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| Registros recuperados: 390 | |
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| Flores,Carlos I.; Holzapfel,Eduardo A.; Lagos,Octavio. |
| An online dynamic decision support system (DDSS) was developed, to support the farm water management in surface irrigation. The online DDSS was based on the formulation and integration of three components: a dynamic-relational data base, an administrator model, and a graphical user interface. The DDSS allows routines of actualization, edition and addition of online data, providing information in real time. The online DDSS was applied in an orange orchard (Citrus sinensis L. Osbeck) cv. Valencia Late under furrow irrigation. The results pointed out that the time irrigation cutoff was the main significant management factor, to decrease the hazard of leaching, superficial runoff and percolation. Applying the results obtained with the DDSS, furrow irrigation... |
| Tipo: Journal article |
Palavras-chave: Furrow irrigation; On-line irrigation management; Orange orchard. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392010000200011 |
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| Niggol Seo,S; Mendelsohn,Robert. |
| This study estimates the impact of climate change on South American agriculture taking into account farm adaptations. The study used a Ricardian analysis of 2300 farms to explore the effects of global warming on land values. In order to predict climate change impacts for this century, were examined climate change scenarios predicted by three Atmospheric Oceanic General Circulation Models (AOGCM): the Canadian Climate Center (CCC), the Centre for Climate System Research (CCSR), and the Parallel Climate Model (PCM) models. Several econometric specifications were tested, and five separate regressions were run: for all farms, small household farms, large commercial farms, rainfed farms, and irrigated farms. Farmland values will decrease as temperature... |
| Tipo: Journal article |
Palavras-chave: Climate change; Agriculture; Ricardian approach; South America. |
| Ano: 2008 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392008000100007 |
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| Castellaro G,Giorgio; Aguilar G,Claudio; Vera I,Raul; Morales S,Luis. |
| Grasslands are complex ecosystems and their processes are affected by soil, meteorological, and management variables. In this context, dynamic simulation models are useful to understand these processes and to design grassland use strategies. The aim of this study was to develop and validate a simulation model of perennial pasture growth based on soil and climate variables. A first approach considered that soil fertility levels were adequate; therefore, soil water availability and phytomass level were the main variables affecting pasture growth. The subroutines considered were water balance, pasture growth, and root biomass dynamics. The hypotheses regarding the functioning of the system were formulated as a group of equations which were solved numerically... |
| Tipo: Journal article |
Palavras-chave: Grassland simulation models; Mesophytic grasslands. |
| Ano: 2012 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392012000300013 |
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| This paper develops a meta-regression analysis to explain the variation of mean technical efficiency (PETP) measurements from a total of 65 frontier studies that report technical efficiency (ET) measurements at the dairy farm level in the literature published in English and Spanish. The analysis includes the effect of methodology on ET measurements, as well as the effect of the econometric procedure on the meta-regression estimates. Eight models were estimated, and two of these were selected: a fixed effects specification with dummy variables for the most significant studies without geographical effects (EFS), and a specification where the multiple observations are averaged and geographical effects included (OP). Based on model performance, the EFS option... |
| Tipo: Journal article |
Palavras-chave: Meta-regression; Frontier models; Technical efficiency; Dairy farms. |
| Ano: 2009 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392009000200011 |
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| Carrasco-Letelier,Leonidas; Mendoza,Yamandu; Ramallo,Gustavo. |
