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Carlos Bojacá
Department of Biological and Environmental Sciences, Faculty of Natural Sciences and Engineering, Universidad Jorge Tadeo Lozano, Bogotá 111321, Colombia

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Journal article
Published: 30 June 2021 in Agronomy
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Cut flower production in the Bogotá savanna is one of Colombia’s main export products. Flower production is mainly carried out in greenhouses, as this type of production system has substantial advantages over crops grown in open fields. Protected agriculture provides timely climate management that improves crop yields. The objective of this work was to build and validate a 3D CFD numerical model to understand the spatial distribution of temperatures because of the air flow dynamics inside a typical greenhouse in the Bogotá savanna. Root mean square error (RMSE) and mean absolute percentage error (MAPE) were the statistical indicators used between experimental and simulated wind speed and temperature data. The simulations considered twelve evaluation scenarios that were established based on the climatic conditions characteristic of the study region. The results indicate that under regional conditions of temperature and wind for this type of passive greenhouse, there is a deficient ventilation rate. This rate does not exceed 35 exchanges h−1 compared to the recommended rates for crops, which is between 45 and 60 air exchanges h−1. This renewal rate contributes to the heterogeneity of the microclimatic dynamics of the greenhouse, presenting hot spots with temperature values above 32 °C in all examined scenarios. For the lower air speed scenarios (<1 ms−1), these areas of high temperature can reach up to 50% of the cultivated area. Therefore, it is suggested that future studies should seek technical solutions to optimize the microclimatic conditions of the greenhouse design used in the Colombian floriculture sector.

ACS Style

Edwin Villagrán; Jorge Flores-Velazquez; Carlos Bojacá; Mohammad Akrami. Evaluation of the Microclimate in a Traditional Colombian Greenhouse Used for Cut Flower Production. Agronomy 2021, 11, 1330 .

AMA Style

Edwin Villagrán, Jorge Flores-Velazquez, Carlos Bojacá, Mohammad Akrami. Evaluation of the Microclimate in a Traditional Colombian Greenhouse Used for Cut Flower Production. Agronomy. 2021; 11 (7):1330.

Chicago/Turabian Style

Edwin Villagrán; Jorge Flores-Velazquez; Carlos Bojacá; Mohammad Akrami. 2021. "Evaluation of the Microclimate in a Traditional Colombian Greenhouse Used for Cut Flower Production." Agronomy 11, no. 7: 1330.

Journal article
Published: 23 April 2021 in Sustainability
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The use of covered structures is an alternative increasingly used by farmers to increase crop yields per unit area compared to open field production. In Latin American countries such as Colombia, productive areas are located in with predominantly hillside soil conditions. In the last two decades, farmers have introduced cover structures adapted to these soil conditions, structures for which the behavior of factors that directly affect plant growth and development, such as microclimate, are still unknown. Therefore, in this research work, a CFD-3D model successfully validated with experimental data of temperature and air velocity was implemented. The numerical model was used to determine the behavior of air flow patterns and temperature distribution inside a Colombian passive greenhouse during daytime hours. The results showed that the slope of the terrain affects the behavior of the air flow patterns, generating thermal gradients inside the greenhouse with values between 1.26 and 16.93 °C for the hours evaluated. It was also found that the highest indoor temperature values at the same time were located in the highest region of the terrain. Based on the results of this study, future researches on how to optimize the microclimatic conditions of this type of sustainable productive system can be carried out.

ACS Style

Edwin Villagran; Carlos Bojacá; Mohammad Akrami. Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure. Sustainability 2021, 13, 4748 .

AMA Style

Edwin Villagran, Carlos Bojacá, Mohammad Akrami. Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure. Sustainability. 2021; 13 (9):4748.

Chicago/Turabian Style

Edwin Villagran; Carlos Bojacá; Mohammad Akrami. 2021. "Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure." Sustainability 13, no. 9: 4748.

Uncertainties in lca
Published: 19 January 2021 in The International Journal of Life Cycle Assessment
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The presence of correlations between input parameters in a life cycle assessment (LCA) is a well-known issue. On top of that, the univariate distribution of environmental indicators, in most cases, does not follow the Gaussian nor the lognormal distribution. In this article, we introduce the copula modeling to build joint multivariate sampling spaces, irrespective of the marginal distributions of the environmental indicators, for LCA uncertainty analyses. To exemplify the proposed method, we integrate the copula modeling to the stochastic multiattribute analysis (SMAA) method to perform the normalization and weighting steps in a comparative agricultural LCA. An attributional LCA was performed to compare the environmental impact of two tomato production systems (GH, greenhouse; OF, open field) with different intensification levels. To choose the best environmental performance system, we implemented the outranking procedure of the SMAA method but based on the true multivariate distribution of the environmental indicators. As required by the SMAA method, initially, we fitted skewed multivariate distributions among the environmental indicators but accounting for their correlation structure through the copula method. Afterwards, the standard SMAA procedure was followed, leading to the calculation of overall scores indicating the environmental performance of the systems under comparison. After individual LCAs were performed for each grower, the variability observed in the primary data was propagated to the environmental indicators. The marginal distributions of the environmental indicators showed a right skewed trend which were fitted to gamma, log-normal, or Weibull distributions as applicable. The application of the copula method for the environmental indicators of the GH and OF systems resulted in D-vine models consisting of 46 and 45 bivariate copulas requiring 47 parameters each, respectively. Sampling the multivariate space configured by the D-vine models and integrating it with the SMAA method indicated that the OF system is more likely to have a better environmental performance with a rank acceptability index (RAI) of 57.6% while the GH system yielded a lower RAI (42.4%). We applied a stochastic unbiased approach to compare the environmental performance of agricultural systems but recognizing the correlation structure of the indicators. The copula method introduced here can be applied to uncertainty or multicriteria decision analysis where correlation needs to be accounted for. Joining the copula and the SMAA methods to produce an unbiased preference indicator allows to evaluate scenarios in a realistic way, producing results that can easily be communicated.

