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| Registros recuperados: 16 | |
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| Islabão,Gláucia Oliveira; Pinto,Marília Alves Brito; Selau,Lisiane Priscila Roldão; Vahl,Ledemar Carlos; Timm,Luís Carlos. |
| One of the largest strawberry-producing municipalities of Rio Grande do Sul (RS) is Turuçu, in the South of the State. The strawberry production system adopted by farmers is similar to that used in other regions in Brazil and in the world. The main difference is related to the soil management, which can change the soil chemical properties during the strawberry cycle. This study had the objective of assessing the spatial and temporal distribution of soil fertility parameters using principal component analysis (PCA). Soil sampling was based on topography, dividing the field in three thirds: upper, middle and lower. From each of these thirds, five soil samples were randomly collected in the 0-0.20 m layer, to form a composite sample for each third. Four... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fragaria x ananassa Duch; Soil fertility; Multivariate analysis; Temporal variability. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000100017 |
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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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| Bamberg,Adilson Luís; Pauletto,Eloy Antonio; Gomes,Algenor da Silva; Timm,Luís Carlos; Pinto,Luiz Fernando Spinelli; Lima,Ana Cláudia Rodrigues de; Silva,Thiago Rech da. |
| A sustentabilidade do arroz (Oryza sativa L.) irrigado em solos de várzea está alicerçada na utilização da rotação e sucessão de culturas, fundamentais para o controle do arroz-vermelho e preto. Os reflexos sobre os atributos dos solos de várzea merecem estudos em especial sobre a compactação do solo. O objetivo deste trabalho foi identificar camadas compactadas em Planossolo submetido a diferentes sistemas de cultivo e preparo, avaliando-se a densidade do solo (Ds) pela Tomografia Computadorizada de Raios Gama (TC). A análise foi realizada em um experimento de longa duração, conduzido de 1985 a 2004, na Estação Experimental da Embrapa Clima Temperado, Capão do Leão, RS, num delineamento experimental em blocos ao acaso, com sete tratamentos, cada um com... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Compactação; Sistemas de cultivo; Solos de várzea; Arroz irrigado. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832009000500001 |
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| Timm,Luís Carlos; Pires,Luiz Fernando; Roveratti,Renato; Arthur,Robson Clayton Jacques; Reichardt,Klaus; Oliveira,Júlio Cesar Martins de; Bacchi,Osny Oliveira Santos. |
| Soil water content (theta) and bulk density (rhos) greatly influence important soil and plant processes, such as water movement, soil compaction, soil aeration, and plant root system development. Spatial and temporal variability of theta and rhos during different periods of the year and different phases of crops are of fundamental interest. This work involves the characterization of spatial and temporal patterns of theta and rhos during different climatic periods of year, aiming to verify whether there are significant temporal changes in rhos at the soil surface layer when submitted to wetting and drying cycles. The field experiment was carried out in a coffee plantation, Rhodic Kandiudalf soil, clayey texture. Using a neutron/gamma surface probe, theta... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Neutron/gamma surface probe; Wetting/drying cycles; Spatial and temporal variability. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000100009 |
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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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| 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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| Pinto,Marília Alves Brito; Parfitt,José Maria Barbat; Timm,Luís Carlos; Faria,Lessandro Coll; Scivittaro,Walkyria Bueno. |
| Resumo O objetivo deste trabalho foi determinar a influência da tensão de água e de atributos físicos e químicos do solo sobre a produtividade do arroz irrigado por aspersão, em terras baixas no Rio Grande do Sul. Na safra 2011/2012, foram avaliados os efeitos das tensões de água no solo de 20 e 40 kPa, durante todo o ciclo da cultura, bem como as de 40 e 20 kPa nas fases vegetativa e reprodutiva, respectivamente. Na safra 2012/2013, foram avaliadas as tensões de 10, 20 e 40 kPa, durante todo o ciclo da cultura, e as de 40 e 10 kPa nas fases vegetativa e reprodutiva, respectivamente. Em ambas as safras, utilizou-se a cultivar de arroz irrigado BRS Pampa. O gasto com água na irrigação por aspersão representou 48% do gasto com a irrigação por inundação. A... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Oryza sativa; Economia de água; Fertilidade do solo; Física do solo; Porosidade do solo; Tensão de água no solo. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2016000901584 |
