In Arctic tundra soils pH serves as an important parameter related to several biotic parameters such as, plant and microbial community composition, biodiversity, nutrient dynamics and productivity. Both abiotic and biotic factors, for instance, base saturation (BS) and plant nutrient uptake may exert a control on soil pH, while it is still unclear to what extent different factors can explain soil pH across different tundra vegetation types. The aim of this study was to investigate to what extent different abiotic and biotic factors influence soil pH in the humus layer across different tundra vegetation types. To do so, eight different tundra vegetation types of which four were underlaid by permafrost (Arctic Alaska) and four with no permafrost (Arctic Sweden) were studied in detail with regard to different properties affecting soil pH. I found that BS was the main factor controlling soil pH across the different vegetation types regardless if the soil was underlain by permafrost or not. Factors, such as, ionic strength or soil water content could not explain any overall pH variation and did only significantly affect the heath soils. Further, the uptake of the most abundant base cations (Ca2+, Mg2+ and K+) from meadow and heath vegetation revealed a high difference between plant functional groups within the same vegetation types. The higher dominance of slow growing woody species in heath vegetation which had a lower uptake corresponded with a lower BC content (especially (Ca2+), pH and BS in the humus soil relative the meadow meanwhile the content of K+ was more than three times higher in heath. Overall, this study suggests that the degree of neutralization (base saturation) regulates pH either via the influence of bedrock and hydrogeochemistry and/or via plant traits that affects the uptake and turnover of base cations.

Atmospheric acidic deposition has negatively impacted many Appalachian watersheds in the eastern United States and soils play a key role in the biogeochemical processes that govern the fate and transport of the acidic pollutants. Thus, the collection of soil chemistry data, a previously lacking component, is essential to understand the soil processes related to the retention or release of basic and acidic ions and is imperative for the prediction of ecosystem recovery. Soil chemical properties related to acidification were characterized for 25 sites within eight acid-sensitive watersheds located in the Great Smoky Mountains National Park (GRSM). Relationships were identified by comparing soil chemistry to watershed characteristics including site location, soil characteristics, forest type, geomorphic factors and the presence of Anakeesta. The Walker Camp Prong watershed had significantly higher soil base saturation, calcium and magnesium than all other study watersheds as a result of the application of dolomitic limestone to roadways for wintertime traction control. Significant differences in soil chemistry between the spatially close watersheds of Cosby and Rock Creek demonstrated how local factors can substantially influence the watershed acidification response. The chemical properties of the six study soil types, representing 60% of the entire GRSM, had no significant differences, suggesting soil chemistry must be governed by external inputs and basin characteristics, more so than parent material. This idea was strengthen by the ability to relate many soil chemical properties to forest type and identifying other chemical properties as functions of elevation, slope and soil depth. Also, the presence of unexposed Anakeesta did not seem to have any significant effect on soil chemical properties because all significant differences could be linked to factors unrelated to surficial geology. The majority of the soils of the GRSM study watersheds seem to be experiencing the deleterious effects of long-term exposure to acidic deposition and it could be assumed that soils in many other areas of the park may be enduring the same. The results provide a comparative baseline dataset and important input parameters for biogeochemical modeling. The relationships identified among watershed factors and soil chemical properties can aid in future study designs.

