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| Registros recuperados: 50 | |
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| Parfitt,José Maria Barbat; Timm,Luís Carlos; Reichardt,Klaus; Pinto,Luiz Fernando Spinelli; Pauletto,Eloy Antonio; Castilhos,Danilo Dufech. |
| The objective of this work was to evaluate the relationship between soil chemical and biological attributes and the magnitude of cuts and fills after the land leveling process of a lowland soil. Soil samples were collected from the 0 - 0.20 m layer, before and after leveling, on a 100 point grid established in the experimental area, to evaluate chemical attributes and soil microbial biomass carbon (MBC). Leveling operations altered the magnitude of soil chemical and biological attributes. Values of Ca, Mg, S, cation exchange capacity, Mn, P, Zn, and soil organic matter (SOM) decreased in the soil profile, whereas Al, K, and MBC increased after leveling. Land leveling decreased in 20% SOM average content in the 0 - 0.20 m layer. The great majority of the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Flooded rice; Soil biological attributes; Soil chemical attributes; Soil management; Soil movement. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2013001100010 |
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| Kelling,Cláudio Renato Schlessner; Reichardt,Klaus; Streck,Nereu Augusto; Lago,Isabel; Zanon,Alencar Junior; Rodrigues,Marcelo Antônio. |
| Resumo:O objetivo deste trabalho foi avaliar a resposta da transpiração e do crescimento foliar de cultivares de crisântemo (Dendranthema grandiflorum) ao conteúdo de água disponível no substrato, representado pela fração de água transpirável no substrato (FATSb). Os experimentos foram realizados em dois períodos, em delineamento inteiramente casualizado, com quatro cultivares de crisântemo (Cherie White, Bronze Repin, Yoapple Valley e Calabria), em duas condições hídricas (com ou sem deficiência hídrica), com 10 repetições. As plantas foram cultivadas em casa de vegetação, em vasos de 2,8 L preenchidos com substrato. A FATSb, a transpiração e o crescimento foliar foram determinados diariamente durante o período de deficiência hídrica. As FATSb críticas... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dendranthema grandiflorum; Área foliar; Deficiência hídrica; Fechamento estomático; Manejo da irrigação. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2015000900735 |
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| Assis,Janilson Pinheiro de; Dourado Neto,Durval; Reichardt,Klaus; Manfron,Paulo Augusto; Martin,Thomas Newton; Bonnecarrère,Reinaldo Antônio Garcia. |
| O objetivo deste trabalho foi avaliar uma metodologia para estimar a produtividade potencial da cultura do milho de acordo com valores médios diários de temperatura do ar e radiação solar, utilizando procedimento estocástico. Valores registrados da temperatura média diária do ar durante 86 anos e da radiação solar global diária durante 25 anos, foram fornecidos pela Estação Agrometeorológica de Piracicaba (Esalq/USP). Valores correspondentes à produtividade potencial foram simulados 1.000 vezes, em cada data de semeadura considerada (15/10 - época normal; 15/2 - safrinha; e 15/8 - safra de inverno). Foram considerados dois casos na distribuição de probabilidade normal truncada (valores extremos: média - 1,96 desvio-padrão e média + 1,96 desvio-padrão):... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zea mays; Modelagem; Simulação. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2006000500003 |
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| Stolf,Rubismar; Thurler,Álvaro de Mendonça; Bacchi,Osny Oliveira Santos; Reichardt,Klaus. |
| Macroporosity is often used in the determination of soil compaction. Reduced macroporosity can lead to poor drainage, low root aeration and soil degradation. The aim of this study was to develop and test different models to estimate macro and microporosity efficiently, using multiple regression. Ten soils were selected within a large range of textures: sand (Sa) 0.07-0.84; silt 0.03-0.24; clay 0.13-0.78 kg kg-1 and subjected to three compaction levels (three bulk densities, BD). Two models with similar accuracy were selected, with a mean error of about 0.02 m³ m-3 (2 %). The model y = a + b.BD + c.Sa, named model 2, was selected for its simplicity to estimate Macro (Ma), Micro (Mi) or total porosity (TP): Ma = 0.693 - 0.465 BD + 0.212 Sa; Mi = 0.337 +... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Degree of compaction; Modeling; Macropore; Texture; Maximum bulk density; Relative bulk density. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832011000200014 |
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| Ottoni Filho,Theophilo Benedicto; Ottoni,Marta Vasconcelos; Oliveira,Muriel Batista de; Macedo,José Ronaldo de; Reichardt,Klaus. |
| Taking into account the nature of the hydrological processes involved in in situ measurement of Field Capacity (FC), this study proposes a variation of the definition of FC aiming not only at minimizing the inadequacies of its determination, but also at maintaining its original, practical meaning. Analysis of FC data for 22 Brazilian soils and additional FC data from the literature, all measured according to the proposed definition, which is based on a 48-h drainage time after infiltration by shallow ponding, indicates a weak dependency on the amount of infiltrated water, antecedent moisture level, soil morphology, and the level of the groundwater table, but a strong dependency on basic soil properties. The dependence on basic soil properties allowed... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Internal drainage; Aeration capacity; Soil water retention. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832014000600010 |
