Análisis geoestadístico espacial de cuatro iones mayoritarios y arsénico en el acuífero Calera, Zacatecas

Conocer la distribución espacial y evolución temporal de la cantidad y calidad del agua subterránea resulta fundamental en el manejo de acuíferos. En este artículo se presentan los resultados de un análisis geoestadístico espacial realizado a cuatro iones mayoritarios (calcio, cloruro, sodio y sulfato) y arsénico (elegido por el alto grado de toxicidad que representa), considerados parámetros indicadores de la calidad del agua para el acuífero Calera, Zacatecas, México. Las configuraciones espaciales obtenidas complementan el modelo conceptual existente del funcionamiento del agua en el acuífero. Se observó que, en general, el agua subterránea en la zona es de buena calidad de acuerdo con los valores establecidos por la NOM-127-SSA1-1994

A photographic method for drop characterization in agricultural sprinklers

42 Pags.- 1 Tabl.- 12 Figs. The defintive publication is available at: http://link.springer.com/journal/271The experimental data set used in the paper is OA available (http://hdl.handle.net/10261/127640)The characterization of drops resulting from impact sprinkler irrigation has been addressed by a number of techniques. In this article, a new technique based on low-speed photography (1/100 s) is presented and validated. The technique permits to directly measure drop diameter, velocity and angle. The photographic technique was applied to the characterization of drops resulting from an isolated sprinkler equipped with a 4.8 mm nozzle and operating at a pressure of 200 kPa. Sprinkler performance was characterized from photographs of 1,464 drops taken at distances ranging from 1.5 to 12.5 m. It was possible to analyze separately the drops emitted by the main jet and those emitted by the impact arm. The proposed technique does not require specific equipment, although it is labor intensive.This research was funded by the Plan Nacional de I+D+i of the Government of Spain, through grant AGL2007-66716-C03. Carlos Bautista received a scholarship from the Agencia Española de Cooperación Internacional (AECI).Peer reviewe

Empleo de sumadores electrónicos en lisímetros de pesada de varías células de carga

Los lisímetros de pesada son los equipos más precisos que existen en la actualidad para conocer el consumo de agua de los cultivos. Hasta el momento, estos equipos solo han estado disponibles en centros de investigación, ya que eran muy costosos y requerían de una gran infraestructura. Mediante modelos matemáticos y sensores calibrados a partir de los datos proporcionados por estos equipos, se ha intentado extrapolar los datos para ayudar a los agricultores a estimar las necesidades de agua de sus cultivos, aunque en la mayoría de los casos suelen diferir de las necesidades reales. En los últimos años, se han realizado enormes avances que están permitiendo incorporar esta tecnología en parcelas comerciales. Para ello, ha sido necesario reducir el tamaño de los equipos, además de abaratar enormemente los costes para que se amortice en poco tiempo. La medida del peso se lleva a cabo con células de carga. Cuando se pretende compensar la temperatura, las células de carga emplean cuatro galgas extensiométricas, las cuales se ubican a ambos lados del bloque metálico para conocer su deformación. La deformación producida es proporcional al peso aplicado, la cual se transforma en una señal eléctrica medible, conectando las galgas dentro de un puente de Wheatstone. Los cuatro hilos obtenidos del puente, dos de alimentación y dos de señal de salida, pueden conectarse directamente a un datalogger con suficiente resolución o a un indicador de pesada. El recipiente donde se aloja el cultivo, se apoya sobre 4 células de cargas, lo que implica disponer de: a) varios datalogger, b) un datalogger con multiplexor o c) 4 indicadores de pesada conectados a un datalogger. En los tres casos se realizaría la medida de forma individual y la suma por software. Otra forma de conocer el peso global del cultivo, utilizando un único datalogger o indicador de pesada, es mediante el empleo de un sumador electrónico. En los sumadores electrónicos se conectan todas las células de carga en paralelo y se regulan mediante potenciómetros de precisión. De esta forma conseguimos sumar todos los pesos y utilizar un único canal para la medida global del recipiente de cultivo (RC). Este sistema ha permitido resolver de una forma más económica y con la misma precisión, la medida del peso del RC

PRODUCTIVIDAD EN CULTIVOS DE ALTO IMPACTO SOCIAL EN AGRICULTURA PROTEGIDA AL NORESTE DE LA REPÚBLICA MEXICANA IMPLEMENTANDO DIVERSAS TECNOLOGÍAS DE RIEGO

