The quality of red lettuce is based on the content of anthocyanin pigments, and the content of these pigments increases when the plant receives ultraviolet radiation. Lettuce crops are increasingly being grown in greenhouses to provide better quality fresh lettuce; however, both quality and productivity are affected by the type of cover used. The effects of UV-transparent and UV-blocking plastic films on the growth and quality of three lettuce cultivars (‘Casabella’ and ‘Vera’, which are both green leaf, and ‘Lollo Rosso’, which is red leaf) were investigated. The crop was cultivated at an altitude of 2576 m a.s.l. to naturally expose it to high ultraviolet radiation. The height and diameter of plants, fresh and dry weight, leaf area index, chlorophyll fluorescence, and leaf colour were determined throughout the crop cycle. Growth characteristics were not significantly influenced by the plastic film in all cultivars, probably due to the high altitude and the high solar radiation received. The UV-transparent film could increase the red colour in ‘Lollo Rosso’, and a higher commercial quality was achieved. No effect of the plastic film on the yield component was observed in the ‘Casabella’ and ‘Vera’ cultivars. The findings of this study provide guidance on what cultivar and plastic film must be used in high-altitude areas where the solar and UV radiation is high.

Blackberries play an important role in human nutrition, due to the elevated content of certain bioactive compounds including ascorbate, anthocyanins, phenolic acids, carbohydrates, and proteins. Blackberry Rubus glaucus from Colombian Andes has a high demand on regional and international markets and there is much interest in its cultivation to increase the com mercial offer. In four blackberry producing municipalities of Cundinamarca province, fruits were harvested for different quality tests based on the availability of hydric resources in the zone and their influence on fruit characteristics according to the precipitation of each zone, since the crops did not have an irrigation system. The variables, such as size, fresh weight, tex ture, pH, titratable total acids (TTA), total soluble solids (TSS), and color were evaluated to compare the quality of the fruits between the municipalities, finding that fruits from Silvania had the greater size but, in turn, were the least consistent. El Colegio zone presented the sweetest fruits and together with Pasca had the highest acidity percentage. The color of Pasca and Silvania fruits was the most attractive for commercialization parameters. These parameters, even when management and agro-climatic conditions between municipalities were very similar, allows knowing the positive attributes and determine the factors that need to be improved and to project on a short-term future productions acceptable on the international market.

El mercado de la fresa en Cundinamarca (Colombia) se rige por el tamaño del fruto, sin tener en cuenta el estado de maduración y calidad nutricional del mismo. Por esta razón, se determinaron las diferencias fisicoquímicas en frutos de siete variedades de fresa (Albion, Dulce Anna, Lucia, Monterey, Ruby June, Sabrina y Ventana) cultivadas en el municipio de Sibaté, segundo productor de Cundinamarca. Se analizaron frutos recolectados de un predio productivo con condiciones homogéneas de manejo, en seis estados de madurez determinados por su grado de pigmentación roja (0, 1, 2, 3, 4, 5) de acuerdo a la Norma Colombiana NTC 4103. Se evaluó el peso fresco, tamaño, color, firmeza, solidos solubles totales (SST), acidez total titulable (ATT), índices de madurez y de respiración. En los estados 4, 2 y 3 los frutos desarrollaron su mayor tamaño y peso, destacándose la variedad Dulce Anna. Los valores más altos en el índice de color se encontraron en el estado de madurez 5, especialmente en la variedad Ventana, seguida de Albion, Ruby June y Sabrina. Los valores más altos de firmeza, en los estados 4 y 5, se observaron para Ventana y Sabrina. Las variedades Sabrina, Dulce Anna y Monterrey acumularon la mayor concentración de SST, mostrando las dos últimas la mejor relación de madurez. Las tasas de respiración aumentaron con la maduración, especialmente a partir del estados 3. Los resultados ofrecen un criterio de selección en el punto óptimo para consumo, acorde con la variedad y sus características más relevantes.

Modeling and simulation have become fundamental tools for the microclimatic analysis of greenhouses under various climatic conditions. These models allow precise control of the climate inside the structures and the optimization of their performance under any situation. In Colombia, the availability of energy balance models adapted to local greenhouses and their climate is limited, which affects the decision-making of both technical advisors and growers. This study focused on calibrating and evaluating a dynamic energy balance model to predict the thermal behavior of an innovative type of plastic-covered greenhouse designed for the Bogotá savanna. The selected model considers fundamental heat and mass transfer processes, incorporating parameters that depend on the architecture of the structure and local climatic conditions, making it suitable for protected agriculture in Colombia. The results of the post-calibration evaluation showed that the model is highly accurate, with a temperature prediction efficiency close to 86%. This ensures that the model can accurately predict the thermal behavior of the greenhouse being evaluated. It is important to note that the model can also anticipate phenomena characteristics of Colombian greenhouses, such as thermal inversion. This advance has become a valuable tool for decision-making in protected agriculture in the region.

The aim of the study is to evaluate the effect of the height of the greenhouse on climatic conditions generated on a mint crop (Mentha spicata). The tests were conducted in the town of Carmen de Viboral, 40 minutes away from the city of Medellin (6º 05’ 09” N and 75º 20’ 19” W, 2150 m.a.s.l.). Three greenhouses with the same dimensions were used, changing only the gutter height in 2 m, 2,5 m and 3 m respectively. Temperature and relative humidity measurements were taken every 30 minutes for 3 years, time during which crop production was assessed. Statistical analyses were performed to determine climatic variations caused by the difference in height between the greenhouses, and to determine differences in production levels. The results indicate that, under the study conditions, the greenhouse height directly affects the weather conditions and the mint crop yields.

Due to the high susceptibility of strawberry fruits to the attack of pests and diseases, a large amount of pesticides is applied during the crop cycle and harvest period. The inadequate use of these substances can generate residuals in agricultural products, which, through intake, pose a risk to human health. The objective of this study was to determine and compare the pesticide residues in strawberry fruits from two different production systems, distributed in the main producing areas of the Cundinamarca Department (Colombia). Eight samples of strawberry crops were collected in four producer municipalities (Guasca, Facatativa, Mosquera and Sibate), two to compare different systems (conventional production vs. production based on the Integrated Pest Management, IPM). Samples at a concentration of 394 molecules were examined by liquid and gas spectrometry. Fisher's exact test was used to determine the association between crop practices and the residual level in fruits. Twenty two different molecules were detected for the samples analyzed, with 37 detection events, of which eight were reported in IPM production systems and 29 in conventional producers. Results revealed a total of two molecules at excessive concentrations after Colombian regulations. Significant differences were found between the two production systems. This is attributable to the producers´ lack of knowledge and understanding about conventional management in Good Agricultural Practices, and the concepts of pesticide restriction period and residuality.