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| Islabão,Gláucia Oliveira; Vahl,Ledemar Carlos; Timm,Luís Carlos; Paul,Donald Luiz; Kath,Aline Hernandez. |
| Rice husk ash (RHA) is a by-product from the burning of rice husk that can have favorable effects on the soil in terms of acidity correction. The objectives of this study were to determine the effective calcium carbonate equivalent (ECC) of RHA under field conditions, and establish technical criteria as a basis for estimating the overall ECC of RHA. The 12 treatments of the experiment consisted of 10 RHA dosages (0, 10, 20, 30, 40, 60, 80, 100, 120, and 140 Mg ha-1) and two references, one of which was an absolute control (AC) and the other a plot limed and fertilized according to official recommendations (recommended fertilization - RF). The soil was sampled twice (15 and 210 days after incorporating RHA), in the layers 0.00-0.10 and 0.10-0.20 m, to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Acidity correction; Neutralizing value; Effective calcium carbonate equivalent. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832014000300025 |
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| Reichardt,Klaus; Silva,José Carlos de Araújo; Bassoi,Luis Henrique; Timm,Luís Carlos; Oliveira,Julio Cesar Martins de; Bacchi,Osny Oliveira Santos; Pilotto,João Eduardo. |
| The effects of soil water spatial variability previous to irrigation and of the field capacity on the estimation of irrigation water depth are evaluated. The experiment consisted of a common bean (Phaseolus vulgaris L.) crop established on a Kandiudalfic Eutrudox of Piracicaba, SP, Brazil, irrigated by central pivot, in which soil water contents were evaluated with a depth neutron gauge, in a grid of 20x4 points with lag of 0.5 m. In a given situation, the 80 calculated irrigation water depths presented a coefficient of variation of 29.3%, with an average water value of 18 mm, maximum of 41mm and minimum of 9 mm. It is concluded that the only practical way of irrigation is the use of an average water depth, due to the inherent variability of the soil, and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Irrigation water depth; Field capacity; Spatial variability. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162001000300017 |
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| Parfitt,José Maria Barbat; Timm,Luís Carlos; Pauletto,Eloy Antonio; Sousa,Rogério Oliveira de; Castilhos,Danilo Dufech; Ávila,Conceição Lagos de; Reckziegel,Nestor Luis. |
| In the areas where irrigated rice is grown in the south of Brazil, few studies have been carried out to investigate the spatial variability structure of soil properties and to establish new forms of soil management as well as determine soil corrective and fertilizer applications. In this sense, this study had the objective of evaluating the spatial variability of chemical, physical and biological soil properties in a lowland area under irrigated rice cultivation in the conventional till system. For this purpose, a 10 x 10 m grid of 100 points was established, in an experimental field of the Embrapa Clima Temperado, in the County of Capão do Leão, State of Rio Grande do Sul. The spatial variability structure was evaluated by geostatistical tools and the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Soil sampling; Spatial dependence. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832009000400007 |
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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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| 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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| Monteiro,Alex Becker; Reisser Júnior,Carlos; Romano,Luciano Recart; Timm,Luís Carlos; Toebe,Marcos. |
| Abstract The use of water potential indicators in the plant has been adopted in irrigation management, in recent years, since it is accepted that the plant is the best indicator of its own water status. The objective of this study was to verify the relationship between water potential in peach tree branches and the evaporative demand of the atmosphere and the water availability in two textural classes of an Aquertic Hapludalf soil, aiming to adopt irrigation management strategies based on the water potential in the plant. Research was carried out in a commercial peach orchard, cv. Esmeralda, in the municipality of Morro Redondo-Rio Grande do Sul state, Brazil. Four peach tree rows were evaluated, being two irrigated and two non irrigated. The irrigation... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Prunus persica (L.); Water status; Evapotranspiration; Soil water content; Irrigation management. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452018000100702 |
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| Registros recuperados: 16 | |
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