamento experimental inteiramente casualizados, em esquema fatorial 3 x 3 (época da poda verde x técnica de manejo da poda verde), com 4 repetições, constituindo-se cada parcela de 2 plantas. As épocas de realização da poda verde foram na terceira, quarta e quinta semanas antes da colheita. As técnicas de manejo foram primeiro, baseadas na retirada dos ramos ladrões no interior e na base dos ramos, ramos quebrados e mal posicionados e, segundo no dobramento destes, permanecendo-os ligados a planta. A campo foi avaliado a capacidade produtiva das plantas e análises fisiológicas nos ciclos 2010/2011 e 2011/2012, e em laboratório foram analisadas as características físico-química e bioquímica dos frutos. Conclui se ao final deste trabalho que o uso da poda verde em plantas de pessegueiro Charme e Maciel a cinco e quatro semanas antes da colheita, com a técnica de corte e de dobramento dos ramos proporcionou melhorias na qualidade de seus frutos. / One of the aspects that it should be considered in the fresh fruit market peach is the fruit quality. The visual aspect is the most important factor, it being the skin color relevant because it is associated with the fruit maturation and flavor. One of cultural techniques to improve the fruit quality is summer pruning, which has as main purpose to increase light penetration within the canopy tree and consequently it to promote the pigmentation, as well as improvements in the fruit flavor. However, this technique can to present results variable according to the time and manner in which it was realized. The aim of this work was evaluate the time and management type for summer pruning to obtain peach quality. The work was carried out at commercial orchard from Dois Vizinhos city, Paraná State, Brazil, in 2009/2010, 2010/2011 and 2011/2012 cycle. It was used Charme and Maciel peach varieties. The experimental design was completely randomized, in factorial 3. x 3 (summer pruning time x summer pruning management type), with 4 replications of two plants by plot. The summer pruning time were in the third, fourth and fifth week before harvest. First the cultural practices were realized removal vigorous vertical shoot inside and in the base of crown, break shoots and bad shoots position in the tree. The second in the bending shoots in the tree. The yield and physiology characteristics tree on orchard in 2010/2011 and 2011/2012 cycle and fruit physical-chemical- biochemistry variables were evaluated on Plant Physiology Laboratory. It was concluded that the summer pruning use in Charme and Maciel peach tree during four and five weeks before harvest, with the pruning and beding shoot increased the fruit quality.

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