A utilização de cereais de inverno com dupla aptidão é uma excelente alternativa para o sistema de integração lavoura-pecuária, comumente utilizado nas pequenas propriedades do Sul do Brasil, pois possibilita a produção de forragem associada à produção de grãos. Atualmente, já existe cultivares comerciais de trigo com duplo propósito desenvolvidos para o Estado do Rio Grande do Sul, sendo necessário avalia-los mais apropriadamente para as condições edafoclimáticas do Estado do Paraná. O objetivo deste estudo foi avaliar o rendimento de grãos e a qualidade dos mesmos, bem como a produção de forragem e composição bromatológica, de cultivares de trigo duplo propósito sob diferentes doses de nitrogênio e submetidos a regimes de corte. O experimento foi realizado na área experimental da Universidade Tecnológica Federal do Paraná, Campus Dois Vizinhos, e o delineamento experimental utilizado foi o de blocos ao acaso com semeaduras em faixas e três repetições. Os fatores avaliados foram: quatro cultivares de trigo duplo propósito (BRS Figueira, BRS Guatambu, BRS Tarumã e BRS Umbu); doses crescentes de nitrogênio (0, 45, 90, 135 e 180 kg ha-1) aplicadas nas parcelas; regimes de corte (sem corte, com um corte e com dois cortes) aplicados às subparcelas. As variáveis avaliadas foram: relação de folhas (RF) na forragem; produção de forragem (PF); proteína bruta (PB), digestibilidade in vitro da matéria orgânica (DIVMO) e nutrientes digestíveis totais (NDT) da fitomassa seca; massa de espiga (ME); número de espiguetas por espiga (NE); número de grãos por espigueta (NG); produção de grãos e o peso do hectolitro (PH). Os dados foram submetidos à análise de variância, através do teste F, a 5% de probabilidade de erro. As médias qualitativas foram comparadas pelo teste de Duncan e as variáveis quantitativas submetidas à análise de regressão. A produtividade média encontrada entre os cultivares e regimes foi de 1.202,23 kg ha-1, com peso do hectolitro médio de 74,3 kg hL-1, e as doses de adubação nitrogenada não influenciaram este rendimento. Os cultivares de ciclo semi-tardio, BRS Figueira e BRS Umbu, apresentaram maior produção de grãos (2.067,2 e 2.075,8 kg ha-1, respectivamente) que os demais, porém este rendimento decresceu severamente em função dos cortes. A adubação nitrogenada apresentou influência significativa apenas sobre a DF e PB, variáveis que demonstraram crescimento linear com as doses de N utilizadas neste estudo. Os cultivares de ciclo tardio-precoce, BRS Guatambu e BRS Tarumã, apresentaram menor PF total (1.230,6 e 714,0 kg ha-1, respectivamente) que os de ciclo semitardio (BRS Figueira com 1.661,5 e BRS Umbu com 1.686,7 kg ha-1), porém com maior qualidade bromatológica medida pela PB e DIVMO. Estes resultados indicam que os cultivares de ciclo tardio-precoce são mais adaptados ao manejo de duplo propósito, pois apesar de apresentar menor PF total, esta tem maior qualidade e, além disso, mostraram maior capacidade de recuperação após os cortes com um decréscimo menor na produção de grãos. / The use of coul season cereals with dual purpose is an excellent alternative for croplivestock integration system, usually used in small properties in South Brazil, as it enables the production of fodder plant associated with the production of grains. Although there are commercial wheat cultivars of dual purpose developed for Rio Grande do Sul State, it is necessary to evaluate them more appropriately considering the soil and climate conditions of Paraná State. The objective of this study was to evaluate the income of grains and their quality, as well as the forage production and chemical composition of dual purpose cultivars of wheat under different rates of nitrogen fertilization and management of system cuts. The experiment was carried out at the experimental area of the Federal Technological University of Paraná, Dois Vizinhos Campus, and the experimental design was a randomized blocks with sowings bands and three replicates. The studied factors were: four cultivars of dual purpose wheat (BRS Figueira, BRS Guatambu, BRS Tarumã, and BRS Umbu); increased rates of nitrogen fertilization (0, 45, 90, 135, and 180 kg ha-1) applied to the plots; management of cuts simulating grazing (without cut, with one cut, and two cuts) applied to sub-plots. The evaluated variables were: leaf blade proportion (LP) in the forage; forage production (FP); crude protein (CP), in vitro digestibility of organic matter (IVDOM), and total digestible nutrients (TDN) in the dry matter; spike weight (SW); number of spiklets per spike (NS); number of grains per spiklet (NG); grain yield and the hectoliter weight (HW). Data were submitted to analysis of variance, through F test, at a 5% probability error. The qualitative variables were compared by the Duncan test and the quantitative variables by