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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.
1

Produção de alface crespa, acúmulo de nitrato na planta e lixiviação do íon no solo em função de adubação nitrogenada

Sylvestre, Thiago de Barros [UNESP] 26 February 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-26Bitstream added on 2014-06-13T20:10:47Z : No. of bitstreams: 1 sylvestre_tb_me_jabo.pdf: 284467 bytes, checksum: df37a241bef4f91a93a3be9eaacea899 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Conduziram-se dois experimentos em Latossolo Vermelho visando a avaliar o efeito da adubação nitrogenada em cobertura, na produção, no acúmulo de nitrato da parte aérea de alface-crespa, cv. Vanda, e na mobilidade do íon no solo, em duas épocas do ano (verão-outono e inverno). Nos dois experimentos, foi empregado delineamento experimental em blocos ao acaso, com sete tratamentos (doses de nitrogênio em cobertura) e cinco repetições. As doses foram 0; 30; 60; 90; 120; 150 e 180 kg ha-1 de N (ureia), parceladas em três aplicações, aos oito (20% da dose), 16 (40% da dose) e 24 (40% da dose) dias após o transplantio. A colheita foi feita aos 34 e aos 42 dias após o transplantio, nos experimentos de verão-outono e inverno, respectivamente. Na matéria seca, foram determinados N orgânico + N-NH4 + (NOA) e N-NO3 -. Após a colheita, foi feita amostragem de solo, parcela por parcela, nas profundidades de 0 a 20; 20 a 40 e 40 a 60 cm para avaliação de N-mineral (N-NH4 + e N-NO3 -). O melhor aproveitamento do adubo nitrogenado aplicado em cobertura no cultivo da alface-crespa é obtido com até 60 kg ha-1 de N, e a melhor combinação de produtividade e qualidade é também obtida com esta dose. Doses de até 180 kg ha-1 de N não resultam em concentrações de NO3 - em alface crespa, cv. Vanda, acima do limite tolerável para consumo, mas aumentam a quantidade de N-NO3 - perdida por lixiviação, avaliada até 60 cm de profundidade / Two experiments were carried out in an Oxisol to evaluate the effect of nitrogen topdressing in the yield, nitrate accumulation in the shoots of lettuce, cv. Vanda, and nitrate leaching in soil, in two seasons (summer-autumn and winter). In both experiments it was used a randomized block design with seven treatments (nitrogen topdressing rates) and five replicates. Nitrogen rates were 0, 30, 60, 90, 120, 150 and 180 kg ha-1 N (urea), applied at eight (20%), 16 (40%) and 24 (40%) days after transplanting. Plants were harvested at 34 and 42 days after transplanting, in summerautumn and winter, respectively. Organic-N+NH4 +-N and NO3 --N concentrations were determined in dry matter. After the harvest soil samples were collected at 0-20, 20-40 and 40-60 cm depth for NH4 +-N and NO3 --N determinations. Better use of nitrogen topdressing for lettuce growth is obtained with 60 kg ha-1 N and the best combination for productivity and quality is also achieved with this rate. Nitrogen rates up to 180 kg ha-1 N do not result in NO3 - concentrations in lettuce, cv. Vanda, above the recommended levels for consumption, but increase the amount of NO3 --N lost by leaching up to 60 cm depth
2

Rose-scented geranium (Pelargonium spp.) herbage yield, essential oil yield and composition as influenced by nitrogen nutrition and liming

