A transição do manejo de cana queimada para a colheita sem despalha a fogo dificulta o manejo da adubação principalmente em relação à fertilização nitrogenada, seja pela maior imobilização do N-fertilizante, quando aplicado sobre a palhada, ou pelas elevadas perdas por volatilização de N-NH3, já que a ureia é a principal fonte de N. O objetivo deste trabalho foi avaliar, em primeira soqueira de cana-de-açúcar, a marcha de absorção, a taxa de acúmulo de fitomassa e nutrientes e a produtividade relacionadas a fontes de N. Foram instalados dois ensaios, sendo o primeiro em um LATOSSOLO VERMELHO eutrófico (LVe) e o segundo em LATOSSOLO VERMELHO distrófico, ambos no Estado de São Paulo. Os tratamentos consistiram na dose de 100 kg ha-1 de N, utilizando as seguintes fontes: cloreto de amônio, nitrato de amônio, ureia, Ajifer®, NitromagTM e sulfato de amônio e um tratamento sem N. Foram realizadas quatro amostragens ao longo do ciclo da cultura. A cana-de-açúcar apresentou três fases de crescimento vegetativo, independente do tratamento. No LVe, a fonte que apresentou maior contribuição foi o NitromagTM que produziu em torno de 45 Mg ha-1 de fitomassa e 110 Mg ha-1 de colmos frescos, enquanto que no LVd o uso do Ajifer® resultou em acúmulo superior de fitomassa em relação às demais fontes com 30 Mg ha- 1 e produtividade de colmo da ordem de 103 Mg ha-1. A maior taxa de produção de fitomassa seca ocorreu aos 220 DAC atingindo cerca de 350 kg ha-1 dia-1, nos tratamentos NitromagTM e nitrato de amônio no LVe. A cana-de-açúcar adubada com as fontes de nitrogênio mostrou maior incremento de fitomassa, com antecipação no acúmulo de N anterior ao de biomassa. A ordem média de extração de macronutrientes foi: K>N>Ca>S>Mg>P no LVd e LVe, sendo a exportação dos nutrientes pelo colmo de 23, 50, 32, 56, 53 e 53% no LVe e 76, 46, 21, 56, 37 e 57% no LVd. A exigência nutricional da cana-de-açúcar para produzir 1 TCH é de 1,45; 0,14; 2,44; 0,61; 0,26 e 0,33 kg Mg-1, no LVe, respectivamente para N, P, K, Ca, Mg e S. O teor de K, Ca, Mg e S no solo afetou diretamente o acúmulo de nutrientes na planta, interferindo na extração e exportação dos nutrientes. / The transition of burnt to unburnt sugarcane management difficult the fertilizer management (especially in relation to nitrogen, N) due to the greater immobilization of N-fertilizer applied over the straw and high N-NH3 volatilization losses since ureia is the main N source. The objective of this study was to evaluate the rate of biomass and nutrients accumulation by sugarcane, as well the stalk yield as related do N-fertilizer sources, in the ratoon sugarcane cycle. Two trials were set up on aTypic Eutrustox (TE) and on a Typic Haplustox (TH), both in Sao Paulo State, Brazil. The treatments consisted of 100 kg N ha-1 applied by means of the the following N sources: ammonium chloride-AC, ammonium nitrate-AN, urea-U, Ajifer®, NitromagTM and ammonium sulfate- AS, and an additional treatment without N. Four measurements were performed throughout the crop cycle. The sugarcane showed three phases of vegetative growth, regardless of treatment. At TE soil the NitromagTM promoted higher biomass accumulation, reaching 45 Mg ha-1 and 110 Mg ha-1 stalk fresh, while at TH soil the Ajifer® increased the biomass as compared to the other sources, reaching 30 Mg ha- 1. The highest rate of biomass accumulation occurred around 220 days after harvest , reaching 350 kg ha-1 day-1 in treatments with NitromagTM and AN. . The N addition increased sugarcane biomass accumulation, and N accumulation occurred before biomass accumulation. . The average order of nutrients extraction by sugarcane was K> N> Ca> S> Mg> P, with 23, 50, 32, 56, 53, 53% (at TE soil) or 76, 46, 21, 56, 37, 57% (at TH soil) of those nutrients being accumulated on the stalks. The nutritional requirement of sugarcane was 1.45, 0.14, 2.44, 0.61, 0.26 and 0.33 kg t-1 of stalks (fresh weight), respectively for N, P, K, Ca, Mg and S. The soil content of K, Ca, Mg and S directly affected the nutrients accumulation by sugarcace, increasing the extraction and exportation of nutrients.