regression analysis. The grain yield found for the cultivars and managements studies averaged 1.202,23 kg ha-1, with an average hectoliter weight of 74.3 kg hL-1. Rates of nitrogen fertilization did not influenced grain yield. The cultivars of half-delayed cycle (BRS Figueira and BRS Umbu) presented greater yield of grain (2.067,2 e 2.075,8 kg ha-1, respectively) than others; however, this income decreased severely as a function of the cuts. The nitrogen fertilization significantly influenced the FP and CP, which presented a linear growth as N fertilization rate increased. Cultivars of delayed-precocious cycle (BRS Guatambu and BRS Tarumã) presented lower total FP (1230,6 and 714 kg ha-1, respectively) than those of half-delayed cycle (BRS Figueira with 1.661,5 and BRS Umbu with 1.686,7 kg ha-1); however, they presented highest chemical quality, measured by CP and IVDOM. These results indicate that cultivars of delayedprecocious cycle are more adapted to the dual purpose management, because although they present lower total FP, their quality is higher. Moreover, they had shown a greater regrowth capacity after cuts, as they presented a lower decrease in grain yield.

CAPES / A adubação nitrogenada é freqüentemente observada como um eficiente fator nutricional fornecido a planta visando melhorar a produção de espécies forrageiras, necessitando ser entendido o comportamento do nitrogênio (N) no sistema. O experimento foi conduzido na área do Instituto Agronômico do Paraná (IAPAR) na estação experimental de Pato Branco, com objetivo de avaliar a dinâmica do N no sistema solo-planta em pastagem de Brachiaria plantaginea. O delineamento experimental foi o de blocos ao acaso com duas repetições. Os tratamentos foram arranjados em parcelas subdivididas. Nas parcelas foram alocados os períodos e nas sub-parcelas a combinação das três doses de N e duas intensidades de pastejo (Massa Alta e Massa Baixa), perfazendo seis tratamentos em esquema fatorial. As doses de N foram compostas de 0, 200 e 400 kg.ha-1 de N e as intensidades de pastejo preconizadas em massa baixa (MB), com 1.500 kg de MS.ha-1, e massa alta (MA) com 3.000 kg de MS.ha-1 em pastejo com lotação contínua e taxa de lotação variável. Utilizaram-se caprinos, meio sangue Bôer, com cinco meses de idade e peso médio de 21 Kg de peso vivo (PV), para definir as massas de forragem (MF) preconizadas. Avaliou-se a produção acumulada e total de biomassa aérea de papuã nos períodos experimentais, os índices nutricionais de nitrogênio, fósforo e potássio, também a curva de diluição, eficiência e recuperação do nitrogênio e o comportamento do nitrogênio no solo. A produção de forragem de B. plantaginea foi maior na dose intermediaria de N (200 kg de N.ha-1), atingindo uma produção de 19.834 kg de MS.ha-1, 31% a mais que no tratamento que não recebeu adubação nitrogenada. Os teores de N encontrados nas plantas que receberam adubação nitrogenada apresentaram valores superiores aos preconizados como críticos, resultando em conteúdos adequados deste elemento na planta, e, ao contrário, as plantas cultivadas sem adubação nitrogenadas apresentaram teores inferiores ao crítico, apontando desta forma que a curva de diluição de N é uma ferramenta adequada para diagnose de nutrição nitrogenada em pastagens. A máxima produtividade foi limitada pela falta de fósforo indicada pelo baixo índice de fósforo obtido conforme os teores do elemento na pastagem e a absorção de K aumentou com a adubação nitrogenada apresentando índices satisfatórios do elemento. A dose de 200 kg de N.ha-1 demonstrou-se a mais eficiente com taxas de recuperação de N superiores em 63% em relação a dose de 400 kg de N.ha-1. Não foi observada lixiviação das formas de nitrogênio inorgânicas estudas (nitrato e amônio) no perfil do solo e observou-se maior quantidade de nitrato e N-Mineral na menor massa de forragem após completada a quantidade de N proposta. / Nitrogen fertilization is usually noticed as an efficient nutritional factor offered to the plant with the aim to improve its production, being necessary to understand the nitrogen behave (N) in the system. The experiment was carried out at the Agronomist institute of Paraná (IAPAR), experimental unit of Pato Branco with the aim to evaluate the dynamic of N in the soil-plant system of a Brachiaria plantaginea. The experiment was laid out as random block design with two replications. The treatments were arranged in a split-plot model. At the plots were allocated the periods and at the sub-plots the combination of three levels of nitrogen and two grazing intensities (High mass and Low Mass), making six treatments in a factorial scheme. The levels of nitrogen used were composed of 0, 200 and 400 kg of N.ha-1 and the grazing intensities characterized by the low forage mass (LM) with 1.500 kg of DM.ha-1 and high