[ES] Actualmente en México existen 85 distritos de riego que cubren 3´498,164 ha del territorio nacional, durante los últimos 20 años la sequía ha originado que en 8 de ellos no se tenga agua para riego. El Distrito de Riego 025 Bajo Río Bravo se localiza en el estado de Tamaulipas con una superficie física de riego de 192,438 ha. En este distrito se practica en un 96% el riego por gravedad mientras que en el resto se lleva a cabo el riego presurizado en sus diversas modalidades. Para un periodo de 11 años de registro se tiene una productividad bruta promedio de 1.16 kg/m3 de agua para los cultivos de maíz y sorgo. El presente trabajo se realizo en una superficie de riego que consistió de tres naves protegidas con casa-malla, cada una con un superficie de 1.3 ha, Los cultivos seleccionados para la producción piloto fueron: tomate en tres de sus variedades, pepino, chile habanero y pimiento morrón, con una superficie física de 6 712 m2 , 6 712 m2 , 6 712 m2 , 20 136 m2 , respectivamente. Se realizaron diversos trabajos para habilitar cada nave como: la preparación de tierras, formación de camas, instalación y reparación del sistema de riego, acolchado plástico sobre las camas de siembra, instalación de medidores de flujo y de presión. Se llevó a cabo el monitoreo del clima con el uso de 4 estaciones climatológicas una a cielo abierto y tres dentro de las naves; como un factor más para la aplicación del riego, se monitoreó la humedad del suelo a profundidades de 30 y 60 cm utilizando 24 sensores puntuales distribuidos equitativamente en todas las naves. Se obtuvieron rendimientos en los cultivos de: 34.61 ton/ha para el pepino, 40.9 ton/ha para el jitomate, 9.19 ton/ha para pimiento morrón y 1.05 ton/ha para el chile habanero.Bautista Capetillo, CF.; Mojarro Dávila, F.; Márquez Villagrana Héctor, H.; Robles Rovelo, O.; Medina Carreón, A.; Félix Félix, J. (2015). PRODUCTIVIDAD EN CULTIVOS DE ALTO IMPACTO SOCIAL EN AGRICULTURA PROTEGIDA AL NORESTE DE LA REPÚBLICA MEXICANA IMPLEMENTANDO DIVERSAS TECNOLOGÍAS DE RIEGO. En XXXIII CONGRESO NACIONAL DE RIEGOS. Valencia 16-18 junio de 2015. Editorial Universitat Politècnica de València. https://doi.org/10.4995/CNRiegos.2015.1453OC

Kinetic energy in sprinkler irrigation: different sources of drop diameter and velocity

44 Pags., 5 Tabls., 7 Figs. The definitive version is available at: http://www.springerlink.com/content/0342-7188/Sprinkler kinetic energy has been linked to a number of problems in irrigated fields. This work presents the characterization of sprinkler drop kinetic energy and specific power from low-speed photographic drop data using a commercial impact sprinkler and three operating pressures. The spatial variability of specific power (W m−2) was assessed for different sprinkler spacings, showing different patterns in rectangular and triangular spacings. The specific power uniformity coefficient ranged from 38–77%, depending on sprinkler spacing and operating pressure. An attempt was made to characterize specific power from estimated (measured diameter and estimated velocity) and simulated data (using a ballistic model). While estimated data produced adequate results, simulated data resulted in a large overestimation. Discrepancies in kinetic variables between measured and simulated drop data permit to conclude that it is important to continue experimental drop characterization efforts as well as sprinkler simulation model development.This research was funded by the Agencia Española de Cooperación Internacional para el Desarrollo (AECID). Thanks are also due to the Universidad Autónoma de Zacatecas, México.Peer reviewe

Using thermal units for crop coefficient estimation and irrigation scheduling improves yield and water productivity of corn (Zea mays L.)

31 Pags., 2 Tabls., 4 Figs. The definitive version is available at: http://cedb.asce.org/cgi/WWWdisplay.cgi?168575Estimates of daily crop coefficient (Kc) for corn and irrigation scheduling were performed during 2009 and 2010 by means of two approaches: treatment I, computation of Kc using the FAO method; treatment II, computation of Kc from relative fraction of thermal units. Corn crop water requirements and irrigation gross depth for treatment I were about 25 to 33 % lower than that for treatment II in 2009 and 2010 respectively. However, the performance of the treatment II was better in terms of grain yield which was 9.2 Mg ha-1 (in 2009) and 9.4 Mg ha-1 (in 2010), about 37 and 29 % higher than that for treatment I. Water productivity was about 10 % higher for treatment II during 2009 and practically the same than that of treatment I for 2010. Due to the year-to-year variability the water productivity was about 25 % (treatment II) and 11 % (treatment I) for 2010 than for 2009. Finally, economic productivity for treatment II was 2162 $ha-1 for both seasons, much higher than that for treatment I, 1575 (in 2009) and 1679 (in 2010)$ ha-1. These results confirm that the use of fraction of thermal units to estimate corn crop coefficient has improved the yield, and the water management of this crop under the conditions of this study. Because of the limitations of the study (only two years and one experimental plot), further evaluations under other conditions (climatic, cultivar, etc.) should be performed.Peer reviewe

Irrigation performance in private urban landscapes: A study case in Zaragoza (Spain)

