Changes in the concentration of some carbohydrates and in amylolytic activity have been followed during germination of Zea. Mays L. var. Hickory King and var. Early Pearl. Assay techniques have been developed which permitted assay of individual grains. Thus during the investigation both groups and individual grains were used as samples. The use of groups permitted control of assay technique. Length of radicle, coleoptile and lateral roots were recorded in order to permit quantitative estimation of correlation between growth and the concentration of the various carbohydrates. Initially, during the study of changes in the carbohydrate concentration in Hickory King grains, total reducing sugar, sucrose and dextrin concentrations were estimated. However, the results obtained for changes in dextrin concentration, although reproduceable, thereby indicating reliable assay technique, presented a confusing picture and, in view of the apparent importance of sucrose and reducing sugar concentration, assay of dextrin concentration was discontinued in a subsequent study of Early Pearl. Instead changes in total reducing sugar, sucrose and glucose concentrations were followed. The results revealed that there is very considerable variability in physiological activity between grains subjected to the same germination conditions. However, all, irrespective of variety, follow the same basic metabolic pattern during germination. The trends observed were: (i) Reducing sugar accumulates slowly during the first 72-96 hours germination, but thereafter accumulation is very rapid, although concentration may decrease towards the end of the gestation period. (ii) Glucose follows a similar pattern to reducing sugar, accumulating slowly during the early stages of germination, followed by a period of rapid increase in concentration, which may decrease towards the end of the germination period. (iii) Sucrose concentration in dormant grains is fairly high, but it decreases markedly during the first 96 hours germination. This is followed by a phase of sucrose accumulation. (iv) Dextrin concentration shows two peaks. Initial level is low, but it accumulates rapidly during the first 72 hours. The level decreases between 72 and 120 hours but increases when the germination period is increased to 192 hours, after which there is a marked decrease. It was impossible, from the data relating to the study of individual grains, to discern a trend in dextrin concentration. With the exception of dextrin, about which there is little information, the results are in general agreement with the literature. Investigation of correlation between the various carbohydrates and between these and growth revealed that: (i) reducing sugar concentration and growth are positively correlated ; (ii) glucose concentration and growth are positively correlated; (iii) sucrose and reducing sugar concentrctions are negatively correlated during the initial stages of germination; (iv) sucrose and glucose concentrations are negatively correlated during early germination; (v) glucose and reducing sugar are positively correlated; (vi) in general, correlation between growth and concentration of the carbohydrates studied, decreases during the later periods of germination. These observations suggested that growth was, at least during the early stages of germination, dependent on the level of reducing sugar, and more particularly on the level of glucose, and that sucrose is the principal source of reducing sugar during this period. The relationship between amylase activity (total alpha- and beta-amylase activity) and reducing sugar concentration tends to be curvilinear, which suggests that amylolytic activity produces relatively little reducing sugar during early gennination, even though amylase activity and growth may be positively correlated. The results suggest, contrary to the observations of previous workers, that alpha-amylolytic activity may be present in dormant grains and that maize is not characterised by low levels of beta-amylase activity during germination. From the observations it is concluded that the initinl accumulati on of reducing sugar is the result of sucrose hydrolysis, and therefore sucrose is an importnnt metabolite durjng early germination. Amylolytic activity contributes little reducing sugar durlng the initia1 stages of germinatIon but that after approximately 72 hours it represents the major source of reducing sugar.