Araya, Hintsa Tesfamicael 31 May 2012 (has links)
Rose-scented geranium (Pelargonium capitatum x P. radens) belongs to the family Geraniaceae and it is a multi-harvest, high value, commercially important essential oil yielding aromatic plant. The essential oil extracted from the herbage of the plant is widely used in the fragrance and cosmetics industry and scenting of soaps. The essential oil is extracted by steam distillation. South Africa is now producing significant quantities of geranium oil. However, previous experience by this research group showed that seedlings often take long to establish, resulting in high death rates and sometimes poor growth after establishment. Stunted growth and yellowing of leaves was also observed in some cases. Poor vegetative growth causes low herbage yield and, consequently, low total essential oil production per hectare. Poor growth is believed to be due to a combination of factors, including nutrient deficiencies and acidic soil conditions and has not been studied under South Africa condition. Production of the crop is also reported to respond differently to rate and source of nutrition in various agro-ecological regions of the world. Therefore, field trials were conducted at the Hatfield Experimental Farm, University of Pretoria, in order to investigate how the plant responds to agronomic practices, such as source and amount of nitrogen, time of N fertilizer application, season of N fertilization and liming. Response of rose-scented geranium to source and amount of N showed that, at the first harvest (summer/autumn), there was no significant effect of conventional N on fresh herbage and oil yield, probably due to leaching of N by rainfall. However, organic N at 100 kg•ha-1 increased fresh herbage and oil yields by 58% and 48% over the control, respectively. In the second harvest (spring/summer), fresh herbage yield increased by 46% (conventional N) and 60% (organic N) at 100 kg•ha-1 compared to the control. Compared to the control, 100 kg•ha-1 conventional and organic N also increased essential oil yields by 94% and 129%, respectively. For both N sources nitrogen use efficiency (NUE) and LAI decreased with an increase in N level, and organic N gave highest essential oil production efficiency and LAI. Essential oil content (% fresh mass basis) also varied between the harvests, being greater in the second harvest (September to December 2005; spring/summer) than the first harvest (February to May 2005; summer/autumn). This was due to environmental variations that occurred between the harvesting periods. N level and source were found to have no noticeable effect on essential oil composition. This study revealed that rose-scented geranium produced higher fresh herbage and essential oil yield when organic fertilizer was used as a source of N. Nitrogen management in terms of rate and time of application is important in rose-scented geranium production. Delaying nitrogen topdressing (conventional N in the form of LAN; N 28%) after harvest to between the 7th and 9th week after cut back, was found to have a significant positive effect on biomass and essential oil production. Essential oil content of the plant did not show any response to a delay in nitrogen topdressing. A delay in nitrogen topdressing, in the first re-growth resulted into a lower citronellol to geraniol (C:G) ratio, which favour essential oil quality of the crop. Generally, the characteristics of the essential oil were within the internationally acceptable range for rose-scented geranium essential oil. In addition, production of rose-scented geranium during cooler periods is not advisable due to limited biomass production which might encourage leaching of nitrogen. The net benefits from N application is dependent on the growing period and in the present study spring and summer were more beneficial than winter and autumn. Organic N at 100 kg•ha-1•year-1 increased herbage and essential oil yield of the crop in spring and summer but further increases in organic or conventional N levels had no significant effect. N application either in winter or autumn did not improve production of the crop. Application of more N than what is required for optimum growth of the plant had no positive effect on essential oil production. Application of organic N also resulted in higher N use efficiency than conventional N. The essential oil contents (% fresh mass basis) achieved in the present study generally fell within the range of 0.04 to 0.2%. Citronellol and geraniol concentration (%), were at peak in spring season followed by summer and autumn and lowest in winter. The ratio between these two components (C:G ratio) is also used as an indicator of rose-scented geranium essential oil quality and most desirable (low C:G ratio) essential oil was attained in spring, summer and autumn harvesting seasons and least desirable oil was attained in winter. The relationship between SPAD-502 chlorophyll meter readings (SPAD units) and leaf N content (% dry weight basis) was a quadratic function. SPAD-502 chlorophyll meter readings (SPAD units) matched well with that of leaf N concentration data of rose-scented geranium. Regardless of the factors that affect the readings, this instrument can be used as an indicator of leaf N status of rose-scented geranium. Soil pH above 5.5 and soil base saturation above 55% increased fresh herbage and essential oil yield (per ha), which corresponded in this case with 2 to 6 t•ha-1 of lime application. Oil content (%) was not significantly affected by application of lime. Therefore, optimum growth of rose-scented geranium can be achieved by application of lime when plants are grown on acidic soils, but without any effect on oil content and essential oil composition. It can be concluded that N rate, source and season of production and soil pH should be considered to ensure optimal rose-scented geranium production. / Thesis (PhD)--University of Pretoria, 2012. / Plant Production and Soil Science / PhD / Unrestricted
3