ACS Style

Rodrigo Gil; Carlos Ricardo Bojacá; Eddie Schrevens. Accounting for correlational structures in stochastic comparative life cycle assessments through copula modeling. The International Journal of Life Cycle Assessment 2021, 26, 604 -615.

AMA Style

Rodrigo Gil, Carlos Ricardo Bojacá, Eddie Schrevens. Accounting for correlational structures in stochastic comparative life cycle assessments through copula modeling. The International Journal of Life Cycle Assessment. 2021; 26 (3):604-615.

Chicago/Turabian Style

Rodrigo Gil; Carlos Ricardo Bojacá; Eddie Schrevens. 2021. "Accounting for correlational structures in stochastic comparative life cycle assessments through copula modeling." The International Journal of Life Cycle Assessment 26, no. 3: 604-615.

Journal article
Published: 06 January 2021 in Environmental Advances
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The environmental fate of pesticides has been widely studied in temperate regions but not in tropical regions. In Colombia, tomato is an important commodity characterized by the excessive use of pesticides; however, the environmental fate of pesticides has not yet been determined. Residues for 30 pesticides were analyzed in fruits, leaves, and soils samples, as well as residues for 490 pesticides in water and sediments, from two open field and greenhouse tomato production regions, by direct sampling in the field and subsequent laboratory analysis through liquid or gas chromatography coupled to mass spectrophotometry. A total of 22 pesticides were detected, being the highest concentrations for thiocyclam in fruits (0.79 mg kg−1), indoxacarb in leaves (24.81 mg kg−1) and dimethomorph in soils (44.45 mg kg−1), however no residues were detected in water or sediments. At least one pesticide was detected in 66.7% of the samples. Methomyl and dimethomorph were common in fruits, leaves and soils for both regions; in addition, seven pesticides exceeded the Maximum Residue Limits. The results showed a high presence and affinity of pesticides in the environmental compartments of high-Andean tomato production regions, mainly in soils and open field productive systems.

ACS Style

Luis Alejandro Arias; Alejandra Garzón; Alejandra Ayarza; Sandra Aux; Carlos Ricardo Bojacá. Environmental fate of pesticides in open field and greenhouse tomato production regions from Colombia. Environmental Advances 2021, 3, 100031 .

AMA Style

Luis Alejandro Arias, Alejandra Garzón, Alejandra Ayarza, Sandra Aux, Carlos Ricardo Bojacá. Environmental fate of pesticides in open field and greenhouse tomato production regions from Colombia. Environmental Advances. 2021; 3 ():100031.

Chicago/Turabian Style

Luis Alejandro Arias; Alejandra Garzón; Alejandra Ayarza; Sandra Aux; Carlos Ricardo Bojacá. 2021. "Environmental fate of pesticides in open field and greenhouse tomato production regions from Colombia." Environmental Advances 3, no. : 100031.

Agricultural engineering
Published: 01 October 2020 in Revista Ceres
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The thermal efficiency of naturally ventilated greenhouses is limited due to the permanent exchange of air through the vents, especially during the night hours. The objective of the work consisted in evaluating a system of inflatable air ducts that close the roof vents during the night as a strategy to reduce the energy loss during these hours. For the development of this work, we applied the computational fluid dynamics (CFD) method to a passive multi span greenhouse operating under the dominant nocturnal climatic conditions of the Bogota savannah (Colombia). The results indicated that the use of the ducts system reduces the value of the negative thermal gradient between the interior and exterior of the greenhouse. The CFD model used was validated by comparing experimental data and simulated data and by calculating goodness-of-fit parameters, finding that the numerical model predicts satisfactorily and with an adequate degree of fit the actual thermal behavior of the greenhouse evaluated.

ACS Style

Edwin Villagrán; Carlos Bojacá. Study using a CFD approach of the efficiency of a roof ventilation closure system in a multi-tunnel greenhouse for nighttime microclimate optimization. Revista Ceres 2020, 67, 345 -356.

AMA Style

Edwin Villagrán, Carlos Bojacá. Study using a CFD approach of the efficiency of a roof ventilation closure system in a multi-tunnel greenhouse for nighttime microclimate optimization. Revista Ceres. 2020; 67 (5):345-356.