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| Nebel,Álvaro Luiz Carvalho; Timm,Luís Carlos; Cornelis,Wim; Gabriels,Donald; Reichardt,Klaus; Aquino,Leandro Sanzi; Pauletto,Eloy Antonio; Reinert,Dalvan José. |
| The estimation of non available soil variables through the knowledge of other related measured variables can be achieved through pedotransfer functions (PTF) mainly saving time and reducing cost. Great differences among soils, however, can yield non desirable results when applying this method. This study discusses the application of developed PTFs by several authors using a variety of soils of different characteristics, to evaluate soil water contents of two Brazilian lowland soils. Comparisons are made between PTF evaluated data and field measured data, using statistical and geostatistical tools, like mean error, root mean square error, semivariogram, cross-validation, and regression coefficient. The eight tested PTFs to evaluate gravimetric soil water... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil water content; Planosol; Gleisol; Hydraulic properties; Geostatistics; Regression models. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832010000300008 |
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| Cássaro,Fabio Augusto Meira; Pires,Luiz Fernando; Santos,Rosiane Antures dos; Giménez,Daniel; Reichardt,Klaus. |
| O movimento da água através da matriz do solo é geralmente modelado pelas equações de Darcy, Darcy-Buckingam e Richards, cujo uso está baseado no conhecimento de algumas propriedades físicas do solo, como, por exemplo, a distribuição de poros e a retenção de água pelo solo. A retenção de água pelo solo é conhecida a partir da determinação de sua curva de retenção (CR) ou curva característica. O primeiro objetivo deste trabalho foi apresentar um aparato simples, desenvolvido pela modificação do funil de placa porosa (funil de Haines), para a investigação e o levantamento de CRs detalhadas, em amostras de solos em condições de umidade próximas à saturação e em amostras com potenciais mátricos (ψm) que vão desde 0 kPa a aproximadamente -12 kPa (120 cm de... |
| Tipo: Info:eu-repo/semantics/report |
Palavras-chave: Van Genuchten; Curva de retenção; Função capacidade de água. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832008000600032 |
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| Timm,Luis C.; Oliveira,Julio C. M. de; Tominaga,Tania T.; Cássaro,Fabio A. M.; Reichardt,Klaus; Bacchi,Osny O. S.. |
| The quantification of soil water balance components was conducted in a sugarcane (Saccharum officinarum L.) field differently managed, as well as a qualitative analysis of the methodologies used for their estimation. The study was conducted in randomized block experiment with four replicates and three treatments: bare soil, mulched soil using trash left on the soil surface after harvest, and soil with burnt trash. The soil was classified as a Rhodic Kandiudalf, locally called 'Terra Roxa Estruturada', the experimental area having a slope of 7.4%. Run-off, soil water fluxes at the lower soil volume limit, and soil water storage changes were not affected by the different soil management practices. Furthermore, it was found that the evaluation of run-off and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Water balance; Soil physical properties; Soil management. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662002000100011 |
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| Silva,Adriana L. da; Bruno,Isabeli P.; Reichardt,Klaus; Bacchi,Osny O. S.; Dourado-Neto,Durval; Favarin,José L.; Costa,Flávio M. P. da; Timm,Luis C.. |
| Basic information for a rational soil-water management of the coffee crop is still insufficient, particularly under irrigated conditions. Of great importance for the estimation of water requirements of coffee crops are their root distribuition and evapotranspiration crop coefficients. This study compares soil water extraction by roots of coffee plants of the variety "Catuaí Vermelho" (IAC-44), grown in Piracicaba, SP, Brazil, 3 to 5 years old, with direct measurements of root dry matter, showing a good agreement between both approaches, and confirming that most of the root system is distributed in the top soil layer (0-0.3 m) and that less than 10% of the root system reaches depths greater than 1.0 m. Calculated evapotranspiration crop coefficients are in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Perenial crop; Soil water storage; Water balance. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662009000300006 |
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| Timm,Luís Carlos; Gomes,Daniel Takata; Barbosa,Emanuel Pimentel; Reichardt,Klaus; Souza,Manoel Dornelas de; Dynia,José Flávio. |
