Attribute Selection Impact on Linear and Nonlinear Regression Models for Crop Yield Prediction

Efficient cropping requires yield estimation for each involved crop, where data-driven models are commonly applied. In recent years, some data-driven modeling technique comparisons have been made, looking for the best model to yield prediction. However, attributes are usually selected based on expertise assessment or in dimensionality reduction algorithms. A fairer comparison should include the best subset of features for each regression technique; an evaluation including several crops is preferred. This paper evaluates the most common data-driven modeling techniques applied to yield prediction, using a complete method to define the best attribute subset for each model. Multiple linear regression, stepwise linear regression, M5′ regression trees, and artificial neural networks (ANN) were ranked. The models were built using real data of eight crops sowed in an irrigation module of Mexico. To validate the models, three accuracy metrics were used: the root relative square error (RRSE), relative mean absolute error (RMAE), and correlation factor (R). The results show that ANNs are more consistent in the best attribute subset composition between the learning and the training stages, obtaining the lowest average RRSE (86.04%), lowest average RMAE (8.75%), and the highest average correlation factor (0.63)

Computational Fluid Dynamics Achievements Applied to Optimal Crop Production in a Greenhouse

Computational fluid dynamics has been successfully used in protected agriculture to simulate greenhouse weather as physical processes. The variables involved are velocity, wind direction related to either absolute or relative humidity, temperature as well as deficit vapor pressure, and carbon dioxide, among others. The research evolution is changing from the traditional validation of new designs and management to testing efficient production with less environmental pollution. This work points out this kind of assessment based on the physical principles of conservation of mass, momentum, and energy. Constitutive relationships like Darcy-Forchheimer porosity model in the momentum equation as well as the geometry and physical properties of the materials involved are needed to fulfill the particular solutions of temperature, wind, and humidity. This chapter is enhanced by the effect of solar radiation in more processes like crop transpiration with dynamical meshes and condensation

Performance assessment of the AquaCrop model to estimate rice yields under alternate wetting and drying irrigation in the coast of Peru

Peru is the second-largest rice producer in Latin America, with 406166 ha grown annually, predominately on the Peruvian north coast. However, rice is primarily irrigated by flooding (93%), which demands high water use (15000-18000 m3 ha−1) owing to low water-use efficiency. Additionally, the intensification of climate change is of great concern as it causes high variability as well as a decreasing trend in water resource availability. Alternate wetting and drying (AWD) irrigation technique reportedly reduce the irrigation volumes while maintaining conventional yield rates. The AquaCrop model was calibrated and assessed to simulate rice yield response to the AWD technique under water shortage conditions on the Peruvian central coast. The AquaCrop model exhibited a “very good” to “good” performance in predicting canopy cover development, soil water content, aerial biomass, and grain yield using performance indicators, such as the Nash-Sutcliffe efficiency coefficient, the RMSE observations standard deviation ratio (RSR), Willmott index, and determination coefficient. The calibrated model showed a good performance of rice under AWD irrigation, indicating that this technique can be used to assess rice production under Peruvian arid conditions

CFD Analysis of Turbulence Models to Achieve the Digester Mixing Process

Mixing efficiency defines the features of physicochemical and biological reactions carried out in reactors or digesters. The reason for this influence is because it conditions the heat and mass transfer. That is why the mixing level and intensity become important aspects to study to know the effects they have on the processes. Furthermore, it should be noted that most of the mixing processes are carried out under turbulent conditions. Mixing enhancement evaluation is achieved in two ways, that is, experimentally and performing simulations. Simulations are based on numerical methods approximating solutions to results in line with reality. In this context, turbulence models applied in systems have great influence on the final numerical solution and, therefore, on the interpretation of improved mixing in reactors. It is also necessary to consider the influence of rheology in these simulations, since the working fluid does not always have a linear stress-strain relationship. In this way, an analysis of turbulence models and their applications in mixing characterization and the adequacy of these models to the reactor configuration and operating conditions is carried out. Mention is also made of the experiences around the study of turbulence in mixing tanks

