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A Dynamic Decision Support System for Farm Water Management in Surface Irrigation: Model Development and Application Chilean J. Agric. Res.
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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A Rainfall Simulator for the in situ Study of Superficial Runoff and Soil Erosion Chilean J. Agric. Res.
Sangüesa,Claudia; Arumí,José; Pizarro,Roberto; Link,Oscar.
A rainfall simulator is an important tool for the study of runoff generation and soil loss because it can be used either under laboratory conditions, or in disturbed or natural soil. The objective of this study was to describe the design and operation of a rainfall simulator to evaluate soil loss in situ. The rainfall simulator has four full-cone spray nozzles with a Unijet system mounted in a straight line pipe configuration, and easily transported and assembled. Simulated rainfall uniformity was evaluated in the laboratory, whereas the applicability of the simulator in natural soil erosion plot conditions in an experimental field with different slopes was tested by quantifying runoff and evaluating soil erosion. Twenty simulations were carried out in the...
Tipo: Journal article Palavras-chave: Soil erosion; Superficial runoff; Erosion plot; Uniformity of rain.
Ano: 2010 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392010000100019
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A Ricardian Analysis of the Impact of Climate Change on South American Farms Chilean J. Agric. Res.
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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A Simulation Model of Mesophytic Perennial Grasslands Chilean J. Agric. Res.
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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A Study of Dairy Farm Technical Efficiency Using Meta-Regression: An International Perspective Chilean J. Agric. Res.
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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Acceptance of Transgenic Milk in La Araucania Region,Chile Chilean J. Agric. Res.
Schnettler M,Berta; Sepúlveda B,Oriana; Ruiz F,Danilo.
Considering the high level of concern caused by genetically modified foods (GMF) in developed countries, the relevance of this variable in decision-making about the purchase of fluid milk among consumers in Temuco (La Araucanía Region, Chile) was determined. By means of a personal survey of 400 people and using conjoint analysis, it was determined that the presence of genetic modifications in food was more important (44.7%) than brand (29.5%) and price (25.5%) in the decision-making process. By cluster analysis three segments were identified; the largest group (46.5%) gave similar relevance to food production and brand, preferring genetically modified milk. For the second group (41.5%), the presence or absence of genetic modification was the most important...
Tipo: Journal article Palavras-chave: Genetically modified foods (GMF); Fluid milk; Cluster analysis; Conjoint analysis.
Ano: 2008 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392008000400008
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Acute Contact Toxicity Test of Oxalic Acid on Honeybees in the Southwestern Zone of Uruguay Chilean J. Agric. Res.
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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Adaptability and Genotype x Environment Interaction of Spring Wheat Cultivars in Chile using Regression Analysis, AMMI, and SRAG Chilean J. Agric. Res.
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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Adaptation and Genotype x Environment Interaction of Flaxseed (Linum usitatissimum L.) Genotypes in South Central Chile Chilean J. Agric. Res.
Berti,Marisol; Fischer,Susana; Wilckens,Rosemarie; Hevia,Felicitas; Johnson,Burton.
Flaxseed (Linum usitatissimum L.) is imported into Chile mostly for bread making and feed. Identification of genotypes best adapted for seed production in South Central Chile would facilitate producer’s decision. The objective of this study was to determine the adaptation and genotype x environment interaction of 16 flaxseed genotypes (including 10 from North American and six from Argentine sources) grown at 11 environments (defined as location-year) in Chile from 2003 to 2007. Genotype seed yield was above 5700 kg ha-1 for some environments indicating a high yield potential. According to the AMMI (Additive Main Effects and Multiplicative Interaction) and SREG (Sites regression) models the 11 environments were classified into four groups by the AMMI and...
Tipo: Journal article Palavras-chave: Adaptation; Genotype; Seed yield; Oil content; Linolenic acid.
Ano: 2010 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392010000300001
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Administration and Management of Irrigation Water in 24 User Organizations in Chile Chilean J. Agric. Res.
Jorge,Jara; López,Marco A; San Martín,Álvaro; Salgado,Luis; Melo,Ovidio.
Approximately 85% of the water consumed in Chile is destined to agricultural irrigation and is managed by the users themselves. This study analyzed the price that irrigation water users pay to their Water User Associations (WUAs) to which they belong and the relationship of this price to the professional level and performance of the WUAs. The study included 24 WUAs: 10 River Administration Boards (JV) and 14 Irrigation Canal Associations (AC). The annual operational budget of each WUA, the price paid by users and the management capacities of the board of directors of each WUA were compared. The study also determined the relative value of user payments to WUAs as a proportion of total production costs of the main crops in each zone. The variability of user...