Orientador: Paulo Roberto Arbex Silva / Banca: Ulisses Rocha Antuniassi / Banca: Adalton Mazetti Fernandes / Banca: Carlos Eduardo Angeli Furlan / Banca: Gisele Herbst Valquez / Resumo: A variação na profundidade de sementes e no espaçamento entre plantas proporcionam diferentes condições para as mesmas se desenvolverem. Sendo assim, o objetivo desse trabalho foi avaliar a cultura do milho semeada em diferentes profundidades e espaçamentos entre plantas, e dessa maneira saber o quanto esses fatores influenciam nas características agronômicas e produtividade da cultura. O experimento foi conduzido em campo, na Fazenda Experimental Lageado, da Faculdade de Ciências Agronômicas - UNESP/Botucatu-SP. Foram realizados dois experimentos, sendo cada fator (profundidade de sementes e espaçamento entre plantas) avaliado separadamente. O experimento com diferentes profundidades de sementes contou com 10 tratamentos, no qual houve variação da profundidade de semeadura entre 2, 4, 6 e 8 cm, adotando diferentes opções de combinações. Nesse experimento além de todas as avaliações morfológicas também foi avaliada a velocidade de emergência das plântulas. O outro experimento foi avaliar diferentes espaçamento entre plantas e constou de 11 tratamentos, variando entre o espaçamento considerado ideal para o híbrido utilizado (17 cm, população de 69.200 plantas ha-1) e intervalos de 10%, 20%, 30%, 40% e 50% para mais e para menos. Ambos com delineamento em blocos ao acaso, com 4 repetições cada. O milho foi semeado manualmente em sistema de preparo de solo convencional, com auxílio de réguas graduadas de acordo com os espaçamentos entre plantas indicado para cada tratamento e a profundidade. Para a análise estatística dos dados, os valores foram submetidos à análise de variância (ANOVA), utilizando o teste F a 5% de probabilidade. Para a variação dos espaçamentos foi realizada análise de regressão com ajuste dos maiores coeficientes de determinação (p ≤0,05). Pode-se concluir que nas profundidades avaliadas houve diferença significativa para ... / Abstract: The variation in depth of seeds and plant spacing provide different conditions for them to develop. Thus, the aim of this study was to evaluate the culture of corn sown at different depths and spacing between plants, and so to determine the effect the agronomic characteristics and crop yield. The experiment was carried out at the College of Agronomy - FCA/UNESP, Botucatu-SP. For depth and for sowing spacing two experiments were carried, by evaluating each individually. In the experiment with different depths of seeds were carried out 10 treatments, in which there was a variation of sowing depth of 2, 4, 6 and 8 cm, adopting different combinations among themselves. For depth of seeds, was also evaluated the speed of emergence of seedlings. For the spacing between plants were 11 treatments, ranging from the ideal of 17 cm between plants and population of plants of 69,200 ha-1, and variations of 10%, 20%, 30%, 40% and 50% besides of the ideal. The outline was random blocks, with four replicates per treatment. The corn seeds were sowed by hand in conventional tillage, with the aid of graduated rulers according to plant spacings and depths, according to each treatment. For statistical analysis, the data were submitted to analysis of variance (ANOVA) using the F test at 5% probability. For the variation of spacings was performed regression analysis with adjustment of the highest coefficients of determination (p≤0,05). It can be concluded that in the depths evaluated there were significant differences for the emergency speed index, the first count of seedlings and the full emergence. The highest yields were obtained for the deepest seeds. For more spaced plants each other, there was production of larger corncobs, but has no higher grain yield. For the spacing between plants the highlights were the 17cm (69,200 seeds ha-1) and 11.1 ... / Doutor

The activity of the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR, EC 1.1.1.34) is highly expressed in 4-day-old etiolated seedlings of normal ('DeKalb XL72AA'), dwarf (<u>d₅</u>), and albino (<u>lw₃</u>) maize (<u>Zea mays</u> L.). HMGR activity of maize seedlings appeared to be exclusively associated with the microsomal rather than the plastidic fraction of maize cells. Maize tissues with high meristematic activity such as germinating seeds, leaf bases, root tips, and the site of origin of lateral roots contained high levels of HMGR activity. The activity of HMGR extracted from leaf tips of normal, dwarf, and albino maize seedlings was regulated by light. HMGR activity from leaf tips of 4-day-old maize seedlings was inhibited significantly following exposure to strong light (600 μol/m²/s) for more than 10 h. In contrast, HMGR activity from leaf bases and root tips of maize was not inhibited by exposure to strong light. These results suggest that HMGR may play an important role in cell division and that light may regulate HMGR activity indirectly by increasing cell differentiation. Under conditions of strong light pretreatment with the bleaching herbicides clomazone, norflurazon, fluridone and acifluorfen stimulated by 4-to 7-fold the activity of HMGR extracted from 'Dekalb XL72AA' maize seedlings. / Ph. D.