Chicago/Turabian Style

Edwin Villagrán; Carlos Bojacá. 2020. "Study using a CFD approach of the efficiency of a roof ventilation closure system in a multi-tunnel greenhouse for nighttime microclimate optimization." Revista Ceres 67, no. 5: 345-356.

Review article
Published: 01 September 2020 in Environment International
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Food can be health-giving. A global transition towards plant-based diets may equally help curb carbon emissions, slow land-system change and conserve finite resources. Yet, projected benefits of such ‘planetary health’ diets imperfectly capture the environmental or societal health outcomes tied to food production. Here, we examine pesticide-related hazards of fruit and vegetable consumption, and list proven management alternatives per commodity, geography and chemical compound. Across countries, pesticide use in these alleged healthful foods is extensive with up to 97% food items containing residues and up to 42% posing dietary risks to consumers. Multiple residues are present in 70–92% of US- and China-grown stone fruit while 58% US cauliflower is tainted with neonicotinoid insecticides. Science-based alternatives and decision-support frameworks can help food producers reduce risks and potential harm by deliberately abstaining from pesticide use. As such, opportunities abound to advance ‘win-win’ diets that simultaneously nurture human health and conserve global biodiversity.

ACS Style

Kris A.G. Wyckhuys; Alexandre Aebi; Maarten F.I.J. Bijleveld van Lexmond; Carlos R. Bojaca; Jean-Marc Bonmatin; Lorenzo Furlan; Jairo A. Guerrero; Trinh V. Mai; Hoi V. Pham; Francisco Sanchez-Bayo; Yoshinori Ikenaka. Resolving the twin human and environmental health hazards of a plant-based diet. Environment International 2020, 144, 106081 .

AMA Style

Kris A.G. Wyckhuys, Alexandre Aebi, Maarten F.I.J. Bijleveld van Lexmond, Carlos R. Bojaca, Jean-Marc Bonmatin, Lorenzo Furlan, Jairo A. Guerrero, Trinh V. Mai, Hoi V. Pham, Francisco Sanchez-Bayo, Yoshinori Ikenaka. Resolving the twin human and environmental health hazards of a plant-based diet. Environment International. 2020; 144 ():106081.

Chicago/Turabian Style

Kris A.G. Wyckhuys; Alexandre Aebi; Maarten F.I.J. Bijleveld van Lexmond; Carlos R. Bojaca; Jean-Marc Bonmatin; Lorenzo Furlan; Jairo A. Guerrero; Trinh V. Mai; Hoi V. Pham; Francisco Sanchez-Bayo; Yoshinori Ikenaka. 2020. "Resolving the twin human and environmental health hazards of a plant-based diet." Environment International 144, no. : 106081.

Scientific article
Published: 01 June 2020 in Ornamental Horticulture
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The spatial behavior of the environmental variables involved in rose production is one of the factors of greatest current interest in the Colombian ornamental sector. The aim of this work consisted in the evaluation of a passive greenhouse through an experimental approach that included the capture and recording of data through a grid of 40 sensors homogeneously distributed inside the greenhouse. The data processing was carried out through the application of geostatistical techniques that allowed to obtain contour plots for 5 levels of radiation intensity. The results of the exploratory analysis showed that the behavior of temperature, relative humidity and vapour pressure deficit are not the most suitable for rose production, mainly for the conditions of the night period where the temperature exhibited values below 12.5 °C, the relative humidity was above 90% and the vapour pressure deficit was below 0.1 kPa. On the other hand in the structural analysis the circular model of theoretical semivariogram was the one that better degree of adjustment presented in comparison with the experimental data finding that a strong spatial dependency exists for the studied variables, the prediction of the not sampled points was made by means of the method of ordinary kriging finding that horizontal gradients of temperature and relative humidity exist inside the greenhouse that increases in magnitude according to the level of radiation arriving to reach values of 6.1 °C and 30.4%.

ACS Style

Edwin Villagran; Carlos Bojacá. Experimental evaluation of the thermal and hygrometric behavior of a Colombian greenhouse used for the production of roses (Rosa spp.). Ornamental Horticulture 2020, 26, 205 -219.

AMA Style

Edwin Villagran, Carlos Bojacá. Experimental evaluation of the thermal and hygrometric behavior of a Colombian greenhouse used for the production of roses (Rosa spp.). Ornamental Horticulture. 2020; 26 (2):205-219.

Chicago/Turabian Style

Edwin Villagran; Carlos Bojacá. 2020. "Experimental evaluation of the thermal and hygrometric behavior of a Colombian greenhouse used for the production of roses (Rosa spp.)." Ornamental Horticulture 26, no. 2: 205-219.