Produção de alface crespa, acúmulo de nitrato na planta e lixiviação do íon no solo em função de adubação nitrogenada /

Sylvestre, Thiago de Barros. January 2010 (has links)
Resumo: Conduziram-se dois experimentos em Latossolo Vermelho visando a avaliar o efeito da adubação nitrogenada em cobertura, na produção, no acúmulo de nitrato da parte aérea de alface-crespa, cv. Vanda, e na mobilidade do íon no solo, em duas épocas do ano (verão-outono e inverno). Nos dois experimentos, foi empregado delineamento experimental em blocos ao acaso, com sete tratamentos (doses de nitrogênio em cobertura) e cinco repetições. As doses foram 0; 30; 60; 90; 120; 150 e 180 kg ha-1 de N (ureia), parceladas em três aplicações, aos oito (20% da dose), 16 (40% da dose) e 24 (40% da dose) dias após o transplantio. A colheita foi feita aos 34 e aos 42 dias após o transplantio, nos experimentos de verão-outono e inverno, respectivamente. Na matéria seca, foram determinados N orgânico + N-NH4 + (NOA) e N-NO3 -. Após a colheita, foi feita amostragem de solo, parcela por parcela, nas profundidades de 0 a 20; 20 a 40 e 40 a 60 cm para avaliação de N-mineral (N-NH4 + e N-NO3 -). O melhor aproveitamento do adubo nitrogenado aplicado em cobertura no cultivo da alface-crespa é obtido com até 60 kg ha-1 de N, e a melhor combinação de produtividade e qualidade é também obtida com esta dose. Doses de até 180 kg ha-1 de N não resultam em concentrações de NO3 - em alface crespa, cv. Vanda, acima do limite tolerável para consumo, mas aumentam a quantidade de N-NO3 - perdida por lixiviação, avaliada até 60 cm de profundidade / Abstract: Two experiments were carried out in an Oxisol to evaluate the effect of nitrogen topdressing in the yield, nitrate accumulation in the shoots of lettuce, cv. Vanda, and nitrate leaching in soil, in two seasons (summer-autumn and winter). In both experiments it was used a randomized block design with seven treatments (nitrogen topdressing rates) and five replicates. Nitrogen rates were 0, 30, 60, 90, 120, 150 and 180 kg ha-1 N (urea), applied at eight (20%), 16 (40%) and 24 (40%) days after transplanting. Plants were harvested at 34 and 42 days after transplanting, in summerautumn and winter, respectively. Organic-N+NH4 +-N and NO3 --N concentrations were determined in dry matter. After the harvest soil samples were collected at 0-20, 20-40 and 40-60 cm depth for NH4 +-N and NO3 --N determinations. Better use of nitrogen topdressing for lettuce growth is obtained with 60 kg ha-1 N and the best combination for productivity and quality is also achieved with this rate. Nitrogen rates up to 180 kg ha-1 N do not result in NO3 - concentrations in lettuce, cv. Vanda, above the recommended levels for consumption, but increase the amount of NO3 --N lost by leaching up to 60 cm depth / Orientadora: Mara Cristina Pessôa da Cruz / Coorientador: José Ricardo Mantovani / Banca: Manoel Evaristo Ferreira / Banca: Francisco Maximino Fernandes / Mestre
4