forage mass (HM) with 3000 kg of DM.ha-1 in a continuous stocking rate. Were used goats half blood Boer with five months old and average life weight of 21 kg of live weight (LW) at the beginning of the experiment with the aim to adjust the forage mass (FM) wanted. Was evaluated the accumulate and total forage production of the papuã aerial biomass at the experimental periods, the nutritional indices of nitrogen, phosphorous and potassium and also the dilution curve, efficiency of N recovery and behave of nitrogen in the soil. The Brachiaria plantaginea forage production was higher at the nitrogen intermediate level (200 kg of N.ha-1), reaching an production of 19.834 kg of DM.ha-1, 31% more then treatment without nitrogen. The N levels found in the plants that received nitrogen fertilization showed higher values than the ones recognized as deficient, resulting in adequate contents of this element in the plant and, in the other hand, the plants cultivated without nitrogen showed levels below the one recognized as sufficient, showing with that the dilution curve of N is an adequate tool to diagnose the forage nitrogen nutrition. The highest production was limited by the lack of phosphorous showed by the phosphorous indices obtained according to the pasture element levels and the absorption of K increased with the nitrogen application, showing satisfactory level of the element. The 200 level of N.ha-1 showed to be the most efficient with recovery N levels 63% higher than the 400 kg.N.ha-1. There was no inorganic (NO3 - e NH4 +) N leaching found in the soil profile and was noticed higher quantities of NO3 - and mineral-N at the lower forage mass after finishing the total N applied.

Made available in DSpace on 2014-06-11T19:29:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-10-19Bitstream added on 2014-06-13T20:19:55Z : No. of bitstreams: 1 valderrama_m_me_ilha.pdf: 219412 bytes, checksum: f658b0b9404e08e89e45e8be74a774f7 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O milho é um dos cereais cultivados no Brasil com maior possibilidade de expressão de produtividade. No entanto, o nível de produtividade é muito baixo e um dos fatores de maior influência é o nitrogênio, que está presente nos mais variados compostos orgânicos tais como aminoácidos, ácidos nucléicos e proteínas. Dentre os nutrientes é o exigido em maiores quantidades pela planta de milho e a ureia é o fertilizante mais utilizado nas adubações de cobertura na cultura. Porém, sua eficiência nos sistemas agrícolas é muito variável, dependendo do tipo de solo, da cultura, da dose, da forma de aplicação, do manejo da cultura e das condições ambientais. No entanto, novas ferramentas, para aumentar a eficiência dos fertilizantes nitrogenados, estão aparecendo, com a finalidade de reduzir as perdas por lixiviação, desnitrificação e volatilização, neste caso quando a fonte utilizada for a ureia. Os fertilizantes revestidos por diferentes compostos, dentre eles os polímeros, tem como objetivo reduzir as perdas dos nutrientes, que no caso do nitrogênio, podem atuar na volatilização e lixiviação. O objetivo deste trabalho foi avaliar a resposta da cultura do milho irrigado ao uso de polímeros revestindo a ureia (K-0043, K-0049 e K-0055) por diferentes composições e concentrações e a ureia convencional (K-0046), com quatro doses de N em cobertura, em delineamento em blocos ao acaso em esquema fatorial, em dois cultivos sucessivos na mesma área, com quatro repetições. O experimento foi conduzido no período de outubro de 2009 a setembro de 2010, sendo este período correspondente aos dois cultivos (safra e safrinha), na Fazenda de Ensino e Pesquisa da Faculdade de Engenharia de Ilha Solteira – UNESP, localizada em Selvíria - MS... / Corn is a cereal grown in Brazil with the highest expression of productivity. However, the level of productivity is very low and one of the most important factor is nitrogen which is present in various organic compounds such as amino acids, nucleic acids and proteins. Among the nutrients it is required in larger quantities by the corn plant and the urea is the fertilizer more used at sidedressing. However, its efficiency in agricultural systems is very variable, depending on soil type, crop, doses, form of application, crop management and environmental conditions. Nowadays, new tools to increase the efficiency of nitrogen fertilizers are appearing, in order to reduce losses by leaching, denitrification and volatilization, in this case when the source used is urea. Fertilizers coated by different compounds, including polymers, aim to reduce losses of nutrients, which in the case of nitrogen, they occur by volatilization and leaching. The objective of this study was to evaluate the efficiency of polymer-coated urea (K-0043, K-0049 and K-0055) in different compositions and