Improving the monitoring of corn phenology in large agricultural areas using remote sensing data series

Aim of study: Mexico's large irrigation areas demand non-structural actions to improve the irrigation service, such as monitoring crop phenology; however, its application has been limited by the large volumes of field information generated, diversity of crop management and climatic variability. The objective of this study was to generate and validate a methodology to monitor corn (Zea mays L.) phenology from the historical relationship of the vegetation indexes (VIs), EVI and NDVI, with the phenological development (PD) of corn grown in large irrigation zones.Area of study: Irrigation District (ID) 075 “Valle del Fuerte”, northern Sinaloa, Mexico.Material and methods: We used a database of 20 years of climate, field crop growth and crop phenology data, and Landsat satellite images. A methodology was proposed on a large scale supported with GIS and remote sensing data series.Main results: The methodology was validated in 19 plots with an acceptable correlation between observed PD and estimated PD for the two VIs, with slightly better values for EVI than for NDVI. NDVI and EVI models agreed with experimental PD observations in 92.1% of the farms used to validate the methodology, in 2.5% only the NDVI model coincided with the real, in 3.1% only the EVI model coincided, and in 2.3% both models disagreed with observation, generated a stage out of phase with respect to the real phenological stage.Research highlights: is possible to generalize the methodology applied to large irrigation zones with remote sensing data and GIS

La infraestructura hidroagrícola ante escenarios del cambio climático

La infraestructura hidroagrícola en grandes sistemas de riego consta de una serie compleja de obras civiles para cumplir con el servicio de riego. Por esta infraestructura se conduce el flujo de agua o gasto del sistema, variable hidráulica necesaria para satisfacer la demanda hídrica de los cultivos. Las proyecciones climáticas de la mayoría de los modelos de circulación general océano-atmósfera indican ambientes más cálidos y secos en la mayor parte de México, con efectos significativos sobre la evapotranspiración de los cultivos, variable agronómica básica en la determinación de la capacidad de la infraestructura hidroagrícola. En este trabajo se presenta el desarrollo de una metodología para evaluar la evapotranspiración integrada de los cultivos, determinada para grandes áreas de riego, con un patrón diversificado de cultivos, con diferentes fechas de siembra y varios ciclos agrícolas, base para analizar los cambios consecuentes sobre la infraestructura en las condiciones proyectadas bajo escenarios de cambio climático y asumiendo dos acciones posibles de adaptación agrícola. Como caso de estudio se analiza la Asociación de Usuarios de Riego Santa Rosa, del Distrito de Riego 075, ”Río Fuerte”, Sinaloa, México. Los resultados obtenidos indican que para las medidas de adaptación al cambio climático analizadas para mediados de siglo y asumiendo el escenario de emisiones A1B, la capacidad de conducción del gasto de diseño de la infraestructura para grandes áreas de riego podría incrementarse en un 5%. De igual manera, para las pequeñas áreas de riego con o sin medidas de adaptación, el incremento en la capacidad de diseño será también de 5%. Respecto al volumen necesario anual, bajo el mismo escenario de emisiones A1B y de acuerdo con las medidas de adaptación estudiadas, habrá un aumento de 8.5%. Se concluye que la metodología desarrollada puede ser aplicable en cualquier distrito de riego de México para analizar el impacto del cambio climático en la infraestructura de riego

Mejoras de eficiencia hidráulica en vertedores con canal de descarga libre en presas: propuesta metodológica

