Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

El aprovechamiento de halóf itas como Salicornia bigelovii representa una alternativa con potencial económico para la agricultura del desierto y zonas costeras. No obstante, el éxito en el establecimiento de parcelas comerciales se ha visto limitado por los bajos porcentajes de germinación de la especie. La propagación por esquejes representa una opción viable y rápida a esta problemática. La formación de raíces funcionales es fundamental en la propagación por esquejes y se ha logrado mediante la aplicación de productos químicos reguladores de crecimiento. La aplicación de quitosano en algunos cultivos ha mostrado ser una alternativa en el proceso de germinación y mejores rendimientos de cosecha; sin embargo, con relación a la halóf ita S. bigelovii, son nulos los estudios sobre el efecto del quitosano. El objetivo de la presente investigación fue evaluar el efecto del quitosano de origen marino y el ácido indol butírico como agentes promotores de raíces en esquejes de Salicornia bigelovii. Se aplicaron las concentraciones (individual y en conjunto) de quitosano al 100 y 50% y ácido indol butírico a razón de 0.937 y 1.25 g kg-1. Se utilizó un diseño completamente al azar con nueve tratamientos con cinco repeticiones, evaluándose 225 unidades experimentales. Como variables respuesta se midieron: longitud radicular, peso fresco y peso seco total de la raíz, número y longitud de nuevos brotes. Los resultados indican que el tratamiento más ef iciente fue 100% de quitosano + 0.937 g kg-1 de ácido indol butírico, el cual promovió la producción de brotes fotosintéticos hasta en un 800%. Estos resultados demuestran que es factible lograr la propagación de Salicornia mediante esquejes utilizando quitosano de origen marino como promotor de crecimiento.

México es un importante productor de café orgánico en el mundo, por lo que un sector de los productores de café del municipio de Ixhuatlán del Café, Veracruz, México, utilizan enmiendas orgánicas como mejoradores edáf icos. Hipotéticamente estas fuentes provocan cambios edáf icos que mejoran la producción de café. Por lo que se planteó el siguiente objetivo que fue determinar los cambios que provoca el aporte de mezclas elaboradas a partir de fuentes orgánicas a la fertilidad química del suelo, así como su contribución para mejorar el rendimiento del cultivo de café. Se aportaron cuatro abonos orgánicos elaborados a partir de cal dolomita, pulpa de café (PC), biol (abono fermentado líquido) y un mejorador de suelo denominado PSD® a suelo Cromic Luvisol (cutanic), a tres, seis y nueve meses después del aporte de los tratamientos al suelo, se determinaron las variables: materia orgánica, pH, conductividad eléctrica, nitrógeno, fosforo, y bases intercambiables (K, Ca, Mg, Na); paralelamente, se evaluó el rendimiento de café cereza. Los resultados indicaron que después de seis meses de la aplicación de los tratamientos, ocurre el mayor agotamiento de las fuentes orgánicas suministradas, que coincide con una mayor liberación de nutrientes. La dosis de 300 g de cal dolomita árbol-1 que se suministró (Tratamiento 1), resultó insuf iciente para neutralizar la fuerte acidez inicial del suelo de 4.3. La pulpa de café y biol utilizados, son abonos orgánicos que por su relación C: N menor a 16, son de rápida mineralización, por lo que incrementaron ligeramente los niveles de nitrógeno, fosforo y bases intercambiables, alcanzando apenas niveles bajos o medianamente bajos. La cal dolomita y PCD® del Tratamiento 4 incrementó, pH, Ca y Mg, aunque esos cambios no se reflejan en el rendimiento de café cereza.

El uso indiscriminado de fertilizantes ha contribuido a la salinidad del suelo tanto como al agotamiento de recursos minerales del mismo ocasionando así dependencia a los fertilizantes sintéticos por parte de los productores agrícolas. El objetivo del presente trabajo fue determinar el contenido inorgánico de N, P, K en las formas asimilables para las plantas de seis abonos orgánicos potenciales a utilizarse en la agricultura orgánica, bajos los principios del cuidado al medio ambiente. Las determinaciones de los elementos fueron realizados a través de un espectrofotómetro marca HANNA modelo HI83225-01. El abono con mayor contenido de nitrógeno es sus formas asimilables fue el guano de murciélago, seguido por la gallinaza y lombricomposta Fertium®. En el caso del fósforo, el abono que mostró la más alta cantidad fue de igual manera el guano de murciélago seguido por la gallinaza y estiércol de vaca. Para la determinación de potasio fue el guano de murciélago quien obtuvo el resultado más alto junto con la gallinaza y lombricomposta Fertium ®. Los seis abonos observaron valores altos de conductividad eléctrica (CE), y la gallinaza, guano de murciélago y estiércol de vaca observaron los mayores valores de éste parámetro, relacionados de forma signif icativa con el contenido de nutrientes. En cuanto al pH los seis abonos se encontraron con valores dentro de los permitidos por las normas mexicanas. Los resultados permiten generar información del contenido de nutrientes de los seis abonos para realizar su adecuada aplicación por los productores.

