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| Registros recuperados: 23 | |
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| Garcia, Ricardo Ferreira; Universidade Estadual do Norte Fluminense Darcy Ribeiro; Vale, Welington Gonzaga do; Universidade Estadual do Norte Fluminense Darcy Ribeiro; Oliveira, Márcia Teresinha Ramos de; Universidade Estadual do Norte Fluminense Darcy Ribeiro; Pereira, Érica Mirre; Universidade Estadual do Norte Fluminense Darcy Ribeiro; Amim, Reynaldo Tancredo; Universidade Estadual do Norte Fluminense Darcy Ribeiro; Braga, Thiago Costa; Universidade Estadual do Norte Fluminense Darcy Ribeiro. |
| O objetivo deste trabalho foi avaliar a influência da velocidade de deslocamento no desempenho de uma semeadora-adubadora de precisão. Os ensaios foram realizados em área experimental da Universidade Estadual do Norte Fluminense Darcy Ribeiro, localizada em Campos dos Goytacazes, RJ. O experimento foi montado em delineamento em blocos casualizados, utilizando duas velocidades de deslocamento, de 2,5 e 4,4 km h-1, com 16 repetições. Na semeadura, utilizou-se o milho híbrido UENF 506-8, com espaçamento entre linhas de 0,9 m e espaçamento teórico entre sementes de 11 cm. Com o aumento da velocidade de deslocamento, houve aumento na patinagem dos rodados da semeadora, na capacidade de campo efetiva, na profundidade de plantio, na velocidade periférica do disco... |
| Tipo: Mensurações |
Palavras-chave: 5.01.03.02-4 danos mecânicos; Patinagem; Profundidade de semeadura; Capacidade de campo Mecanização Agrícola mechanical damage; Slippage; Seeding depth; Field capacity. |
| Ano: 2011 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/6085 |
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| Vale, Welington Gonzaga do; UENF; Garcia, Ricardo Ferreira; UENF; Thiebaut, José Tarcísio Lima; UENF; Amim, Reynaldo Tancredo; UENF; Tourino, Maria Cristina Cavalheiro; UFV. |
| O objetivo deste trabalho foi analisar o desempenho e o tamanho amostral ideal (n) da patinagem e a capacidade de campo de uma semeadora em plantio direto (PD) e convencional (PC). Foi utilizado o método de amostragem ao acaso para determinação de n, considerando populações infinitas. Para estimar a patinagem no PC, com α = 5% e precisão igual a 5, 10, 15 e 20%, é necessário um número de repetição igual a 115, 29, 13 e 8, respectivamente. Já no PD, observou-se 422, 106, 47 e 27, respectivamente. Para a capacidade de campo teórica (Ct) no PC, é necessário um número de repetição igual a 27, 7, 3 e 2, respectivamente. Já no PD, observou-se 45, 12, 5 e 3, respectivamente. Para a capacidade de campo efetiva (Ce) da semeadora no PC, é necessário um número de... |
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Palavras-chave: 5.01.00.00-9 Agronomia amostragem; Capacidade de campo; Patinagem. sampling; Field capacity; Slip. |
| Ano: 2008 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/5295 |
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| Amponsah, Shadrack Kwadwo; Sheriff, J Thajudhin; Byju, Gangadharan. |
| Abstract: In India, cassava is consumed as a secondary staple along with the main staple, rice, and many rural poor consume it as the staple in different forms of preparations. Though harvesting is known to be one of the most difficult and cost-intensive field operation in cassava cultivation, mechanisation of cassava harvesting is still very low in most cassava growing areas of India due to topographic constraints, methods and scale of cultivation. The most viable solution to overcome these constraints is to promote the use of more efficient manual harvesting tools. Thus, the main objective of this study was to field evaluate the efficiency of four manual cassava harvesting techniques under different land preparation methods in terms of field capacity,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Farm power and machinery; Agronomy cassava; Field capacity; Drudgery; Coppiced; Efficiency. |
| Ano: 2014 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2793 |
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| Santos,Walbert Júnior Reis dos; Curi,Nilton; Silva,Sérgio Henrique Godinho; Araújo,Elias Frank de; Marques,João José. |
| Water retention in soil is used in many agronomic and environmental applications, but its direct measurement is time-consuming and expensive. Therefore, pedotransfer functions (PTFs) are alternatives to obtain this information faster and more economically. The objectives of this study were to generate and validate PTFs to estimate the water content at potentials of -33 kPa (field capacity) and -1500 kPa (permanent wilting point) for different soil classes from the central-south portion of Rio Grande do Sul State. The physical and chemical analyses database from soil surveys of the Celulose Riograndense Corp were used. The database is composed of particle size distribution (coarse and fine sand, silt and clay), soil organic matter, and water content data at... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Permanent wilting point; Field capacity; Water retention curve. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542013000100006 |
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| Maia,Felipe C. de O.; Bufon,Vinicius B.; Leão,Tairone P.. |
| ABSTRACT Water stored in the soil between field capacity and the permanent wilting point, is known as the available water capacity. Its availability to be effectively used by plants depends on the type of soil and its water retention characteristics. The aim of this work was to compile information about water retention curves in Latosols, and to provide a first approximation of values and most likely amplitudes for water storage and available water capacity of these soils. The database was constituted from information collected from articles, theses, dissertations and other publications. Soil water retention curves, as well as available water, were estimated for the order Latosols, and for the suborders Red Latosol (RL), Red-Yellow Latosol (RYL) and Yellow... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Field capacity; Permanent wilting point; Van Genuchten; Tropical soils. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162018000400546 |
