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Search Results: 1 - 10 of 673102 matches for " Prometeo Sánchez García "
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Emisión de N2O con fertilización nitrogenada en fertirriego y fertilización convencional
Sandra Grisell Mora Ravelo,Manuel Sandoval Villa,Francisco Gavi Reyes,Prometeo Sánchez García
Revista internacional de contaminación ambiental , 2005,
Abstract: El relacionar el uso de fertilizantes químicos u orgánicos nitrogenados con la contaminación ambiental, implica adoptar alternativas que reduzcan las pérdidas de nitrógeno (N) del suelo que podría ser utilizado por los cultivos. La fertirrigación es una técnica de aplicación de agua y fertilizante que mejora la eficiencia en el uso de los fertilizantes mediante el riego por goteo. No existen reportes sobre como la fertirrigación afecta a la desnitrificación. El objetivo del presente trabajo es estudiar cómo afectan la fertirrigación y la fertilización convencional a la desnitrificación y verificar si, efectivamente, es posible reducir las emisiones de óxido nitroso (N 2 O) hacia la atmósfera. Se utilizó la captura de N 2 O in situpor el método adaptado por Grageda (1999) y Vivanco (2000). Las muestras de N 2 O se tomaron a las 2, 24, 48 y 72 h después del riego. La temperatura del suelo se midió con un termómetro aproximadamente a 10 cm de profundidad del suelo. La humedad del suelo (0 12 cm) se determinó con la ayuda de un instrumento DT DeltaT devices, tipo ML2 ThetaProbe. La cuantificación de N 2 O fue por cromatografía de gases. Los cálculos y análisis estadístico se efectuaron con el paquete estadístico SAS (SAS 1998). Los resultados obtenidos para la emisión de N 2 O manifiestan que el factor que más influyó en el sistema de riego convencional fue la humedad ya que existió una diferencia significativa a las 2, 24 y 48 h después del riego con respecto al fertirriego (riego por goteo). A pesar de que estadísticamente no hubo diferencia significativa en la emisión de N 2 O entre sistemas se obtuvo una concentración en riego por goteo de 0.69 y 2.82 mM menor que en el sistema convencional a las 48 y 72 h. Las temperaturas registradas a lo largo del desarrollo del cultivo estuvieron por debajo de las reportadas, por lo que se asume que este factor influyó en la disminución de la producción de N 2 O. Con respecto al pH del suelo se trabajó en un rango de 8.0 a 8.4, promedio superior al reportado como pH óptimo para el crecimiento de brócoli por lo que probablemente también influyó en la emisión de N 2 O en el sistema convencional y en el fertirriego.
Acidos fenólicos en paja de trigo. Son estos los compuestos fenólicos más importantes en la inhibicion del crecimiento de las plantas? Acidos fenólicos en paja de trigo. Son estos los compuestos fenólicos más importantes en la inhibicion del crecimiento de las plantas?
Fidel René Díaz Serrano,Luis Felipe Ramírez Santoyo,Marcos R. Soto Hernández,Prometeo Sánchez García
Acta Universitaria , 2012,
Abstract: Se identificaron los principales ácidos fenólicos presentes en paja de trigo por cromatografía líquida de alta resolución (CLAR), coincidiendo en general con los ácidos fenólicos reportados en la literatura científica como los principales compuestos alelopáticos presentes en la paja de trigo. Las concentraciones de estos ácidos fenólicos, cuantificadas en los extractos metanólicos por CLAR, fueron muy bajas (entre 0.17 % y 3.06 %) en relación con la cuantificación de fenólicos solubles totales realizada por colorimetría. Asimismo, los porcentajes de recuperación de los ácidos fenólicos por CLAR, con respecto a las concentraciones de fenólicos solubles totales, determinadas por colorimetría en los extractos metanólicos variaron entre 1.28 % y 15.18 %. Los resultados indican que es posible que los ácidos fenólicos identificados y cuantificados por CLAR en la paja de trigo, pueden no ser los compuestos fenólicos más importantes como agentes alelopáticos en algunos sistemas agrícolas, de acuerdo con las concentraciones cuantificadas. They were identified the main phenolic acids in wheat straw by high performance liquid chromatography (HPLC), according with those reported by scientific literature as the main allelopathic compounds from wheat straw. The concentrations of these phenolic acids quantified on methanolic extracts by HPLC were very low (among 0.17 and 3.06 %) in relationship to the concentration of total soluble phenolics quantified by colorimetry. In the same way, the recuperation percentages of phenolic acids by HPLC in relationship to the total concentration of soluble phenolics quantified by colorimetry in the methanolic extracts varied among 1.28 and 15.18 %. The results shown that it is possible that the identified and quantified phenolic acids by HPLC on wheat straw, could not be the most important phenolic compounds that act as allelopathic agents in some agricultural systems according to their concentrations.
