|
|
|
| Registros recuperados: 2.661 | |
|
|
| 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 |
| |
|
|
| Brighenti,Carla Regina Guimarães; Cirillo,Marcelo Ângelo; Costa,André Luís Alves; Rosa,Sttela Dellyzete Veiga Franco da; Guimarães,Renato Mendes. |
| ABSTRACT: Tetrazolium tests use conventional sampling techniques in which a sample has a fixed size. These tests may be improved by sequential sampling, which does not work with fixed-size samples. When data obtained from an experiment are analyzed sequentially the analysis can be terminated when a particular decision has been made, and thus, there is no need to pre-establish the number of seeds to assess. Bayesian statistics can also help, if we have sufficient knowledge about coffee production in the area to construct a prior distribution. Therefore, we used the Bayesian sequential approach to estimate the percentage of viable coffee seeds submitted to tetrazolium testing, and we incorporated priors with information from other analyses of crops from... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Beta distribution; Seed analysis; Sampling; Coffee; Prior distribution. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162019001300198 |
| |
|
|
| Dias,Raquel Souza; López,Secundino; Borgatti,Laura Maria Oliveira; Kebreab,Ermias; Vitti,Dorinha Miriam Silber Schmidt; Abdalla,Adibe Luiz; Appuhamy,Jayasooriya Arachchige Don Ranga Niroshan; France,James. |
| ABSTRACT: A reliable determination of endogenous phosphorus (P) excretion is required to measure P utilization in chickens accurately. The objective of this study was to investigate phosphorus (P) retention in broilers fed diets formulated with different feed ingredients. Sixty-four 15-d old broiler chicks were fed diets in which part of the dietary P was provided from dicalcium phosphate, maize, barley or soybean. Level of supplementation of each ingredient was calculated to provide two levels of total P (4.5 or 5.0 g kg−1 feed). Birds received a single injection of 3 MBq of 32P to determine endogenous P excretion using the isotope dilution technique. Four days after injection, blood and excreta were collected for analysis of inorganic and radioactive P.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chicken; Endogenous; Isotope dilution; Phosphorus retention. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162019000100018 |
| |
|
|
| Murbach,Marcos Roberto; Boaretto,Antonio Enedi; Muraoka,Takashi; Souza,Euclides Caxambu Alexandrino de. |
| Few reports have been presented on nutrient cycling in rubber tree plantations (Hevea brasiliensis Muell. Arg.). This experiment was carried out to evaluate: the effect of K rates on the amount of nutrients transfered to the soil in a 13-year old Hevea brasilensis RRIM 600 clone plantation, nutrient retranslocation from the leaves before falling to the soil, and nutrient loss by dry rubber export. The experiment started in 1998 and potassium was applied at the rates of 0, 40, 80 and 160 kg ha-1 of K2O under the crowns of 40 rubber trees of each plot. Literfall collectors, five per plot, were randomly distributed within the plots under the trees. The accumulated literfall was collected monthly during one year. The coagulated rubber latex from each plot was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Litterfall; Fertilization; Nutrition; Rubber; Nutrient exportation. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162003000200021 |
| |
|
|
| Brainer,Mônica Maria de Almeida; Menten,José Fernando Machado; Vale,Marcos Martinez do; Morais,Sônia Cristina Daroz de. |
| Feeding cupric citrate as alternative to cupric sulfate to broilers has been suggested in the literature. Day-old male broiler chicks (1,200) were used in an experiment to evaluate the efficacy of cupric citrate supplementation (75 mg Cu kg-1) during the 1-21, 22-42 or 1-42 d periods in comparison to an unsupplemented diet and a diet supplemented with cupric sulfate (200 mg Cu kg-1, 1-42 d). A randomized block design was used, with five treatments, six replicates and 40 birds per pen. The diets, based on corn and soybean meal, and water were offered ad libitum during the 42-day experimental period. Over the entire period, there was no effect of copper supplementation (P > 0.05) on bird live weight, weight gain, feed intake, feed conversion and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Broiler litter; Poultry; Copper; Performance. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162003000300004 |
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
| Vicentini,Nívea Maria; Cereda,Marney Pascoli; Câmara,Francisco Luís de Araújo. |
| Uma proposta em estudo para minimizar as perdas pós-colheita, é o uso de revestimentos derivados da fécula de mandioca. Frutos de pimentão (Capsicum annuum L.) cultivar Magali, foram mergulhados (1 minuto) em suspensões a 1 e 3% de fécula geleificada, secos naturalmente ao ar e armazenados em condições ambientais onde a temperatura média do período variou de 20,2-21,8°C. O delineamento experimental foi inteiramente casualizado com 3 tratamentos, 6 repetições e 5 frutos por parcela. As análises de controle (perda de massa e alteração da coloração), foram feitas a cada dois dias por um período de 10 dias. Os frutos com película a 3%, apresentaram inibição no desenvolvimento da coloração vermelha; porém não houve efeito sobre a perda de massa. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Capsicum annuum; Pimentão; Amido; Filmes comestíveis. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161999000300028 |
| |
|
|
| Kersten,E.; Lucchesi,A.A.; Gutierrez,L.E.. |