concentrations beside the conventional urea (K-0046), in four application rates, disposed in a randomized blocks design in a factorial scheme, in two successive crops in the same area. The experiment was conducted from October 2009 to September 2010, and this period corresponding to two crops (season and no season), at Experimental Station located in Selviria – MS belonged to Engineering Faculty of Ilha Solteira- UNESP - SP. The soil of this area is classified as a dystrophic clayey Oxisol and the hybrid used was biogenic Y. 7049. The sources were applied at sidedressing 30 days after crop emergence, when plants had six fully developed leaves, using doses of 0, 40, 80 and 120 kg ha-1 N. The plots consisted of 4 rows, 7 m long, spaced by 0.90 m. We evaluated the... (Complete abstract click electronic access below)

There is consensus that high CO2 results in enhanced growth and yield for most crop plants. However, most of these studies were carried out in the presence of adequate nutrients, which is also the case in agricultural systems (managed ecosystems). About 20% of the earth’s land mass have sufficiently low levels of nutrients to cause some kind of stress to plants. On the other hand, elevated [CO2] decreases foliar nutrient elements in plants and as a result partitioning of certain nutrient elements in plants is altered. Little data is available on the partitioning of most nutrient elements in plants, and this will definitely impact on growth and yield. To investigate this, wheat (Triticum aestivum L. c.v. Gamtoos) was grown in controlled environment cabinets at 360 and 700 µmol mol -1 CO2. The full Long-Ashton nutrient solution comprising of three-nitrogen concentrations ([N]) viz. (4,6 and 12 mM) was used to water plants everyday. The measurement of net assimilation rate (NAR), stomatal conductance (gs), transpiration rate (E), water use efficiency (WUE), foliar [N], nitrogen use efficiency (NUE) and growth parameters (total plant biomass (TPB), total plant height (TPH), leaf area (LA), shoot and root dry weight) were made 7 days after germination (7 DAG) till the onset of flowering. The increase in nitrogen supply in the order of 4, 6 and 12mM resulted in an increase in NAR, g_s_ , WUE and a decline in E under elevated [CO2]. Under elevated [CO2] NAR was observed to increase during the first two weeks reaching its maximum at 14 DAG, thereafter followed by a decline reaching its maximum at 28 DAG. This was later followed by an increase at 35 DAG onwards. Under elevated [CO2], NAR was increased significantly between the nitrogen regimes during the first (7-14 DAG) and the last two (35-42 DAG) weeks. The response of assimilation as a function of internal [CO2] (Ci), showed a decrease with age at ages 14, 28 and 35 DAG. This negatively affected the initial slope and the CO2 saturated photosynthetic rates under all treatments. This suggest that acclimation may have been as a result of both stomatal and biochemical limitations. All the photosynthetic pigment levels (chl_a_, chl_b_, chl_(a+b)_, and C_(x+c)_ ) increased with an increase in nitrogen supply from 4 to 6mM [N]. A 12mM [N] resulted in a significant decline in the photosynthetic pigment levels compared to a 6mM [N]. Chla remained higher than chlb under all treatments. Also, NAR was seen to increase and decrease concomitantly with the photosynthetic pigment levels. Foliar [N] was seen to decrease with an increase in nitrogen supply from 4 to 6 mM [N] under elevated [CO2] and the effects were adverse under the 4mM [N]. Under the 6mM N regime foliar [N] was positively correlated to NAR for elevated [CO2] grown plants. Similarly, E was positively correlated to foliar [N] under the same conditions. Elevated CO2 and increase in nitrogen supply had a pronounced effect on total plant height (TPH), total plant biomass (TPB), leaf area (LA), shoot and root dry weight and nitrogen use efficiency (NUE). The effects were more pronounced under a 6mM [N] as a result of high NUE. However, under 12mM [N] growth was not as expected as a result of lower NUE. Under all treatments shoot dry weight (SDW) was positively correlated to NUE. Anatomical studies revealed that total leaf and midrib thickness was significantly increased with an increase in nitrogen supply under elevated CO2 to support the larger leaf areas. There were no significant changes in the chloroplast ultrastructure as a result of the increase in nitrogen supply and CO2 enrichment. Starch grain surface area was seen to decline with an increase in nitrogen under both ambient and elevated CO2. Elevated CO2 and increase in nitrogen supply significantly increased total grain dry weight per plant by 47 and 46% respectively under 6 and 12mM [N]. In contrast, the increase was by about 21, 61 and 67% respectively under 4, 6 and 12mM [N] between the CO2 regimes.

