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Search Results: 1 - 10 of 88918 matches for " Carlos Alexandre Costa;Garcia "
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Crescimento radicular e aéreo de cultivares de arroz de terras altas em fun??o da calagem
Crusciol, Carlos Alexandre Costa;Mancuso, Mauricio Antonio Cuzato;Garcia, Rodrigo Arroyo;Castro, Gustavo Spadotti Amaral;
Bragantia , 2012, DOI: 10.1590/S0006-87052012005000018
Abstract: this work aimed to evaluate root growth, shoot development and nutrient absorption efficiency by rice cultivars caiapó and maravilha as affected by lime application. the experiment was carried out in a greenhouse, with treatments set up by caiapó and maravilha cultivars in combination with the base saturation (v%) of 10%, 40% and 70%. the experiment was in a randomized complete block design, with four replications. the number of tillers, root length, root dry matter, leaves and stems, leaf content and macronutrients absorption efficiency were evaluated. comparing cultivars, maravilha cultivar presented higher root dry weight, root length, number of stems, dry matter of stems and shoot than caiapó cultivar, as well as accumulated more nutrients in the shoots. on the other hand, nutrient contents were higher in the cultivar caiapó compared to maravilha. maravilha cultivar shows greater root and shoot growth while caiapó shows higher nutrient absorption efficiency from the soil. the base saturation of 40% is the most effective for both cultivars.
Atributos químicos do solo, crescimento radicular e produtividade do arroz de acordo com a aplica??o de escórias
Carvalho-Pupatto, Juliana Garcia;Büll, Leonardo Theodoro;Crusciol, Carlos Alexandre Costa;
Pesquisa Agropecuária Brasileira , 2004, DOI: 10.1590/S0100-204X2004001200008
Abstract: use of industrial residues as alternative sources of nutrients to the plants is due to the necessity of reducing their accumulation in the production sites. the objective of this work was to evaluate the effect of metallurgy slag in soil chemical attributes, in development and in grain yield of upland rice sprinkler irrigated. the experiment was carried out in a randomized block design, with three treatments constituted by two scums, blast furnace (196 g kg-1 of si) and steel slag (56 g kg-1 of si), and a control without application, with eight replications. the scums can be used as corrective of soil acidity and silicon source. alterations in the soil chemical attributes are related to the chemical composition of the scums. blast furnace slag resulted in higher root growth in depth and better distribution in the profile soil provides higher shoot dry matter yield and grain yield.
Nitrate role in basic cation leaching under no-till
Crusciol, Carlos Alexandre Costa;Garcia, Rodrigo Arroyo;Castro, Gustavo Spadotti Amaral;Rosolem, Ciro Antonio;
Revista Brasileira de Ciência do Solo , 2011, DOI: 10.1590/S0100-06832011000600014
Abstract: especially under no-tillage, subsuface soil acidity has been a problem, because it depends on base leaching, which has been associated with the presence of low molecular weigth organic acids and companion anions. the objective of this study was to evaluate exchangeable base cation leaching as affected by surface liming along with annual urea side-dressing of maize and upland rice. treatments consisted of four lime rates (0, 1500, 3000, and 6000 kg ha-1) combined with four nitrogen rates (0, 50, 100, and 150 kg ha-1) applied to maize (zea mays) and upland rice (oryza sativa), in two consecutive years. maize was planted in december, three months after liming. in september of the following year, pearl millet (pennisetum glaucum) was planted without fertilization and desiccated 86 days after plant emergence. afterwards, upland rice was grown. immediately after upland rice harvest, 18 months after surface liming, ph and n-no3-, n-nh4+, k, ca, and mg levels were evaluated in soil samples taken from the layers 0-5, 5-10, 10-20 and 20-40 cm. higher maize yields were obtained at higher n rates and 3000 kg ha-1 lime. better results for upland rice and pearl millet yields were also obtained with this lime rate, irrespective of n levels. the vertical mobility of k, ca and mg was higher in the soil profiles with n fertilization. surface liming increased ph in the upper soil layers causing intense nitrate production, which was leached along with the base cations.