Scientific article
Published: 01 June 2020 in Ornamental Horticulture
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Carnation production in Colombia, the world’s main exporter, takes place entirely in naturally ventilated greenhouses. This type of structure presents non-homogeneous microclimate conditions which differentially affect crop growth and development, which is why this issue has been of great research interest in recent years. The objective was to determine the microclimatic behavior of a passive spatial-type greenhouse used in Colombia for carnation production. The experimental approach included the collection of meteorological data in the external environment through a weather station and in the inside of the greenhouse through a grid of 40 sensors uniformly distributed in a horizontal plane. Data processing to determine the spatial variability of temperature, relative humidity and vapour pressure deficit (VPD) is done by using geostatistical techniques and predicting these variables at unsampled points through the ordinary Kriging method. The main results obtained allowed us to determine that the conditions generated inside the greenhouse are not the optimal ones recommended for carnation production and that, in addition, the behavior of the variables studied shows a heterogeneous distribution, obtaining spatial variations in the horizontal profile evaluated for the night period of 0.5 °C, 9.1% and 1.5 kPa and for the daytime period of 7.2 °C, 42.6% and 1.5 kPa for temperature, humidity and VPD respectively.

ACS Style

Edwin Villagran; Carlos Bojacá. Analysis of the microclimatic behavior of a greenhouse used to produce carnation (Dianthus caryophyllus L.). Ornamental Horticulture 2020, 26, 190 -204.

AMA Style

Edwin Villagran, Carlos Bojacá. Analysis of the microclimatic behavior of a greenhouse used to produce carnation (Dianthus caryophyllus L.). Ornamental Horticulture. 2020; 26 (2):190-204.

Chicago/Turabian Style

Edwin Villagran; Carlos Bojacá. 2020. "Analysis of the microclimatic behavior of a greenhouse used to produce carnation (Dianthus caryophyllus L.)." Ornamental Horticulture 26, no. 2: 190-204.

Scientific article
Published: 01 December 2019 in Ornamental Horticulture
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In passive plastic greenhouses that do not have heating systems, the phenomenon of thermal inversion occurs, which means that the temperature inside the greenhouse is lower than the outdoor environment; therefore, the plants are exposed to thermal conditions that are unsuitable for production. The aim of this work was to evaluate passive air climatization alternatives seeking to optimize the nocturnal microclimate of a multi-tunnel Gothic greenhouse projected for rose production in Bogota savannah. The experimental approach included the use of a CFD-2D simulation model successfully validated by recording and archive of temperature data in a greenhouse. A total of 24 steady-state simulations were developed that included 3 nighttime temperature values, 2 sky conditions and 4 greenhouse configurations. The results showed that under the clear sky condition there was a thermal inversion with a value of −0.53 and −1.11 °C for the standard night-time greenhouse configuration. The installation of a thermal screen and porous mesh in the fixed roof vents allowed to control the presence of thermal inversion under clear sky conditions and optimizing the indoor temperature value in the greenhouse under cloudy sky conditions.

ACS Style

Edwin Andres Villagran Munar; Carlos Ricardo Bojaca Aldana. Numerical evaluation of passive strategies for nocturnal climate optimization in a greenhouse designed for rose production (Rosa spp.). Ornamental Horticulture 2019, 25, 351 -364.

AMA Style

Edwin Andres Villagran Munar, Carlos Ricardo Bojaca Aldana. Numerical evaluation of passive strategies for nocturnal climate optimization in a greenhouse designed for rose production (Rosa spp.). Ornamental Horticulture. 2019; 25 (4):351-364.

Chicago/Turabian Style

Edwin Andres Villagran Munar; Carlos Ricardo Bojaca Aldana. 2019. "Numerical evaluation of passive strategies for nocturnal climate optimization in a greenhouse designed for rose production (Rosa spp.)." Ornamental Horticulture 25, no. 4: 351-364.

Journal article
Published: 22 May 2019 in Ornamental Horticulture
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In tropical regions the production of ornamentals is developed exclusively in naturally ventilated plastic greenhouses, which sometimes leads to inappropriate microclimates with high temperatures and humidity that limit the productive development of plants. The aim of this work was to study air flows, temperature distribution and relative humidity inside an alternative greenhouse designed to produce rose (Rosa spp.). Three configurations of ventilation, side ventilation (SV), roof ventilation (RC) and combined roof and side ventilation (RSV) were analyzed. The methodological development was based on the use of a previously validated CFD-2D numerical simulation model, which showed an adequate fit between the measured and simulated data, obtaining MAE and RMSE values for temperature and relative humidity of 0.44 and 0.47 °C, 3.99% and 4.04% respectively. The results obtained for the predominant climatic conditions of the study region showed that the highest ventilation rates were obtained for RSV, with values of 0.044 and 0.182 m3 m-2s-1, this ventilation efficiency propitiated the generation of a homogeneous microclimate, with temperature and relative humidity values adequate to produce rose (Rosa spp).

ACS Style

Edwin Andres Villagran Munar; Carlos Ricardo Bojaca Aldana. Study of natural ventilation in a Gothic multi-tunnel greenhouse designed to produce rose (Rosa spp.) in the high-Andean tropic. Ornamental Horticulture 2019, 25, 133 -143.

AMA Style

Edwin Andres Villagran Munar, Carlos Ricardo Bojaca Aldana. Study of natural ventilation in a Gothic multi-tunnel greenhouse designed to produce rose (Rosa spp.) in the high-Andean tropic. Ornamental Horticulture. 2019; 25 (2):133-143.

