• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • Tagged with
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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

Adubação nitrogenada e doses do herbicida glyphosate como regulador de crescimento em grama esmeralda /

Gazola, Raíssa Pereira Dinalli January 2017 (has links)
Orientador: Salatiér Buzetti / Resumo: A adubação nitrogenada proporciona, além da nutrição, a manutenção da coloração verde intensa em gramados ornamentais, imprescindível do ponto de vista estético. Mas, o nitrogênio (N) aumenta o crescimento da parte aérea e, assim, maior será frequência de cortes, principal fator do custo de manutenção em gramados. Neste contexto, objetivou-se avaliar a adubação nitrogenada (via solo com ou sem via foliar), e o uso de doses do herbicida glyphosate em grama esmeralda (Zoysia japonica Steud.), visando reduzir o crescimento do gramado, bem como manter sua qualidade visual (verde intenso) e nutricional. O experimento foi conduzido na Fazenda de Ensino, Pesquisa e Extensão da UNESP, Campus de Ilha Solteira/SP, de agosto de 2014 a fevereiro de 2017, em um ARGISSOLO VERMELHO Eutrófico areno-argiloso. Utilizou-se o delineamento em blocos casualizados com 20 tratamentos dispostos em fatorial 5 x 4, com quatro repetições, em 10 m2 por parcela. Os tratamentos foram: testemunha (sem N); 15 g m-2 de N aplicado via solo e sem N via foliar; 30 g m-2 de N aplicado via solo e sem N via foliar; 15 g m-2 de N aplicado via solo e com N via foliar (1% de ureia) e 30 g m-2 de N aplicado via solo e com N via foliar (1% de ureia), combinados com quatro doses de glyphosate (0, 200, 400 e 600 g ha-1 do ingrediente ativo - i.a.). As doses de N via solo foram parceladas em cinco aplicações durante o ano e, portanto, corresponderam a 3 e 6 g m-2 de N a cada aplicação, respectivamente, para as doses de 15 ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Nitrogen fertilization provides, in addition to nutrition, the maintenance of intense green color in ornamental turfgrasses, necessary underesthetic view point. However, nitrogen (N) increases the shoots growth and, thus, the frequency of cuts, the main factor in the cost of turfgrasses maintenance. In this context, this study aimed to evaluate nitrogen fertilization (via soil and/or foliar) and the use of rates of glyphosate in zoysiagrass (Zoysia japonica Steud.) to reduce growth and maintain the visual quality (intense green) and good nutritional quality. The research was conducted at the Experimental Station of UNESP, Ilha Solteira/SP, from August/2014 to February/2017, on an Ultisol. It was used a randomized block design with 20 treatments arranged in a factorial scheme 5 x 4 with four replications and 10 m2 per plot. The treatments was: control (without N), 15 g m-2 of N in the soil without application of foliar N; 30 g m-2 of N in the soil without application of foliar N; 15 g m-2 in the soil with foliar application of N (1% urea) and 30 g m-2 of N in the soil with foliar application of N (1% urea) combined with four rates of glyphosate (0, 200, 400 and 600 g ha-1 active ingredient (a.i.)). N rates in the soil were split in five times during the year and, therefore, corresponded to 3 and 6 g m-2 of N at each application, respectively, for the rates of 15 and 30 g m-2 of N. Were evaluated: the chemical attributes of the soil, height and dry matter of leaves, leaf area, ... (Complete abstract click electronic access below) / Doutor
2

Adubação nitrogenada e doses do herbicida glyphosate como regulador de crescimento em grama esmeralda / Nitrogen fertilization and glyphosate rates as growth regulators in zoysiagrass