Poor management of nitrogen (N) fertilisers and water in agro-ecosystems reduces yield, quality and N-use efficiency, and leads to pollution. The objective of this study was to improve irrigation and N management for planted pastures through adaptive management with simple tools and modelling. Field experiments were conducted in 2007 and 2008 at Cedara (KwaZulu Natal) and Hatfield (Gauteng) using annual ryegrass as a case study under a range of N and irrigation application strategies. Collected data sets were also used to calibrate and validate the SWB-Pro (simple) and SWB-Sci (detailed) model versions. After validation, the model was used to develop irrigation calendars and strategies, and estimate irrigation requirements for annual ryegrass. The highest forage yields were produced when N application rates ranged between 30 to 60 kg N ha-1 for each growth cycle, except for the first 2-3 growth cycles when there was high soil N carryover from the previous season. The current farmers’ recommendation (fixed N application rate of 50 kg ha-1 per growth cycle) maximised biomass but reduced pasture quality. Adaptive strategies based on nitrate concentration in wetting front detectors at different depths, reduced fertiliser N application by 28–32% and reduced potentially leachable residual soil N, while improving forage quality without yield reduction. The rate 30-40 kg N ha-1 per growth cycle provided a compromise between forage yield and quality. The SWB model performed well in simulating ryegrass growth, leaf area index, forage yield, root zone soil water deficit, daily evapotranspiration, biomass N uptake and soil nitrate. Site specific and monthly variable irrigation calendars were developed using the SWB-Pro model, for four major milk producing areas of South Africa. The simpler monthly irrigation calendars can be used in the absence of irrigation monitoring tools or more accurate site specific calendars. The SWB-Pro model requires relatively few and simple inputs. However, irrigation monitoring/scheduling with the aid of real time modelling or measurements is better than calendars developed using the SWB-Pro model with long-term historical weather data. The SWB-Sci model showed ways of improving water use efficiency using ‘room for rain’ and ‘mildly deficit irrigation’ approaches in high rainfall areas. Scenario modelling demonstrated that the best management strategy of achieving maximum yield together with low N leaching is by integrating N and water management. This integrated management can be based on the wetness of the soil and nitrate concentration in the deep root zone using wetting front detectors. The model can be used to generate monitoring protocols such as depth of wetting front detector placement and selecting N thresholds to be used for adaptive management. Setting approximate thresholds for wetting depth and nitrate concentration is a first step in implementing an adaptive management strategy. However, the challenge is to find monitoring tools which allow effective implementation of the strategy. In this study, the wetting front detector proved to be a robust, on-farm water and nitrate monitoring tool which is relatively simple and cost effective. Should it become widely adopted, farmers are expected to improve these thresholds as more experience is gained. The SWB model could also be used to evaluate alternative thresholds for adaptive N and water management. / Thesis (PhD)--University of Pretoria, 2012. / Plant Production and Soil Science / unrestricted

Please read the abstract in the dissertation / Dissertation (MSc (Agric))--University of Pretoria, 2006. / Plant Production and Soil Science / unrestricted

Please read the abstract in the section 00front of this document / Dissertation (MSc Agric (Animal Nutrition))--University of Pretoria, 2006. / Animal and Wildlife Sciences / unrestricted