Chicago/Turabian Style

Edwin Andres Villagran Munar; Carlos Ricardo Bojaca Aldana. 2019. "Study of natural ventilation in a Gothic multi-tunnel greenhouse designed to produce rose (Rosa spp.) in the high-Andean tropic." Ornamental Horticulture 25, no. 2: 133-143.

Journal article
Published: 24 April 2019 in Revista Tecnología en Marcha
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El estudio del comportamiento térmico de las estructuras de agricultura protegida de tipo pasivo establecidas en condiciones de clima tropical sigue siendo un aspecto relevante, esto con el fin de garantizar las condiciones micro climáticas adecuadas para el crecimiento y desarrollo de las plantas. En Colombia este comportamiento al igual que el del fenómeno de ventilación natural es aun poco estudiado para condiciones de clima cálido. El objetivo de este trabajo fue determinar el comportamiento térmico y los índices de renovación de una estructura de macro túnel usada para la producción de hongos comestibles, este comportamiento se determinó a través de modelaciones numéricas CFD 3D. los resultados obtenidos mostraron un comportamiento térmico adecuado del macro túnel para las condiciones meteorológicas predominantes de la zona de estudio. Los índices de renovación obtenidos oscilaron entre 22.5 y 45.6 renovaciones hora para los casos simulados. El modelo CFD fue validado a través de registro del valor de la variable temperatura en la estructura construida a escala real y los resultados obtenidos mostraron un ajuste adecuado entre los datos simulados y los registrados.

ACS Style

Sebastian Montaño-Rodríguez; Edwin Andrés Villagrán-Munar; David Felipe Osorio-Fiaga3; Carlos Ricardo Bojacá Aldana; Wilmer Leonardo Velásquez-Vargas. Simulación numérica del comportamiento térmico de un macro túnel utilizado para la producción de hongos comestibles bajo condiciones de clima tropical. Revista Tecnología en Marcha 2019, ́g. 78 -85.

AMA Style

Sebastian Montaño-Rodríguez, Edwin Andrés Villagrán-Munar, David Felipe Osorio-Fiaga3, Carlos Ricardo Bojacá Aldana, Wilmer Leonardo Velásquez-Vargas. Simulación numérica del comportamiento térmico de un macro túnel utilizado para la producción de hongos comestibles bajo condiciones de clima tropical. Revista Tecnología en Marcha. 2019; ():́g. 78-85.

Chicago/Turabian Style

Sebastian Montaño-Rodríguez; Edwin Andrés Villagrán-Munar; David Felipe Osorio-Fiaga3; Carlos Ricardo Bojacá Aldana; Wilmer Leonardo Velásquez-Vargas. 2019. "Simulación numérica del comportamiento térmico de un macro túnel utilizado para la producción de hongos comestibles bajo condiciones de clima tropical." Revista Tecnología en Marcha , no. : ́g. 78-85.

Journal article
Published: 23 April 2019 in Journal of Agricultural Engineering
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The growing expansion of protected horticulture in many regions is occurring around densely populated areas where land for agriculture is scarce, expensive or is used for other purposes. Inexpensive plastic passively ventilated greenhouses are the common choice for protected cultivation in these developing regions. The objective of this work was to analyse the effect of surrounding constructions and natural obstacles on the thermal performance of two naturally ventilated greenhouses. A saw tooth type greenhouse (TCG), typical for Colombian production, and an optimised greenhouse (OG) alternative with greater ventilation areas were analysed using computational fluid dynamics (CFD) with and without the surrounding objects of a real environment. The results showed that air exchange rate of a greenhouse with restricted ventilation areas are greatly reduced when neighbouring objects are high enough. This ventilation restriction is intensified under low wind speed conditions. The temperature gradients of the OG greenhouse were lower than those of the TCG scenarios due to the increased ventilation rates. The rooftop ventilation index for the OG greenhouse was increased by 65% with respect to the TCG greenhouse index, resulting in a direct effect on the ventilation rates. An improved air exchange with the outside can be reached by increasing the greenhouse ventilation areas, especially the roof vents, to overcome the airflow restrictions imposed by the surrounding environment. This simulation exercise was validated with field temperature data collected for a real OG prototype built in the Bogota plateau, with results showing a similar pattern for the internal temperature gradient as exhibited by the CFD model.

ACS Style

Edwin Andrés Villagrán; Carlos Ricardo Bojacá. Effects of surrounding objects on the thermal performance of passively ventilated greenhouses. Journal of Agricultural Engineering 2019, 50, 20 -27.

AMA Style

Edwin Andrés Villagrán, Carlos Ricardo Bojacá. Effects of surrounding objects on the thermal performance of passively ventilated greenhouses. Journal of Agricultural Engineering. 2019; 50 (1):20-27.

Chicago/Turabian Style

Edwin Andrés Villagrán; Carlos Ricardo Bojacá. 2019. "Effects of surrounding objects on the thermal performance of passively ventilated greenhouses." Journal of Agricultural Engineering 50, no. 1: 20-27.