32 Pag., 6 Fig. y Tabl. The definitive version is available at: http://www.sciencedirect.com/science/journal/01692046Irrigation water use in private landscapes represents an increasing share of total water use in semiarid areas. In this work, 102 households located in the Montecanal neighbourhood (Zaragoza, Spain) were analysed. Research took advantage of the dual water supply network (separate indoor and irrigation water networks). The analysis was based on bi-monthly water billing records for the period 2005–2007. The total household landscape area (93 m2) and the area occupied by turf, trees and shrubs were derived from aerial photographs. A method based on reference evapotranspiration was used to estimate net landscape irrigation requirements. The total average water use was 0.80 m3 household−1 day−1, with irrigation water use amounting to 46% of the total water use. Average air temperature largely determined irrigation water use (the correlation coefficient was 0.958). Overirrigation was common in the three years of study, with the average irrigation water application (IWA) being much higher than the Net Irrigation Requirements (1359 and 555 mm, respectively). Only 34% of the households showed adequate irrigation, while 6% of the households underirrigated their landscape areas. In the rest of the households (60%), overirrigation was observed. Significant time correlations were found for IWA and for an adequacy index, suggesting that landowners applied their inadequate irrigation criteria in a consistent way. Local private landscape irrigation performance was found to be very poor, probably owing to low water cost and over-the-average household income.Peer reviewe

A particle tracking velocimetry technique for drop characterization in agricultural sprinklers

Pags.- 1 Tabl.- 9 Figs. Published online: 7 June 2014. The definitive version is available at: http://link.springer.com/journal/271A variety of techniques have been proposed in the literature for sprinkler drop characterization. An optical particle tracking velocimetry (PTV) technique is proposed in this paper to determine drop velocity, diameter and angle. The technique has been applied to the drops emitted by an isolated impact sprinkler equipped with two nozzles (diameters 3.20 and 4.37 mm) operating at a pressure of 175 kPa. PTV has been previously used to determine the velocity vector of different types of particles. In this research, PTV was used to photograph sprinkler drops over a region illuminated with laser light. Photographs were taken at four horizontal distances from the sprinkler, which was located at an elevation of 1.65 m over the soil surface. Drop angle and velocity were derived from the displacement of the drop centroid in two images separated by a short time step. Centrality and dispersion parameters were obtained for each drop variable and observation point. Results derive from the analysis of 2,360 images. Only 37.5 % of them (884 images) contained drops which could be processed by the PTV algorithm, resulting in a total of 3,782 drops. A filtering algorithm just validated 1,893 valid drops, which were successfully analyzed. The proposed technique uses expensive equipment requiring continued protection against irrigation water. This methodology has proven valuable to characterize irrigation water drops. Despite its robust measurement procedure, further comparison with other techniques seems necessary before this optical technique can be recommended for practical use in sprinkler drop characterization.Thanks are due to the Centro Interamericano de Recursos del Agua from the Universidad Autónoma del Estado de México and to the Maestría en Ingeniería Aplicada Orientación Recursos Hidráulicos of Universidad Autónoma de Zacatecas. Thanks are also due to CONACYT for providing a scholarship to Cruz Octavio Robles Rovelo to pursue Master Degree studies.Peer reviewe

Discharge coefficient analysis for triangular sharp-crested weirs using a low-speed photographic technique

18 Pags., 1 Tabl., 3 Figs. The definitive version is available at: http://ascelibrary.org/toc/jidedh/140/3Triangular weirs are commonly used to measure discharge in open channel flow, representing an inexpensive, reliable methodology to monitor water allocation. In this work, a low-speed photographic technique was used to characterize the upper and lower nappe profiles of flow over fully aerated triangular weirs. A total of 112 experiments were performed covering a range of weir vertex angles (from 30° to 90°), crest elevations (8 or 10 cm), and discharges (0.01–7.82  l s−1). The experimental nappe profiles were mathematically modeled and combined with elements of free-vortex theory to derive a predictive equation for the weir discharge coefficient. Comparisons were established between measured Cd, the proposed discharge coefficient equation, and discharge coefficient equations identified in the literature. The proposed equation predicts Cd with a mean estimation error (MEE) of 0.001, a root-mean square error (RMSE) of 0.004, and an index of agreement (IA) of 0.984. In the experimental conditions of this study, this performance slightly improves that of the equation proposed by Greve in 1932, and showed the same absolute value of MEE but lower values of RMSE and IA.This research was funded by the Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación of the Mexican Government (SAGARPA, Mexico) and the Secretaría del Campo of Zacatecas State Government (SECAMPO, Zacatecas). Thanks are also expressed to the Universidad Autónoma of Zacatecas, Mexico. Cruz Octavio Robles Rovelo received a scholarship from the Mexican Consejo Nacional de Ciencia y Tecnología (CONACYT).Peer reviewe

Closure to “Using thermal units for crop coefficient estimation and Irrigation scheduling improves yield and water productivity of corn (Zea mays L.)” by C. Bautista-Capetillo, M. Zavala, and A. Martínez-Cob

4 Pags.Peer reviewe