Orientador: Mara Cristina Pessôa da Cruz / Banca: Manoel Evaristo Ferreira / Banca: Renato Yagi / Resumo: O cultivo de plantas de cobertura em sistema plantio direto e a adubação nitrogenada podem alterar a ciclagem e o acúmulo de P no solo. O conhecimento da solubilidade, distribuição e proporção das formas de P pode fornecer informações importantes para a avaliação da disponibilidade do elemento para as plantas e possibilitar a maximização da eficiência do uso de fertilizantes fosfatados. Diante disso, pretendeu-se avaliar os efeitos de plantas de cobertura em pré-safra de milho, e de doses de adubo nitrogenado em cobertura no milho, nas formas de P do solo, em experimento de longa duração. O experimento está instalado em Latossolo Vermelho Distrófico, textura argilosa. O delineamento experimental é em blocos ao acaso, em parcelas subdivididas, com quatro repetições. Os tratamentos principais são culturas de cobertura: crotalária, feijão-de-porco, lablab, mucuna-cinza, milheto e vegetação espontânea; os tratamentos secundários são doses de N em cobertura na cultura de milho equivalentes a 0 e 120 kg ha-1. Amostras de solo foram coletadas doze anos após o início do experimento, 30 dias após a dessecação das plantas de cobertura, nas entrelinhas da cultura do milho e nas camadas de 0 a 5; 5 a 10; 10 a 20 e 20 a 40 cm. Nelas foram determinados matéria orgânica, pH CaCl2, P- resina, P orgânico total, P total e formas orgânicas (Po) e inorgânicas (Pi) de P. As formas de P foram obtidas usando os seguintes extratores, em sequência: resina trocadora de ânions (PResina), soluções de NaHCO3 (Pbic), NaOH (PNaOH) e HCl (PHCl), e mistura de H2SO4 + HF + H2O2. As formas obtidas foram classificadas em P lábil (PResina + Pbic), P moderadamente lábil (PNaOH) e P não lábil. O cultivo de crotalária, lablab, feijão-de-porco, mucuna-cinza e milheto como plantas de cobertura em pré-safra de milho aumenta o P orgânico moderadamente lábil (Po NaOH I) na camada superficial do solo. A adubação nitrogenada favorece... / Abstract: Growing cover crops under no-tillage system and nitrogen fertilization can change the cycling and the accumulation of phosphorus in soil. The knowledge of the solubility, distribution and proportion of forms of P in soil can provide important information for assessing the availability of this element for plants and enable maximum efficiency of phosphate fertilizers use. With that, we aimed to evaluate, in a long term experiment, the effects of cover crops in pre-cropping corn, and sidedress nitrogen levels in corn, in the forms of soil phosphorus. The experiment was installed in a sandy clay Oxisol. The experimental design was randomized blocks with split plots and four replications. The main treatments were cover crops: Crotalaria juncea, Canavalia ensiformis, Dolichos lablab, Mucuna cinerea, Pennisetum americanum, and spontaneous vegetation; the secondary treatments were sidedress N doses in corn, equivalent to 0 and 120 kg ha-1. Organic matter, pH CaCl2, P-resin, total organic P, total P, and organic (Po) and inorganic (Pi) forms of P were determined in samples collected twelve years after the start of the experiment in 0-5, 5-10, 10-20 and 20-40 cm layers. The P forms were obtained using the following extractants, in order: anion exchange resin (PResin), NaHCO3 (Pbic), NaOH (PNaOH) and HCl (PHCl), and a mixture of H2SO4 + HF + H2O2. The obtained forms were classified as labile P (PResin + Pbic), moderately labile P (PNaOH), and non-labile P. The cultivation of Crotalaria juncea, Canavalia ensiformis, Dolichos lablab, Mucuna cinerea and Pennisetum americanum as cover crops in corn pre-cropping increases moderately labile organic P (Po NaOH I) in the topsoil. Nitrogen fertilization favors Po mineralization in soil and redistributes forms of Pi and Po between the labile and moderately labile compartments, without impacting available P / Mestre

Orientador: Ciro Antonio Rosolem / Banca: Roberto Lyra Villas Bôas / Banca: José Roberto Sartori / Resumo: A cama de frango é um adubo orgânico cuja principal característica é a concentração de nitrogênio, porém, há uma alta taxa de volatilização de nitrogênio em forma de amônia. No presente estudo, foi possível avaliar a eficiência do gesso agrícola em diminuir as perdas de nitrogênio da cama de frango por volatilização e melhorar sua característica como fertilizante na adubação da cultura do milho. Os ensaios constituíram pela aplicação de gesso agrícola em cama de frangos de corte nos quais, foram empregados doses de 15%, 30% e 