Gazola, Raíssa Pereira Dinalli [UNESP] 31 March 2017 (has links)
Submitted by Raíssa Pereira Dinalli null (raissa_dinalli@terra.com.br ) on 2017-05-09T18:03:41Z No. of bitstreams: 1 gazola_rpd_dr_ilha.pdf: 2690397 bytes, checksum: a283bcf04932e50d9083b9864d363052 (MD5) / Rejected by Luiz Galeffi (luizgaleffi@gmail.com), reason: Solicitamos que realize uma nova submissão seguindo a orientação abaixo: Incluir o número do processo de financiamento nos agradecimentos da dissertação/tese. Corrija esta informação e realize uma nova submissão com o arquivo correto. Agradecemos a compreensão. on 2017-05-10T18:32:39Z (GMT) / Submitted by Raíssa Pereira Dinalli null (raissa_dinalli@terra.com.br ) on 2017-05-10T18:58:01Z No. of bitstreams: 1 gazola_rpd_dr_ilha1.pdf: 2690242 bytes, checksum: f9ff56aed030d09608bd93914ed45f22 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-10T19:12:26Z (GMT) No. of bitstreams: 1 gazola_rpd_dr_ilha.pdf: 2690242 bytes, checksum: f9ff56aed030d09608bd93914ed45f22 (MD5) / Made available in DSpace on 2017-05-10T19:12:26Z (GMT). No. of bitstreams: 1 gazola_rpd_dr_ilha.pdf: 2690242 bytes, checksum: f9ff56aed030d09608bd93914ed45f22 (MD5) Previous issue date: 2017-03-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A adubação nitrogenada proporciona, além da nutrição, a manutenção da coloração verde intensa em gramados ornamentais, imprescindível do ponto de vista estético. Mas, o nitrogênio (N) aumenta o crescimento da parte aérea e, assim, maior será frequência de cortes, principal fator do custo de manutenção em gramados. Neste contexto, objetivou-se avaliar a adubação nitrogenada (via solo com ou sem via foliar), e o uso de doses do herbicida glyphosate em grama esmeralda (Zoysia japonica Steud.), visando reduzir o crescimento do gramado, bem como manter sua qualidade visual (verde intenso) e nutricional. O experimento foi conduzido na Fazenda de Ensino, Pesquisa e Extensão da UNESP, Campus de Ilha Solteira/SP, de agosto de 2014 a fevereiro de 2017, em um ARGISSOLO VERMELHO Eutrófico areno-argiloso. Utilizou-se o delineamento em blocos casualizados com 20 tratamentos dispostos em fatorial 5 x 4, com quatro repetições, em 10 m2 por parcela. Os tratamentos foram: testemunha (sem N); 15 g m-2 de N aplicado via solo e sem N via foliar; 30 g m-2 de N aplicado via solo e sem N via foliar; 15 g m-2 de N aplicado via solo e com N via foliar (1% de ureia) e 30 g m-2 de N aplicado via solo e com N via foliar (1% de ureia), combinados com quatro doses de glyphosate (0, 200, 400 e 600 g ha-1 do ingrediente ativo - i.a.). As doses de N via solo foram parceladas em cinco aplicações durante o ano e, portanto, corresponderam a 3 e 6 g m-2 de N a cada aplicação, respectivamente, para as doses de 15 e 30 g m-2 de N. Foram avaliados: os atributos químicos do solo, a altura e a matéria seca das folhas, a área foliar, o índice de clorofila foliar (ICF), os teores de clorofila a e b, a análise por imagem digital e a porcentagem de fitointoxicação da parte aérea, além da determinação da ocorrência de plantas daninhas e do número de inflorescências, bem como a concentração, o acúmulo de macro e micronutrientes nas folhas do gramado e as relações log-isométricas no balanço de macronutrientes nas folhas e do balanço catiônico no solo (relação log isométrica - ilr). Foi realizada também a avaliação do sistema radicular (matéria seca e concentração de macro e micronutrientes nas raízes + rizomas). Foram realizadas dez avaliações (cortes), após as quais eram aplicados os tratamentos. Os teores de K no solo aumentaram com as doses de glyphosate. Houve maior matéria seca das raízes + rizomas quando da adubação com N e diminuição desses