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| Costa,André da; Albuquerque,Jackson Adriano; Almeida,Jaime Antônio de; Costa,Adriano da; Luciano,Rodrigo Vieira. |
| Studies on water retention and availability are scarce for subtropical or humid temperate climate regions of the southern hemisphere. The aims of this study were to evaluate the relations of the soil physical, chemical, and mineralogical properties with water retention and availability for the generation and validation of continuous point pedotransfer functions (PTFs) for soils of the State of Santa Catarina (SC) in the South of Brazil. Horizons of 44 profiles were sampled in areas under different cover crops and regions of SC, to determine: field capacity (FC, 10 kPa), permanent wilting point (PWP, 1,500 kPa), available water content (AW, by difference), saturated hydraulic conductivity, bulk density, aggregate stability, particle size distribution (seven... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Field capacity; Permanent wilting point; Plant available water; Correlation analysis; Path analysis. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000400007 |
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| Silva,Bruno Montoani; Silva,Érika Andressa da; Oliveira,Geraldo César de; Ferreira,Mozart Martins; Serafim,Milson Evaldo. |
| The plant-available water capacity of the soil is defined as the water content between field capacity and wilting point, and has wide practical application in planning the land use. In a representative profile of the Cerrado Oxisol, methods for estimating the wilting point were studied and compared, using a WP4-T psychrometer and Richards chamber for undisturbed and disturbed samples. In addition, the field capacity was estimated by the water content at 6, 10, 33 kPa and by the inflection point of the water retention curve, calculated by the van Genuchten and cubic polynomial models. We found that the field capacity moisture determined at the inflection point was higher than by the other methods, and that even at the inflection point the estimates... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Field capacity; Permanent wilting point; Soil water retention curve modeling; Oxisol; Land use planning. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832014000200011 |
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| Martínez,Emma María; Serafín Cuesta,Tomas; Cancela,Javier José. |
| The soil water available to crops is defined by specific values of water potential limits. Underlying the estimation of hydro-physical limits, identified as permanent wilting point (PWP) and field capacity (FC), is the selection of a suitable method based on a multi-criteria analysis that is not always clear and defined. In this kind of analysis, the time required for measurements must be taken into consideration as well as other external measurement factors, e.g., the reliability and suitability of the study area, measurement uncertainty, cost, effort and labour invested. In this paper, the efficiency of different methods for determining hydro-physical limits is evaluated by using indices that allow for the calculation of efficiency in terms of effort and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Field capacity; Permanent wilting point; Pedotransfer functions; Water activity meter. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832012000600009 |
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| Costa,André da; Albuquerque,Jackson Adriano; Costa,Adriano da; Pértile,Patricia; Silva,Franciani Rodrigues da. |
| The retention and availability of water in the soil vary according to the soil characteristics and determine plant growth. Thus, the aim of this study was to evaluate water retention and availability in the soils of the State of Santa Catarina, Brazil, according to the textural class, soil class and lithology. The surface and subsurface horizons of 44 profiles were sampled in different regions of the State and different cover crops to determine field capacity, permanent wilting point, available water content, particle size, and organic matter content. Water retention and availability between the horizons were compared in a mixed model, considering the textural classes, the soil classes and lithology as fixed factors and profiles as random factors. It may... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Field capacity; Permanent wilting point; Available water capacity; Particle size; Mixed models. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000600010 |
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| Moreira,Samuel D.; França,André C.; Rocha,Wellington W.; Tibães,Evandro S. R.; Neiva Júnior,Eudes. |
| ABSTRACT Water stress can be alleviated in plants inoculated with arbuscular mycorrhizal fungi compared to that experienced by those without mycorrhizae. The objective of this study was to evaluate the growth of coffee plants colonized by arbuscular mycorrhizal fungi under different soil moisture conditions. Seeds of the coffee cultivar Catuaí Vermelho IAC 99 and three fungal inoculants (Rhizophagus clarus, Claroideoglomus etunicatum and Dentiscutata heterogama) were used in this study. The soil moisture contents tested were 40, 60, 80, and 100% of field capacity. Seedlings in the matchstick stage were inoculated with mycorrhizae, and then later planted in plastic pots when they developed four to five pairs of definitive leaves. Both the extent of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea arabica L.; Rubiaceae; Field capacity; Arbuscular mycorrhiza. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018001100747 |
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| Registros recuperados: 23 | |
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