Made available in DSpace on 2014-06-11T19:23:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-22Bitstream added on 2014-06-13T20:10:46Z : No. of bitstreams: 1 rodrigues_ms_me_jabo.pdf: 1277888 bytes, checksum: fca43b2044e8d0aa95f9d93c7040361b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Diversos fatores são responsáveis pela variabilidade espacial na produtividade das culturas e dentre estes estão os atributos do solo. Contudo, o que se tem observado, geralmente, é uma baixa correlação entre os mapas de produtividade e os mapas de atributos do solo. Uma hipótese para essa baixa correlação é a diferença na amostragem de cada uma dessas variáveis. O trabalho objetivou estudar o padrão de distribuição espacial dos atributos do solo e da produtividade do milho e as relações de causas e efeitos utilizando-se diferentes intensidades de amostragem. Os dados foram coletados seguindo uma grade amostral contendo 100 pontos georreferenciados. Os pontos foram dispostos em intervalos equidistantes, sendo de 10 m no sentido das linhas da cultura, ao longo de quatro transeções paralelas com 250 m de comprimento, distanciadas entre si 4,5 m, formando um retângulo com quatro colunas e 25 linhas, constituindo os 100 pontos de amostragem. Cada ponto amostral foi composto por cinco linhas de 10 m da cultura, constituindo uma célula amostral de 45 m2. Em cada ponto amostral retiraram-se amostras de solo nas profundidades de 0-0,1 e 0,1-0,2 m. Foram avaliados os atributos do solo textura, pH, teores de matéria orgânica, P, K+, Ca2+, Mg2+, H+Al, soma de bases, capacidade de troca de cátions, saturação por bases, densidade, porosidade total, macroporosidade e microporosidade. Foram estabelecidas intensidades de amostragens por meio de eliminação de pontos intermediários partindo da amostragem inicial, que continha 100 pontos, obtendo-se conjunto de dados com 100, 75, 50 e 25 pontos. Realizou-se a análise estatística descritiva dos dados e geoestatística. Baseado na análise de correlação simples, regressão múltipla ‘stepwise’ e semelhança dos mapas de isolinhas, os atributos que mais se correlacionaram... / Soil attributes play an important role in spatial variability of crop yield. However, what has been observed, generally, is a low correlation between the yield maps and maps of soil attributes. One hypothesis for this low correlation is the difference in the sampling of each of these variables. This research had as objective to study spatial distribution pattern of soil attributes affecting corn yield and their causeeffect relationship, for different sampling intensities. Spatial variability was determined for 100 georeferenced sample points from a sampling grid. Sample points were arranged in regular 10-m intervals along the rows and in four parallel 250-m long and 4.5-m spaced transects, resulting in a 4-column and 25-row rectangle (100 sample points). Each sample point consisted of five 10-m rows, totaling 45 m2. Samples were taken from the depths 0-0,1 and 0,1-0,2 m. Soil texture attributes, pH, organic matter content, P, K+, Ca2+, Mg2+ and H+Al levels, sum of bases, cation exchange capacity, base saturation, bulk density, total porosity, macroporosity and microporosity were evaluated. Sampling intensities were established by eliminating intermediary points from the initial 100-point sampling, resulting data sets of 100, 75, 50 and 25 points. Statistical analysis consisted of data description and geostatistics. Based on the simple correlation analysis, stepwise multiple regression and similarity among isoline maps, the attributes that showed stronger spatial correlation to corn yield were base saturation and clay content. For these attributes, data sets of 75 and 100 points showed higher similarity in the spatial distribution pattern for corn yield. The analysis of cross-semivariograms showed that the best correlation between corn yield and soil attributes was obtained with a sampling intensity of 100 points. It was possible to confirm the hypothesis that, when performing the soil... (Complete abstract click electronic access below)

