Orientador: Pedro Luís da Costa Aguiar Alves / Banca: Dagoberto Martins / Banca: Roberto Estêvão Bragion de Toledo / Banca: Maria Aparecida Pessoa da Cruz Centurion / Banca: Silvano Bianco / Resumo: Este trabalho teve como objetivo identificar os períodos de interferência das plantas daninhas no algodoeiro de fibra naturalmente colorida (BRS Safira e BRS Verde), e avaliar o efeito da competição das plantas daninhas na produtividade desta cultura. Dois experimentos foram instalados na área experimental da Embrapa Algodão em Missão Velha, CE, (7º42'07'' de latitude e 39º24'18'' de longitude, altitude de 360 m) na safra 2007/2008, utilizando-se o espaçamento de 1,00 x 0,20 m. Utilizou-se o delineamento experimental em blocos ao acaso, com quatro repetições, os tratamentos constaram de duas: modalidades de competição (convivência e controle de plantas daninhas) e períodos de interferência das plantas daninhas. Os períodos iniciais de controle ou de convivência após a emergência da cultura foram 0-20, 0-40, 0-60, 0-80 dias após a emergência (DAE) e 0-colheita (120 dias). Para determinação dos períodos de interferência, considerando-se perdas na produtividade de 2, 5 e 10%; foi realizada análise de regressão do modelo sigmoidal de Boltzmann, utilizando-se os dados de produtividade separadamente dentro de cada modalidade de competição. A comunidade infestante para ambas cultivares, foi composta por 21 espécies, destacando-se: Richardia grandiflora, Amaranthus deflexus, Eleusine indica, Merremia aegyptia, Eragrotis pilosa, Cenchrus echinatus e Waltheria indica. Observou-se para cultivar BRS Safira, que os períodos anteriores a interferência (PAI) foram, respectivamente, 8, 14 e 20 DAE, para perdas na produtividade de 2, 5 e 10%; e os períodos críticos de prevenção a interferências (PCPI), para esses mesmo níveis de perdas, foram respectivamente, 100, 82 e 60 dias. Para cultivar BRS Verde, os PAIs foram, respectivamente, 25, 31 e 35 DAE, para perdas de 2, 5 e 10%; e os PCPIs, para esses mesmo níveis de perdas, foram respectivamente ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to determine the late-season presence of weeds in reddish brown cotton and green cotton (cultivars BRS Safira and BRS Verde) and the critical times for removing weeds. And assess the effect of weeds competition in the crop productivity. Two experiments were carried out in the area of Embrapa in Missão Mission-CE, Brazil, the region Cariri, located at 7º42'07'' S latitude and 39º24'18'' WGr. longitude, altitude of 360 m, in the 2007/2008 season. The treatments consisted of two control groups: weed-free crop during the initial period after crop emergency, and crop kept with weeds during initial period after plant emergency. Both consisted, 0, 20, 40, 60, 80 e 120 days after crop emergency (DAE). Regression analysis was performed of the model of sigmoidal Boltzmann, using data from productivity separately within each type of competition, to identify the critical periods of competition considering 2, 5 and 10% reduction in yield. The community of weeds, for both cultivars, was composed by 21 predominant species, standing out among them: Richardia grandiflora, Amaranthus deflexus, Eleusine indica, Merremia aegyptia, Eragrotis pilosa, Cenchrus echinatus and Waltheria indica. For cultivar BRS Safira, considering 2, 5 and 10% reduction in yield fiber as acceptable, the period preceding the interference was, respectively, 8, 14 and 20 (DAE). And the critical periods of prevention to interferences, for those same levels of losses, they were respectively, 100, 82 and 60 (DAE). For cultivar BRS Verde, considering 2, 5 and 10% reduction in yield fiber as acceptable, the period preceding the interference was, respectively, 25, 31 and 35 (DAE). And the critical periods of prevention to interferences, for those same levels of losses, they were respectively, 67, 43 and 22 (DAE). The BRS Safira cultivar was more susceptible to interference of the weed community that BRS Verde. / Doutor