Data article
Published: 20 March 2019 in Data in Brief
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Datasets presented here were employed in the main work “Understanding the heterogeneity of smallholder production systems in the Andean tropics – The case of Colombian tomato growers” Gil, et al., 2019. In this region, tomato crop is developed under two technological levels: low, carried out under open field (OF) conditions and, a high, by using greenhouses (GH). For OF, data belong to five municipalities of the Guanentá province (Santander department), while for GH, data belong to five municipalities of the Alto Ricaurte province (Boyacá department). The data presented here includes information on soil parental materials and climate variables (averages ± standard deviations) relevant from the agricultural point of view, which were calculated from historical climate series. Soils natural fertility data, obtained by sampling the production areas, are also presented. After filtering the data, 67 samples were obtained for OF and 70 for the GH. For GH, a dataset with the results of 38 soil samples taken inside greenhouses were paired with the results of samples taken outside these greenhouses in uncropped areas. In the case of these soil analyses, the data correspond to tables with the results reported by the laboratory for both, chemical and physical variables, for each location in which soil samples were taken. In this work, the main dataset is one that contains the inputs of fertilizers and water, and the corresponding yields of tomato production cycles managed by local growers. This information was collected through two data collection tools: surveys (SVY) to growers about these aspects in their last production cycle, and through detailed follow-ups of selected production cycles (FWU). For the OF, we collected data from 71 cycles through the surveys and 22 through the follow-ups, while for the GH, information from 138 to 38 tomato cycles was collected through surveys and follow-ups, respectively. A table with the results aggregated by tomato cycle is attached.

ACS Style

R. Gil; C.R. Bojacá; E. Schrevens. Datasets of the environmental factors and management practices of the smallholder tomato production systems in the Colombian Andes. Data in Brief 2019, 24, 103844 .

AMA Style

R. Gil, C.R. Bojacá, E. Schrevens. Datasets of the environmental factors and management practices of the smallholder tomato production systems in the Colombian Andes. Data in Brief. 2019; 24 ():103844.

Chicago/Turabian Style

R. Gil; C.R. Bojacá; E. Schrevens. 2019. "Datasets of the environmental factors and management practices of the smallholder tomato production systems in the Colombian Andes." Data in Brief 24, no. : 103844.

Journal article
Published: 12 February 2019 in NJAS - Wageningen Journal of Life Sciences
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In developing countries, a common goal is to improve horticultural production systems as a strategy to increase food security and to improve the living conditions of these rural communities. However, smallholder-based agricultural systems are highly heterogeneous due to the wide range of biophysical conditions to which the crops are exposed, and the diversity in the management practices. In order to implement programs aimed at improving the productivity of these systems it is necessary to recognize its variability in quantitative terms. The main objective of this work was to describe the heterogeneity associated to smallholder production systems, using as a case study the Colombian tomato growers. Data were collected from two tomato production zones located in the Colombian Andes and under two cropping systems being the open field (OF) and the greenhouse (GH) production models. In both zones, the climate was described based on historical records, soil samples were taken to determine the natural fertility and the growers’ management practices were inquired. We also compared two instruments for data collection, surveys and detailed follow-ups. A higher heterogeneity in environmental conditions and management practices was evidenced for the OF system compared to the GH system. The fertilization strategies used by GH growers caused a significant increase in soil nutrient content, electrical conductivity and acidity. We found a higher productivity per square meter in the GH system, however the yield per plant was higher for the OF system (4.88 kg plant−1) in comparison with the GH system (2.84 kg plant−1). Results also indicated that follow-ups are an appropriate instrument to obtain accurate inventories. Knowledge empowerment arises as the key point to improve the smallholder’s productivities; in opposition to results elsewhere, where economic constraints are highlighted as the important sources of variability and low yields.

ACS Style

Rodrigo Gil; Carlos Ricardo Bojacá; Eddie Schrevens. Understanding the heterogeneity of smallholder production systems in the Andean tropics – The case of Colombian tomato growers. NJAS - Wageningen Journal of Life Sciences 2019, 88, 1 -9.

AMA Style

Rodrigo Gil, Carlos Ricardo Bojacá, Eddie Schrevens. Understanding the heterogeneity of smallholder production systems in the Andean tropics – The case of Colombian tomato growers. NJAS - Wageningen Journal of Life Sciences. 2019; 88 (1):1-9.

Chicago/Turabian Style

Rodrigo Gil; Carlos Ricardo Bojacá; Eddie Schrevens. 2019. "Understanding the heterogeneity of smallholder production systems in the Andean tropics – The case of Colombian tomato growers." NJAS - Wageningen Journal of Life Sciences 88, no. 1: 1-9.

Journal article
Published: 01 July 2018 in Revista U.D.C.A Actualidad & Divulgación Científica
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En Colombia, la producción de flores se lleva a cabo en invernaderos de diferentes tipos y formas geométricas, pero con la una característica común de usar ventilación natural, para control de clima. En la actualidad, el conocimiento sobre el desempeño climático de estas estructuras es escaso. El objetivo del trabajo consistió en evaluar el comportamiento térmico de un invernadero espacial en condiciones de clima diurno y nocturno. La evaluación realizada, mediante modelado computacional, empleó la dinámica de fluidos computacional (CFD, en idioma inglés), aplicada a un invernadero dedicado a la producción de clavel (Dianthus caryophyllus), bajo las condiciones meteorológicas de la Sabana de Bogotá (Colombia). Este enfoque metodológico permitió obtener los patrones de distribución térmica en el interior del invernadero, encontrando que, para las condiciones meteorológicas evaluadas, el invernadero genera unas condiciones térmicas inadecuadas para el desarrollo del cultivo. La validación del modelo CFD, se realizó comparando los resultados de las simulaciones y las temperaturas registradas en el prototipo real del invernadero, obteniendo un grado de ajuste adecuado entre los valores simulados y medidos.