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2018-02-09T11:41:07Z No. of bitstreams: 1 2016 - Ramon de Souza Victorino da Silva.pdf: 1815548 bytes, checksum: d38cb3bc107f782e4c75f4e66118d838 (MD5) / Made available in DSpace on 2018-02-09T11:41:07Z (GMT). No. of bitstreams: 1 2016 - Ramon de Souza Victorino da Silva.pdf: 1815548 bytes, checksum: d38cb3bc107f782e4c75f4e66118d838 (MD5) Previous issue date: 2016-02-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES, Brasil. / The aim of this project was to develop a statistical classifier based on algorithms using Bayesian theorem for prediction of nitrogen applied to the soil using low cost multispectral images Tifton85 pastures From information obtained from these images the indexes were calculated spectrum, which was used in a feature vector for discriminating N levels applied to the soil. The research was developed in the Rural Federal University of Rio de Janeiro, Department of Engineering, Machinery Area and Energy in Agriculture. The data were obtained from an experiment installed in the production area of Company Feno Rio Agro LTDA, partner in the project. Images were acquired in 2 times one after 36 days due to the cutting standardization of culture using a UAV (Unmanned Aerial Vehicle) and at 7, 14, 21, 28, 35, 42, 56 days using an imaging platform an experiment with 6 portions 250m2 (10x25m) containing respectively the treatments (0, 50, 100, 150, 200 and 250 kg ha-? N), statistical analyzes were performed the computer program SAS version student using PROCDISCRIM procedure. It was determined discriminant functions for each dose of nitrogen, using as feature vectors vegetation indices (NDVI, GNIR, SAVI, GNDVI, RNIR). These discriminant functions were tested in a Bayesian classifier, and the highest accuracies were using vegetation indices together getting a Kappa coefficient and overall accuracy of 83% and 80%, respectively. The results indicate that low cost multispectral images can be used to develop classifiers of nitrogen applied to the soil. These binders may be applied in computational algorithms in agricultural machinery control systems for fertilizer application at variable rates in precision agriculture. / O objetivo geral deste projeto foi desenvolver um classificador estat?stico com base em algoritmos utilizando o teorema bayesianos para predi??o de doses de nitrog?nio aplicadas ao solo, atrav?s de imagens multiespectrais de baixo custo em pastagens de Tifton85 A partir de informa??es obtidas nessas imagens foram calculados os ?ndices espectrais, os quais foram utilizados em um vetor de caracter?sticas para discriminar n?veis de N aplicados ao solo. A pesquisa foi desenvolvida na Universidade Federal Rural do Rio de Janeiro, Departamento de Engenharia, ?rea de M?quinas e Energia na Agricultura. Os dados foram obtidos de um experimento instalado no campo de produ??o da Empresa Feno Rio Agro LTDA, parceira do projeto. As imagens foram adquiridas em 2 momentos uma ap?s 36 dias decorrentes ao corte de uniformiza??o da cultura utilizando um VANT (Ve?culo A?reo N?o Tripulado) e aos 7, 14, 21, 28, 35, 42, 56 dias utilizando uma plataforma de capta??o de imagens de um experimento com 6 parcelas contendo respectivamente os tratamentos (0, 50, 100, 150, 200 e 250 kg ha -? de N), as an?lises estat?sticas foram realizadas no programa computacional SAS vers?o estudante, utilizando o procedimento PROCDISCRIM. Determinou-se fun??es discriminantes para cada dose de nitrog?nio, utilizando-se como vetores de caracter?sticas os ?ndices de vegeta??o (NDVI, GNIR, SAVI, GNDVI, RNIR). Essas fun??es discriminantes foram testadas em um classificador bayesiano, sendo que a maior acur?cia de classifica??o foi utilizando os ?ndices de vegeta??o em conjunto obtendo um coeficiente Kappa e a exatid?o global de 83% e 80%, respectivamente. Os resultados indicam que imagens multiespectrais de baixo custo podem ser utilizadas para desenvolver classificadores de doses de nitrog?nio aplicadas ao solo. Esses classificadores poder?o ser aplicados em algoritmos computacionais em sistemas de controle de m?quinas agr?colas para aplica??o de fertilizantes a taxas vari?veis em agricultura de precis?o.