valores com as doses de herbicida. A maior quantidade de N via solo, com ou sem N via foliar, resultou em maior crescimento da grama esmeralda, sendo o mesmo reduzido com a dose de 600 g ha-1 do i.a. do glyphosate. Todavia, esta dose do herbicida não foi adequada do ponto de vista estético – coloração verde. Concluiu-se que a adubação com 15 g m-2 de N via solo e sem N via foliar, parcelada em cinco aplicações ao ano, propiciou qualidade visual e nutricional do gramado, e que o glyphosate na dose de 400 g ha-1 do i.a. foi eficiente na redução do crescimento da grama esmeralda, sem prejuízo na sua coloração verde e também propiciou menor acúmulo de macronutrientes pelas folhas, reduzindo a necessidade de reposição pela adubação. / Nitrogen fertilization provides, in addition to nutrition, the maintenance of intense green color in ornamental turfgrasses, necessary underesthetic view point. However, nitrogen (N) increases the shoots growth and, thus, the frequency of cuts, the main factor in the cost of turfgrasses maintenance. In this context, this study aimed to evaluate nitrogen fertilization (via soil and/or foliar) and the use of rates of glyphosate in zoysiagrass (Zoysia japonica Steud.) to reduce growth and maintain the visual quality (intense green) and good nutritional quality. The research was conducted at the Experimental Station of UNESP, Ilha Solteira/SP, from August/2014 to February/2017, on an Ultisol. It was used a randomized block design with 20 treatments arranged in a factorial scheme 5 x 4 with four replications and 10 m2 per plot. The treatments was: control (without N), 15 g m-2 of N in the soil without application of foliar N; 30 g m-2 of N in the soil without application of foliar N; 15 g m-2 in the soil with foliar application of N (1% urea) and 30 g m-2 of N in the soil with foliar application of N (1% urea) combined with four rates of glyphosate (0, 200, 400 and 600 g ha-1 active ingredient (a.i.)). N rates in the soil were split in five times during the year and, therefore, corresponded to 3 and 6 g m-2 of N at each application, respectively, for the rates of 15 and 30 g m-2 of N. Were evaluated: the chemical attributes of the soil, height and dry matter of leaves, leaf area, LCI (leaf chlorophyll index), the chlorophyll a and b, the digital image analysis and the percentage of phytotoxicity of the shoot, beyond the occurrence of weed species and number of inflorescences, as well as the concentration and accumulation of macro and micronutrients by leaves of turfgrass and log-isometrics balance of macronutrients in the leaves and cationic balance in the soil (isometric log ratio - ilr). It was being also assessed the root system (dry matter and macro and micronutrients in roots + rhizomes). Ten evaluations (cuts) were carried out. The levels of K in the soil increased with the glyphosate rates. There was higher dry matter of the roots + rhizomes when N fertilization and decrease of these values with the doses of herbicide. The greater amount of N via soil, with or without N via foliar, resulted in greater growth of the zoysiagrass, being reduced with the dose of 600 g ha-1 of a.i. of glyphosate. However, this herbicide rate was not aesthetically ideal - green color. It was concluded that the fertilization with 15 g m-2 of N in the soil without foliar N, split in five times during the year, provided visual and nutritional quality of the grass, and the rate of glyphosate of 400 g ha-1 a.i. was effective in reducing zoysiagrass growth, did not sacrifice its coloration and provided less accumulation of macronutrients in the leaves, reducing the need for replenishment by fertilization. / FAPESP: 2014/02449-8
3

