oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 19 )

2018 ( 34 )

2017 ( 23 )

2016 ( 23 )

Custom range...

Search Results: 1 - 10 of 17952 matches for " Manuel; Parra Terraza "
All listed articles are free for downloading (OA Articles)
Page 1 /17952
Display every page Item
Relación nitrato/amonio/urea y concentración de potasio en la producción de tomate hidropónico
Parra Terraza, Saúl;Mendoza Palomares, Guadalupe;Villarreal Romero, Manuel;
Revista mexicana de ciencias agrícolas , 2012,
Abstract: tomato plants (solanum lycopersicum l. cv. ib-9) were grown in ahydroponic system in orderto evaluate the effect of the ratio nitrate, ammonium, urea (100/0/0, 85/15/0, 85 / 0/15 and 85/7.5/7.5) and the concentration of potassium (7 and 9 mol m-3) in fruit yield and mineral composition of plants. the fruit yield was unaffected by the treatments, so that it can substitute 15% of the total nitrate nitrogen to the nutrient solution with an equal percentage of nitrogen or urea, or a mixture of ammonia and urea, each at 7.5 %. the phosphorus content in leaves was significantly increased by the interaction of 85/15/0 and 9 mol of potassium m-3, while the calcium concentration in leaves 100/0/0 statistically decreased and 9 mol m-3 potassium.
Relación nitrato/amonio/urea y concentración de potasio en la producción de tomate hidropónico Relation nitrate / ammonium / urea and potassium concentration in hydroponic tomato production
Saúl Parra Terraza,Guadalupe Mendoza Palomares,Manuel Villarreal Romero
Revista mexicana de ciencias agrícolas , 2012,
Abstract: Plantas de tomate (Solanum lycopersicum L. cv. IB-9) fueron cultivadas en un sistema hidropónico con el objetivo de evaluar el efecto de la relación nitrato, amonio, urea (100/0/0, 85/15/0, 85/0/15y85/7.5/7.5) y la concentración de potasio (7 y 9 mol m-3) en el rendimiento de fruto y composición mineral de las plantas. El rendimiento de fruto no fue afectado por los tratamientos, por lo que se puede sustituir 15% del total de nitrógeno nítrico de la solución nutritiva con un porcentaje igual de nitrógeno amoniacal o ureico, o una mezcla de amonio y urea, cada una a 7.5%. El contenido de fósforo en las hojas aumentó significativamente con la interacción de 85/15/0 y 9 mol m-3 de potasio, mientras que la concentración de calcio en las hojas disminuyó estadísticamente con 100/0/0 y 9 mol m-3 de potasio. Tomato plants (Solanum lycopersicum L. cv. IB-9) were grown in ahydroponic system in orderto evaluate the effect of the ratio nitrate, ammonium, urea (100/0/0, 85/15/0, 85 / 0/15 and 85/7.5/7.5) and the concentration of potassium (7 and 9 mol m-3) in fruit yield and mineral composition of plants. The fruit yield was unaffected by the treatments, so that it can substitute 15% of the total nitrate nitrogen to the nutrient solution with an equal percentage of nitrogen or urea, or a mixture of ammonia and urea, each at 7.5 %. The phosphorus content in leaves was significantly increased by the interaction of 85/15/0 and 9 mol of potassium m-3, while the calcium concentration in leaves 100/0/0 statistically decreased and 9 mol m-3 potassium.
CRECIMIENTO DE PLANTAS Y RENDIMIENTO DE TOMATE EN DIVERSAS RELACIONES NITRATO/AMONIO Y CONCENTRACIONES DE BICARBONATO
Saúl Parra Terraza,Praxédes Lara Murrieta,Manuel Villarreal Romero,Sergio Hernández Verdugo
Revista fitotecnia mexicana , 2012,
Abstract: Aunque se ha reportado el efecto principal de diferentes relaciones de nitrato/amonio y de concentraciones de bicarbonato en la solución nutritiva sobre el crecimiento de las plantas, se conoce poco de la influencia de la interacción de ambos factores sobre eltomate (Lycopersicon esculentum Mill.). Por ello se hicieron dos estudios para determinar la influencia de tres relaciones porcentuales nitrato/amonio (100/0, 85/15 y 70/30) y tres concentraciones de HCO3 - (0, 2.5 y 5 molc m-3 ) en la solución nutritiva, sobre el crecimiento, rendimiento y composición mineral de tomate cv. 'Slolly F-1' desarrollado en hidroponía. La relación 70/30 de nitrato/amonio redujo (P < 0.05) el peso seco de raíz y el volumen radical, mientras que la concentración de 5 molc HCO3-m-3disminuyó el diámetro de tallo, el peso seco de hojas, el volumen radical y la relación vástago/raíz de las plantas jóvenes. La concentración de calcio en hojas y tallos de plantas jóvenes y plantas adultas se redujo (P < 0.05) con la relación 70/30; en contraste, la concentración de fósforo en dichos órganos se incrementó (P < 0.05). La adición de 5 molc HCO3 - m-3 a la solución nutritiva redujo (P < 0.05) la concentración de fósforo en hojas y tallos de plantas jóvenes, y en tallos y frutos de plantas adultas. La interacción 70/30 y 0 molc de HCO3-m-3incrementó (P 0.05) la altura de plantas jóvenes y redujo la concentración de magnesio en hojas y tallos. Sustituir 30 % del nitrógeno nítrico con nitrógeno amoniacal o a adir 5 mol HCO3-m-3a la solución nutritiva en la etapa de planta joven, redujo algunos indicadores del crecimiento pero no afectó al rendimiento de tomate.
Efecto del calcio y potencial osmótico de la solución nutritiva en la pudrición apical, composición mineral y rendimiento de tomate