Rose-scented geranium (Pelargonium capitatum x P. radens) belongs to the family Geraniaceae and it is a multi-harvest, high value, commercially important essential oil yielding aromatic plant. The essential oil extracted from the herbage of the plant is widely used in the fragrance and cosmetics industry and scenting of soaps. The essential oil is extracted by steam distillation. South Africa is now producing significant quantities of geranium oil. However, previous experience by this research group showed that seedlings often take long to establish, resulting in high death rates and sometimes poor growth after establishment. Stunted growth and yellowing of leaves was also observed in some cases. Poor vegetative growth causes low herbage yield and, consequently, low total essential oil production per hectare. Poor growth is believed to be due to a combination of factors, including nutrient deficiencies and acidic soil conditions and has not been studied under South Africa condition. Production of the crop is also reported to respond differently to rate and source of nutrition in various agro-ecological regions of the world. Therefore, field trials were conducted at the Hatfield Experimental Farm, University of Pretoria, in order to investigate how the plant responds to agronomic practices, such as source and amount of nitrogen, time of N fertilizer application, season of N fertilization and liming. Response of rose-scented geranium to source and amount of N showed that, at the first harvest (summer/autumn), there was no significant effect of conventional N on fresh herbage and oil yield, probably due to leaching of N by rainfall. However, organic N at 100 kg•ha-1 increased fresh herbage and oil yields by 58% and 48% over the control, respectively. In the second harvest (spring/summer), fresh herbage yield increased by 46% (conventional N) and 60% (organic N) at 100 kg•ha-1 compared to the control. Compared to the control, 100 kg•ha-1 conventional and organic N also increased essential oil yields by 94% and 129%, respectively. For both N sources nitrogen use efficiency (NUE) and LAI decreased with an increase in N level, and organic N gave highest essential oil production efficiency and LAI. Essential oil content (% fresh mass basis) also varied between the harvests, being greater in the second harvest (September to December 2005; spring/summer) than the first harvest (February to May 2005; summer/autumn). This was due to environmental variations that occurred between the harvesting periods. N level and source were found to have no noticeable effect on essential oil composition. This study revealed that rose-scented geranium produced higher fresh herbage and essential oil yield when organic fertilizer was used as a source of N. Nitrogen management in terms of rate and time of application is important in rose-scented geranium production. Delaying nitrogen topdressing (conventional N in the form of LAN; N 28%) after harvest to between the 7th and 9th week after cut back, was found to have a significant positive effect on biomass and essential oil production. Essential oil content of the plant did not show any response to a delay in nitrogen topdressing. A delay in nitrogen topdressing, in the first re-growth resulted into a lower citronellol to geraniol (C:G) ratio, which favour essential oil quality of the crop. Generally, the characteristics of the essential oil were within the internationally acceptable range for rose-scented geranium essential oil. In addition, production of rose-scented geranium during cooler periods is not advisable due to limited biomass production which might encourage leaching of nitrogen. The net benefits from N application is dependent on the growing period and in the present study spring and summer were more beneficial than winter and autumn. Organic N at 100 kg•ha-1•year-1 increased herbage and essential oil yield of the crop in spring and summer but further increases in organic or conventional N levels had no significant effect. N application either in winter or autumn did not improve production of the crop. Application of more N than what is required for optimum growth of the plant had no positive effect on essential oil production. Application of organic N also resulted in higher N use efficiency than conventional N. The essential oil contents (% fresh mass basis) achieved in the present study generally fell within the range of 0.04 to 0.2%. Citronellol and geraniol concentration (%), were at peak in spring season followed by summer and autumn and lowest in winter. The ratio between these two components (C:G ratio) is also used as an indicator of rose-scented geranium essential oil quality and most desirable (low C:G ratio) essential oil was attained in spring, summer and autumn harvesting seasons and least desirable oil was attained in winter. The relationship between SPAD-502 chlorophyll meter readings (SPAD units) and leaf N content (% dry weight basis) was a quadratic function. SPAD-502 chlorophyll meter readings (SPAD units) matched well with that of leaf N concentration data of rose-scented geranium. Regardless of the factors that affect the readings, this instrument can be used as an indicator of leaf N status of rose-scented geranium. Soil pH above 5.5 and soil base saturation above 55% increased fresh herbage and essential oil yield (per ha), which corresponded in this case with 2 to 6 t•ha-1 of lime application. Oil content (%) was not significantly affected by application of lime. Therefore, optimum growth of rose-scented geranium can be achieved by application of lime when plants are grown on acidic soils, but without any effect on oil content and essential oil composition. It can be concluded that N rate, source and season of production and soil pH should be considered to ensure optimal rose-scented geranium production. / Thesis (PhD)--University of Pretoria, 2012. / Plant Production and Soil Science / PhD / Unrestricted