Relación amonio / nitrato en la producción de hierbas aromáticas en hidroponía
González García, José Luis;Rodríguez Mendoza, María de las Nieves;Sánchez García, Prometeo;Gaytán Acu?a, Elda Araceli;
Agricultura técnica en México , 2009,
Abstract: the production of aromatic herbs could be a profitable alternative for greenhouse production. the objective of this research was to determine the effects of different nh4+ /no3- ratios on the growth and production of three aromatic herbs: chives (allium schoenoprasum), basil (ocimum basilicum l.) and dill (anethum graveolens l.). the experiment was conducted in the colegio de postgraduados at montecillo, estado de mexico, mexico, from january to may 2005, under greenhouse conditions. the herbs were cultivated in a hydroponic system with drip irrigation. a mixture of volcanic rock, locally called "tezontle" and coconut fiber (60:40) was used as substrate; the universal steiner's nutritive solution was modified to obtain four different nh4+/no3- ratios: 0/100, 20/80, 40/60 and 100/0. the studied parameters were: plant height, leaf area and total biomass. the 0/100-ratio significantly increased leaf area and total biomass production of chives. the greater height, leaf area and total biomass production of basil were observed with the 20/80 ratio. for dill, no significant differences were observed for the effects of the nh4+ /no3- ratios studied.
Tama?o de partícula y relación micromorfológica en propiedades físicas de perlita y zeolita
Anicua Sánchez, Rosa;Gutiérrez Castorena, Ma. del Carmen;Sánchez García, Prometeo;Ortiz Solorio, Carlos;Volke Halle, Victor H.;Rubi?os Panta, Juan Enrique;
Agricultura técnica en México , 2009,
Abstract: the selection of growth media is based upon its water retention capacity and drainage; however, there is a limited knowledge of the type, form and arrangement of the particles that determine these characteristics. the objective was to determine the physical (particle density, total porosity, air capacity, readily available water, reserve water, less available water, and solid material) and micromorphological properties of different particle size of perlite and zeolite. the study was carried out at the colegio de postgraduados, texcoco, estado de mexico, mexico, in 2006. the particle sizes were >3.36, 2.00, 1.0, 0.5, 0.25 and <0.13 mm. the study of pores and particles was made by impregnating thin resin sections of substrates; the studied parameters were: size, abundance, shape, surface roughness, and distribution. a completely random block design with 3 replications was used. results showed that shape, size, packing, internal and external porosity of particles determines the physical properties of growth media, that vary in function of particle size and differ in water retention capacity and water movement.
Aplicación foliar de calcio y su relación con la calidad en frutos de mango cv. Haden
Romero-Gomezca?a, Nelly Rosa;Sánchez-García, Prometeo;Rodríguez-Alcázar, Jorge;Saucedo-Veloz, Crescenciano;
Agricultura técnica en México , 2006,
Abstract: the aim of this research was to determine the effect of calcium foliar sprinkling and its relationship with other nutrients on fruit quality of mangoes cv. haden. an experiment was conducted on 16-year old trees during 2003 at san lucas, michoacan, mexico (18° 19' north latitude, 100° 40' west longitude and 251 masl). treatments consisted of five concentrations of ca(no ) (0, 5, 10, 15 and 20 g l-1), five foliar sprays of each were made every 15 days in pre-harvest. a completely random design with four replicates was utilized; each experimental unit consisted of three trees. ca treated trees had significantly higher fruit yield than the control. fruits kept at 20 ± 2 °c and 74 ± 4% r.h. showed significant differences (p<0.05) in respiration, fruit weight loss, acidity, and total soluble solids, but not for fruit firmness and color, as well as for pectin-metylesterase activity. fruit firmness correlated positively with the k/ca ratio (r= 0.9571**) and with pectin-metylesterase activity (r= 0.6844**). likewise, regression analysis of fruit firmness with k/ca and k+mg/ ca ratios were significant (p<0.05) with r2 of 0.9160 and 0.8504, respectively. furthermore, regression analysis between °brix/acidity and ca2+ rates was significant with a r2 of 0.82 (p<0.05). also, the analysis of °brix/acidity with k/ca and k+mg/ca, resulted significant (p<0.05) with r2 values of 0.82 and 0.86, respectively, and not for the n/ca ratio. fruit firmness had a positive relationship with k/ca and with pectin-metylesterase activity. with the increases in the k/ca and k+mg/ca ratios, fruit firmness also increased.