Tipo: Journal article Palavras-chave: Water cost; Water users associations; WUAs; Water canal associations; River administration board.
Ano: 2009 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392009000200012
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Adoption of Bt Cotton: Threats and Challenges Chilean J. Agric. Res.
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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Advances in Apple Transformation Technology to Confer Resistance to Fungal Diseases in Apple Crops: A Chilean Perspective Chilean J. Agric. Res.
Polanco,Víctor; Paredes,Mario; Becerra,Viviana; Pérez,Eduardo.
Apple (Malus domestica Borkh.) is one of the most consumed fruit in the world. Genetic transformation is a key process to sustain this demand by permitting the potential enhancement of existing cultivars as well as the development of new cultivars resistant to pests, diseases, and storage problems that occur in the major production areas. This review summarizes the advances of genetic engineering applied to the development of resistant apple cultivars to fungus disease, with particular attention in the generation of apples resistant to Venturia inaequalis (Cooke) G.Winter, the main phytosanitary problem that affects apple crops in Chile.
Tipo: Journal article Palavras-chave: Apple; Fungal disease; Transgenic; Cisgenesis.
Ano: 2010 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392010000200013
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Agricultural Labor Demand in Chile: A Cointegration Approach Chilean J. Agric. Res.
Saens N,Rodrigo; Lobos A,Germán; Rivera A,Edinson.
International evidence shows that the positive relationship between product and agricultural labor has weakened during the last 30 years, especially in emergent economies. Chilean agriculture has not been left out of this phenomenon The main purpose of this reseach was to estimate the causality relationships that govern the product, employment and salaries in the Chilean silviculture-agricultural-livestock sector, using a cointegration approach. Quarterly data from the 1996-2005 period were employed to estimate agricultural labor demand. A Cobb-Douglas agricultural production function was employed and from it were derived the minimum cost function and the labor demand as bases of this study; the latter was approximated log-linearly to find different...
Tipo: Journal article Palavras-chave: Agricultural labor; Cobb-Douglas; Employment-product elasticity; Employment-salary elasticity.
Ano: 2008 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392008000400009
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Algorithms of Expert Classification Applied in Quickbird Satellite Images for Land Use Mapping Chilean J. Agric. Res.
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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Allelopathic Activity of Crop Residue Incorporation Alone or Mixed Against Rice and its Associated Grass Weed Jungle Rice (Echinochloa colona [L.] Link) Chilean J. Agric. Res.
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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Allelopathic effects of aqueous and organic fractions of Euphorbia dracunculoides Lam. on germination and seedling growth of chickpea and wheat Chilean J. Agric. Res.
Tanveer,Asif; Kamran Jabbar,Muhammad; Kahliq,Abdul; Matloob,Amar; Nadeem Abbas,Rana; Mansoor Javaid,Muhammad.
Identification of weed species with allelopathic potential and characterization of their adverse effects against associated crops is required for better understanding of weed-crop interactions. Phytotoxic activity of Euphorbia dracunculoides Lam. on germination and seedling growth of chickpea (Cicer arietinum L.) and wheat (Triticum aestivum L.) was investigated under controlled conditions. Two separate studies were done with each of four organic solvent fractions (n-hexane, chloroform, ethylacetate, 1-butanol) and crude aqueous (1:10 and 1:20) whole plant fractions of E. dracunculoides using distilled water and 0.05% (v/v) dimethyl sulfoxide (DMSO) as control. Different aqueous and organic fractions of E. dracunculoides had a significant bearing on...
Tipo: Journal article Palavras-chave: Allelopathy; Weeds; Germination attributes; Suppression; Phenolics.
Ano: 2012 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392012000400006
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Allelopathic Effects of Sunflower Residue on Growth of Rice and Subsequent Wheat Crop Chilean J. Agric. Res.
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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Alstroemeria presliana Herb. (Alstroemeriaceae) in Chile from a Cytogenetic Perspective Chilean J. Agric. Res.
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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Alterations of the Antioxidant Enzyme Activities are not General Characteristics of the Colonization Process by Arbuscular Mycorrhizal Fungi Chilean J. Agric. Res.
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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Alternative management of a problematic weed of wheat Avena fatua L. by metabolites of Trichoderma Chilean J. Agric. Res.
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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