| O presente trabalho foi realizado com o objetivo de avaliar o efeito de quatro concentrações de ácido indolbutírico (IBA), no enraizamento de estacas de ramos de ameixeira (Prunus salicina, Lindl.), coletadas de plantas tratadas com bórax e sulfato de zinco e controle, executado em quatro épocas. Os experimentos foram conduzidos em viveiros, sob condição de nebulização artificial intermitente. Os resultados obtidos mostram a influência de cultivar, época e concentração de IBA, não sendo verificado efeito de bórax ou sulfato de zinco na percentagem de estacas enraizadas. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ácido indolbutírico (IBA); Estacas; Enraizamento; Ameixeira. |
| Ano: 1993 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161993000100004 |
| |
|
|
| Bocianowski,Jan. |
| Epistasis (additive × additive interaction) plays an important role in the genetic architecture of complex traits. This study presents analytical and numerical comparisons of two methods of estimation of additive × additive interaction of QTL effects. In the first method, we observed only the plant phenotype, while in the second method we have additional information from the molecular markers observations. In this study, two data sets were analyzed: i) 150 barley (Hordeum vulgare L.) doubled-haploid lines derived from the cross Steptoe × Morex and ii) 145 doubled-haploid lines of barley obtained from the cross Harrington × TR306. In total, 153 sets of observations were analyzed. The additive × additive interaction effect calculated on the basis of the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nonallelic interaction effect; Doubled haploid lines; Quantitative trait loci. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162012000400002 |
| |
|
|
| Nava,Dori Edson; Parra,José Roberto Postali. |
| Urbanus proteus proteus (L.) is a defoliating pest of legumes, causing damage mainly on soybean (Glycine max (L.) Merr.) and bean (Phaseolus vulgaris L.), and, being a minor pest, little is known about its bioecology. The objective of this paper was to study the larval and pupal development of the insect and the foliar consumption during its instars. Durations of 16.7; 1.1; 11.4 and 29.2 days were determined for the caterpillar, prepupal, and pupal stages, and the period from caterpillar-adult, respectively, with a total viability of 84.8%. The larval stage had five instars and the consumption of leaf area was 214.3 cm², with the consumption of the two last instars representing 96.9% of the total. Based on this value, the control level of the pest was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hesperiidae; Leaf consumption; Soybean pests; Control level; Bean leaf roller. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162002000400006 |
| |
|
|
| Pires,Nádja de Moura; Prates,Hélio Teixeira; Pereira Filho,Israel Alexandre; Oliveira Jr.,Rubem Silvério de; Faria,Trícia Cristina Lessa de. |
| Alelopatia é o efeito direto ou indireto de uma planta sobre outra, por meio da produção de compostos químicos liberados no ambiente. Os metabólitos secundários ou produtos naturais envolvidos em alelopatia são denominados aleloquímicos e estão presentes nos tecidos de diferentes partes das plantas. O objetivo deste trabalho foi determinar o potencial alelopático da leucena (Leucaena leucocephala (Lam.) de Wit.) sobre as plantas daninhas Desmodium purpureum (desmódio), Bidens pilosa (picão-preto) e Amaranthus hybridus (caruru). Os bioensaios foram conduzidos em laboratório e em casa de vegetação com extratos aquosos da parte aérea da leucena nas concentrações de 100, 50, 25, 12,5 % (v v-1). O extrato apresentou maior efeito quando aplicado em papel filtro.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Desmodium purpureum; Bidens pilosa; Amaranthus hybridus; Extrato de planta; Mimosina. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162001000100011 |
| |
|
|
| Carvalho,João Luís Nunes; Otto,Rafael; Franco,Henrique Coutinho Junqueira; Trivelin,Paulo Cesar Ocheuze. |
| Sugarcane (Saccharum spp.) crops provide carbon (C) for soil through straw and root system decomposition. Recently, however, sugarcane producers are considering straw to be removed for electricity or second generation ethanol production. To elucidate the role of straw and root system on the carbon supply into the soil, the biomass inputs from sugarcane straw (tops and dry leaves) and from root system (rhizomes and roots) were quantified, and its contribution to provide C to the soil was estimated. Three trials were carried out in the State of Sao Paulo, Brazil, from 2006 to 2009. All sites were cultivated with the variety SP81 3250 under the green sugarcane harvest. Yearly, post-harvest sugarcane residues (tops, dry leaves, roots and rhizomes) were... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162013000500008 |
| |
|
|
| Botelho,Paulo Sérgio Machado; Silveira Neto,Sinval; Magrini,Eliana Aparecida. |
| Estudou-se a biologia e a flutuação de Anticarsia gemmatalis em campos de soja com o objetivo de construir tabelas de vida ecológica visando determinar o estágio e o fator chave. Os experimentos foram conduzidos durante os períodos agrícolas de 1992 a 1997. Em cada ano foram realizados dois estudos biológicos. Simultaneamente durante o ciclo da soja, nos seis anos estudados, foram realizadas amostragens para determinar a flutuação natural de ovos e de lagartas de A. gemmatalis. De posse desses dados foram construídas tabelas de vida ecológica, tendo-se observado que a taxa líquida de reprodução da espécie aumentou de 2,9 a 7,5 vezes em relação a população inicial, sendo que, para a tabela construída com a média dos dados, esse valor subiu para 15,5 vezes.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bioecologia; Lagarta-da-soja; Soja. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161999000400014 |
| |
|
| |
|
| |
|
| |
| Registros recuperados: 2.661 | |
|
|
|