Doses de nitrogênio em cobertura no feijoeiro de inverno em sucessão a sistemas de cultivo com milho exclusivo e consorciado com braquiária e com crotalária / Topdressed nitrogen rates on winter common bean in sucession to crop systems with exclusive maize, intercropped with brachiaria and with crotalaria

Souza, Stefany Silva de [UNESP] 29 July 2016 (has links)
Submitted by STEFANY SILVA DE SOUZA null (stefany_souzakz@hotmail.com) on 2016-12-08T20:27:59Z No. of bitstreams: 1 Dissertação Stefany Souza.pdf: 871630 bytes, checksum: 2d9ee09b4965ac7906e1ffbde0303a84 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-12T12:59:58Z (GMT) No. of bitstreams: 1 souza_ss_me_jabo.pdf: 871630 bytes, checksum: 2d9ee09b4965ac7906e1ffbde0303a84 (MD5) / Made available in DSpace on 2016-12-12T12:59:58Z (GMT). No. of bitstreams: 1 souza_ss_me_jabo.pdf: 871630 bytes, checksum: 2d9ee09b4965ac7906e1ffbde0303a84 (MD5) Previous issue date: 2016-07-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo do trabalho foi avaliar a resposta do feijoeiro, conduzido em Jaboticabal (SP), às doses de nitrogênio aplicadas via adubação de cobertura, em sistema de plantio direto, após cultivo de milho exclusivo, consorciado com braquiária e com crotalária. A cultivar de feijoeiro utilizada foi a IAC Alvorada. O solo da área experimental é do tipo Latossolo Vermelho eutroférrico, de textura argilosa. O delineamento experimental utilizado foi o de blocos casualizados, no arranjo de parcelas subdivididas com quatro repetições. As parcelas consistiram de sistemas de cultivos de milho, sendo: exclusivo, em consórcio com braquiária (Urochloa ruziziensis) e com (Crotalaria spectabilis), precedentes à semeadura do feijão. As subparcelas foram constituídas por cinco doses de nitrogênio: 0, 50, 100, 150 e 200 kg ha-1, aplicadas na adubação de cobertura do feijoeiro em sistema plantio direto. Os consórcios de milho com braquiária e com crotalária, não reduziram a produtividade de grãos do milho, demonstrando a viabilidade destes sistemas de produção. O sistema de cultivo de milho consorciado com crotalária foi responsável por maior produção e acúmulo de nitrogênio da palhada. A adubação nitrogenada em cobertura influenciou positivamente a produtividade de grãos do feijoeiro em sucessão aos consórcios de milho com braquiária e com crotalária, apresentando crescimento linear com o fornecimento do nitrogênio. Para o sistema de cultivo de milho exclusivo, a adubação nitrogenada não influenciou a produtividade de grãos do feijoeiro subsequente. Quando o milho consorciado crotalária foi o cultivo antecedente, o teor de nitrogênio foliar do feijoeiro foi maior, sendo que esta variável aumentou com a elevação das doses de nitrogênio. O feijoeiro em sucessão ao milho consorciado com braquiária e com crotalária obteve a maior quantidade de grãos retidos na peneira maior ou igual a 12. / The objective of this study was to evaluate the comon bean response, conducted in Jaboticabal (SP), to the nitrogen rates applied by topdressing in sucession to exclusive maize, intercropped with brachiaria and crotalaria. The common bean cultivar used was the IAC Alvorada. The soil of experimental area was eutrophic red latosol type. The experimental design was randomized block in a split plot arrangement, with four replications. The plots consisted of maize cropping systems, as follows: exclusive, intercropped with brachiaria (Urochloa ruziziensis) and crotalaria (Crotalaria spectabilis), preceding the sowing of common bean. The subplots consisted of five nitrogen rates: 0, 50, 100, 150 and 200 kg ha-1, applied on common bean in no-tillage system. Maize intercropped with brachiaria and crotalaria didn’t reduce the maize grain yield, demonstrating the viability of this production system. The maize intercropped with crotalaria system was responsible for increased production and nitrogen accumulation of mulchin. The nitrogen tropdressing positively influenced the common bean grain yield in succession to maize intercropped with bhachiaria and crotalaria, showing linear growth with the supply of nitrogen. For the exclusive maize cropping system, nitrogen topdressing did not influence the subsequent bean grain yield. When the maize intercropped with crotalaria was the previous crop, leaf nitrogen content of the bean was higher, and this variable increased with increasing the nitrogen rates. The common bean in succession to maize intercropped with brachiaria and crotalaria had the highest amount of grain held in the largest or equal to 12 sieve.
5