Biomass production and accumulation of nutrients in shoots of Giant Guinea sorghum plants
Mateus, Gustavo Pavan;Borghi, émerson;Castro, Gustavo Spadotti Amaral;Garcia, Rodrigo Arroyo;Crusciol, Carlos Alexandre Costa;
Revista Ciência Agron?mica , 2011, DOI: 10.1590/S1806-66902011000400024
Abstract: choosing species with high phytomass production to be cropped in no tillage system is extremely important in dry winter regions. the purpose of this research was to study plant biomass production and accumulation of nutrients in shoots of giant guinea sorghum plants (sorghum bicolor subspecies bicolor race guinea) sown in different sowing dates. a randomized complete block design with six treatments and four replications was performed. treatments consisted of six sowing dates (09/25/2000; 10/25/2000; 11/24/2000; 12/22/2000; 02/22/2001 and 04/03/2001). at flowering, dry matter production, number and diameter of stems and plant height were evaluated. macro and micronutrient levels and accumulation were determined as well as c/n ratio. plant cycle decreased as sowing date was delayed and, consequently, dry matter production and c/n ratio decreased as well. the opposite was observed for nutrient contents. "giant guinea" sorghum is sensitive to photoperiod thus late sowing reduces plant development, which leads to low biomass production and nutrient accumulation. "giant guinea" sorghum cultivated as cover crop is a good option when implementing no tillage system due to high dry matter production and n, p, and k recycling.
Efeito de escória de alto forno no crescimento radicular e na produtividade de arroz
Carvalho-Pupatto Juliana Garcia,Büll Leonardo Theodoro,Crusciol Carlos Alexandre Costa,Mauad Munir
Pesquisa Agropecuária Brasileira , 2003,
Abstract: A utiliza o agrícola de resíduos industriais como fertilizantes decorre da necessidade de diminuir o efeito nocivo do acúmulo de nutrientes nos centros de produ o. O objetivo deste trabalho foi avaliar os efeitos de escória de alto forno no crescimento radicular e na produtividade do arroz de terras altas irrigado por aspers o. O experimento foi realizado no campo, adotando-se o delineamento experimental de blocos casualizados, com cinco doses de escória de alto forno (0, 2.550, 5.100, 10.200 e 15.300 kg ha-1) com quatro repeti es. A utiliza o de escória melhorou a condi o química do solo, aumentou o crescimento e a superfície radicular, diminuiu o diametro das raízes e elevou os teores de silício no solo e na planta, resultando em aumento da produtividade.
Desenvolvimento da aveia branca e disponibilidade de fósforo em raz?o da aplica??o de silicato de potássio
Garcia, Rodrigo Arroyo;Merlin, Alexandre;Toledo, Mariana Zampar;Fernandes, Dirceu Maximino;Crusciol, Carlos Alexandre Costa;Büll, Leonardo Theodoro;
Revista Ceres , 2011, DOI: 10.1590/S0034-737X2011000600022
Abstract: potassium silicate application in soil can increase phosphorus availability and influence white oat growth. this work had the objective of evaluating the effects of silicate doses applied to the soil on the white oat growth and on soil p availability. the experimental design was completely randomized, with six replications, analyzed as a 2 x 4 factorial. treatments consisted of two p doses (20 and 200 mg dm-3 of p2o5) combined with four si doses (0, 150, 300 and 450 mg dm-3), applied at sowing. dry matter of leaves+stems, panicles and total shoot were evaluated right after harvest. p and si contents were evaluated in grains and panicle straw, previously separated, as well as in leaves+stems. concentrations of si and p in soil after harvest were also determined. fertilization with potassium silicate increases si levels in soil and increases p availability. dry matter of leaves+stems is increased by silicate whenever initial p levels are low. even considering the highest p dose, silicate application increases p availability in soil, and the plant p uptake. si contents in panicle straw, leaves+stems and grains are influenced by the higher availability of this element in soil.
Metal fractionation in sediments of the Sergipe River, northeast, Brazil
Passos, Elisangela de Andrade;Alves, Jose do Patrocínio H;Garcia, Carlos Alexandre B;Costa, Antonio C. Spinola;
Journal of the Brazilian Chemical Society , 2011, DOI: 10.1590/S0103-50532011000500004
Abstract: the sequential extraction procedure proposed by the european community bureau of reference (bcr) was applied for the fractionation of cd, cr, cu, ni, pb and zn in sediments from the sergipe estuary, brazil. the method showed satisfactory recoveries, detection limits and standard deviations for trace metals determinations in sediment samples. cd was the metal with the greatest percentage in the exchangeable fraction. pb and ni were present mainly in the reducible and oxidizable fractions. cr, cu and zn were predominantly associated with the residual fraction. the order of mobility of metals extracted was pb > cd > ni > cu > cr > zn. according to the risk assessment code (rac), the sediments showed low to medium risk for all metals.
