Introduction: The ability to manipulate environmental conditions within a greenhouse allows production control; however, technological constraints still persist in these systems.
Objective: To model the environment of a zenith greenhouse cultivated with tomato using computational fluid dynamics (CFD), to propose environmental management alternatives and to estimate the energy expenditure and economic cost of using fans.
Methodology: The energy expenditure (kW∙h^-1) and cost (MXN) of using natural and mechanical ventilation in greenhouses were estimated based on climate data from municipalities in San Luis Potosí and the State of Mexico. The analysis inside the greenhouse was carried out with CFD and climatological normals. In addition, the ventilation rate and thermal gradients were estimated to infer a local climatic potential as a function of optimum tomato temperatures. In addition, the ventilation rate and thermal gradients were estimated to infer a local climatic potential as a function of optimum tomato temperatures.
Results: It was observed that in regions with mild summers, the use of mechanical ventilation combined with natural ventilation is a viable alternative by reducing temperature and energy costs. The 3D simulations carried out made it possible to have a detailed view of the spatial distribution of temperature and airflow inside the greenhouse. Study limitations: The model only considers wind speed and temperature. To include other variables, it must be calibrated.
Originality: Ventilation rates (n = 35) and thermal gradients (3 K) were estimated using CFD to infer a regional climatic potential as a function of optimum tomato temperatures. Conclusions: Combined ventilation reduces problems due to high temperatures in hours of maximum radiation, with no significant impact on production costs.

Introduction: There is a traditional irrigation system in Mexico called entarquinamiento (spate irrigation), which falls into the flood irrigation category, also known as cajas de agua (literally water boxes). Certain effects generated by traditional irrigation systems are intentional and others not entirely.
Objective: To demonstrate that spate irrigation systems generate unintended effects such as flood control, in a 100-year return period, in the presence of maximum floods.
Methodology: A hydrological analysis was carried out for two scenarios: 1) current situation (water boxes operating) and 2) hypothetical situation (boxes for this purpose are suppressed or disused). Within the hydrological model, with the HEC-HMS program, the methodologies of the Soil Conservation Service (SCS) of the United States (runoff curve number and unit hydrograph) and a design storm of 167.8 mm were considered. Flood routing in channels was performed using the Muskingum method.
Results: With the current situation, the flow rate generated at the box system outlet was 0 m³ ·s^-1, which is the product of the partial storage of the runoff, while with the hypothetical situation, the maximum flow rate becomes 535.5 m³ .s^-1.
Study limitations: The efficiency of the water box system as an irrigation technique was not evaluated. Originality: There are few hydrological studies that demonstrate quantitative benefits of traditional irrigation techniques.
Conclusions: The operating water box system functions as a reservoir. If the boxes were removed, a runoff would be generated that would flood agricultural and urban areas.o que inundaría zonas agrícolas y urbanas.

Introducción: El lirio acuático (Eichhornia crassipes) es una especie tropical que posee características con potencial biotecnológico; sin embargo, su composición química puede variar en función de la zona geográfica y las condiciones climáticas, lo cual influye en su uso final.
Objetivo: Evaluar el efecto del lugar de colecta (Ciudad de México, Hidalgo, Jalisco y Tabasco) y la sección de la planta de Eichhornia crassipes sobre su composición química para aplicaciones biotecnológicas.
Metodología: El lirio acuático se seccionó en tres partes y se analizó para establecer una relación de acuerdo con la zona geográfica de colecta.
Resultados: Se observó un comportamiento heterogéneo; tanto la zona geográfica como la sección de la planta tienen un impacto fuerte en la composición de la planta. La mayor concentración de cenizas se observó en las muestras de Tabasco (25 % en tallos y 16 % en hojas), mientras que la concentración de lignina fue mayor en las muestras de Hidalgo (11 % en hojas y 6 % en tallos). Por su parte, los compuestos extraíbles en solventes fueron mayores en los tallos de todas las muestras, y los extraíbles en agua fueron superiores en las hojas. El contenido de holocelulosa fue el constituyente con menos variabilidad.
Limitaciones del estudio: Se colectaron muestras de solo tres zonas geográficas de México, por lo que se hace necesario extender el estudio a más regiones.
Originalidad: Es el primer estudio que se realiza en México que compara tanto el efecto de la zona de colecta como la fracción del lirio acuático sobre su composición química.
Conclusiones: Para el procesamiento del lirio acuático es importante tomar en cuenta la zona geográfica y la fracción de la planta.

