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

This is the final version. Available from MDPI via the DOI in this record. 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

Evaluation of the microclimate in a traditional Colombian greenhouse used for cut flower production

This is the final version. Available from MDPI via the DOI in this record. 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.Sistema General de Regalías and the Gobernacion de Cundinamarc

Microclimatic Evaluation of Five Types of Colombian Greenhouses Using Geostatistical Techniques

This is the final version. Available on open access from MDPI via the DOI in this recordn Colombia, the second-largest exporter of cut flowers worldwide and one of the South American countries with the largest area of crops under cover, passive or naturally ventilated greenhouses predominate. Locally, there are several types of greenhouses that differ in architecture, size, height, shape of roof and ventilation surfaces, of which many characteristics of the microclimate generated in their interior environment are unknown. This generates productive limitations that in some way may be limiting the yield, quality and health of the final products harvested; in addition, Colombian producers do not have the ability to monitor the microclimate of their farms, much less to correlate microclimate data with data on crop production and yield. Therefore, there is a need for the Colombian grower to know the most relevant microclimate characteristics generated in the main greenhouses used locally. The objective of this work was to carry out a microclimatic characterization of the five most used types of greenhouses in Colombia. The main results allowed determining that in these structures, there are conditions of high humidity and low vapor pressure for several hours of the day, which affects the physiological processes of growth and development of the plants. It was also identified that for each type of greenhouse, depending on the level of radiation, there is a significant microclimatic heterogeneity that may be the cause of the heterogeneity in plant growth, which is a common characteristic observed by the technical cultivation personnel. Therefore, it can be concluded that it is urgent to propose microclimatic optimization strategies to help ensure the sustainability of the most important production systems in the country.Servicio Nacional de Aprendizaje (SENA)Asociación Colombiana de Exportadores de Flores (Asocolflores)Centro de Innovación de la Floricultura Colombiana (Ceniflores

Influence of the Height in a Colombian Multi-Tunnel Greenhouse on Natural Ventilation and Thermal Behavior: Modeling Approach

This is the final version. Available on open access from MDPI via the DOI in this recordfirst_pagesettings Open AccessArticle Influence of the Height in a Colombian Multi-Tunnel Greenhouse on Natural Ventilation and Thermal Behavior: Modeling Approach by Edwin Villagrán 1,Jorge Flores-Velazquez 2,*ORCID,Mohammad Akrami 3,*ORCID andCarlos Bojacá 1ORCID 1 Department of Biological and Environmental Sciences, Faculty of Natural Sciences and Engineering, Jorge Tadeo Lozano University, Bogotá 111321, Colombia 2 Coordination of Hydrosciences, Postgraduate Collage, Carr Mex Tex km 36.5, Montecillo Edo de Mexico 62550, Mexico 3 Department of Engineering, University of Exeter, Exeter EX4 4QF, UK * Authors to whom correspondence should be addressed. Academic Editors: Muhammad Sultan, Yuguang Zhou, Walter Den and Uzair Sajjad Sustainability 2021, 13(24), 13631; https://doi.org/10.3390/su132413631 Received: 25 October 2021 / Revised: 25 November 2021 / Accepted: 6 December 2021 / Published: 9 December 2021 (This article belongs to the Special Issue Sustainable Agricultural Engineering Technologies and Applications) Download PDF Browse Figures Citation Export Abstract The dimensions of a passive greenhouse are one of the decisions made by producers or builders based on characteristics of the available land and the economic cost of building the structure per unit of covered area. In few cases, the design criteria are reviewed and the dimensions are established based on the type of crop and local climate conditions. One of the dimensions that is generally exposed to greater manipulation is the height above the gutter and the general height of the structure, since a greenhouse with a lower height has a lower economic cost. This has led some countries in the tropical region to build greenhouses that, due to their architectural characteristics, have inadequate microclimatic conditions for agricultural production. The objective of this study was to analyze the effect on air flows and thermal distribution generated by the increase of the height over gutter of a Colombian multi-tunnel greenhouse using a successfully two-dimensional computational fluid dynamics (CFD) model. The simulated numerical results showed that increasing the height of the greenhouse allows obtaining temperature reductions from 0.1 to 11.7 °C depending on the ventilation configuration used and the external wind speed. Likewise, it was identified that the combined side and roof ventilation configuration (RS) allows obtaining higher renovation indexes (RI) in values between 144 and 449% with respect to the side ventilation (S) and roof ventilation (R) configurations. Finally, the numerical results were successfully fitted within the surface regression models responses.Servicio Nacional de Aprendizaje (SENA)Asociación Colombiana de Exportadores de Flores (Asocolflores)Centro de Innovación de la Floricultura Colombiana (Ceniflores