| This work studies the acute contact toxicity of oxalic acid (OA) on a honeybee polyhybrid subspecies (Apis mellifera), which is the dominant biotype in southwestern zone of Uruguay (SWZU) and the country's most important honey-producing region. We determined the mean lethal dose (LD50), as well as the no observed effect level (NOEL) and the lowest observed effect level (LOEL) values. We also estimated the total number of honeybees per hive in the test area. The aim was to assess the relationship between the maximum OA dose used in Uruguay (3.1 g OA per hive) and the toxicological parameters of honeybees from SWZU. The current dose of 3.1 g OA per hive corresponds to 132.8 OA per honeybee since determined NOEL is 400 OA per honeybee; our results indicate... |
| Tipo: Journal article |
Palavras-chave: LD50; Uruguay. |
| Ano: 2012 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392012000200019 |
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| Castillo,Dalma; Matus,Iván; del Pozo,Alejandro; Madariaga,Ricardo; Mellado,Mario. |
| Wheat (Triticum aestivum L.) genetic improvement objectives include obtaining cultivars capable of expressing their maximum potential yield and quality in diverse environments. This make necessary to know and define the environment in which a variety can express its maximum potential yield and quality. The objective of this study was to assess which method is the most efficient to study cultivars response in multiple environments. For this, we analyze the adaptability, stability, and genotype x environment (GxE) interaction effect, grain yield, sedimentation, and wet gluten content of 13 spring wheat cultivars sown in six environments in the central-south and southern zones of Chile during two seasons. The data were analyzed by regression analysis,... |
| Tipo: Journal article |
Palavras-chave: AMMI; SREG; GxE; Bread wheat. |
| Ano: 2012 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392012000200001 |
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| Faisal Bilal,Muhammad; Farrukh Saleem,Muhammad; Ashfaq Wahid,Muhammad; Shakeel,Amir; Maqbool,Mudassar. |
| Adopting new technology always involves advantages and risks; Bt cotton (Gossypium hirsutum L.) is a new technology well known in developed countries for its many advantages, such as reduced pesticide application, better insect pest control, and higher lint yield. However, its success in developing countries is still a question mark. Global adoption of Bt cotton has risen dramatically from 0.76 million ha when introduced in 1996 to 7.85 million ha in the 2005 cotton-growing season where 54% of the cotton crops in the USA, 76% in China, and 80% in Australia were grown with single or multiple Bt genes. Bollworms are serious cotton pests causing 30-40% yield reduction in Pakistan and 20-66% potential crop losses in India. The major advances shown in this... |
| Tipo: Journal article |
Palavras-chave: Bt cotton; Management; Gossypium hirsutum. |
| Ano: 2012 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392012000300017 |
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| Perea,Alberto Jesús; Meroño,José Emilio; Aguilera,María Jesús. |
| The objective of this paper was the development of a methodology for the classification of digital aerial images, which, with the aid of object-based classification and the Normalized Difference Vegetation Index (NDVI), can quantify agricultural areas, by using algorithms of expert classification, with the aim of improving the final results of thematic classifications. QuickBird satellite images and data of 2532 plots in Hinojosa del Duque, Spain, were used to validate the different classifications, obtaining an overall classification accuracy of 91.9% and an excellent Kappa statistic (87.6%) for the algorithm of expert classification. |
| Tipo: Journal article |
Palavras-chave: Expert classification; Vegetation index; Land cover; Object-based classification. |
| Ano: 2009 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392009000300013 |
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| Khaliq,Abdul; Matloob,Amar; Ata Cheema,Zahid; Farooq,Muhammad. |
| Weed suppression is one of the several benefits achieved by soil incorporation of crop residues and such suppression is believed to be allelopathic in nature. The allelopathic potential of different crop residues: viz. sorghum (Sorghum bicolor [L.] Moench), sunflower (Helianthus annuus L.), brassica (Brassica campestris L.) was evaluated in rice (Oryza sativa L.) and jungle rice (Echinochloa colona [L.] Link). Chopped crop residues were soil-incorporated alone and mixed at 6 g kg-1 soil (12 t ha-1) and compared with a control without residues. Soil incorporation of residues substantially delayed germination of jungle rice. The time to start germination, time to 50% emergence, mean emergence time, emergence index, and final germination percentage were all... |