Efeito de escória de alto forno no crescimento radicular e na produtividade de arroz
Carvalho-Pupatto, Juliana Garcia;Büll, Leonardo Theodoro;Crusciol, Carlos Alexandre Costa;Mauad, Munir;Silva, Rosemeire Helena da;
Pesquisa Agropecuária Brasileira , 2003, DOI: 10.1590/S0100-204X2003001100011
Abstract: agricultural use of industrial residues as fertilizers is due to the need of reducing nutrient accumulation in centers of production. the objective of this study was to evaluate the effects of blast furnace slag on root growth and productivity of highland rice irrigated by sprinkler. the experiment was carried out on field conditions. the experimental design was a randomized block, with five rates of blast furnace (0, 2,550, 5,100, 10,200, and 15,300 kg ha-1) and four replications. use of the slag improved chemical attributes of the soil, increased root growth and surface and reduced root diameter. it increased the silicon content in the soil and in the plant, resulting in higher yield.
Achados fundoscópicos em crian as portadoras de anemia falciforme no estado do Rio Grande do Norte
Garcia Carlos Alexandre de Amorim,Fernandes Maria Zélia,Uch?a Uchoandro Bezerra Costa,Cavalcante Bruno de Morais
Arquivos Brasileiros de Oftalmologia , 2002,
Abstract: Objetivos: Detectar os principais achados fundoscópicos em crian as portadoras de hemoglobinopatias falciformes. Métodos: Foram estudados 26 pacientes com hemoglobinopatias falciformes, no Servi o de Oftalmologia do Hospital Universitário Onofre Lopes, Natal, RN, que foram submetidos a protocolo de pesquisa pré-estabelecido. Os resultados foram avaliados estatisticamente pelo teste qui-quadrado. Resultados: A idade média foi de 10,6 anos, com acuidade visual igual ou melhor que 20/25 na maioria, excetuando-se 3 olhos, que apresentavam outras doen as associadas. O tipo mais freqüente foi o SS com 57,7% (15/26) dos casos, seguido pelos SC e SA com 15,4% (4/26) cada, e pelo S-Thal com 11,5% (3/26). A freqüência da retinopatia por células falciformes foi maior após os 10 anos de idade, sendo mais freqüente, em valores relativos, no tipo S-Thal (100% dos casos) e, em valores absolutos, no tipo SS (9 casos). Os dois achados mais comuns foram tortuosidade venosa (12/26) e "black sunburst" (7/26). Conclus es: Observamos que a incidência de retinopatia por células falciformes aumentou após os 10 anos de idade e n o evidenciamos achados da doen a proliferativa. Portanto, enfatizamos a necessidade do exame oftalmológico precoce nos portadores de anemia falciforme, como forma de prevenir futuras complica es oculares.
Achados fundoscópicos em crian?as portadoras de anemia falciforme no estado do Rio Grande do Norte
Garcia, Carlos Alexandre de Amorim;Fernandes, Maria Zélia;Uch?a, Uchoandro Bezerra Costa;Cavalcante, Bruno de Morais;Uch?a, Raquel Araújo Costa;
Arquivos Brasileiros de Oftalmologia , 2002, DOI: 10.1590/S0004-27492002000600003
Abstract: purpose: to point out the main fundoscopic findings in children with sickle cell trait hemoglobinopathies. methods: we studied 26 patients with sickle cell hemoglobinopathies in the ophthalmological ward at the hospital universitário onofre lopes, natal, rn. the patients were submitted to a research questionnaire and the results were statistically evaluated by the c2 test. results: the average age was 10,6 years, with visual acuity equal or better than 20/25 in the majority, except for three eyes which presented other associated pathologies. the most frequent type was ss in 57.7% (15/26) of cases, followed by sc e sa in 15.4% (4/26) each, and by s-thal in 11.5% (3/26). the frequency of sickle cell retinopathy was higher after 10 years of age, being more frequent, in relative values, in type s-thal (100%) and, in absolute values, in type ss (9 cases). the two most common findings were venous tortuosity (12/26) and "black sunburst" (7/26). conclusion: we observed that the incidence of retinopathy in sickle cell increased with age over 10 years and no evidence of proliferative disease was found. therefore, we emphasize the need for early ophthalmological examination in carriers of sickle cell disease as a form of preventing future complications.
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