Calidad de la educación: entre la exclusión y la utopía

Education Quality is a topic to which factors of different nature (social, economic, political, cultural, among others) are associated. It is thus frequent to find diverse points of view about education quality in the forms of research reports, papers, articles and academic discourses. This is an evidence on the great concern and tension this discussion creates. Given the great variety of associated factors to education quality, this paper searches these in four discourses, being the basic one the World Bank discourse entitled La calidad de la educación en Colombia: Un análisis y algunas opciones para un programa de política (2009). There are three other discourses that question the pertinence of thinking education quality only in terms of measurement. These are: “Diez factores para una educación de calidad para todos en el siglo XXI” (2006), by the scholar Cecilia Braslavsky, “Calidad educativa: más que resultados en pruebas estandarizadas” (2004), by professor Ricardo L. Gómez and “¿Por qué las pruebas estandarizadas no miden la calidad educativa?” (1999), by Northamerican researcher James Popham. The analysis is held under three categories: context, the expressions with specific meaning for the context, and the vocabulary used. The analysis allows to conclude that the World Bank uses a selective and exclusive terminology, and equivalence series to equate education quality to students’ learning, while Braslavsky has a proactive, ample and optimistic intention. On the other hand, Gomez’ discourse may be characterized by a mild resistance. Finally, Popham assumes an ironic and radical resistance posture by the means of the constant use of figures of speech.La calidad de la educación es un tema al que se asocian factores diversos (sociales, económicos, políticos, culturales, entre otros), por lo que es frecuente encontrar distintos puntos de vista al respecto, que se plasman en investigaciones, ensayos, informes y discursos especializados. Ello evidencia la gran preocupación y tensión que genera esta discusión. Dada la gran variedad de elementos influyentes en la calidad educativa, se realizó una búsqueda de aquellos factores asociados a través de algunas herramientas del Análisis del Discurso. Se tomó como base el Discurso del Banco Mundial titulado La calidad de la educación en Colombia: Un análisis y algunas opciones para un programa de política (2009). A él se suman tres discursos que dudan de la pertinencia de pensar en la calidad educativa solamente desde la perspectiva de medición. Estos son: “Diez factores para una educación de calidad para todos en el siglo XXI” (2006), de la académica Cecilia Braslavsky, “Calidad educativa: más que resultados en pruebas estandarizadas” (2004), del profesor Ricardo L. Gómez, y “¿Por qué las pruebas estandarizadas no miden la calidad educativa?” (1999), del investigador norteamericano James Popham. Se realiza el análisis desde tres categorías: contexto, expresiones con significados específicos para el contexto y vocabulario empleado. El objetivo de este ejericio de análisis es identificar los puntos en tensión del concepto calidad de la educación como categoría que se fomenta o critica dependiendo de la cercanía con los discursos oficiales. El análisis permite concluir que el Banco Mundial utiliza un lenguaje excluyente y cadenas de equivalencia para equiparar la calidad de la educación con el aprendizaje de los estudiantes, mientras que Braslavsky tiene una intención propositiva, amplia y optimista. Por su parte, el discurso de Gómez puede caracterizarse como de resistencia moderada. Finalmente, Popham asume una postura irónica y de resistencia radical, mediante el uso reiterado de tropos del lenguaje