Parra Terraza,Saúl; Villarreal Romero,Manuel; Sánchez Pe?a,Pedro; Corrales Madrid,José L; Hernández Verdugo,Sergio;
Interciencia , 2008,
Abstract: blossom-end rot (ber), a physical common disorder in tomato production, is caused by many factors and the control measures are not well defined. in order to study the effects of ca concentration and osmotic potential (ys) of the nutrient solution (ns), and their interaction, on the number of fruits with blossom-end rot (nfber), nutrient contents and yield in two tomato hybrids, b-52 ball type and anibal ?saladette? type, two experiments were carried out under net house conditions at the culiacan valley, sinaloa, méxico. in experiment 1, nine treatments resulting from the combination of varying ca concentrations (4.5, 6.75 and 9.0meq·l-1) and ys in the ns (-0.047, -0.072 and -0.097mpa) were evaluated. in experiment 2 other concentrations of ca (7, 9 and 11meq·l-1) and different ys (-0.036, -0.048 and -0.072mpa) were tested. in experiment 1, increasing levels of ca in ns significantly reduced nfber, while decreasing levels of ys increased it. in experiment 2 the fruits with ber had significantly lower contents of ca and p, and higher mg as compared to the fruits without ber. no significant effects in tomato fruit yield were obtained with the ca and ys factors in the two experiments; thus, it is possible to reduce by 50% the investment in fertilizer.
Cobertura vegetal, vermicompost y actividad microbiana del suelo en la producción de tomate Soil cover crop, vermicompost and soil microbial activity in the tomato production
Manuel Villarreal-Romero,Saúl Parra-Terraza,Pedro Sánchez-Pe?a,Sergio Hernández-Verdugo
Revista mexicana de ciencias agrícolas , 2010,
Abstract: Se estudió en el cultivo de tomate, el efecto combinado de fertilización química de N, P y K con aplicación de vermicompost, cobertura vegetal del suelo con Mucuna pruriens y labranza mínima; en contraste, al sistema de labranza convencional con fertilización química y acolchado plástico del suelo; para la nutrición de las plantas, medición de algunos parámetros de calidad del fruto y la actividad microbiana del suelo de 2007 a 2008. Se establecieron cinco tratamientos para la siembra del tomate, en los dos tipos de manejo del cultivo. Los resultados mostraron rendimientos similares y calidad poscosecha (firmeza y pérdida de peso) de fruto y absorción de N, P, K, Ca y Mg por las plantas de tomate, entre la labranza convencional del cultivo y el de uso de cobertura vegetal del suelo, labranza mínima y fertilización con vermicompost más 250 N-55 P-100 K. Los frutos procedentes de tratamiento T2 presentaron un comportamiento adecuado en firmeza y pérdida de peso en el estudio poscosecha y este resultado fue estadísticamente igual a los frutos del T5 durante el estudio. Las plantas de M. pruriens acumularon en su biomasa nitrógeno fijado de la atmósfera y residual del suelo en cantidad importante que estuvo disponible para el cultivo de tomate. La colonización micorrízica en las plantas de tomate y la liberación de CO2 del suelo, fueron más altas con la cobertura vegetal y vermicompost que el sistema de manejo convencional del cultivo. The combined effect of N, P and K chemical fertilizers with vermicompost was studied in tomato planting, vegetation cover of the soil with Mucuna pruriens and minimal farming; in contrast to the conventional farming system with chemical fertilizers and plastic soil padding, for plant nutrition, measurement of some fruit quality parameters and soil microbial activity from 2007 to 2008. The tomato underwent five treatments in two types of crop management. Results showed similar yields and postharvest fruit yields (firmness and weight loss) and absorption of N, P, K, Ca and Mg by the tomato plants, between conventional farming and the use of vegetation cover, minimum farming and fertilization with vermicompost plus 250 N-55 P-100 K. The fruits from treatment T2 displayed appropriate behavior in firmness and weight loss in the postharvest study, and this result was statistically equal to the fruits of treatment T5 during the study. The M. pruriens plants accumulated nitrogen fixed from the atmosphere and residual nitrogen from the soil in an important amount en its biomass, keeping it available for the tomato. The mychorrhizal co
Variación en la germinación entre poblaciones y plantas de chile silvestre
Hernández-Verdugo, Sergio;López-Espa?a, Ricardo G.;Porras, Flor;Parra-Terraza, Saúl;Villarreal-Romero, Manuel;Osuna-Enciso, Tomás;
Agrociencia , 2010,
