Orientador: Antonio Ismael Inácio Cardoso / Banca: Roberto Lyra Villas Bôas / Banca: Santino Seabra Júnior / Banca: Pedro Jovchelevich / Banca: Jackson Mirellys Azevêdo Souza / Resumo: A couve-flor, comparada a outras brássicas, é a mais exigente em solos férteis e com alto teor de matéria orgânica. O nitrogênio pode ser perdido facilmente no solo, seja por volatilização ou por lixiviação, sendo indicado que seu fornecimento ocorra juntamente com a aplicação de materiais ricos em matéria orgânica, parte no plantio e parte em cobertura. Diante do exposto, objetivou-se com este estudo avaliar o efeito das doses e épocas de aplicação de torta de mamona em cobertura na produção, características físico-químicas e acúmulo de macronutrientes na cultura da couve-flor em manejos orgânicos. Foram realizados dois experimentos um no município de São Manuel, SP, e o outro em Botucatu, SP. Em São Manuel, SP foram estudados 14 tratamentos, em esquema fatorial 3 x 4 + 2, sendo três doses de torta de mamona (2150, 3225 e 4300 kg ha-1), combinadas com quatro parcelamentos em cobertura (¼ + 2/4 + ¼; 1/3 + 1/3 + 1/3 e 1/3 + 2/3 e 2/3 + 1/3), além de duas testemunhas (sem adubação em cobertura e com adubação inorgânica). Em Botucatu, SP, foram 10 tratamentos, em esquema fatorial 3 x 3 + 1, sendo três doses de torta de mamona (1290, 2580 e 3870 kg ha-1) combinadas com três épocas de aplicação em cobertura (única aos 30 ou aos 45 dias após o transplante (DAT) e parcelada aos 30 e 45 DAT), além de uma testemunha (sem adubação em cobertura). Os experimentos foram no delineamento experimental de blocos ao acaso, com quatro repetições. Foram analisadas as seguintes características: c... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Currently, conventional cauliflower cultivation is still predominant; however, cultivation in alternative systems, such as organic, has been growing. Compared to other brassicas, it is the most demanding in fertile soils with a high content of organic matter. Nitrogen and potassium are the most accumulated nutrients in cauliflower. Nitrogen can be easily lost in the soil, either by volatilization or by leaching, and it is indicated that its supply occurs along with the application of materials rich in organic matter, part in planting and part in cover. In view of the above, this study aimed to evaluate the effect of doses and times of application of castor bean cake on yield, physical-chemical characteristics and accumulation of macronutrients in cauliflower crop in organics managements. Two experiments were carried out, one in the municipality of São Manuel, SP, and the another in Botucatu, SP. In the experiment 1 (São Manuel, SP), 14 treatments were studied in a 3 x 4 + 2 factorial scheme, with three doses of castor bean (2150, 3225 and 4300 kg ha-1), combined with four installments (¼ + 2/4 + ¼; 1/3 + 1/3 + 1/3; 1/3 + 2/3 and 2/3 + 1/3), besides two controls (without cover fertilization and with inorganic fertilization). In experiment 2 (Botucatu, SP), 10 treatments were used, in a 3 x 3 + 1 factorial scheme, three castor bean doses (1290, 2580 and 3870 kg ha-1) combined with three installments (one application at 30 or at 45 days after transplanting (DAT) and parceled at 30 and 45 DAT), in addition to one control (no fertilization in coverage). The experiments were in a randomized complete block design, with four replications. The following characteristics were analyzed: cycle (DAT), number of leaves, inflorescence diameter and height, inflorescence fresh matter weight and fresh matter weight of the vegetative part (stem and leaves), pH, titratable acidity (TA), acid ascorbic acid (AA) ... / Doutor