ACS Style

Edwin Andrés Villagran Munar; Corporación Universitaria Minuto De Dios; Carlos Ricardo Bojacá Aldana; Niccole Alejandra Rojas Bahamon; Universidad Jorge Tadeo Lozano. Determinación del comportamiento térmico de un invernadero espacial colombiano mediante dinámica de fluidos computacional. Revista U.D.C.A Actualidad & Divulgación Científica 2018, 21, 415 -426.

AMA Style

Edwin Andrés Villagran Munar, Corporación Universitaria Minuto De Dios, Carlos Ricardo Bojacá Aldana, Niccole Alejandra Rojas Bahamon, Universidad Jorge Tadeo Lozano. Determinación del comportamiento térmico de un invernadero espacial colombiano mediante dinámica de fluidos computacional. Revista U.D.C.A Actualidad & Divulgación Científica. 2018; 21 (2):415-426.

Chicago/Turabian Style

Edwin Andrés Villagran Munar; Corporación Universitaria Minuto De Dios; Carlos Ricardo Bojacá Aldana; Niccole Alejandra Rojas Bahamon; Universidad Jorge Tadeo Lozano. 2018. "Determinación del comportamiento térmico de un invernadero espacial colombiano mediante dinámica de fluidos computacional." Revista U.D.C.A Actualidad & Divulgación Científica 21, no. 2: 415-426.

Journal article
Published: 01 September 2017 in Agronomía Colombiana
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Potential crop models simulate the plant growth under nonlimiting biophysical conditions with no other factor than the climate to which the plants are exposed to. These models may fail to adequately represent the crop performance if they are not adapted to the local conditions. The particularities of Colombian tomato systems (greenhouse and open field) demand the recalibration of existing models to make a more realistic representation of those systems. Therefore, a locally calibrated crop model was proposed considering both production systems. To this purpose, four on-farm calibration experiments were carried out, two under greenhouse conditions with average temperatures of 17.4 and 17.9ºC in Santa Sofía (Boyacá) and two under open field conditions in Páramo and San Gil (Santander), with average temperatures of 20.6 and 24.0ºC, respectively. The crops were commercially managed according to the local practices. Plant data was collected through destructive measurements carried out on a fortnightly basis, while climate data were collected for the entire crop growth cycle. Independent calibration of the dry matter fractions allocated at the plant organs in function of thermal time resulted in an acceptable model performance. The calibration of the model under commercial conditions gave a better representation of the local systems but at the expense of accuracy since on-farm experiments cannot be controlled as those performed in research facilities.

ACS Style

Rodrigo Gil; Carlos Ricardo Bojacá Aldana; Eddie Schrevens. A tailor-made crop growth model for the tomato production systems in Colombia. Agronomía Colombiana 2017, 35, 301 -313.

AMA Style

Rodrigo Gil, Carlos Ricardo Bojacá Aldana, Eddie Schrevens. A tailor-made crop growth model for the tomato production systems in Colombia. Agronomía Colombiana. 2017; 35 (3):301-313.

Chicago/Turabian Style

Rodrigo Gil; Carlos Ricardo Bojacá Aldana; Eddie Schrevens. 2017. "A tailor-made crop growth model for the tomato production systems in Colombia." Agronomía Colombiana 35, no. 3: 301-313.

Article
Published: 11 May 2017 in Water Resources Management
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The water footprint has been established as an indicator to assess water use by a product. However, the grey component of the water footprint (GWF) has received the least focus compared to the green and blue components. In developing countries, the GWF estimation is restricted by the availability of data concerning crop practices. The various biophysical and socioeconomic settings configure a system difficult to standardize even for small areas. The objective of this study was to assess the GWF uncertainty due to primary data for the main greenhouse tomato production from Colombia. The GWF for N and P fertilizers and pesticides were estimated based on detailed crop information collected from 2010 to 2013. The uncertainty was evaluated by fitting univariate theoretical distributions to the empirical distributions of the pollutants’ GWFs. Growers applied on average 419.2 and 201.9 kg ha−1 of N and P fertilizers per cycle, respectively. The average rates of application for fungicides and insecticides were 11.8 and 3.5 kg ha−1, respectively. The average GWF for N and P fertilizers and pesticides were 79, 6182.1 and 223.2 m3 t−1, respectively. The empirical distributions of the GWF for N fertilizer and pesticides were fitted to a lognormal distribution while for P fertilizer the Weibull distribution showed the best fit. The pesticides GWF showed the highest coefficient of variation (615.3%), however the results for N and P fertilizers were also high with values of 79.8 and 74.1%, respectively. Additional to the methodological choices involved in the GWF estimation, the primary data is a relevant uncertainty source, which should be considered for systems operating under unstandardized practices. The decision making process to regulate the pollutants losses from the agroecosystem, based on environmental assessments such as the GWF, should consider all sources of uncertainty and address its implications in a quantitatively form.