Orientador: Paulo Roberto Arbex Silva / Coorientador: Critiano Magalhães Pariz / Banca: Saulo Fernando Gomes de Sousa / Banca: Elcio Hiroyoshi Yano / Resumo: O objetivo deste trabalho foi avaliar a produtividade e o desempenho operacional e econômico de diferentes operações mecanizadas para semeadura do capim-marandu e crotalária juncea, consorciados com a cultura do milho para ensilagem. Foram avaliados os desempenhos operacionais e econômicos das operações mecanizadas envolvidas em cada tratamento, bem como as características agronômicas do milho e das culturas de cobertura desse sistema. O experimento foi conduzido em campo, Fazenda de Ensino, Pesquisa e Extensão (FEPE), pertencente à Faculdade de Ciências Agronômicas da Universidade Estadual Paulista "Júlio de Mesquita Filho", situada no município de Botucatu. Foram utilizados quatro tipos de operações mecanizadas para a semeadura do capim-marandu e da crotalária juncea. O tratamento que apresentou a maior produtividade de matéria verde total ensilada e matéria seca total ensilada foi o tratamento em que semeou as culturas de cobertura com o cultivador adubador juntamente com a adubação nitrogenada de cobertura da cultura do milho (T4), o mesmo tratamento apresentou menor consumo operacional de combustível do que os outros tratamentos e um menor custo horário das operações mecanizadas realizadas. O tratamento que utilizou um distribuidor de sementes e fertilizantes a lanço para inserir as culturas de cobertura (T2), apresentou maior produtividade de matéria seca remanescente na área experimental, valores mais baixos de altura de inserção de espiga e peso seco total ensilado de... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this resarch was to evaluate the productivity and the operational and economic performance of different mechanized operations for sowing of palisade grass and crotalaria juncea, intercropped with maize silage. The operational and economic performances of the mechanized operations involved in each treatment were evaluated, as well as the agronomic characteristics of the maize and the cover crops of this system. The experiment was carried out in the Fazenda de Ensino, Pesquisa e Extensão (FEPE), belonging to the Faculdade de Ciências Agronômicas of the Universidade Estadual Paulista "Júlio de Mesquita Filho", located in the city of Botucatu. Four types of mechanized operations were used for the sowing of the palisade grass and the crotalaria juncea. The treatment that presented the highest yield of total green matter and total silage was the treatment in which sowed the cover crops with the fertilizer cultivator together with the nitrogen fertilization of the corn crop (T4), the same treatment presented lower operational fuel consumption than other treatments and a lower hourly cost of the mechanized operations performed. The treatment that used a seed and fertilizer distributor to insert cover crops (T2), showed higher dry matter yield remaining in the experimental area and lower values of ear insertion height and total dry silage weight of grains and lower total operating cost of mechanized operations and greater operational capacity in this operation. / Mestre

Made available in DSpace on 2014-06-11T19:22:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-20Bitstream added on 2014-06-13T19:27:25Z : No. of bitstreams: 1 repke_ra_me_botfca.pdf: 372100 bytes, checksum: 4623078fb547030ef25834dc12556967 (MD5) / O milho é um dos cereais mais cultivados no mundo, porém apresenta desafios quanto ao manejo correto da adubação. Sua elevada demanda por nitrogênio tem sido a principal responsável por excessivas doses de fertilizantes nitrogenados sintéticos aplicados na cultura. Como consequência, há aumento no custo de produção da lavoura e impactos negativos ao meio ambiente. Dessa forma, é necessário estudar métodos alternativos que promovam o desenvolvimento das plantas e garantam a produtividade, buscando aliar eficiência, viabilidade econômica e segurança ambiental. Bactérias diazotróficas podem fixar nitrogênio atmosférico e produzir substâncias promotoras do crescimento, podendo reduzir a utilização de fertilizantes nitrogenados na cultura do milho. Para testar essa hipótese, este trabalho teve como objetivo avaliar a eficiência agronômica na cultura do milho, do uso de bactéria diazotrófica Azospirillum brasilense, inoculada via sementes em combinação com doses de