O nitrogênio é o principal nutriente determinante da produção e sustentabilidade das pastagens e a absorção radicular das formas nitrato e amônio pode resultar em alterações no crescimento, características estruturais e morfogênicas das plantas. Assim, é imprescindível conhecer a expressão de resposta de cultivares com lançamento recente quanto às disponibilidades e formas de fornecimento de nitrogênio. Nesse sentido, objetivou-se avaliar as modificações nutricionais, produtivas e morfológicas na Brachiaria brizantha cv. Xaraés no crescimento inicial e na rebrotação. O experimento foi conduzido em casa de vegetação, onde foram avaliadas três proporções de nitrato/amônio (30/70, 85/15 e 100/0) e três doses de nitrogênio (3; 15 e 27 mmol L-1) em solução nutritiva. As plantas tiveram dois períodos de crescimento, nos quais foram realizadas análises de crescimento e avaliadas a taxa de aparecimento foliar (TAF), filocrono, número de folhas vivas por perfilho, comprimento final da lâmina foliar, número de perfilhos, concentrações de nitrogênio total, nitrato e amônio na parte aérea e de nitrogênio total nas lâminas de folhas recém-expandidas e valor SPAD. Ao final do período de rebrotação a massa seca de raízes, o comprimento e a superfície radicular e a concentração de nitrogênio total foram avaliados. As proporções com baixa dose de nitrogênio e elevado amônio comprometeram o crescimento, produção de massa seca e área foliar das plantas em ambos os crescimentos. Os números de folhas vivas e de perfilhos foram favorecidos pelo aumento das doses de nitrogênio e pelo fornecimento conjunto de nitrato e amônio na proporção 85/15, enquanto houve redução no filocrono com o fornecimento intermediário e alto de nitrogênio e proporções de nitrato/amônio de 85/15 e 100/0. A maior presença de amônio na solução nutritiva resultou em maiores atividade da redutase do nitrato e concentração de nitrogênio total e amônio na parte aérea e nas folhas diagnósticas do capim, enquanto reduziu o valor SPAD e o comprimento e superfícies radiculares. O valor SPAD não apresentou boa estimativa da concentração de nitrogênio total nas folhas diagnósticas do capim-xaraés nas condições de suprimento de nitrogênio com alta proporção de amônio. / Nitrogen is the major determinant of pasture production and sustainability, and the uptake of nitrate and ammonium by the roots can result in changes in growth, morphogenesis and structural characteristics of plants. Thus, it is essential to know the response of recently developed cultivars to nitrogen availability forms and rates. Accordingly, the objective was to evaluate the nutritional, productive and morphological modifications of Brachiaria brizantha cv. Xaraés in initial growth and regrowth. The experiment was conducted in a greenhouse, where three nitrogen rates (3, 15 and 27mmol L-1) and three ratios of nitrate/ammonium (30/70, 85/15 and 100/0) in nutrient solution were evaluated. The plants were cultivated in two growth periods in which growth analysis was done and the leaf appearance rate, phyllochron, number of living leaves per tiller, final length of the leaf blades, number of tillers, total nitrogen, nitrate and ammonium concentration in the shoot and total nitrogen in the diagnostic leaves and SPAD readings were evaluated. At the end of the regrowth period dry weight of roots, roots length and surface and total nitrogen were assessed. The lowest nitrogen rate and the 30/70 nitrate/ammonium ratio reduced growth, dry matter production and leaf area of plants on both growth periods. The number of living leaves and tillers increased by increasing nitrogen rates and by nitrate and ammonium in the proportion 85/15, while there was a reduction in the phyllochron when the intermediate and high nitrogen rate and nitrate/ammonium ratios of 85/15 and 100/0 were applied. The highest ammonium proportion in the nutrient solution increased the activity of the nitrate reductase enzyme and total nitrogen concentration in the diagnostic leaves and shoots, while it reduced SPAD value, length and root surface. SPAD reading was not a good estimation of total nitrogen content in the diagnostic leaves of Xaraés palisadegrass supplied with high ammonium proportions.

