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Search Results: 1 - 10 of 1911 matches for " Aldo;Sangoi "
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A desuniformidade de emergência reduz o rendimento de gr?os de milho
Merotto Junior, Aldo;Sangoi, Luis;Ender, Marcio;Guidolin, Altamir Frederico;Haverroth, Hector Silvio;
Ciência Rural , 1999, DOI: 10.1590/S0103-84781999000400004
Abstract: high maize grain yields are related to a fast, complete and regular plant emergence. this experiment was carried out in lages, sc, brazil, with the objective of evaluating the effects of an uneven plant emergence on maize grain yield at different plant populations. a split plot design was used, with the main plots disposed in randomized complete blocks. four plant populations, equivalent to 40,000, 60,000, 80,000 and 100,000 pl.ha-1 were tested in the main plots. different levels of unevenness in plant emergence were analyzed in the split plots by varying the sowing dates of adjacent hills inside each as it follows: 1 - even emergence (0-0-0-0); 2 - unevenness of 12 days (0-12-0-12); 3 - unevenness of 19 days (0-19-0-19); 4 - unevenness of 12 and 19 days (0-12-19-0-12-19). the increase in plant population up to 76,500 pl.ha-1 enhanced grain yield to 12,900kg.ha-1. at this plant population, the difference in yield grain per hectare among treatments with even and uneven emergence was nearly 2,900kg. this indicates that under similar productivity levels replanting maize may be on economically viable option. besides reducing grain yield, uneven emergence also limited maize response to the increment in plant population.
Incremento na densidade de plantas: uma alternativa para aumentar o rendimento de gr?os de milho em regi?es de curta esta??o estival de crescimento
Almeida, Milton Luiz de;Merotto Junior, Aldo;Sangoi, Luís;Ender, Márcio;Guidolin, Altamir Frederico;
Ciência Rural , 2000, DOI: 10.1590/S0103-84782000000100004
Abstract: the development of earlier hybrids, with shorter plant height, lower leaf number and upright leaves has increased maize potential adaptability to withstand high plant densities. this trend may be emphasized on the high lands of southern brazil due to their mild spring and summer temperatures and shorter maize growing season. four trials were carried out, aiming to investigate the viability of using higher than recommended plant populations, as an alternative to improve grain yield. the maize hybrids cargill 901 and xl 370 were evaluated at several plant populations, ranging from 37000 to 100000pl ha-1, under different management situations. in three out of four experiments, plant populations above 60000pl ha-1 maximized grain yield. the greater competition among individuals verified at high plant populations did not decrease substantially the number of ears per plant, which contributed to improve maize adaptation to high plant densities. therefore, for regions with a short growing season, the use of early small stature maize hybrids may be accompanied by an increment in plant population up to a value varying between 65000 and 80000pl ha-1. this is conceivable as long as there is adequate soil fertility, water availability and stem lodging resistant genotypes.
Tiller emission and dry mass accumulation of wheat cultivars under stress
Almeida Milton Luiz de,Sangoi Luís,Merotto Jr. Aldo,Alves Ant?nio Carlos
Scientia Agricola , 2004,
Abstract: Tillers are important structures for wheat (Triticum aestivum L.) because they contribute to increase the number of spikes per area, enhancing grain yield. Stresses during plants early growth have a sizable effect on tiller production. Three experiments were conducted to evaluate the effects of stresses induced by unevenness in sowing depth, defoliation and differences in soil pH on tiller emission and dry mass accumulation of wheat cultivars. The experiments were carried out in Lages, Southern Brazil, during the winter growing seasons of 2000 and 2001. They were performed in square boxes, under natural conditions of radiation and irrigation. In the first experiment, five types of sowing depths were tested to simulate different systems of unevenness in plant emergence of cultivar Embrapa 16. In the second experiment, two wheat cultivars (BRS 177 and BRS 179) were submitted to four types of main stem defoliation. The third experiment assessed the effects of three levels of soil acidity correction on the tillering pattern of Fundacep 29. Unevenness in sowing depth, alternating pairs of seeds at 3 cm and 5 cm deep, reduced tiller emission and dry mass accumulation. The removal of the first and second main stem leaves reduced significantly BRS 179 tiller dry mass and number and did not affect the tillering pattern of BRS 177. The lack of liming restricted tiller emission and reduced plant dry mass accumulation.