Amarre de fruto en aguacate "Hass" con aplicaciones de AG3, N y anillado
Espíndola Barquera, María de la Cruz;Cano Medrano, Raquel;Rodríguez Alcázar, Jorge;Sánchez García, Prometeo;
Agricultura técnica en México , 2008,
Abstract: the aim of this study was to evaluate the effect of girdling and applications of ga3 and n on fruit set of avocado trees (persea americana mill.). the experiment was conducted during three production cycles, from 2003 to 2006 at 'la labor' experimental station of cictamex, s. c., san andrés, temascaltepec, estado de méxico. 'hass' avocado trees 8-year-old grafted on seedling of mexican race rootstocks were utilized. the factors evaluated were n (160 g and 0 g per tree), ga3 (25 and 0 mg l-1) and girdling (girdling and no girdling). a completely random experimental design was used with a factorial arrangement, with six replications per treatment and a single tree as experimental unit. ga3 and n were applied during the eight stage of the inflorescence development -known as the "cauliflower" stage-, and girdling was performed at full bloom. on the "low yield" crop year, the treatments of n or girdling increased initial and final fruit set; the combinations of n (160 g tree-1) + ga3 (25 mg l-1) + girdling and n (160 g tree-1) + girdling, increased the initial and final fruit set, respectively. on the "high yield" crop year, the initial fruit set was increased with the application of n or ga3, and the final fruit set with girdling and the combination of n (160 g tree-1) + ga3 (25 mg l-1) + girdling. the application of n promoted the accumulation of glucose and fructose in leaves and panicles with developing fruits. the combinations of treatments showed an additive effect of girdling on the accumulation of glucose, and sucrose and fructose in panicles and leaves, respectively.
Efecto del potencial osmótico y contenido de Ca en el medio de cultivo sobre la distribución de Ca2+ Y K+, producción de biomasa y necrosis apical de VID "R110"
Molinos da Silva,Christiane; Villegas Monter,ángel; Sánchez García,Prometeo; Alcántar González,Gabriel; Rodríguez Mendoza,Ma. Nieves; Ruiz Posadas,Lucero del Mar;
Interciencia , 2004,
Abstract: the osmotic potential, ionic balance and the nutrient ratios of culture medium are determinant for in vitro propagated plants growth; however, in most investigations, these factors are not considered. the effect of different osmotic potentials (-0.106, -0.113, -0.120, -0.128, -0.143 and -0.157mpa) and ca2+ contents of culture medium salts on the distribution of ca2+ and k+, and on dry biomass of explants of grapevine were evaluated. the ca2+ and k+ concentrations were measured with a low vacuum scanning electron microscope (meb-lv). ca2+ and k+ translocation from stems to leaves was favored by the higher osmotic potential of culture medium (-0.106mpa), whereas the larger contents of these elements at the base of the stems were found at the most negative osmotic potential (-0.157mpa). the greater dry biomass weight (57mg) and the smaller percentage of explants with ca2+ deficiency symptoms (20%) were obtained at -0.106mpa, the lower osmotic potential, and 1.5mm ca2+ in the culture medium.