The aim of this research project was to use 15N nuclear magnetic resonance (NMR) spectroscopy to better understand nitrogen (N) cycling processes in forest plantations. In particular, the studies were designed to link to the effects of forest management practices and environmental conditions. 15N NMR cross polarization/magic angle spinning (CPMAS) and dipolar dephasing (DD)-CPMAS experiments of some simple N-containing compounds found widely in nature were first undertaken. This was done in order to understand how different sample conditions, such as the presence of moisture, sample mixing and dilution, affected the intensity and the observability of the NMR peaks corresponding to N containing functional groups. Our results exhibited changes in NMR signal intensities and various time constants calculated. In the case of variable contact time experiments, use of an equation that predicts both a bi-exponential rise and decay was found to fit the data obtained more accurately. The optimised parameters for 15N NMR CPMAS were then used along with other analytical techniques such as ion chromatography, total C and N and elemental analyses to study plant nutrient uptake, plant decomposition and the effect of forest ecosystem disturbances, in this case an insect infestation. These analytical data were also correlated with the changes in the 13C NMR spectra in order to gain a more comprehensive understanding of the chemical transformations in the forest ecosystem. / Doctor of Philosophy (PhD)

Rotating wheat with other crops is a common practice in the Willamette Valley of western Oregon. Depending upon previous crop and soil type, current N fertilizer recommendations for wheat in the Willamette Valley vary widely. Excessive fertilizer poses environmental risk, whereas lower N inputs than required by the crop represent economic losses to growers. Growers and their advisors face the challenge to minimize the environmental risk, and at the same time to maintain or increase economic returns. Questions are often raised concerning the efficient use of N fertilizer and accurately predicting the amount of N needed by wheat following different crops. The first study measured growth, N uptake and N use efficiency (NUE) of winter wheat grown after either a legume or oat for three years. In all three growing seasons, winter wheat showed higher biomass, N uptake and NUE when grown after a legume than after oat. The contribution of legume was evident before the wheat was fertilized in spring, indicating that legume N had mineralized in fall or winter. Contribution of soil N to wheat suggested that fertilizer N can be reduced by 44 kg N ha����� if a legume is grown previously. Nitrogen use efficiency estimated 50 to 70 days after N application by isotopic method (24 to 94%) was comparable with that estimated simply by difference (21 to 94%) at the same time. The second study predicted gross mineralization rates using analytical models. Comparable N mineralization was predicted by a model assuming remineralization and a model assuming no remineralization, suggesting that remineralization was negligible. In the spring, mineralization-immobilization turnover was at a lower pace than expected in both rotations. In two growing seasons, gross mineralization rates were higher where the previous crop was legume (0.37 to 0.74 kg����� ha����� day�����) as compared to where oat was grown previously (0.14 to 0.6 kg����� ha����� day). Negative net mineralization indicated that fertilizer N was immobilized in the oat-wheat rotation. The third study evaluated calibration and digestion techniques used to determine elemental concentration in grasses. Use of a dry ashed standard to calibrate the ICP spectrometer generated highly variable calibration curves and was not a viable calibration method. Good agreement was found between chemical and microwave digested standards. Dry ashing resulted in considerable S and Mn losses, whereas, perchloric acid digestion and microwave digestion showed similar results. Our study suggests that if routine analysis are to be performed for macro nutrients or involve trace level work, the best method is microwave digestion with chemical standard calibration of ICP spectrometer. / Graduation date: 1999

Graduation date: 1993

A two year field study was carried out in western Quebec to investigate methods of predicting and reducing NO3--N leaching. Corn (Zea mays L.) was planted on the expel site and them were four treatments: water table controlled at 600 mm and 120 kg/ha of N fertilizer (WT120), water table controlled at 600 mm and 200 kg/ha of N fertilizer (WT200), free drainage and 120 kg/ha of N fertilizer (FD120), and free drainage and 200 kg/ha of N fertilizer (FD200). Drain flow was monitored and water samples were taken and analyzed for NO3- -N. Soil NO3- levels were measured along with led chlorophyll and denitrification throughout the two growing seasons. / Drain flow was dependent on both rainfall and the soil moisture content. In 1996, water table control decreased drain flow. However, in 1997 (a drier year), the drain flows for all treatments were similar. NO3 --N was reduced significantly in the controlled water table plots. In 1996, there was 59.2% less NO3--N in the controlled water table plots than in the free drainage plots and in 1997 this increased to 75.9% less NO3--N in the controlled water table compared to the fire drainage plots. In 1996, denitrification was enhanced by the controlled water table plots, with 72.2% more denitrification occurring in the controlled water table plots than in the free drainage plots. In 1997, there was a 93.2% increase in denitrification occurring in the water table plots than in the free drainage plots. / The controlled water table plots had no effect on plant chlorophyll levels. Chlorophyll contents of the corn plants were higher where fertilizer was applied at 200 kg/ha. Overall, it was shown that water table management can significantly decrease NO3--N pollution in drainage water. (Abstract shortened by UMI.)