nitrogênio. A pesquisa foi composta por um ensaio conduzido no campo experimental da Fazenda Lageado em Botucatu-SP, pertencente à Universidade Estadual Paulista “Júlio de Mesquita Filho” – Faculdade de Ciências Agronômicas, em delineamento experimental de blocos ao acaso, com quatro repetições, em esquema fatorial duplo. Tendo o fator 1, dois níveis: sem e com aplicação da solução da bactéria Azospirillum brasilense nas sementes e o fator 2, seis doses totais de nitrogênio: zero, 180, 155, 130, 105 e 80 kg ha-1. Foi utilizado o híbrido de milho transgênico 2B587 Hx, ciclo precoce, porte baixo, indicado para semeadura no verão. As avaliações morfológicas da planta e da espiga foram realizadas aos 20, 40, 60, 80 e 100 dias... / Corn is a cereal grown worldwide; however it presents challenges with regards to the proper fertilizer management. Its high demand for nitrogen has been primarily responsible for excessive doses of synthetic nitrogen fertilizer applied to the crop. As a result, it can be observed an increase in cost of crop production and negative impacts to the environment. Thus, it is necessary to study alternative methods that promote the plant growth and ensure productivity, improving efficiency, economic viability and environmental safety. Diazotrophic bacteria can fix atmospheric nitrogen and produce growth promoting substances which can reduce the use of nitrogen fertilizers in the corn cultivation. To test this hypothesis, this study had the objective to evaluate the agronomic efficiency in corn, using Diazotrophic Azospirillum brasilense inoculated via seeds in combination with nitrogen levels. The research consisted in a field trial, where the experimental design was a randomized block, with four replications in a double factorial. Factor 1: with and without the application of the solution of the bacterium Azospirillum brasilense in seeds, and factor 2: six total doses of nitrogen: zero, 180, 155, 130, 105 and 80 kg ha-1. The hybrid of the transgenic corn 2B587 Hx, early maturity, small size was used, suitable for planting in the summer. The morphological evaluations of plant and cob were evaluated at 20, 40, 60, 80 and 100 days after emergence (DAE). Grain yield was measured at 115 DAE. Inoculation of corn seeds with Azospirillum had no effect on growth and productivity of corn plants. The adoption of this practice did not replace the use of nitrogen... (Complete abstract click electronic access below)

Orientador: Paulo Roberto Arbex Silva / Banca: Tiago Pereira da Silva Correia / Banca: Juliano Carlos Calonego / Resumo: Para obter uma produção agrícola de qualidade, é de extrema importância realizar uma semeadura adequada. A boa semeadura visa à distribuição longitudinal de sementes no solo para, somada ao fator profundidade de deposição das sementes, obter um estande correto e uniforme. A deposição incorreta da semente pode limitar o desenvolvimento das plantas por todo o seu ciclo e acarretar baixas produtividades. O objetivo desse trabalho foi avaliar as características agronômicas e a produtividade da cultura do milho nas diferentes profundidades de deposição de sementes em semeadura mecanizada. O presente trabalho foi conduzido no ano agrícola de 2015/2016, na área experimental da Fazenda Lageado, pertencente à Faculdade de Ciências Agronômicas - UNESP, situada no Município de Botucatu/SP. O delineamento experimental utilizado foi em blocos casualizados com 4 repetições. Os tratamentos utilizados foram as diferentes profundidades reais de deposição das sementes definidas pela regulagem na semeadora-adubadora, sendo 0,062 m, 0,052 m, 0,039 m, 0,023 m e 0,013 m. A semeadura foi realizada com o auxílio da semeadora-adubadora em sistema de preparo convencional do solo, com espaçamento de 0,90 m entre as linhas de cultivo. Os tratamentos foram conduzidos de acordo com cada regulagem, conforme posição da roda de profundidade de sementes. Foram feitas avaliações morfológicas, de velocidade de emergência das plântulas e a profundidade real de deposição das sementes. Para a análise estatística d... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: To attain a high quality agricultural production, it is extremely important to perform an adequate seeding. A good seeding procedure aims to longitudinally distribute the seeds into the soil to, combined with the depth of the seed deposition, obtain a true and uniform plant stand. The incorrect deposition of the seeds can limit the development of the plant throughout its cycle and lead to low productivity. The purpose of this work was to evaluate the agronomical characteristics and the production culture of corn on the different depths of seed deposition available on a seeder-fertilizer. The experiment was conducted on the agricultural year of 2015/2016, in the experiment area of Lageado Farm, belonging to the College of Agronomy - UNESP - Botucatu/SP. The outline used was randomized blocks with 4 years repetitions. The treatments utilized were the actual different depths of seed deposition determined by the seeder-fertilizer regulation, being 0.062 m, 0.052 m, 0.039 m, 0.023 m and 0.013 m. The seeding was performed with the assistance of a seeder-fertilizer on a conventional tillage system, performed according to each regulation defined by the treatment, with 0,90 m of spacing between the cultivation lines. The treatments were conducted according to each adjustment, in accordance with the position of the seed depth-wheel. Morphological evaluation, seedling's emergence speed and real depth deposition of the seeds were evaluated. For the statistical analysis of the data, the r... (Complete abstract click electronic access below) / Mestre

Orientador: Regiane Cristina Oliveira de Freitas Bueno / Banca: Roberto Postali Parra / Banca: Pedro Takao Yamamoto / Banca: Juliano Carlos Calonego / Banca: Sandra Regina Magro / Resumo: A exemplo de praticamente todos os cultivos agrícolas no Brasil, a cultura do milho é hospedeira de insetos fitófagos de diferentes espécies, que invariavelmente ocasionam prejuízos econômicos à produção do país. Para diminuir os prejuízos causados pelos insetos-praga, o uso de inseticidas se tornou uma pratica cada vez mais comum nos plantios. No entanto, as pulverizações excessivas, e muitas vezes realizadas sem necessidade tornaram essa tática de controle pouco eficiente no manejo das principais pragas da cultura do milho. Dentro desse contexto, torna-se cada vez mais importante a adoção das práticas do MIP, ainda muito pouco utilizadas no Brasil, em que as táticas de controle são utilizadas de forma isolada ou integrada afim de regular a população da praga e preservar os inimigos naturais. Para tanto, o monitoramento das pragas e o reconhecimento do papel regulador dos insetos benéficos são primordiais. Sendo assim, o objetivo desse estudo foi a avaliar a eficiência de T. pretiosum e T. remus no manejo de S. frugiperda na cultura do milho. Os experimentos foram conduzidos nas áreas pertencentes a Fazenda de Ensino, Pesquisa e Extensão (FEPE) da FCA/UNESP, Campus Botucatu - SP, durante as safras 2015/16 e 2016/17. Durante a segunda safra (safrinha) 2016 o experimento foi conduzido na Fazenda São José, localizada no munícipio de Sidrolândia-MS. Os quatro tratamentos adotados em Botucatu-SP foram alocados em uma área contendo três hectares, dividida em parcelas de 1 hectare ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: As practically all agricultural crops in Brazil, maize crop is a host of phytophagous insects of different species, that invariably cause economic losses to the country's production. To reduce the damage caused by insect pests, the use of insecticides has become an increasingly common practice in planting. However, excessive spraying, and often carried out without necessity, has rendered this tactic control inefficient in the management of main maize crop pests. In this context, it becomes increasingly important to adopt Integrated Pest Management (IPM) practices, still underused in Brazil, where control tactics are used in isolation or integrated to regulate the population of the pest and preserve natural enemies. To this end, pest monitoring and recognition of the regulatory role of agents beneficial are paramount. Therefore, the objective of this study was to evaluate the management of lepidopteran pests with the release of the parasitoids of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) and Telenomus remus Nixon (Hymenoptera: Platygastridae) eggs in maize. The experiments were conducted in the areas belonging to FCA / UNESP in the Farm of Education, Research and Extension (FEPE), Campus Botucatu - SP, during the 2015/16 and 2016/17 seasons. In the second harvest 2016 the experiment was conducted at São José Farm, located in the Municipality of Sidrolândia-MS. The four treatments adopted in Botucatu-SP were allocated in an area containing three hectares, divided in plots of 1 hectare each and sized with GPS assistance, the areas were far apart so that one treatment did not influence the other. In Sidrolândia-MS, only three treatments were tested and installed each in an area of three hectares, divided into plots of 1 hectare each, between treatments was left 150 meters of planted area to avoid the influence of one treatment on the other. Spodoptera frugiperda (JE Smith) ... / Doutor