45% em relação ao volume de maravalha, e um tratamento controle sem adição de gesso. Durante todo o período de cria, nos três lotes consecutivos de frangos, foram coletadas amostras de amônia volatilizada por meio de sensor durante três períodos do dia a cada sete dias. Uma amostragem da cama foi coletada ao final de cada ciclo para análises químicas. Ao término da cria a cama foi retirada do galpão e aplicada como fertilizante em vasos para o cultivo do milho em casa de vegetação, mantendo os tratamentos inicias combinados com e sem a aplicação de 100mg de nitrogênio/kg da massa de solo, formando um esquema fatorial de quatro tratamentos com duas variáveis (4x2). Após 50 dias de cultivo foram coletadas amostras de solo para análises, observou-se que o gesso foi incapaz de controlar a volatilização de amônia, não diferindo nos teores de nitrogênio inorgânico. Portanto, os tratamentos não incrementaram eficiência em produção de matéria seca do milho, outrora, essas combinações entre ... / Abstract:Poultry litter is organic fertilizer whose major characteristic is the nitrogen concentration, but, there is a high volatization nitrogen rate in the form ammonia. This study, was possible appreciate the phosphorgypsum efficiency to reduce nitrogen losses on poultry litter through volatilization and upgrade characteristic like a fertilizer in the cultivation corn. The testing considered in application phosphogypsum in poultry litter, were employed 15%, 30% and 45% doses compared to wood shaving volume, and control treatment without addition gypsum. While the period creates, three consecutive poultry lots, was collected samples volatilized ammonia by a sensor during three periods in the day each seven days. Was collected sampling bed in every final cycle to chemical analysis, finishing all cycle the bed was removed to be applied as fertilizer inside vase corn cultivation in house vegetation, keeping the treatments initial combination with and without application 100mg nitrogen / kg soil volume, constituted a factorial arrangement of four treatments with two variables (4x2). After 50 days cultivation was collected samples soil to analyze, it was observed that gypsum is unable to control ammonia volatization, not differing inorganic nitrogen. Therefore, treatments was not increase efficiency in production corn dry matter, in the other hand, this combinations between poultry litter, gypsum and nitrogen increased the concentration phosphorus and nitrogen in cultivation ... / Mestre

Understanding the redistribution and fate of N is essential for justification of Best Management Practices (BMP). This project was conducted on a Hecla fine sandy loam (sandy, mixed, Aquic Haploboroll) soil at the BMP field site near Oakes, North Dakota. One objective of this investigation was to evaluate the residence times of N03- -N in 20 undisturbed lysimeters and its infiltration time through the soil profile to tile drains. Corn (Zea mays L.) was fertilized with 135 kg N ha -1 as ¹⁵N-enriched urea plus 13.5 and 48.1 kg N ha -1 preplant for 1993 and 1994, respectively. Urea-N was band applied to 20 and 10 undisturbed lysimeters at 2.0 and 5.93 atom percent (at %) ¹⁵N in 1993 and 1994, respectively. Average resident times of N03- -N in the lysimeters was 11.7 months. Lysimeter and tile drainage indicate the presence of preferential pathways. Residence times of N03- -N depend on frequency and intensity of precipitation events. Another objective was to determine what portion of the total N in the crop was from applied urea-N and what portion was from the native soil-N. Nitrogen plots received ¹⁵N enrichments of 4.25 and 5.93 at % ¹⁵N in 1993 and 1994, respectively. At the end of the 1993 and 1994 growing season, 41.5% and 35.7% of the labeled fertilizer N remained in the soil profile, while the total recovery of applied ¹⁵N in the soil-plant system was 86.2% and 75.4%, respectively. Low recoveries of applied N may have been the result of soil or aboveground plant biomass volatilization, or denitrification or preferential flow processes. Further research needs to be conducted with strict accountability of gaseous loss and the mechanism(s) responsible. / U.S. Bureau of Reclamation