Hybrid poplars are fast-growing trees, well-suited for the production of bioenergy and wood products. They are often planted on marginal agricultural lands where soil fertility is low. The application of nitrogen (N) fertilizers is expected to replenish soil N reserves and support hybrid poplar productivity throughout the short-rotation growth period. The objective of this thesis was to assess the effect of two organic N fertilizers, papermill biosolids and pig slurry, on tree growth, nutrient uptake and soil fertility in a Populus trichocarpa x Populus deltoides hybrid poplar plantation. I also evaluated how these organic amendments influenced N transformation rates and denitrification losses. Hybrid poplar growth was greater when trees were fertilized with mixed biosolids: pig slurry fertilizer treatments compared to biosolids or pig slurry alone. Assessment of foliar nutrition with the critical value approach (CVA) and compositional nutrient diagnosis (CND) methods revealed that foliar N and P concentrations were limiting to tree growth. Vector analysis (VA) reflected growth responses in fertilized trees, relative to an unfertilized control, but may not be useful as a diagnostic tool due to the indeterminate growth habit of hybrid poplars. Nevertheless, surface application of papermill biosolids and pig slurry had the potential to improve soil fertility by increasing soil pH and extractable nutrients in the hybrid poplar plantations. Nutrient use efficiency (NUE) was greater in plots receiving the mixed biosolids:pig slurry treatment than biosolids or pig slurry alone. Laboratory incubations and 15N isotope pool technique revealed that pig slurry was a source of readily-mineralizable N one month after fertilizer application, and stimulated the gross nitrification rate and immobilization, while papermill biosolids contributed to a larger mineral N pools at the end of the season. Our results suggest that denitrification will be greater in biosolids-treated soils, which have a higher extractable Ca concentration and soil pH, as well as more NO3-N and available C for denitrifiers. Further investigation under field conditions would help us to evaluate the N transformations and losses mediated by microbial activities following organic fertilizer application in a hybrid poplar plantation.

In 1991, a project was initiated at Quinn and Ormstown, two sites with soils representative of Quebec's present-day agriculture. Three field management techniques were studied related to their possible impact on the soils: tillage, rotation, and N fertilization. The three treatments were randomly assigned in two blocks of a split-split-plot design. The main treatment, tillage, had two levels, conventional tillage (CT) and no-till (NT). The sub-treatment was represented by five 4-year rotations, starting from 1991 as follows: CCCC (continuous corn), CSAC (corn-soybean-alfalfa-corn), CSCS (corn-soybean-corn-soybean), SCSC (soybean-corn-soybean-corn) and SSSS (soybean monocrop). The third factor was N fertilization, at three different rates: 0, 90, and 180 kg/ha, excepting the continuous soybeans which received lower rates of, respectively, 0, 20 and 40 kg N/ha. Soil sampling was performed in 1994, during the last year of the 4-year rotations, at two different moments over the growing season, June and August, for all analysed soil properties, except aggregate stability and organic matter for which samples were taken only in September. (Abstract shortened by UMI.)

Thesis (Ph.D.) -- University of Western Sydney, 2008. / A thesis submitted to the University of Western Sydney, College of Health and Science, School of Natural Sciences, in fulfilment of the requirements for the degree of Doctor of Philosophy. Includes bibliographical references.