Formulación de mezclas de sustratos mediante programación lineal
Zamora Morales,Bertha Patricia; Sánchez García,Prometeo; Volke Haller,Víctor H.; Espinosa Victoria,David; Galvis Spínola,Arturo;
Interciencia , 2005,
Abstract: the purpose of the present study was to formulate substrate mixtures through lineal programming, using the physical and chemical properties of seven organic and inorganic substrates: tezontle, agrolita, peat-mossa, vermicompost from kitchen waste, compost of goat manure and straw, vermicompost of agave residues and germinase (coconut fiber), using the software blp88. design variables were established (volume balance, organic matter, total porous space and field capacity) and final values for each mixture to be designed (restrictions) were also set. the object function was to minimize costs in terms of three levels of restriction value for each of the variables designed. feasible mixtures were obtained from the combination of design variables. lineal programming reduced the number of feasible mixtures by 93%. in order to evaluate the design criteria, 25% of the feasible mixtures were selected, which were reconstructed with the defined proportions of each original material. the results indicated that the values for each one of the variables evaluated were within the pre-established limits. thus, lineal programming can be use as a reliable method for substrate mixture formulation.
La relación K+/Ca2+ de la solución nutritiva afecta el crecimiento y calidad postcosecha del tulipán
Ramírez Martínez, Maribel;Trejo-Téllez, Libia I.;Gómez Merino, Fernando C.;Sánchez García, Prometeo;
Revista fitotecnia mexicana , 2010,
Abstract: tulip (tulipa gesneriana l.) is a plant species of importance for floriculture, and for the industries of cosmetics and pharmaceutics. for its production, this species needs particular soil and weather conditions and little is known about its nutritional requirements for optimal production, particulary the potassium/calcium ratios in hydroponics. in this study we evaluated the effect of nine ratios of k+/ca2+ (5.5/7.5; 5.5/9.0; 5.5/10.5; 7.0/7.5; 7.0/9.0; 7.0/10.5; 8.5/7.5; 8.5/9.0; y 8.5/9.0 molc m-3) in steiner's universal nutrimental solution, by measuring growth indicators and postharvest quality of tulip cv. 'ile de france'. this cultivar showed differential responses k+/ca2+ ratios in the nutrient solution. the best response was produced by k+/ca2+ of 8.5/9.0 molc m-3, in which the highest and strongest flower stem, highest levels of total chlorophylls in leaves and sugars in petals, and the longest postharvest life were registered. as for k and ca partitioning in the plant, we observed that k+ did not accumulate in a particular trend related to treatments, whereas. ca2+ affected flower quality and postharvest life. plants in the 8.5/9.0 ratio showed the lowest ca2+ accumulation ratios both in bulb/stem and in stem/leaf, and ca2+ accumulated higher in leaves than in stems, thus improving growth responses and postharvest quality.
Propuesta para la formulación de soluciones nutritivas en estudios de nutrición vegetal
Juárez Hernández,Ma. De Jesús; Baca Castillo,Gustavo A; Lorenzo,A; Navarro,Aceves; Sánchez García,Prometeo; Tirado Torres,Juan Luis; Sahagún Castellanos,Jaime; Colinas De León,María Teresa;
Interciencia , 2006,
Abstract: several studies in plant nutrition have been done in the past using nutrient formulations. in order to evaluate the effect of one or more nutrients on crop growth, development, yield, quality product as well as nutrient uptake, numerous studies have been carried out, without there being a generally accepted technique for this purpose. commonly, the main nutrient concentration (anion or cation) is modified, whereas the other nutrients remain at a constant level. nutrient solutions containing n-nh4+ and n-no3- are good examples of solutions with parallel changes on the anion and cation nutrient. a number of papers with systematic studies on the chemical characteristics of nutrient solutions and their effect on crops has been analyzed regarding the use of n-nh4+ and/or n-no3-. these studies did not allow to conclude either about the n-nh4+ or n-no3- direct effect or on their interaction. a nutrient solution formulation is herein proposed which, according to its factorial design structure based on the combinations of n-nh4+:cations groups with others of similar characteristics of n-no3-:anions, permits the elaboration of several nutrient solutions (treatments). the treatments allow the direct evaluation of n-nh4+ and n-no3- effects as well as their interaction, without interference of nutrient solution osmotic pressure or ph.
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