| Tipo: Journal article |
Palavras-chave: Residues; Allelopathy; Sorghum; Sunflower; Brassica; Weed control. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392011000300012 |
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| Bashir,Uzma; Javaid,Arshad; Bajwa,Rukhsana. |
| Sunflower (Helianthus annuus L.) is a well known allelopathic plant species. However, Pakistani farmers generally incorporate the sunflower residue in the soil with the aim to enhance soil fertility and organic matter. Field experiments were, therefore, carried out to evaluate the effect of sunflower residue incorporation on growth and yield of rice (Oryza sativa L.) and subsequent wheat (Triticum aestivum L.) crop. For rice crop, there were four treatments viz. control, sunflower residue incorporation (RI), NPK fertilizers, and NPK+RI. Two rice varieties (Basmati Pak and Basmati Super) were cultivated. Incorporation of sunflower residue markedly reduced plant growth and yield in 'Basmati Pak'. There was 34% reduction in yield of this variety due to RI.... |
| Tipo: Journal article |
Palavras-chave: Allelopathy; Genotypic tolerance; Oryza sativa; Helianthus annuus; Triticum aestivum. |
| Ano: 2012 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392012000300004 |
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| Baeza,Carlos M; Schrader,Otto; Ruiz,Eduardo; Negritto,M. |
| Alstroemeria (Alstroemeriaceae) is an endemic genus of South America with two major distribution centers in the continent: Chile and Brazil. In Chile the genus is distributed from the North, near Iquique (20º13 S, 70º09 W) to the Chilean and Argentine Patagonia (53º10 S, 70º54 W). The central zone of Chile presents the highest number of species. A. presliana Herb. grows from Curicó (34º59 S, 71º14 W) to Cautín (38º45 S, 72º34 W) in Chile and Neuquén (36º50 S, 71º05 W), Argentina. A comparative karyotype study was made between a population of A. presliana subsp. presliana and a population of A. presliana subsp. australis Ehr. Bayer. Both populations presented asymmetric karyotypes, with 2n = 2x = 16 chromosomes, but with different chromosome... |
| Tipo: Journal article |
Palavras-chave: Alstroemeriaceae; Karyotype; Chromosome numbers; Chile. |
| Ano: 2008 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392008000400002 |
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| Rodríguez,Yakelin; Vierheilig,Horst; Mazorra,Luis M. |
| Antioxidant system is involved in arbuscular mycorrhizal symbiosis, but its role during the colonization process is still poorly understood. To gain new insights into the role of antioxidant system during root colonization by arbuscular mycorrhizal fungi, the activities of key antioxidant enzymes were evaluated in tomato (Solanum lycopersicum L.) roots inoculated with six strains of different genera and species: two Glomus mosseae, Glomus cubense, Glomus intraradices, Glomus sp. and Acaulospora scrobiculata. Glomus cubense and A. scrobiculata strains reached the highest infectivity levels with maximum values of colonization frequency and intensity of 29-10.88% and 18-9.20%, respectively; G. mosseae strains showed an intermediate infectivity, both with 15%... |
| Tipo: Journal article |
Palavras-chave: Peroxidases; Polyphenol oxidases; Superoxide dismutase; Colonization intensity; Solanum lycopersicum. |
| Ano: 2012 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392012000300016 |
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| Javaid,Arshad; Ali,Sajjad. |
| Wild oat (Avena fatua L.) is a problematic weed of wheat (Triticum aestivum L.) in Pakistan. The present study was designed to evaluate the herbicidal activity of culture filtrates of four Trichoderma spp., namely T. harzianum, T. pseudokoningii, T. reesei and T. viride, against this weed species. In a laboratory bioassay, original (100%) and diluted (50%) culture filtrates of T. harzianum and T. pseudokoningii significantly reduced shoot and root growth of A. fatua seedlings. Only original culture filtrates of T. reesei exhibited significant effects, while the effect of filtrates of T. viride was insignificant against shoot and root growth of the target weed species. Generally, original concentrations of culture filtrates of all Trichoderma spp., except... |
| Tipo: Journal article |
Palavras-chave: Alternative herbicides; Fungal metabolites. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392011000200004 |
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| Registros recuperados: 390 | |
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