Resumo: Diversos fatores são responsáveis pela variabilidade espacial na produtividade das culturas e dentre estes estão os atributos do solo. Contudo, o que se tem observado, geralmente, é uma baixa correlação entre os mapas de produtividade e os mapas de atributos do solo. Uma hipótese para essa baixa correlação é a diferença na amostragem de cada uma dessas variáveis. O trabalho objetivou estudar o padrão de distribuição espacial dos atributos do solo e da produtividade do milho e as relações de causas e efeitos utilizando-se diferentes intensidades de amostragem. Os dados foram coletados seguindo uma grade amostral contendo 100 pontos georreferenciados. Os pontos foram dispostos em intervalos equidistantes, sendo de 10 m no sentido das linhas da cultura, ao longo de quatro transeções paralelas com 250 m de comprimento, distanciadas entre si 4,5 m, formando um retângulo com quatro colunas e 25 linhas, constituindo os 100 pontos de amostragem. Cada ponto amostral foi composto por cinco linhas de 10 m da cultura, constituindo uma célula amostral de 45 m2. Em cada ponto amostral retiraram-se amostras de solo nas profundidades de 0-0,1 e 0,1-0,2 m. Foram avaliados os atributos do solo textura, pH, teores de matéria orgânica, P, K+, Ca2+, Mg2+, H+Al, soma de bases, capacidade de troca de cátions, saturação por bases, densidade, porosidade total, macroporosidade e microporosidade. Foram estabelecidas intensidades de amostragens por meio de eliminação de pontos intermediários partindo da amostragem inicial, que continha 100 pontos, obtendo-se conjunto de dados com 100, 75, 50 e 25 pontos. Realizou-se a análise estatística descritiva dos dados e geoestatística. Baseado na análise de correlação simples, regressão múltipla 'stepwise' e semelhança dos mapas de isolinhas, os atributos que mais se correlacionaram... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Soil attributes play an important role in spatial variability of crop yield. However, what has been observed, generally, is a low correlation between the yield maps and maps of soil attributes. One hypothesis for this low correlation is the difference in the sampling of each of these variables. This research had as objective to study spatial distribution pattern of soil attributes affecting corn yield and their causeeffect relationship, for different sampling intensities. Spatial variability was determined for 100 georeferenced sample points from a sampling grid. Sample points were arranged in regular 10-m intervals along the rows and in four parallel 250-m long and 4.5-m spaced transects, resulting in a 4-column and 25-row rectangle (100 sample points). Each sample point consisted of five 10-m rows, totaling 45 m2. Samples were taken from the depths 0-0,1 and 0,1-0,2 m. Soil texture attributes, pH, organic matter content, P, K+, Ca2+, Mg2+ and H+Al levels, sum of bases, cation exchange capacity, base saturation, bulk density, total porosity, macroporosity and microporosity were evaluated. Sampling intensities were established by eliminating intermediary points from the initial 100-point sampling, resulting data sets of 100, 75, 50 and 25 points. Statistical analysis consisted of data description and geostatistics. Based on the simple correlation analysis, stepwise multiple regression and similarity among isoline maps, the attributes that showed stronger spatial correlation to corn yield were base saturation and clay content. For these attributes, data sets of 75 and 100 points showed higher similarity in the spatial distribution pattern for corn yield. The analysis of cross-semivariograms showed that the best correlation between corn yield and soil attributes was obtained with a sampling intensity of 100 points. It was possible to confirm the hypothesis that, when performing the soil... (Complete abstract click electronic access below) / Orientador: José Eduardo Corá / Coorientador: Carolina Fernandes / Banca: Marcílio Vieira Martins Filho / Banca: Zigomar Menezes de Souza / Mestre