Abstract: populations of wild chili pepper (capsicum annuum var. glabriusculum) are a valuable genetic resource for agriculture and nutrition. knowledge about the germination capacity is of great importance for its management and conservation. therefore, we evaluated, in the laboratory, the distribution of variation among populations and plants in the germination percentage and mean germination time (t50) of four populations of wild c. annuum from northwest méxico, at constant (25 °c) and fluctuating temperatures (25/35 °c). also the variation of seed weight and its relationship with the germination capacity was examined. populations and plants within populations differed significantly in the germination percentage and t50 in both conditions of germination. in the germination percentage, 15.72% of the total variation was attributed to differences among populations, 55.61% among individuals and 15.72% within individuals. in t50, 23.70% of the total variation was found among populations, 45.04% among individuals and 31.26% within individuals. the differences in the germination capacity among the populations were not significantly correlated with the main climate factors of the collection sites; therefore, they should be considered independent reactions to the environmental conditions of their sites of origin. the weight of seeds varied significantly among and within populations; and positively and significantly correlated with the percentage of germination in the population alcoyonqui and with t50 in the population yecorato mezquite, but negatively with t50 in the population yecorato camino. this indicates that the environment of growth of mother plants influences the capacity of germination and weight of wild c. annuum seeds.
Cobertura vegetal, vermicompost y actividad microbiana del suelo en la producción de tomate
Villarreal-Romero, Manuel;Parra-Terraza, Saúl;Sánchez-Pe?a, Pedro;Hernández-Verdugo, Sergio;Osuna-Enciso, Tomás;Basilio Heredia, José;
Revista mexicana de ciencias agrícolas , 2010,
Abstract: the combined effect of n, p and k chemical fertilizers with vermicompost was studied in tomato planting, vegetation cover of the soil with mucuna pruriens and minimal farming; in contrast to the conventional farming system with chemical fertilizers and plastic soil padding, for plant nutrition, measurement of some fruit quality parameters and soil microbial activity from 2007 to 2008. the tomato underwent five treatments in two types of crop management. results showed similar yields and postharvest fruit yields (firmness and weight loss) and absorption of n, p, k, ca and mg by the tomato plants, between conventional farming and the use of vegetation cover, minimum farming and fertilization with vermicompost plus 250 n-55 p-100 k. the fruits from treatment t2 displayed appropriate behavior in firmness and weight loss in the postharvest study, and this result was statistically equal to the fruits of treatment t5 during the study. the m. pruriens plants accumulated nitrogen fixed from the atmosphere and residual nitrogen from the soil in an important amount en its biomass, keeping it available for the tomato. the mychorrhizal colonization in tomato plants and the release of co2 from the soil were higher with the vegetation cover and vermicompost than the conventional handling of the crop.
Fertirrigación con diferentes formas de nitrógeno en el cultivo de tomate en un suelo arcilloso
Villarreal Romero,Manuel; Parra Terraza,Saúl; Sánchez Pe?a,Pedro; Hernández Verdugo,Sergio; Osuna Enciso,Tomás; Corrales Madrid,José Luís; Armenta Bojorquez,Adolfo D;
Interciencia , 2009,
Abstract: the effect of nitrogen form (urea, nitrate and ammonium) provided at various stages of development of the tomato crop on the yield and quality of fruit was studied. the work was conducted under field conditions in a pellustert soil, drip irrigation and a warm and semi-arid climate. three fertilization treatments (t1, t2 and control) were arranged in a randomized complete-block design with three replicates. t1 and t2 were fertilized with 250-50-190kg·ha-1 n, p and k, respectively; which n was supplied in different ratios of ureic-n, ammonium-n and nitric-n along growing tomato plants; t3 was provided in a similar way as is generally employed by the tomato producers in the culiacan valley, sinaloa, mexico (450-118-413kg·ha-1 n-p-k), with 75% of n in nitrate form. the concentration of n-no-3 in the petiole cell extract in t1 and t2 ranged from 500 to 1360ppm, and in the control it was 300-1175ppm. these values were related with the total n doses supplied but not with the ratio of nh4/no3 provided, neither influenced on the total amount of exportation fruit. the fruit production was statistically similar in the high and moderated fertilizer doses with a fertilizer savings of 75% of nitrate n. with respect to the post-harvest quality in the tomato fruit, moderated fertilization associated with high application of ureic-n and ammonium-n did not affect the fruit firmness, obrix or the weight loss in the fruit.
Is it justified to use HRT in active aging?
Manuel Parra A.
Medwave , 2010,
Abstract:
Envelopes of commutative rings
Rafael Parra,Manuel Saorin
Mathematics , 2009,
Abstract: Given a significative class $F$ of commutative rings, we study the precise conditions under which a commutative ring $R$ has an $F$-envelope. A full answer is obtained when $F$ is the class of fields, semisimple commutative rings or integral domains. When $F$ is the class of Noetherian rings, we give a full answer when the Krull dimension of $R$ is zero and when the envelope is required to be epimorphic. The general problem is reduced to identifying the class of non-Noetherian rings having a monomorphic Noetherian envelope, which we conjecture is the empty class.
Page 1 /17952
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.