En México, la infraestructura hidráulica está avejentada y en muchos casos urge rehabilitarla. Esta tarea requiere la aplicación de nuevos métodos de rediseño tanto hidráulico como hidrológico y en lo posible acorde con los desarrollos tecnológicos actuales. Una obra de infraestructura hidráulica utilizada en embalses son los vertedores con canal de descarga libre, generalmente ubicada en canales muy anchos o con cargas hidráulicas altas, características de importancia vital al determinar la altura de la cortina. Se presenta una propuesta de alternativa de diseño y de mejoras de la eficiencia hidráulica, al sustituir la estructura del cimacio por un vertedor tipo laberinto. Esta propuesta adopta las bases del diseño de vertedores de “pico de pato”. Como caso de estudio, se aplicó para el vertedor de la presa “El Ejidatario”, ubicada en Sombrerete, Zacatecas, México. Los resultados muestran que con la instalación del vertedor “pico de pato” se aumentó la longitud de vertido 5.67 veces en relación con la proporcionada con el cimacio; asimismo, se reduce la carga vertedora en 62.5%, al pasar de una carga de 80 a 30 cm y se incrementa en un 12% la capacidad del embalse con la misma altura del NAME. Además, se comparó la eficiencia hidráulica del “pico de pato” respecto al vertedor “tecla de piano” para la misma longitud de vertido y condiciones de instalación, siendo mayor en 208%. Se recomienda en la instalación del nuevo vertedor utilizar el mismo sitio del cimacio, sólo adecuando la entrada al tanque amortiguador y conservando la salida del canal de descarga. Se concluye recomendar un vertedor “pico de pato” en donde las condiciones físicas o de estudio se requiera, ya que al aumentar la eficiencia hidráulica del vertedor para este caso, aumenta la capacidad del embalse y, por lo tanto, la vida de servici

Respuesta del tomate (Solanum lycopersicum L.) al consumo hídrico, área foliar y rendimiento con respecto al número de tallos

The objective of this study was to analyze tomato responses to water requirements (evaluated by means of balance lysimeters), leaf area, yield, quality and its relationship with weather, depending on the number of stems. The work was carried out in a greenhouse under hydroponic conditions. Tezontle (Stuff) was used as a substrate and a drip irrigation system was installed. The experiment consisted of three treatments, with one (T1), two (T2) and three (T3) stems per plant. The daily crop evapotranspiration was 0.30 L m-2 in the initial stage, up to 4.41, 4.77 and 6.0 L m-2, in the stage of maximum demand for T1, T2 and T3. The gross volume applied throughout the cycle was 352.2, 388.4 and 434.7 L m-2 for T1, T2 and T3, with productivities of 49, 41 and 36 kg m3 and yields of 20, 18 and 16 kg m-2 for T1, T2 and T3. Regarding quality parameters in size, T1 was the best, with 69, 23, 8 and 1% fruits of first, second, third and small fruits per plant respectively. The meteorological variables such as; temperature, wind, relative humidity, vapor pressure deficit and atmospheric water potential determined the consumption of water and nutrients in crops and are variables for irrigation scheduling.El objetivo de este estudio fue analizar las respuestas del jitomate a los requerimientos hídricos (evaluado por medio de lisímetros de balance), área foliar, rendimiento, calidad y su relación con el tiempo atmosférico, en función del número tallos. El trabajo se realizó en un invernadero en condiciones de hidroponía. Se utilizó tezontle como sustrato y un sistema de riego por goteo. El experimento consistió en tres tratamientos, con uno (T1), dos (T2) y tres (T3) tallos por planta. El consumo por evapotranspiración diaria del cultivo fue 0,30 L m-2 en la etapa inicial, hasta 4,41, 4,77 y 6,0 L m-2 en la etapa de máxima demanda para T1, T2 y T3. El volumen bruto aplicado durante todo el ciclo fue 352,2; 388,4 y 434,7 L m-2 para T1, T2 y T3, con productividades de 49, 41 y 36 kg m3 y rendimientos de 20, 18 y 16 kg m-2 para T1, T2 y T3. Con relación a los parámetros de calidad en tamaño, el T1 fue mejor, con 69, 23, 8 y 1% frutos de primera, segunda, tercera y frutos pequeños por planta. Las variables meteorológicas como temperatura, viento, humedad relativa, déficit de presión de vapor y potencial hídrico atmosférico determinan el consumo de agua y nutrimentos en los cultivos y son variables para calendarización del riego