Made available in DSpace on 2015-03-26T13:15:03Z (GMT). No. of bitstreams: 1 texto completo.pdf: 988080 bytes, checksum: 11aca439385a355233640d577498e78e (MD5) Previous issue date: 2009-08-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Understanding the nutritional demands of species is one of the major factors needed to obtain greater yield and quality, besides greater economy of seedling production process. This work aimed to evaluate the influence of base saturation and phosphorus doses on the growth of Cariniana legalis and Mabea fistulifera, in three soils. The experiment was arranged in a statistical randomized block design, in a factorial scheme, constituted by five levels of P (0, 150, 300, 450 and 600 mg/dm3) combined with five levels of base saturation (original, 30, 45, 60 and 75%), for Dystrophic and Allyc Red-Yellow Latosols and four levels for Red-Yellow Argisol (original, 50, 60 and 70%), with three replications for Cariniana legalis, with the experimental plot being constituted by nine plastic bags with a capacity of 0.6 dm3 soil and four replications for Mabea fistulifera, with the experimental plot constituted of a polyethylene vase with capacity for 1.5 dm3 of soil. For the establishment of different values of base saturation, CaCO3 and MgCO3, were used in the stechiometric relation 4:1. The P source used was NaH2PO4.H2O. At 150 and160 days after sowing, for Cariniana legalis and Mabea fistulifera, respectively, the morphological parameters and indices determining seedling quality were evaluated. The Cariniana legalis seedlings presented a significant response to the increase of base saturation and P application, for most of the characteristics evaluated in the three soils used. However, the best seedlings were obtained at the initial contents of Ca, Mg and P (control treatment),as the original contents of these nutrients were shown to be higher than the critical doses required by this species. The Mabea fistulifera seedlings presented negative responses to the increase of base saturation and P dose application, showing better performance at the initial contents of Ca2+ (0.14 cmolc/dm3), Mg2+ (0.03 cmolc/dm3) and P (0.9 mg/dm3) in Allyc Red-Yellow Latosol. Regarding Dystrophic Red-Yellow Latosol and Red-Yellow Argisol, the best seedlings of Mabea fistulifera were obtained in the original base saturations, with phosphorus doses of 130 and 125 mg/dm3 being obtained for the respective substrates, based on production of 90% of total dry matter. / O conhecimento das demandas nutricionais das espécies é um dos principais fatores para obtenção de maior produtividade e qualidade, além de maior economia no processo de produção de mudas. O objetivo deste trabalho foi avaliar a influência da saturação por bases e doses de fósforo sobre o crescimento e a qualidade de mudas de Cariniana legalis e Mabea fistulifera, em três solos. Adotou-se o delineamento estatístico de blocos ao acaso, disposto em esquema fatorial, constituído por cinco níveis de P (0, 150, 300, 450 e 600 mg/ dm3) combinados com cinco níveis de saturação por bases (original, 30, 45, 60 e 75%), para os Latossolos Vermelho-Amarelo Distrófico e Álico, e quatro níveis para o Argissolo Vermelho-Amarelo (original, 50, 60 e 70%), com três repetições para Cariniana legalis, sendo a parcela experimental constituída de nove sacolas plásticas com capacidade de 0,6 dm3 de solo e quatro repetições para Mabea fistulifera, sendo a parcela experimental constituída de um vaso de polietileno com capacidade para 1,5 dm3 de solo. Para o estabelecimento de diferentes valores de saturação por bases, foram utilizados CaCO3 e MgCO3, na relação estequiométrica 4:1. A fonte de P utilizada foi o NaH2PO4.H2O. Aos 150 e 160 dias após a semeadura, para Cariniana legalis e Mabea fistulifera, respectivamente, foram avaliados os parâmetros morfológicos e os índices que determinam a qualidade das mudas. As mudas de Cariniana legalis apresentaram resposta significativa à elevação da saturação por bases e à aplicação de P, para a maioria das características avaliadas nos três solos utilizados. No entanto, as melhores mudas foramobtidas com os teores iniciais de Ca, Mg e P (tratamento-testemunha), pois os teores originais destes nutrientes demonstraram ser superiores às doses críticas requeridas por essa espécie. As mudas de Mabea fistulifera apresentaram respostas negativas à elevação da saturação por bases e à aplicação de doses de P, demonstrando melhor desempenho com os teores iniciais de Ca2+ (0,14 cmolc/dm3), Mg2+ (0,03 cmolc/dm3) e de P (0,9mg/ dm3) no Latossolo Vermelho Amarelo Álico. Já no Latossolo Vermelho-Amarelo Distrófico e no Argissolo-Vermelho Amarelo, as melhores mudas de Mabea fistulifera foram obtidas nas saturações por bases originais, sendo recomendadas as doses de fósforo de 130 e 125 mg/dm3, para os respectivos substratos, com base na produção de 90% da matéria seca total.