Orientador: Antonio Ismael Inácio Cardoso / Banca: João Nakagawa / Banca: Hélio Grassi Filho / Banca: Cristiaini Kano / Banca: Pâmela Gomes Nakada Freitas / Resumo: Objetivou-se avaliar o efeito de doses e parcelamentos da adubação nitrogenada em cobertura na produção e teor de macronutrientes de frutos imaturos de abobrinha-demoita. Foram conduzidos dois experimentos, com treze tratamentos, no esquema fatorial 4x3+1, com quatro doses de nitrogênio em cobertura (62,5; 125,0; 187,5; 250,0 kg ha-1 de N), três parcelamentos (1 6 ⁄ + 1 3 ⁄ + 1 2 ⁄ ; 1 4 ⁄ + 1 2 ⁄ + 1 4 ⁄ e 1 3 ⁄ + 1 3 ⁄ + 1 3 ⁄ ) e um tratamento sem adubação em cobertura (dose zero), com quatro repetições. Os experimentos 1 e 2 foram conduzidos no ano de 2014 e 2015, respectivamente. Foram avaliados número de frutos total e comercial por planta, produção (g planta-1) total e comercial, comprimento, diâmetro e massa média de fruto comercial. Apenas no experimento 2 foi avaliado o teor de macronutrientes nos frutos. No experimento 1, o parcelamento 1 4 ⁄ + 1 2 ⁄ + 1 4 ⁄ proporcionou maior número de frutos total e comercial. No experimento 2, o aumento das doses nos parcelamentos 1 6 ⁄ + 1 3 ⁄ + 1 2 ⁄ e 1 3 ⁄ + 1 3 ⁄ + 1 3 ⁄ proporcionou incremento linear na produço de frutos total e comercial. A ordem decrescente de teores de macronutrientes nos frutos imaturos, foi de K>N>P>Ca>Mg>S. / Abstract: We evaluated the effect of nitrogen fertilization rates and plots on yield and macronutrient content of immature fruits of zucchini. Two experiments were carried out, with thirteen treatments, in the factorial scheme 4x3+1, with four nitrogen rates in top (62.5, 125.0, 187.5, 250.0 kg ha-1 of N), three splitting forms ( 1 6 ⁄ + 1 3 ⁄ + 1 2 ⁄ ; 1 4 ⁄ + 1 2 ⁄ + 1 4 ⁄ and 1 3 ⁄ + 1 3 ⁄ + 1 3 ⁄ ) and one treatment without fertilization in top (zero rate) with four replications. Experiment 1 and 2 were conducted in 2014 and 2015, respectively. Total and commercial fruit number per plant, total and commercial production (g plant1), length, diameter and average commercial fruit mass were evaluated. Only in experiment 2 the macronutrient content in the fruits was evaluated. In experiment 1, the 1 4 ⁄ + 1 2 ⁄ + 1 4 ⁄ splitting provided greater number of total and commercial fruit. In experiment 2, the increase of the rates in the 1 6 ⁄ + 1 3 ⁄ + 1 2 ⁄ and 1 3 ⁄ + 1 3 ⁄ + 1 3 ⁄ splitting resulted in a linear increase in total and commercial fruit production. The decreasing order of macronutrient contents in immature fruits was K>N>P>Ca>Mg>S. / Doutor

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No description available.