Factors governing zoysiagrass response to herbicides applied during spring green-up

Craft, Jordan Michael 29 March 2021 (has links)
Zoysiagrass (Zoysia spp.) is utilized as a warm-season turfgrass because of its density, visual quality, stress tolerance, and reduced input requirements. Turf managers often exploit winter dormancy in warm-season turfgrass to apply nonselective herbicides such as glyphosate and glufosinate to control winter annual weeds. Although this weed control strategy is common in bermudagrass (Cynodon spp.), it has been less adopted in zoysiagrass due to unexplainable turf injury. Many university extension publications recommend against applying nonselective herbicides to dormant zoysiagrass despite promotional language found in a few peer-reviewed publications and product labels. Previous researchers have used vague terminology such as "applied to dormant zoysiagrass" or "applied prior to zoysiagrass green-up" to describe herbicide application timings. These ambiguous terms have led to confusion since zoysiagrass typically has subcanopy green leaves and stems throughout the winter dormancy period. No research has sought to explain why some turfgrass managers are observing zoysiagrass injury when the literature only offers evidence that these herbicides do not injure dormant zoysiagrass. We sought to explore various herbicides, prevailing temperatures surrounding application, heat unit based application timings, and spray penetration into zoysiagrass canopies as possible contributors to zoysiagrass injury. The results indicated that a wide range of herbicides may be safely used in dormant zoysiagrass. However, as zoysiagrass begins to produce more green leaves, herbicides such as metsulfuron, glyphosate, glufosinate, flumioxazin, and diquat become too injurious. Glufosinate was consistently more injurious regardless of application timing than glyphosate and other herbicides. When temperatures were 10 °C for 7 d following treatment, a delayed effect of glyphosate and glufosinate effect on digitally-assessed green cover loss was noted on zoysiagrass sprigs. In subsequent studies on turf plugs, a 14-d incubation period at 10 °C reduced glyphosate but not glufosinate effects on turf green color reduction. Glyphosate applied at 125, and 200 GDD5C can safely be applied to zoysiagrass while glufosinate applied at the same timings caused inconsistent and often unacceptable zoysiagrass injury in field studies conducted at Blacksburg, VA, Starkville, MS, and Virginia Beach, VA. Zoysiagrass green leaf density was described as a function of accumulated heat units consistently across years and locations but variably by turf mowing height. Turf normalized difference vegetative index was primarily governed by green turf cover but reduced by herbicide treatments, especially when applied at greater than 200 GDD5C. Substantial spray deposition occurred to subcanopy tissue regardless of nozzle type, pressure and height above the zoysiagrass canopy based on spectrophotometric assessment of a colorant admixture. However, increasing nozzle height above the turf canopy and avoiding air induction type nozzles significantly reduced the percentage of green tissue exposed at lower canopy levels. Absorption of radio-labeled glyphosate and glufosinate was up to four times greater when exposed to zoysiagrass stems compared to leaves. Glyphosate translocated more than glufosinate and both herbicides moved more readily from stem to leaf than from leaf to stem / Doctor of Philosophy / Zoysiagrass (Zoysia spp.) is utilized as a warm-season turfgrass because of its density, visual quality, stress tolerance, and reduced input requirements. Being that zoysiagrass is a warm-season turfgrass, it enters a dormancy period during the winter months. During this period, zoysiagrasses' active growth is halted, and leaves lose their green color and turn a golden-brown color. The winter dormancy period presents turfgrass managers with a unique opportunity to apply nonselective herbicides such as glyphosate and glufosinate to control a broad spectrum of winter annual weeds. Although this weed control strategy is common in bermudagrass (Cynodon spp.), it has been less adopted in zoysiagrass due to turfgrass managers observing unexplainable turfgrass injury. Many university extension publications recommend against applying nonselective herbicides to dormant zoysiagrass despite language found in peer-reviewed publications and product labels suggesting they could be safely applied. Previous researchers have used vague terminology such as "applied to dormant zoysiagrass" or "applied prior to zoysiagrass green-up" to describe herbicide application timings. These terms have led to confusion about when to make these applications since zoysiagrass typically has subcanopy green leaves and stems throughout the winter dormancy period. No research has sought to explain why some turfgrass managers observe zoysiagrass injury when the literature only offers evidence that these herbicides do not injure dormant zoysiagrass. Research projects were designed to explore various herbicides, temperatures surrounding herbicide applications, application timings, and spray penetration into zoysiagrass canopies as possible contributors to zoysiagrass injury. The results indicated that a wide range of herbicides may be safely used in dormant and semidormant zoysiagrass. However, as zoysiagrass begins to produce more green leaves and stems, herbicides such as metsulfuron, glyphosate, glufosinate, flumioxazin, and diquat become too injurious and should be avoided. Across multiple research studies, glufosinate was consistently more injurious regardless of application timing than glyphosate and other herbicides. When temperatures were 10 °C for 7-d following treatment, it delayed zoysaigrass response to glyphosate and glufosinate. In a subsequent study, when temperatures were at 10 °C for a 14-d period, glyphosate and the nontreated reached 50% green cover at the same time, which suggests cold temperatures could mitigate glyphosate injury on zoysiagrass over a 14-d period. The 10 ° temperature only delayed glufosinate injury on zoysiagrass, and no safening was observed. The results also indicated that as temperatures increased, glyphosate and glufosinate rate in which injury was observed increased on the zoysiagrass. Glyphosate applied at 125, and 200 GDD5C can safely be applied to zoysiagrass while glufosinate applied at the same timings caused inconsistent and often unacceptable zoysiagrass injury in field studies conducted at Blacksburg, VA, Starkville, MS, and Virginia Beach, VA. Zoysiagrass injury increased when glyphosate and glufosinate were applied later into the spring when more green leaves were present regardless of location. Accumulated heat units and zoysiagrass green leaf density were closely related, indicating that accumulated heat units could be a useful tool for turfgrass managers to track zoysiagrass spring green-up. Substantial spray deposition was found on subcanopy zoysiagrass leaves and stems regardless of nozzle type, pressure, and height above the zoysiagrass canopy based on recovered colorant at the upper, middle and lower levels of the zoysiagrass canopy. However, avoiding air induction-type nozzles and raising spray height may slightly decrease penetration of spray droplets into a zoysiagrass subcanopy, but a large percentage of droplets still reached the middle and lower canopy layers in this research. Absorption of radio-labeled glyphosate and glufosinate was up to four times greater when applied directly to zoysiagrass stolen compared to leaves. Glyphosate translocated more than glufosinate, and both herbicides moved more readily from stem to leaf than from leaf to stem. These data suggest limiting the number of green zoysiagrass leaves at application would be an effective method to avoid injury zoysiagrass when applying nonselective herbicides

Page generated in 0.0698 seconds