This paper presents a study that was conducted in a commercial area of grain production in the municipality of Santo Ângelo, region of the Missions - northwest of Rio Grande do Sul, during the Master Course in Precision Agriculture, Federal University Santa Maria / UFSM. The Climate is second Köppen classification of humid subtropical Cfa and gently undulating, with a fertility for the nutrient phosphorus (P) already built. This study aimed to determine whether use of precision agriculture tools, by applying fertilizers correction broadcasted with the variable rate shows an increase in soil fertility levels, and to verify the yield of soybean and wheat over three years subsequent and its technical and economic viability. The Trial period was set for the months of June 2011 to June 2014. Methodologically the project had an applied research, quantitative nature, from the point of view of its objectives was contemplating a descriptive case study. technical and economic. The Soil analyzes were performed by BaseAP Company, highlighting the main variables pH soil, Saturation for bases and potassium with need correction. Obtained was a 43% reduction in the use of lime and an increase in soybean and wheat productivity between 19 and 28%. The study showed an economic return to the producer of 22% compared to a control area without Precision Agriculture. It was expected an increase in the potassium concentration in the resampling but not found, raising the possibility of doing a maintenance fertilization on crop instead of making a soil amendment. / Este trabalho apresenta um estudo que foi realizado em uma área comercial de produção de grãos, no Município de Santo Ângelo, região das Missões - Noroeste do Rio Grande do Sul, durante a conclusão do curso de Pós-Graduação em Agricultura de Precisão pela Universidade Federal de Santa Maria/UFSM. O clima da região é segundo classificação de Köppen-Geiger do tipo Cfa subtropical úmido e o relevo levemente ondulado, com uma fertilidade para o nutriente fósforo (P) já construída. Esse trabalho teve como objetivo verificar se o uso de ferramentas de Agricultura de Precisão, pela aplicação de correção de fertilizantes a lanço e a taxa variada apresenta um aumento nos teores de fertilidade solo, verificando também as produtividades de soja e trigo ao longo de três anos subsequentes e sua viabilidade técnica e econômica. O período do experimento foi definido para os meses de junho de 2011 a junho de 2014. Metodologicamente o projeto teve uma pesquisa aplicada, de cunho quantitativo, do ponto de vista de seus objetivos foi descritiva contemplando um estudo de caso. As análises de solo foram realizadas pela Empresa BaseAP, destacando-se como variáveis principais pH do solo, Saturação por bases e Potássio que apresentaram necessidade de correção. Obteve-se uma redução de 43% no uso de calcário dolomítico e um aumento de produtividade de soja e trigo entre 19 e 28%. O estudo mostrou um retorno econômico ao produtor de 22% comparado a uma área testemunha sem Agricultura de Precisão. Esperava-se um aumento nos teores de potássio na reamostragem mas não foi encontrado, levantando a hipótese de se fazer uma adubação de manutenção na cultura ao invés de se fazer uma correção de solo.