Made available in DSpace on 2016-03-07T19:21:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-07. Added 1 bitstream(s) on 2016-03-07T19:25:23Z : No. of bitstreams: 1 000858648.pdf: 820635 bytes, checksum: 64b79ffe4c7898ff7369de564c8e60f5 (MD5) / Atualmente, a recomendação da fertilização nitrogenada para a cultura do milho (Zea mays) em sistema plantio direto no Brasil é realizada com base no conceito da produtividade esperada. Tem surgido a possibilidade de novas alternativas de manejo da adubação nitrogenada nesses sistemas. A exemplo, alguns agricultores têm aplicado todo o nitrogênio (N) antecipadamente na planta produtora de palha, ou sobre a palhada às vésperas da semeadura da cultura seguinte. O objetivo do presente trabalho foi verificar a viabilidade da técnica dessa prática, nesse sistema de produção. O ensaio foi avaliado durante três anos safra (2011/12, 2012/13 e 2014/15), na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas - UNESP, localizada no município de Botucatu - SP. O delineamento experimental foi em blocos casualizados, com quatro repetições, no esquema fatorial 2x6. Os tratamentos foram constituídos pelas plantas de cobertura do solo Urochloa brizantha e U. ruziziensis, combinadas com seis formas de manejo da adubação nitrogenada, sendo estas: 1- aplicação de nitrogênio 20 dias antes da dessecação (DAD), 2- 10 DAD, 3- 5 DAD, 4- aplicação sobre a palhada 1 dia antes da semeadura (DAS), 30 dias após a dessecação, 5- convencional (30 kg ha-1 de N na semeadura + 170 kg ha-1 de N em cobertura), e um tratamento controle, sem aplicação de N. Foram realizadas as seguintes avaliações nas plantas forrageiras: produção de massa de matéria seca e quantidade de macronutrientes acumulados; e para a cultura do milho foi determinada a massa de matéria seca da parte aérea, diagnose foliar, altura de plantas, componentes de produção e produtividade de grãos. A Urochloa brizantha produz palha e cicla nutrientes em maiores quantidades que a Urochloa ruziziensis, porém o percentual ... / Currently, the recommendation of nitrogen fertilization for corn (Zea mays) in no-tillage system in Brazil is carried out based on the concept of expected yield. The possibility of new alternatives has emerged for management of nitrogen fertilization on these systems. Some farmers are applying all nitrogen (N) in advance to the straw producing crop or on the straw on the eve of sowing the maize crop. The objective of this study was to verify the technical viability of this practice, in no-tillage system. The experiment was evaluated for three crop years (2011/12, 2012/13 and 2014/15), at Lageado Experimental Farm, Faculty of Agricultural Sciences - UNESP, Botucatu, SP, Brazil. The experimental design was a randomized block with four replications, in factorial 2x6. The treatments were a combination of cover crops Urochloa brizantha or U. ruziziensis, with six forms of management of nitrogen fertilization: 0 kg ha-1 N (control); three managements anticipated in the cover crops (20, 10 and 5 days before desiccation); pre-sowing (1 day before) at a dose of 200 kg ha-1 N; and conventional application in maize (30 and 170 kg ha-1, at seeding and sidedressed at the four leaf stage, respectively). The following evaluations were performed on forage plants: dry matter mass yield and accumulated amount of macronutrients, an the corn crop were determined dry matter of shoots, leaf analysis, plant height, yield components and grain yield. The application of N before the desiccation of cover crops, increased dry matter yield and the accumulation of macronutrients, mainly for Urochloa brizantha. Regardless of the management of nitrogen, there was an increase in the number of ears per plant, grain per spike, the mass of one hundred grains and productivity of grains in succession to Urochloa brizantha. It was feasible to anticipate the application of N at ...