ACS Style

Rodrigo Gil; Carlos Ricardo Bojacá; Eddie Schrevens. Uncertainty of the Agricultural Grey Water Footprint Based on High Resolution Primary Data. Water Resources Management 2017, 31, 3389 -3400.

AMA Style

Rodrigo Gil, Carlos Ricardo Bojacá, Eddie Schrevens. Uncertainty of the Agricultural Grey Water Footprint Based on High Resolution Primary Data. Water Resources Management. 2017; 31 (11):3389-3400.

Chicago/Turabian Style

Rodrigo Gil; Carlos Ricardo Bojacá; Eddie Schrevens. 2017. "Uncertainty of the Agricultural Grey Water Footprint Based on High Resolution Primary Data." Water Resources Management 31, no. 11: 3389-3400.

Journal article
Published: 09 June 2015 in Agronomía Colombiana
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Greenhouse tomato production uses structures that protect crops from extreme environmental conditions; however, the climate inside Colombian greenhouses is often not optimal and crops are susceptible to attack by fungal diseases. The use of simulation models for early warnings of attack by diseases have helped to rationalize the use of chemical pesticides by increasing their efficiency when sprayed at critical times of disease onset. The aim of this study was to calibrate the surface wetness energy balance (SWEB) model to estimate the leaf wetness duration (LWD) for greenhouse tomatoes in the Alto Ricaurte province (Boyaca). For the validation, the performances of the SWEB model were evaluated by comparing a simulated LWD with records from dielectric leaf wetness sensors. The model adequately represented the phenomenon of free water on the leaves for plants in two greenhouses of Santa Sofia and Sutamarchan. The model simulated an average LWD of 9.9 and 12.1 hours day-1 in Santa Sofia and Sutamarchan, respectively. However, the simulations for the two greenhouses indicated different behaviors, with average differences between the observed and simulated daily number of hours with free water of 0.8 h for Santa Sofia, while, for Sutamarchan, the difference reached 4 hours. The fraction of correct estimates index indicated the model had the ability to correctly predict 92 and 72% of the hours with a presence or absence of LWD in Santa Sofia and Sutamarchan, respectively. The SWEB model is a useful tool for early warnings for the attack of fungal diseases in greenhouse tomatoes. However, due to the shortcomings of the greenhouse structures used for production, the crops are highly susceptible to attack from these pathogens.

ACS Style

Rodrigo Gil; Carlos Ricardo Bojacá; Miguel Angel Rodriguez. Adaptation of a leaf wetness duration model for tomato under Colombian greenhouse conditions. Agronomía Colombiana 2015, 33, 11 -19.

AMA Style

Rodrigo Gil, Carlos Ricardo Bojacá, Miguel Angel Rodriguez. Adaptation of a leaf wetness duration model for tomato under Colombian greenhouse conditions. Agronomía Colombiana. 2015; 33 (1):11-19.

Chicago/Turabian Style

Rodrigo Gil; Carlos Ricardo Bojacá; Miguel Angel Rodriguez. 2015. "Adaptation of a leaf wetness duration model for tomato under Colombian greenhouse conditions." Agronomía Colombiana 33, no. 1: 11-19.

Journal article
Published: 01 January 2014 in Food Control
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ACS Style

Luis Alejandro Arias; Carlos Ricardo Bojacá; Diego Alejandro Ahumada; Eddie Schrevens. Monitoring of pesticide residues in tomato marketed in Bogota, Colombia. Food Control 2014, 35, 213 -217.

AMA Style

Luis Alejandro Arias, Carlos Ricardo Bojacá, Diego Alejandro Ahumada, Eddie Schrevens. Monitoring of pesticide residues in tomato marketed in Bogota, Colombia. Food Control. 2014; 35 (1):213-217.

Chicago/Turabian Style

Luis Alejandro Arias; Carlos Ricardo Bojacá; Diego Alejandro Ahumada; Eddie Schrevens. 2014. "Monitoring of pesticide residues in tomato marketed in Bogota, Colombia." Food Control 35, no. 1: 213-217.

Journal article
Published: 01 November 2012 in Energy
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ACS Style

Carlos Ricardo Bojacá; Héctor Albeiro Casilimas; Rodrigo Gil; Eddie Schrevens. Extending the input–output energy balance methodology in agriculture through cluster analysis. Energy 2012, 47, 465 -470.

AMA Style

Carlos Ricardo Bojacá, Héctor Albeiro Casilimas, Rodrigo Gil, Eddie Schrevens. Extending the input–output energy balance methodology in agriculture through cluster analysis. Energy. 2012; 47 (1):465-470.

Chicago/Turabian Style

Carlos Ricardo Bojacá; Héctor Albeiro Casilimas; Rodrigo Gil; Eddie Schrevens. 2012. "Extending the input–output energy balance methodology in agriculture through cluster analysis." Energy 47, no. 1: 465-470.