Efeitos do arranjo e da popula??o de plantas sobre o crescimento do feij?o em semeadura tardia
Guidolin, Altamir Frederico;Merotto Júnior, Aldo;Ender, Márcio;Sangoi, Luís;Duarte, Iran de Azevedo;
Ciência Rural , 1998, DOI: 10.1590/S0103-84781998000400003
Abstract: the bean crop is often sown after the ideal time in southem brazil which brings along a decrease in grain yield. this experiment was carri?a out in lages, sc, with the purpose of looking for alternativos in the arrangement and population of plants as a way of compensating the small production of grains in late sowings. a split-split piot design with the main piots arranged in randomized complete blocks was used. two cultivars, barriga verde (indeterminate erect, type ii growing habit) and carioca 80 sh (indeterminate prostate, type iii growing habit) were tested in the main piot. row spacings o f 0.2 5m and 0.50m were used in the split piot and plant populations o f 200, 300 and 400 thousand pl ha-1were observed in the split split piot. the increase in plant population promoted a greater number o f grains per área, specially for the indeterminate erect cultivar at the narrower row spacing, having a concomitant decrease in seed weight. the use of0.2 5m row spacing enhanced barriga verde's grain yield and decreased carioca's grain productivity at high plant populations.
Tiller emission and dry mass accumulation of wheat cultivars under stress
Almeida, Milton Luiz de;Sangoi, Luís;Merotto Jr., Aldo;Alves, Ant?nio Carlos;Nava, Itamar Cristiano;Knopp, Armando Cristiano;
Scientia Agricola , 2004, DOI: 10.1590/S0103-90162004000300004
Abstract: tillers are important structures for wheat (triticum aestivum l.) because they contribute to increase the number of spikes per area, enhancing grain yield. stresses during plants early growth have a sizable effect on tiller production. three experiments were conducted to evaluate the effects of stresses induced by unevenness in sowing depth, defoliation and differences in soil ph on tiller emission and dry mass accumulation of wheat cultivars. the experiments were carried out in lages, southern brazil, during the winter growing seasons of 2000 and 2001. they were performed in square boxes, under natural conditions of radiation and irrigation. in the first experiment, five types of sowing depths were tested to simulate different systems of unevenness in plant emergence of cultivar embrapa 16. in the second experiment, two wheat cultivars (brs 177 and brs 179) were submitted to four types of main stem defoliation. the third experiment assessed the effects of three levels of soil acidity correction on the tillering pattern of fundacep 29. unevenness in sowing depth, alternating pairs of seeds at 3 cm and 5 cm deep, reduced tiller emission and dry mass accumulation. the removal of the first and second main stem leaves reduced significantly brs 179 tiller dry mass and number and did not affect the tillering pattern of brs 177. the lack of liming restricted tiller emission and reduced plant dry mass accumulation.
Análise de trilha dos componentes do rendimento de gr?os em genótipos de canola
Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Almeida, Milton Luiz de;Sangoi, Luís;Ender, Márcio;Merotto Júnior, Aldo;
Ciência Rural , 2004, DOI: 10.1590/S0103-84782004000500015
Abstract: grain yield is a variable of complex association which has an economic importance. a trial was conducted in lages, sc, during the 1996-growing season, in order to determine the association and the direct and indirect effects of some agronomic traits on grain yield of 12 canola genotypes, through the study of the phenotypic correlation and path analysis. a randomized complete block design with four replications per treatment was used. according to the analyses performed on the trial, plant height didn?t show any association with weight of 1,000 grains and grain yield. path analysis showed that the primary components plant population per area and number of grains per plant have the largest direct impact on grain yield. on the other hand, the number of grains produced per plant is the major responsible for the increase in the weight of 1,000 grains. path analysis also evidenced that the secondary component number of grains per pod has the highest direct effect on grain yield.
On the Expansion and Fate of the Universe  [PDF]
Aldo Bonasera
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.311212
Abstract: The evolution of the universe from an initial dramatic event, the Big-Bang, is firmly established. Hubble’s law [1] (HL) connects the velocity of galactic objects and their relative distance: v(r) = Hr, where H is the Hubble constant. In this work we suggest that HL is not valid at large distances because of total energy conservation. We propose an expansion of the velocity in terms of their relative distance and produce a better fit to the available experimental data. Using a simple “dust” universe model, we can easily calculate under which conditions an (unstable) equilibrium state can be reached and we estimate the values of the matter present in the universe as well as the “dark energy”. Within the same formalism we can derive the “deceleration parameter”. We do not need to invoke any “dark energy”, its role being played by the kinetic correction. The resulting picture is that the universe might reach an unstable equilibrium state whose fate will be decided by fluctuations: either collapse or expand forever.