Numerous Investigators have reported that NH₄⁺ uptake reduces the yield and quality of flue-cured tobacco (Nicotiana tabacum L.). Metalaxyl, a fungicide commonly used in the production of flue-cured tobacco, has been patented as a nitrification inhibitor. The objectives of this study were to 1) determine the influence of metalaxyl at commonly applied rates on the + nitrification of NH₄⁺ from various sources; 2) study the Influence of soil pH on inhibition of nitrification by metalaxyl; 3) study the Influence of N source and metalaxyl on N accumulation in the plant; and 4) evaluate the influence of N source and metalaxyl on the yield, quality, and chemical composition of flue-cured tobacco leaf. Field, greenhouse, and laboratory experiments were conducted in the Southern Piedmont region of Virginia in 1984 and 1985 to carry out these objectives. Metalaxyl was found to reduce the population of NH₄⁺ oxidizers in soil and inhibit nitrification at applications of 0.56, 1.12, and 3.36 kg ha⁻¹. The inhibitory effects of metalaxyl were much weaker than nitrapyrin. Nitrification was inhibited by metalaxyl only in soils where nitrification was slowed by low pH and wet conditions. In soils of high nitrifying capacity, metalaxyl did not inhibit nitrification. Nitrogen uptake was enhanced by high NO₃⁻ concentrations in the soil, except where metalaxyl reduced NO₃⁻ leaching. Cured leaf concentrations of N were not affected by N source but were slightly reduced by metalaxyl. Nitrogen source and metalaxyl did not affect yield, total alkaloids, or reducing sugars. Quality Index was reduced by decreased soil NO₃⁻ from both N source and metalaxyl. / M.S.

Adequate nutrient supply to the medium solution of container-grown crops is a major concern to container plant production practices. The extent to which nutrients are removed by the plant from the medium solution of a container, however, has never been demonstrated. Mariogold, Tagetes erecta ‘Inca’ seeds were glasshouse-grown in 500 cc plastic pots containing 1 peat: 1 perlite (v/v) medium and fertilized daily with 200 ppm N as ammonium nitrate. Thirty, 35, 40, 45 and 50 day old plants were subjected to either 20, SO, 80 or 110 ppm N. Medium solutions were tested at hour 0 and 6, and analyzed for N, P and K. Nitrogen removal from the medium solution was greatest by 45 and 50 day old plants at the higher N treatments. Phosphorous and K removal also increased with plant age. Medium solutions were tested and analyzed again, 10 days later. Nitrogen removal, 10 days later, was greatest for 50, 55 and 60 day old plants at the higher N treatments. Phosphorus removal was greatest by 55 and 60 day old plants whereas K removal increased up to day 60 through all age groups. Total N, P and K in the tissue reflected nutrient removal rates; however, no differences in dry weight due to N treatment were detected. In a second experiment, to determine the age at which dry weight is affected by N treatment, plants of one age group were treated with either 10, 30, 50 or 70 ppm N. Shoot dry weights did not differ until day 27 when plants grown at 10 ppm were smaller than for other treatments. As plants aged, higher levels of N were required to prevent growth reduction. These results indicate that age influences the N removal rate from the medium solution of container-grown plants. This relationship affects the amount of N applied to the medium solution to satisfy plant N requirement. / M.S.

Master of Science

The NRT2 (high affinity nitrate transporter 2) family is a part of the iHATS (inducible high affinity system) that studies have shown is responsible for the influx of nitrate into the plant cell after provision of nitrate. The ZmNRT2.1 from Zea mays was constitutively expressed in Nicotiana tabacum. To assess how over-expression of this foreign NRT2.1 affects nitrate influx by plants, nitrate content in leaf and root tissue, gene expression, and vegetal growth were analyzed in media with deficient or high nitrate concentrations (0.1, 1, or 10 mM). Compared to wild type plants: the transgenic lines had a significantly larger fresh weight in all nitrate conditions; primary root length was significantly longer in the 0.1 and 1 mM nitrate conditions; both the fresh weight and the primary root length were significantly higher when 50 mM NaCl was applied as a stress factor to medias containing 0.1 and 10 mM nitrate. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Copy of author's previously published work inserted. Bibliography: leaves 147-189. This project examines the uptake of mineral N from the subsoil after anthesis and its effect on grain protein concentration (GPC) of wheat. The overall objective is to examine the importance of subsoil mineral N and to investigate the ability of wheat to take up N from the subsoil late in the season under different conditions of N supply and soil water availability. Greenhouse experiments investigate the importance of subsoil mineral N availability on GPC of wheat and the factors that contribute to the effective utilisation of N. The recovery of N from subsoil, the effect of split N application on GPC and short term N uptake by the wheat at different rooting densities are also studied.

Graduation date: 1993