Sun protection has gained worldwide attention because repetitive overexposure to ultraviolet radiation can result in harmful effects on human skin, including sunburn, premature skin ageing, and in the worst case, skin cancer (Eckhardt and Rohwer, 2000; Sengupta and Blain, 2001). The diminishing stratospheric ozone layer, due to environmental degradation in the past few decades, combined with the modern outdoor-oriented lifestyles, are leading to unexpected levels of skin cancer (Davis, Capjack, Kerr, and Fedosejevs, 1997). Wearing Ultraviolet protective clothing is a simple way of practicing sun safety; however, regular cotton generally has very low ultraviolet protection and it is one of the most environmentally damaging crops despite of it is commonly used to make summer clothing. With the increased interest of public awareness related to sustainability and environmental issues, naturally colored cotton was recommended as it provides better ultraviolet protection than regular cotton. In addition, the production of naturally colored cotton is more environmentally friendly than regular cotton. Although several studies have been conducted on the UVR protection of naturally colored cotton, many questions regarding the factors that influence the UVR protection of fabrics remain unanswered. The primary purpose of the study was to examine the effects of perspiration application, weathering exposures, washing action of automatic home clothes washers, and repeated laundering on the UVR protection of a NC lightweight cotton fabric. In addition, five fabric property changes in the test specimen after the treatments of perspiration, weathering exposure, washing action, and repeated laundering (i.e., fabric count change, thickness change, weight change, color change and dimensional change) were included in this study to serve as secondary dependent variables to examine if the four treatment factors (i.e., perspiration application, weathering exposures, washing action of automatic home clothes washers, and repeated laundering) will cause changes in these five fabric properties, and if these changes will lead to changes of UVR protection of NC lightweight cotton fabric. Based on the purpose and objectives of the study, a split-plot repeated measures experimental design was used for the current study. In this study, the whole plot treatment was the weathering exposure, which contained three levels (i.e., semi-tropical climate without water spray, semi-arid climate, and standard conditioning), and the split plot treatments were the combinations of two treatment factors. In order to understand the effects of repeated laundering on the UVR protection and the five fabric properties, except for the control group, all test specimens were laundered after being treated with the three treatment factors (i.e., perspiration, weathering exposure, and washing action), and this process was repeated 15 times. The UVR protection (i.e., express in UPF value change in current study) and the five fabric properties of these treated test specimens were measured before laundering, and after each laundering cycle. The results of UPF value change showed that test specimens treated with perspiration had a lower change in UPF value than the specimens without treatment. The test specimens exposed to Florida condition had the most UPF value change, followed by Arizona and Standard textile testing conditions. A significant difference also found in test specimens that laundered in a traditional washer after ninth cycle and the UPF value decreased as the number of laundering cycle increased. However, test specimens that laundered in a front-loading HE washer showed no significant UPF value change. For the five fabric properties that listed in secondary objective, all four treatments significantly influenced fabric count, fabric thickness and fabric weight. However, perspiration treatment had no significant effect on the dimensional change in warp direction of test specimens, and washing action had no significant effect on the dimensional change in filling direction of the test specimen as well as both Delta E and Delta L of color change. For testing the relationship between the changes of the five fabric properties and UPF value change, Delta E and Delta L of color change had the highest correlation coefficient with UPF value change. Therefore, it is possible that the changes of these two properties caused by the four treatments and lead to the UPF value change. Future research is needed to confirm this relationship. In conclusion, of perspiration application, weathering exposures, washing action of automatic home clothes washers, and repeated laundering do have influence on the ultraviolet protection of the naturally colored cotton. The color change of the test specimens caused by these four treatments possible lead to the change of the ultraviolet protection of the test specimens. More studies are needed to confirm this relationship. / Ph. D.