Doses de nitrogênio em cobertura no feijoeiro de inverno em sucessão a sistemas de cultivo com milho exclusivo e consorciado com braquiária e com crotalária /

Souza, Stefany Silva de January 2016 (has links)
Orientador: Leandro Borges Lemos / Resumo: O objetivo do trabalho foi avaliar a resposta do feijoeiro, conduzido em Jaboticabal (SP), às doses de nitrogênio aplicadas via adubação de cobertura, em sistema de plantio direto, após cultivo de milho exclusivo, consorciado com braquiária e com crotalária. A cultivar de feijoeiro utilizada foi a IAC Alvorada. O solo da área experimental é do tipo Latossolo Vermelho eutroférrico, de textura argilosa. O delineamento experimental utilizado foi o de blocos casualizados, no arranjo de parcelas subdivididas com quatro repetições. As parcelas consistiram de sistemas de cultivos de milho, sendo: exclusivo, em consórcio com braquiária (Urochloa ruziziensis) e com (Crotalaria spectabilis), precedentes à semeadura do feijão. As subparcelas foram constituídas por cinco doses de nitrogênio: 0, 50, 100, 150 e 200 kg ha-1, aplicadas na adubação de cobertura do feijoeiro em sistema plantio direto. Os consórcios de milho com braquiária e com crotalária, não reduziram a produtividade de grãos do milho, demonstrando a viabilidade destes sistemas de produção. O sistema de cultivo de milho consorciado com crotalária foi responsável por maior produção e acúmulo de nitrogênio da palhada. A adubação nitrogenada em cobertura influenciou positivamente a produtividade de grãos do feijoeiro em sucessão aos consórcios de milho com braquiária e com crotalária, apresentando crescimento linear com o fornecimento do nitrogênio. Para o sistema de cultivo de milho exclusivo, a adubação nitrogenada não influe... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
6

EVALUATING SOIL PHYSICAL AND CHEMICAL PROPERTIES FOLLOWING ADDITION OF NON-COMPOSTED SPENT COFFEE AND TEA FOR ATHLETIC FIELDS

Zhou, Shuang 01 January 2017 (has links)
Physical and chemical properties of non-composted spent coffee (CF) and tea (T) suggest they may have applications as soil amendments for improving poor soils. Studies were conducted to determine 1) the effect of amendments on grass growth and soil properties, 2) the effect of incorporation versus surface application of amendments on soil properties, and 3) the effect of amendment application frequency on grass growth and soil properties. In the first study, amendments were mixed with sand and planted to bermudagrass. Treatments included CF, T, and peat moss (PM) mixed with sand, and 100% sand as a control. In the second study, amendments were topdressed onto a sand base with different timings. Pots were either aerified or not. Treatments included T, CF, PM, and a control. Nutrient contents and soil CEC and OM under CF and T treatments were equivalent to or greater than PM treatments. Tea showed comparable grass cover to the PM treatment, while CF showed an inhibitory effect to grass growth in the first year of the study. Aerification showed no benefit. Additionally, a field study was conducted to evaluate CF and T on surface hardness, VWC, and quality after trafficking. Differences were not observed among treatments.
7

Effects of Repeated Compost Topdressing Applications on Turfgrass Quality on Athletic Turf under Traffic

Munoz, Marcela Paz 29 July 2011 (has links)
No description available.

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