Introduction: The use of colored shading nets and greenhouses is a strategy to improve the use of solar radiation and regulate temperature, in addition to increasing productivity in horticultural crops.
Objective: To evaluate the effect of different photoselective covers on agronomic variables in wild piquin pepper ecotypes.
Methodology: Microclimatic variables and photosynthetically active radiation (PAR) were measured from plant transplant, and agronomic variables at 40 days after transplant and at the last cut of the cycle (160 days).
Results: Temperature, relative humidity and PAR changed with the use of the different covers. Blue netting reduced PAR by 50.10 % compared to the open field. Principal component analysis grouped the uncovered cultivated plants with the lowest results in the evaluated variables, and the RTZ ecotype revealed the greatest tendency towards quadrant 1, with most of the variables. The yield in the white netting increased 1 290.9 % compared to that obtained in the field. Study limitations: The study generated information only for the plant genetic resources of the Northeast Region of Mexico.
Originality: The crop is not domesticated, so this work was done under different shade netting covers and a greenhouse.
Conclusions:White netting favored the development of the ecotypes, with RTZ being the one that presented the best values, which is why this combination is considered viable for the preservation and production of this species on a large scale.

Introduction: A major design issue in implementing a subsurface drip irrigation (SDI) system is determining the appropriate drip tape placement depth to allow basic farming operations while still providing adequate water to the crop.
Objective: To determine the appropriate placement depth of the SDI tapes using modeling techniques and classical soil mechanics theory.
Methodology: The HYDRUS-2D program was used to determine the wetting pattern, after 12 h of irrigation, of a SDI emitter installed at 50 cm depth in three soil types: sandy clay loam (SCL), clay loam (CL) and loam (L), and classical soil mechanics theory was used to calculate the increase in soil stress at different depths.
Results: The vertical capillary rise above the dripline was 27, 30 and 22 cm for SCL, CL and LF soils, respectively. The minimum dripline placement depth to avoid failure is 40 cm in SCL and L soils, and 35 cm for CL soil.
Study limitations: The physical properties and hydraulic parameters of the soil were obtained from the literature, and the soil mechanics theory results were not calibrated with field measurements.
Originality: This is the first study in which soil mechanics is used to determine the spacing and installation depth of SDI system tapes.
Conclusions: This type of study is helpful in determining the SDI dripline placement depth to ensure adequate trafficability under these irrigation system

Introduction: In recent years the brewing industry has shown great growth, which makes it necessary to generate knowledge about the use of new varieties of barley produced in Mexico.
Objective: To evaluate the potential of Doña Josefa barley to brew gourmet-type beer with different flavor notes according to the type of malt.
Methodology: Five malts were prepared: Pilsen, Vienna, Melano, Café and Chocolate. Their diastatic power, concentration of total and reducing sugars and content of β-glucans were analyzed. Subsequently, Pilsen was mixed with each of the other malts to obtain beer worts, from which different craft beers were brewed and later physically evaluated and compared sensorially with commercial beers.
Results: Pilsen malt had the highest concentration of total sugars (67.09 g∙100 g-1 malt) and Melano the lowest (24 g∙100 g-1 malt). Vienna malt had the lowest diastatic power. The beers showed an alcohol content between 4 and 7 %, associated with the pH trend. Sensorially, only the Café and Chocolate beers were accepted by consumers.
Study limitations: Only one type of fermentation (lager) and one strain of yeast were used.
Originality: Doña Josefa barley is a new variety that has greater resistance to disease and is slightly larger than those currently used to produce beer.
Conclusions: The malting provided suitable conditions for making different brewing malts from the Doña Josefa barley. The malts had total and reducing sugar values appropriate for brewing beers. Chocolate beer had the same level of acceptance as a commercial beer.