Made available in DSpace on 2014-06-11T19:33:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-09Bitstream added on 2014-06-13T19:44:35Z : No. of bitstreams: 1 cardoso_gd_dr_jabo.pdf: 279202 bytes, checksum: 9e92c9473063ab02a0b348aed72354f8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho teve como objetivo identificar os períodos de interferência das plantas daninhas no algodoeiro de fibra naturalmente colorida (BRS Safira e BRS Verde), e avaliar o efeito da competição das plantas daninhas na produtividade desta cultura. Dois experimentos foram instalados na área experimental da Embrapa Algodão em Missão Velha, CE, (7º42’07’’ de latitude e 39º24’18’’ de longitude, altitude de 360 m) na safra 2007/2008, utilizando-se o espaçamento de 1,00 x 0,20 m. Utilizou-se o delineamento experimental em blocos ao acaso, com quatro repetições, os tratamentos constaram de duas: modalidades de competição (convivência e controle de plantas daninhas) e períodos de interferência das plantas daninhas. Os períodos iniciais de controle ou de convivência após a emergência da cultura foram 0-20, 0-40, 0-60, 0-80 dias após a emergência (DAE) e 0-colheita (120 dias). Para determinação dos períodos de interferência, considerando-se perdas na produtividade de 2, 5 e 10%; foi realizada análise de regressão do modelo sigmoidal de Boltzmann, utilizando-se os dados de produtividade separadamente dentro de cada modalidade de competição. A comunidade infestante para ambas cultivares, foi composta por 21 espécies, destacando-se: Richardia grandiflora, Amaranthus deflexus, Eleusine indica, Merremia aegyptia, Eragrotis pilosa, Cenchrus echinatus e Waltheria indica. Observou-se para cultivar BRS Safira, que os períodos anteriores a interferência (PAI) foram, respectivamente, 8, 14 e 20 DAE, para perdas na produtividade de 2, 5 e 10%; e os períodos críticos de prevenção a interferências (PCPI), para esses mesmo níveis de perdas, foram respectivamente, 100, 82 e 60 dias. Para cultivar BRS Verde, os PAIs foram, respectivamente, 25, 31 e 35 DAE, para perdas de 2, 5 e 10%; e os PCPIs, para esses mesmo níveis de perdas, foram respectivamente... / This study aimed to determine the late-season presence of weeds in reddish brown cotton and green cotton (cultivars BRS Safira and BRS Verde) and the critical times for removing weeds. And assess the effect of weeds competition in the crop productivity. Two experiments were carried out in the area of Embrapa in Missão Mission-CE, Brazil, the region Cariri, located at 7º42’07’’ S latitude and 39º24’18’’ WGr. longitude, altitude of 360 m, in the 2007/2008 season. The treatments consisted of two control groups: weed-free crop during the initial period after crop emergency, and crop kept with weeds during initial period after plant emergency. Both consisted, 0, 20, 40, 60, 80 e 120 days after crop emergency (DAE). Regression analysis was performed of the model of sigmoidal Boltzmann, using data from productivity separately within each type of competition, to identify the critical periods of competition considering 2, 5 and 10% reduction in yield. The community of weeds, for both cultivars, was composed by 21 predominant species, standing out among them: Richardia grandiflora, Amaranthus deflexus, Eleusine indica, Merremia aegyptia, Eragrotis pilosa, Cenchrus echinatus and Waltheria indica. For cultivar BRS Safira, considering 2, 5 and 10% reduction in yield fiber as acceptable, the period preceding the interference was, respectively, 8, 14 and 20 (DAE). And the critical periods of prevention to interferences, for those same levels of losses, they were respectively, 100, 82 and 60 (DAE). For cultivar BRS Verde, considering 2, 5 and 10% reduction in yield fiber as acceptable, the period preceding the interference was, respectively, 25, 31 and 35 (DAE). And the critical periods of prevention to interferences, for those same levels of losses, they were respectively, 67, 43 and 22 (DAE). The BRS Safira cultivar was more susceptible to interference of the weed community that BRS Verde.