Orientador : Carlos Alexandre Costa Crusciol / Coorientador: Rogerio Peres Soratto / Banca: Heitor Cantarela / Banca: Luis Ignácio Prochnow / Resumo: Atualmente, a recomendação da fertilização nitrogenada para a cultura do milho (Zea mays) em sistema plantio direto no Brasil é realizada com base no conceito da produtividade esperada. Tem surgido a possibilidade de novas alternativas de manejo da adubação nitrogenada nesses sistemas. A exemplo, alguns agricultores têm aplicado todo o nitrogênio (N) antecipadamente na planta produtora de palha, ou sobre a palhada às vésperas da semeadura da cultura seguinte. O objetivo do presente trabalho foi verificar a viabilidade da técnica dessa prática, nesse sistema de produção. O ensaio foi avaliado durante três anos safra (2011/12, 2012/13 e 2014/15), na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas - UNESP, localizada no município de Botucatu - SP. O delineamento experimental foi em blocos casualizados, com quatro repetições, no esquema fatorial 2x6. Os tratamentos foram constituídos pelas plantas de cobertura do solo Urochloa brizantha e U. ruziziensis, combinadas com seis formas de manejo da adubação nitrogenada, sendo estas: 1- aplicação de nitrogênio 20 dias antes da dessecação (DAD), 2- 10 DAD, 3- 5 DAD, 4- aplicação sobre a palhada 1 dia antes da semeadura (DAS), 30 dias após a dessecação, 5- convencional (30 kg ha-1 de N na semeadura + 170 kg ha-1 de N em cobertura), e um tratamento controle, sem aplicação de N. Foram realizadas as seguintes avaliações nas plantas forrageiras: produção de massa de matéria seca e quantidade de macronutrientes acumulados; e para a cultura do milho foi determinada a massa de matéria seca da parte aérea, diagnose foliar, altura de plantas, componentes de produção e produtividade de grãos. A Urochloa brizantha produz palha e cicla nutrientes em maiores quantidades que a Urochloa ruziziensis, porém o percentual ... / Abstract: Currently, the recommendation of nitrogen fertilization for corn (Zea mays) in no-tillage system in Brazil is carried out based on the concept of expected yield. The possibility of new alternatives has emerged for management of nitrogen fertilization on these systems. Some farmers are applying all nitrogen (N) in advance to the straw producing crop or on the straw on the eve of sowing the maize crop. The objective of this study was to verify the technical viability of this practice, in no-tillage system. The experiment was evaluated for three crop years (2011/12, 2012/13 and 2014/15), at Lageado Experimental Farm, Faculty of Agricultural Sciences - UNESP, Botucatu, SP, Brazil. The experimental design was a randomized block with four replications, in factorial 2x6. The treatments were a combination of cover crops Urochloa brizantha or U. ruziziensis, with six forms of management of nitrogen fertilization: 0 kg ha-1 N (control); three managements anticipated in the cover crops (20, 10 and 5 days before desiccation); pre-sowing (1 day before) at a dose of 200 kg ha-1 N; and conventional application in maize (30 and 170 kg ha-1, at seeding and sidedressed at the four leaf stage, respectively). The following evaluations were performed on forage plants: dry matter mass yield and accumulated amount of macronutrients, an the corn crop were determined dry matter of shoots, leaf analysis, plant height, yield components and grain yield. The application of N before the desiccation of cover crops, increased dry matter yield and the accumulation of macronutrients, mainly for Urochloa brizantha. Regardless of the management of nitrogen, there was an increase in the number of ears per plant, grain per spike, the mass of one hundred grains and productivity of grains in succession to Urochloa brizantha. It was feasible to anticipate the application of N at ... / Mestre