UNDERSTANDING PLANT DENSITY EFFECTS ON MAIZE GROWTH AND DEVELOPMENT: AN IMPORTANT ISSUE TO MAXIMIZE GRAIN YIELD
Sangoi, Luís;
Ciência Rural , 2001, DOI: 10.1590/S0103-84782001000100027
Abstract: maize is the agronomic grass species that is most sensitive to variations in plant density. for each production system, there is a population that maximizes grain yield. this article presents an overview of the factors that affect optimum plant population, emphasizingthe effects of dense stands on ear development and discussing important changes in plant traits that have contributed to increase the tolerance of modern hybrids to high plant densities. population for maize maximum economic grain yield varies from 30,000 to over 90,000pl.ha-1, depending on water availability, soil fertility, maturity rating, planting date and row spacing. when the number of individuals per area is increased beyond the optimum plant density, there is a series of consequences that are detrimental to ear ontogeny and result in barrenness. first, ear differentiation is delayed in relation to tassel differentiation. later-initiated earshoots have a reduced growth rate, resulting in fewer spikelet primordia transformed into functional florets by the time of flowering. functional florets extrude silks slowly, decreasing the number of fertilized spikelets due to the lack of synchrony between anthesis and silking. limitations in carbon and nitrogen supply to the ear stimulate young kernel abortion immediately after fertilization. availability of earlier hybrids, with shorter plant height, lower leaf number, upright leaves, smaller tassels and better synchrony between male and female flowering time has enhanced the ability of maize to face high plant populations without showing excessive barrenness. improved endurance in high stands has allowed maize to intercept and use solar radiation more efficiently, contributing to the remarkable increase in grain yield potential experienced by this crop.
Dry matter production and partitioning of maize hybrids and dwarf unes at four plant populations
Sangoi, Luis;Salvador, Ricardo;
Ciência Rural , 1997, DOI: 10.1590/S0103-84781997000100001
Abstract: this experiment was conducted in ames, iowa, usa, to compare dry matter accumulation patterns of maize genotypes contrasting in height and leafiness, and to test whether reduction in plant height an leaf number through the use of dwarfing genes or earliness can improve grain dry matter allocation. five plant genotypes were tested: a full season hybrid adapted to central lowa (nk 4525), a short season hybrid adapted to northern minnesota (c1070), and three dwarf lines (156-a, 302-e and i17- a). the dwarves contained, respectively, the homozygous, independent, recessive dwarfing genes d3, d1 and br2. each genotype was sown at four plant populations: 25, 50, 75 and 100.000 plants. ha-1. hybrids had the greatest rates of decrease in total biomass and grain dry matter per plant when population was increased, though they also had larger absolute values of these variables at any given density. hybrids produced more grain dry matter per unit of leaf area, and a higher harvest index, regardless the plant population used. reduction in plant height or leaf number did not improve maize efficiency in producing and partitioning dry matter to the grain.
Relatos autobiográficos: uma possibilidade para refletir sobre as lembran as escolares das alfabetizadoras
Helenise Sangoi Antunes
Educa??o : Revista do Centro de Educa??o UFSM , 2007, DOI: 10.5902/19846444661
Abstract: Este artigo foi elaborado com o objetivo de conhecer as lembran as escolares das alfabetizadoras através de seus relatos autobiográficos. O referencial teórico baseiase nos estudos de Bosi (1999), Bergson (1999) e Bem-Peretz (1992), entre outros que contribuíram para as reflex es propostas nesse trabalho. A metodologia é de caráter qualitativo, a partir dos estudos realizados por Bogdan; Biklen (1994), e emprega entrevistas semi-estruturadas, relatos autobiográficos e registros em diário de campo com alfabetizadoras do sistema de ensino de Santa Maria/RS. Acredita-se que o desenvolvimento de uma postura reflexiva por parte das alfabetizadoras passa também pela necessidade de produ o de saberes e de valores comprometidos com os princípios da ética, através do fortalecimento da autonomia nas várias dimens es que fazem parte da existência humana. Como resultados, percebeu-se que a organiza o do cotidiano escolar acaba, na maioria das vezes, impedindo a troca de saberes construídos pelo exercício profissional e n o incentivando o professor a investir nas experiências significativas dos seus percursos de forma o e na reflex o teórico-prática. Porém, destaca-se que, no momento em que as alfabetizadoras refletem, via relatos autobiográficos, sobre seus processos formativos, percebem o quanto precisam buscar novos subsídios teórico-práticos para poderem instaurar práticas educativas críticas e reflexivas, construindo novos sentidos em rela o às suas histórias de vida e às suas práticas docentes. Palavras-chave: Alfabetiza o. Forma o de Professores. Relatos Autobiográficos.
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