Environmental filtering controls soil biodiversity in wet tropical ecosystems

9 páginas..- 4 figuras.- referencias.- Supplementary data to this article can be found online at https://doi. org/10.1016/j.soilbio.2022.108571The environmental factors controlling soil biodiversity along resource gradients remain poorly understood in wet tropical ecosystems. Aboveground biodiversity is expected to be driven by changes in nutrient availability in these ecosystems, however, much less is known about the importance of nutrient availability in driving soil biodiversity. Here, we combined a cross-continental soil survey across tropical regions with a three decades' field experiment adding nitrogen (N) and phosphorus (P) (100 kg N ha(-1)y(-1) and 100 kg P ha(-1)y(-1)) to Hawai'ian tropical forests with contrasting substrate ages (300 and 4,100,000 years) to investigate the influence of nutrient availability to explain the biodiversity of soil bacteria, fungi, protists, invertebrates and key functional genes. We found that soil biodiversity was driven by soil acidification during long-term pedogenesis and across environmental gradients, rather than by nutrient limitations. In fact, our results showed that experimental N additions caused substantial acidification in soils from Hawai'i. These declines in pH were related to large decreases in soil biodiversity from tropical ecosystems in four continents. Moreover, the microbial activity did not change in response to long-term N and P additions. We concluded that environmental filtering drives the biodiversity of multiple soil organisms, and that the acidification effects associated with N additions can further create substantial undesired net negative effects on overall soil biodiversity in naturally tropical acid soils. This knowledge is integral for the understanding and management of soil biodiversity in tropical ecosystems globally.Supported by a Ramón y Cajal grant (RYC2018-025483-I), a “Ayuda P.P. 2020. Desarrollo Lineas Investigación Propias (UPO), a project from the Spanish Ministry of Science and Innovation (PID2020-115813RA-I00), and a project PAIDI 2020 from the Junta de Andalucía (P20_00879). H.Y.C. is supported by National Natural Science Foundation of China (32101335), China Postdoctoral Science Foundation (2021M690589), Innovation Project of Young Technological Talents in Changchun City (21QC07), and Fundamental Research Funds for the Central Universities (2412021QD014). J.P.V. is thankful to DST and SERB (Science and Engineering Research Board), India for financial support for plant-microbe interaction research. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Peer reviewe

Publisher Correction: Soil contamination in nearby natural areas mirrors that in urban greenspaces worldwide

Correction to: Nature Communications, published online 27 March 2023 In the version of this article originally published, the current affiliation 25, “CEAZA, Universidad Católica del Norte, Coquimbo, Chile,” initially appeared as the last affiliation, offsetting all author footnotes from 25-39. The affiliation order has been restored in the article.Peer reviewe

Differential Effects of Desiccation on Hornworts with Contrasting Life Histories in Tropical Montane Forests: A Functional Trait&mdash;Based Perspective

Desiccation tolerance (DT) is the ability of an organism or structure to dry completely and subsequently survive in that air-dry state. Hornworts are excellent plant models to study desiccation effects as they have contrasting life histories which are likely associated with DT. We tested whether (1) epiphytic species had more efficient DT responses to drying and postrehydration than non-epiphytic species and whether (2) &ldquo;green&rdquo; spores were more sensitive than non-green spores to extreme drying. Hornwort species were collected from the Atlantic Forest of Rio de Janeiro, Brazil. We studied five species (gametophytes and spores: Dendroceros crispus, D. crispatus, Nothoceros vincentianus, Phaeoceros carolinianus; and only spores of Anthoceros lamellatus), using different relative humidity values, drying durations, and postrehydration conditions. All DT treatments affected the chlorophyll fluorescence (Fv/Fm) of gametophytes, with species-specific responses. D. crispatus and D. crispus (epiphytes) performed better than P. carolinianus and N. vincentianus, with fast recovery of Fv/Fm values postrehydration. The ability of non-green spores of P. carolinianus and A. lamellatus and green spores of D. crispus to support desiccation led us to reject our second hypothesis. The DT strategies of hornworts highlighted the trade-offs that are important in spore dispersal and plant establishment, such as fast colonization in Dendroceros spp. and potential spore soil banks in Phaeoceros and Anthoceros species