Orientador: Silvio José Bicudo / Banca: Claudio Cavariani / Banca: Marcio Christian S. Domingues / Resumo: O milho é um dos cereais mais cultivados no mundo, porém apresenta desafios quanto ao manejo correto da adubação. Sua elevada demanda por nitrogênio tem sido a principal responsável por excessivas doses de fertilizantes nitrogenados sintéticos aplicados na cultura. Como consequência, há aumento no custo de produção da lavoura e impactos negativos ao meio ambiente. Dessa forma, é necessário estudar métodos alternativos que promovam o desenvolvimento das plantas e garantam a produtividade, buscando aliar eficiência, viabilidade econômica e segurança ambiental. Bactérias diazotróficas podem fixar nitrogênio atmosférico e produzir substâncias promotoras do crescimento, podendo reduzir a utilização de fertilizantes nitrogenados na cultura do milho. Para testar essa hipótese, este trabalho teve como objetivo avaliar a eficiência agronômica na cultura do milho, do uso de bactéria diazotrófica Azospirillum brasilense, inoculada via sementes em combinação com doses de nitrogênio. A pesquisa foi composta por um ensaio conduzido no campo experimental da Fazenda Lageado em Botucatu-SP, pertencente à Universidade Estadual Paulista "Júlio de Mesquita Filho" - Faculdade de Ciências Agronômicas, em delineamento experimental de blocos ao acaso, com quatro repetições, em esquema fatorial duplo. Tendo o fator 1, dois níveis: sem e com aplicação da solução da bactéria Azospirillum brasilense nas sementes e o fator 2, seis doses totais de nitrogênio: zero, 180, 155, 130, 105 e 80 kg ha-1. Foi utilizado o híbrido de milho transgênico 2B587 Hx, ciclo precoce, porte baixo, indicado para semeadura no verão. As avaliações morfológicas da planta e da espiga foram realizadas aos 20, 40, 60, 80 e 100 dias... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Corn is a cereal grown worldwide; however it presents challenges with regards to the proper fertilizer management. Its high demand for nitrogen has been primarily responsible for excessive doses of synthetic nitrogen fertilizer applied to the crop. As a result, it can be observed an increase in cost of crop production and negative impacts to the environment. Thus, it is necessary to study alternative methods that promote the plant growth and ensure productivity, improving efficiency, economic viability and environmental safety. Diazotrophic bacteria can fix atmospheric nitrogen and produce growth promoting substances which can reduce the use of nitrogen fertilizers in the corn cultivation. To test this hypothesis, this study had the objective to evaluate the agronomic efficiency in corn, using Diazotrophic Azospirillum brasilense inoculated via seeds in combination with nitrogen levels. The research consisted in a field trial, where the experimental design was a randomized block, with four replications in a double factorial. Factor 1: with and without the application of the solution of the bacterium Azospirillum brasilense in seeds, and factor 2: six total doses of nitrogen: zero, 180, 155, 130, 105 and 80 kg ha-1. The hybrid of the transgenic corn 2B587 Hx, early maturity, small size was used, suitable for planting in the summer. The morphological evaluations of plant and cob were evaluated at 20, 40, 60, 80 and 100 days after emergence (DAE). Grain yield was measured at 115 DAE. Inoculation of corn seeds with Azospirillum had no effect on growth and productivity of corn plants. The adoption of this practice did not replace the use of nitrogen... (Complete abstract click electronic access below) / Mestre