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No. of bitstreams: 2 Dissertação - Camilla Oliveira Muniz - 2015.pdf: 2176417 bytes, checksum: 6d7842c4868c26a9bbeb1cdf0304713f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-03-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Global demand for wood is growing every day. In Brazil, the wide availability of area, favorable climate and soil conditions for the plant, made possible investment in forest monocultures. Among the species of hardwood, African mahogany (Khaya ivorensis A. Chev.) Is the one with physical and mechanical characteristics closer to Brazilian mahogany (Swietenia macrophylla). Due to resistance attack on Hypsipyla grandella has been a viable service to the international furniture market. However, little is known about the culture, particularly their nutritional requirements. This study aimed to evaluate the development of Khaya ivorensis in different base saturation levels and levels of nitrogen, phosphorus and potassium. For this, an eight-hectare area in which four hectares had the high saturation bases to 55% and the remaining 75% was used. The experimental design was a randomized block design with eight replications in factorial 4 x 4 x 4, with four levels of nitrogen (60g, 120g, 180g and 240g of urea), four doses of phosphorus (60g, 120g, 180g and 240g super triple phosphate) and four potassium doses (42g, 84g, 126g and 168g of potassium chloride). The base saturation was evaluated in the block effect. After twelve months of planting were performed dendrometric reviews. The basal diameter was measured with a digital caliper and height with tape. Each plot consisted of six plants and averaging them considered in the statistical analysis. In stem diameter was no statistical difference between blocks and nitrogen. However, this difference may be related to genetics of plants, since the plant is young and seminal seedlings were used. At the time only the NPK ratio presented statistical variation. However, growth decreasing trend was observed with the increase of N rates and improved with increasing doses of P and K. All treatments favored the growth of African mahogany. The most suitable foundations saturation is 55%, since there is no improvement in the growth of plants is high when V% to 75%. Excess N affect the growth of the species. The best treatment was that received 60g of urea, 240g and 168g ST KCl. / A demanda mundial por madeira cresce a cada dia. No Brasil, a grande disponibilidade de área e condições edafoclimáticas favoráveis ao crescimento de plantas, têm viabilizado o investimento em monocultivos florestais. Dentre as espécies de madeira nobre, o mogno africano (Khaya ivorensis A. Chev.) é a que possui características físicas e mecânicas mais próximas ao mogno brasileiro (Swietenia macrophylla). Devido à resistência ao ataque da Hypsipyla grandella tem sido uma alternativa viável de atendimento ao mercado moveleiro internacional. No entanto, pouco se conhece sobre a cultura, sobretudo suas exigências nutricionais. O presente trabalho teve como objetivo avaliar o desenvolvimento da Khaya ivorensis em diferentes saturações por bases e níveis de nitrogênio, fósforo e potássio. Para isso, foi utilizada uma área de oito hectares em que quatro hectares tiveram a saturação por bases elevada a 55% e os demais a 75%. O delineamento experimental empregado foi blocos casualizados com oito repetições no esquema fatorial 4 x 4 x 4, com quatro doses de nitrogênio (60g, 120g, 180g e 240g de uréia), quatro doses de fósforo (60g, 120g, 180g e 240g de super fosfato triplo) e quatro doses de potássio (42g, 84g, 126g e 168g de cloreto de potássio). A saturação por bases foi avaliada no efeito de blocos. Após doze meses de plantio foram realizadas as avaliações dendrométricas. O diâmetro do colo foi mensurado com paquímetro digital e a altura com fita métrica. Cada parcela experimental foi composta por seis plantas e a média entre elas considerada na análise estatística. No diâmetro do colo houve diferença estatística entre blocos e doses de nitrogênio. No entanto, esta diferença pode estar relacionada à genética das plantas, visto que o plantio é jovem e foram utilizadas mudas seminais. Na altura apenas a relação NPK apresentou variação estatística. No entanto, foi observada tendência de decréscimo de crescimento com a elevação das doses de N e melhoria com o aumento das doses de P e K. Todos os tratamentos favoreceram o crescimento do mogno africano. A saturação por bases mais indicada é a de 55%, visto que não há melhoria no crescimento das plantas quando V% é elevada a 75%. O excesso de N prejudica o crescimento da espécie. O melhor tratamento foi o que recebeu 60g de uréia, 240g de ST e 168g de KCl.