| The study of soil property relationships is of great importance in agronomy aiming for a rational management of environmental resources and an improvement of agricultural productivity. Studies of this kind are traditionally performed using static regression models, which do not take into account the involved spatial structure. This work has the objective of evaluating the relation between a time-consuming and "expensive" variable (like soil total nitrogen) and other simple, easier to measure variables (as for instance, soil organic carbon, pH, etc.). Two important classes of models (linear state-space and neural networks) are used for prediction and compared with standard uni- and multivariate regression models, used as reference. For an oat crop... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil attributes; Prediction models; Spatial transect; Latent variables. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000400010 |
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| Fenilli,Tatiele Anete Bergamo; Reichardt,Klaus; Dourado-Neto,Durval; Trivelin,Paulo César Ocheuze; Favarin,José Laercio; Costa,Flávio Murilo Pereira da; Bacchi,Osny Oliveira Santos. |
| The relationship between growth and fertilizer nitrogen recovery by perenial crops such as coffee is poorly understood and improved understanding of such relations is important for the establishment of rational crop management practices. In order to characterize the growth of a typical coffee crop in Brazil and quantify the recovery of 15N labeled ammonium sulfate, and improve information for fertilizer management practices this study presents results for two consecutive cropping years, fertilized with 280 and 350 kg ha-1 of N, respectively, applied in four splittings, using five replicates. Shoot dry matter accumulation was evaluated every 60 days, separating plants into branches, leaves and fruits. Labeled sub-plots were used to evaluate N-total and 15N... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea arabica L.; Stable isotope; Nitrogen; Dry matter accumulation; 15N. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162007000500012 |
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| Timm,Luís Carlos; Barbosa,Emanuel Pimentel; Souza,Manoel Dornelas de; Dynia,José Flávio; Reichardt,Klaus. |
| The assessment of the relationship among soil properties (such as total nitrogen and organic carbon) taken along lines called transects is a subject of great interest in agricultural experimentation. This question has been usually approached through standard state-space methods by some authors in the soil science literature. Important limitations of the mentioned procedures used in practice are pointed out and discussed in this paper, specially those related to the model parameters, meaning and practical interpretation. In the standard state-space approach, based on an autoregressive structure, it does not present any parameters that express the variables relationship at the same point in space, but only at lagged points. Also, its model parameters (in the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dynamic regression; Soil properties; Spatial heterogeneity; Kalman filter. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162003000200023 |
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| Fante Jr.,Lorival; Reichardt,Klaus; Jorge,Lucio André de Castro; Bacchi,Osny Oliveira Santos. |
| Avaliou-se a distribuição das raízes de uma aveia forrageira através da aplicação dos métodos do anel volumétrico, da placa com pregos, do trado e do auxiliado por processamento de imagens. A aveia forrageira foi cultivada em latossolo vermelho-escuro, sob dois tratamentos distintos em função da manutenção da capacidade de água disponível no solo (CAD): tratamento 1 - 50% da CAD; tratamento 2 - 80% da CAD. Foram realizadas 3 amostragens, aos 25, 60 e 115 dias após a emergência. As raízes da aveia forrageira concentraram-se nas camadas iniciais do solo, cerca de 90% entre 0 a 20 cm. Os resultados encontrados para a quantificação das raízes variaram com o tratamento, a metodologia e a época de amostragem. Verificou-se a existência de correlações entre os... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aveia forrageira; Sistema radicular; Processamento de imagem; Água do solo. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161999000500010 |
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| Dourado-Neto,Durval; Timm,Luís Carlos; Oliveira,Julio Cesar Martins de; Reichardt,Klaus; Bacchi,Osny Oliveira Santos; Tominaga,Tania Toyomi; Cássaro,Fabio Augusto Meira. |
| The state-space approach is used to describe surface soil water content and temperature behaviour, in a field experiment in which sugarcane is submitted to different management practices. The treatments consisted of harvest trash mulching, bare soil, and burned trash, all three in a ratoon crop, after first cane harvest. One transect of 84 points was sampled, meter by meter, covering all treatments and borders. The state-space approach is described in detail and the results show that soil water contents measured along the transect could successfully be estimated from water content and temperature observations made at the first neighbour. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil water; Soil temperature; State-space; Transect. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161999000500025 |
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| Registros recuperados: 50 | |
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