Ingeniería Agrícola y Biosistemas

Volume 6, issue 1, January - June 2014

Electronic ISSN: 2007-4026
Print ISSN: 2007-3925

 

 

Ingeniería Agrícola y Biosistemas
Volume 6, issue 1, January - June 2014
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Trapezoidal rule as a non-destructive method for determining leaf area duration in soybean

Regla del trapecio como método no destructivo para determinar duración del área foliar en soya

Juan Manuel Loeza-Corte; Ernesto Díaz-López; Irma Brena-Hernández; Jesús Manuel Campos-Pastelín; Israel Jesús Orlando-Guerrero; Cándido Humberto Bravo-Delgado

http://dx.doi.org/10.5154/r.inagbi.2013.09.021

Received: 27-09-2013

Accepted: 16-05-2014

Available online: 2014-06-15 / pages 5 - 14

  • Plant growth analysis is a useful tool to predict response variables such as leaf area and leaf area index over time. These parameters are of great use for generating mathematical models and predicting plant growth behavior, thus minimizing destructive sampling. In this work, a mathematical model was generated and solved using the trapezoidal method, in order to describe leaf area duration in terms of leaf area index as a function of time. The trapezoidal method proved to be a non-destructive method, which is useful for explaining the agronomic yield behavior of soybean in relation to leaf area duration. Additionally, leaf area index and time data were used to generate a Vandermonde matrix, from which the polynomial of degree n was obtained by least squares. The integration of the polynomial allowed calculating the leaf area duration in soybean crops planted in the Cañada region. The results show that LabVIEW software can be used to calculate the actual value of leaf area duration. Moreover, the trapezoidal method, compared with the traditional method, is a useful, non-destructive tool for determining the integral of the polynomial generated.

Methodology for selecting and applying photovoltaic systems for greenhouses

Metodología para la selección de sistemas fotovoltaicos a invernaderos y su aplicación

Telésforo Martínez-Castellanos; Eugenio Romantchik-Kriuchkova; Francisco Betanzos-Castillo; Efraín Contreras-Magaña; René Martínez-Elizondo; Edilberto S. Poblano-Ortiz

http://dx.doi.org/10.5154/r.inagbi.2014.06.023

Received: 20-02-2014

Accepted: 16-06-2014

Available online: 2014-06-15 / pages 15 - 30

  • High pollution levels resulting from the production of electricity from fossil fuels has led to the search for new energy alternatives, such as photovoltaic (PV) systems. In this work, a novel methodology for selecting PV components in order to generate the electricity demanded by different greenhouse systems based on equipment, hours of use and energy consumption was developed. For the selection of the PV components, catalogs with information on greenhouse equipment, sites with peak solar hours, PV modules, batteries, controllers and inverters were made, and algorithms for an economical selection were also developed. The methodology developed was applied in greenhouses covering a total area of 6,165 m2 at the “Tlapeaxco” experimental field belonging to the Universidad Autónoma Chapingo. A PV system, consisting of 16 PV modules with total output of 3.68 kWp, 2 80-A controllers, 12 1800-Ah batteries and a 7-kW inverter/charger, was selected and installed to generate and supply power to an irrigation system with a flow rate of 1.15±0.35 liters/s and a pressure of 0.28±0.02 MPa, composed of 2 2.2-kW pumps and a 1.1- kW motor for the agitator. Power system analysis showed a power factor (PF) of 0.8, so a 2 kVAR capacitor bank was installed to increase this factor to 0.94. The PV system was monitored and a daily energy production of 14.5±1.5 kWh in December, which ensures a sufficient power supply to the irrigation system, was estimated.

Analysis of the current situation, issues and alternatives for ethanol production and use in Mexico

Análisis de la situación actual, problemática y alternativas para la producción y uso de etanol en México

Luis Ramiro García-Chávez

http://dx.doi.org/10.5154/r.inagbi.2014.06.028

Received: 12-12-2013

Accepted: 27-06-2014

Available online: 2014-06-30 / pages 31 - 42

  • While in several countries of the world the biofuels industry is developing rapidly, in Mexico it is still not clear whether it is feasible to produce and use ethanol and biodiesel as fuel. The volatility of world sugar prices coupled with the high cost of hydrocarbons justify the diversification of sugarcane use to ensure the economic viability of the activity and the rural development of the country, plus the potential of biofuels to reduce greenhouse gas emissions helps improve energy security. In this study the current status, issues and alternatives for the production and use of anhydrous ethanol were analyzed, with the main focus being on the conditions in Mexico, taking as reference information available internationally. Economic and public policy issues related to the production of sugar cane for making anhydrous ethanol and its incorporation into mixtures with gasoline were analyzed and discussed. The results indicated that the production of anhydrous ethanol in Mexico is economically viable and has domestic and international market potential, but it requires concrete actions to stimulate investments in sugarcane fields and sugar mills, diversify the use of sugar cane and increase its productivity and competitiveness.