The consumption of fruits and vegetables is of great importance in the treatment and prevention of aging, cancer and chronic-degenerative diseases caused by oxidative stress, which in turn causes the release of reactive oxygen chemical species. The demand of organic food is on the rise, and it is reflected in the significant growth of 11% in the organic food trading in the United States, the world's largest organic market. More farmers are actually producing on more certified organic land and up to now 179 countries reported activities in organic agriculture. Vegetables analyzed for this study were obtained from commercial shopping centers of the city of La Paz Baja California Sur, and were classified in four groups: tomatoes, peppers, citrus fruit and leafy vegetables; conventional, wild and organically produced. The 1,1-Diphenyl-2-picrylhydrazyl (DPPH) technique was used to measure the antioxidant activity of the plant extracts. Tomato grape organic certified with 1,273 trolox equivalent mg per gram of sample presented the highest antioxidant power. Additionally; certified organic bell pepper had the highest antioxidant power with 1,119 mg equivalent of trolox gram of sample. With regard to the group of citrus fruits, we found that the wild naranjitas had higher antioxidant power with 1.623 mg trolox equivalent per gram of sample. Finally, as far as the leafy vegetables group, wild quelite showed the highest antioxidant power with 1,313 mg trolox equivalent per gram of sample.

In Mexico there are more than 201 400 ha grown with different mango (Mangifera indica L.) cultivars. This may cause variations in mineral requirement, fruit mineral concentrations and nutrient removal. The objective of this research was to make a survey of mineral concentration in fruit tissues and calculate nutrient removal by fruit tissues during harvest of the most important mango cultivars (Ataulfo, Kent and Tommy Atkins) from several production regions (Campeche, Chiapas, Oaxaca, Nayarit, and Sinaloa) of Mexico. Fruit at physiological maturity were harvested from commercial mango orchards and concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), manganese (Mn), zinc (Zn) and boron (B) was determined for skin, mesocarp, endocarp, and seed tissues. Each tissue was cut into thin slices and they were dehydrated in a forced air oven at 70 °C, after that, were pulverized and they were analyzed: nitrogen by semi-microKjeldahl digestion, phosphorus with the ascorbic acid method and the other nutrients with atomic absorption. The removal of nutrients was calculated considering the weight of the fruit and the content of nutrients in each tissue. Signif icant differences in the concentration of N, K, Mg, and Zn were found among cultivars and tissues. Concentration of P, S, Cu, and Mn in the skin, Ca, Cu, and Mn in the mesocarp, Ca, S, Mn, and B in endocarp, and S, Fe, and Mn in the seed were not affected by mango cultivar. Production region affected concentration of minerals in ‘Ataulfo’ fruit more than in ‘Tommy Atkins’ and ‘Kent’. Nutrient removal by mango fruit tissues was little affected in cvs. Ataulfo, Tommy Atkins and Kent. The regions with the greatest nutrient removal were Oaxaca, Campeche and Sinaloa for ‘Ataulfo’, ‘Tommy Atkins’ and ‘Kent’, respectively.

There is considerable diversity in fertilization management of ‘Ataúlfo’ mango (Mangifera indica L.) in the state of Nayarit, Mexico, and there is no systematic information available in this regard. The aim of this research was to evaluate the medium-term effect (2010‑14) of the site-specif ic fertilization approach on fruit yield and size in ‘Ataúlfo’ mango grown under rainfed conditions (annual average summer rainfall 1300-1450 mm). Two commercial orchards at 8 × 8 m spacing, one each in San Blas and Compostela municipalities in Nayarit were chosen. Fertilization treatments were: 1) Normal dose, which considered tree nutrient demand, periods of maximum root growth, nutrients provided by the soil, leaf nutrient concentrations and fertilization eff iciency; 2) High dose (1.5 times the normal dose); 3) Control, annual application of 3 kg per tree of 17-17-17 (N, P2O5, K2O). Soil and leaf samples were taken for nutrient analysis throughout the study. Treatments were randomly applied to 20 single tree-replicates at each orchard. For cumulative yield and fruit size a 2 × 3 factorial arrangement (orchards × treatments) was used. For leaf nutrient concentrations, the year and fertilization treatments effect was analyzed using 10 replicates per treatment. Means comparison was performed with the Waller-Duncan test (P ≤ 0.05). The Normal dose increased yield 38% as compared to the Control, as well as fruit size. The highest total fruit yield and C22 (196-220 g) and C20 (221-250 g), as well as the highest cost-benef it, were obtained with the Normal dose. This treatment consisted of applying per year and tree, depending on the orchard, 509-608 g N, 21-206 g P, 132-582 g K, 19-234 g Mg, 6.5-18 g Fe, 6-46 g Mn, 2-6 g Zn and 3-13 g B.

Erosion estimates for black soils in Mexico based on the Universal Soil Loss Equation (USLE) present discrepancies due to generalizations that lead to errors in permissible limits, with the erodibility factor or K factor (FK) being the most sensitive. The objective of the present investigation was to obtain a reasonable FK range for a Phaeozem (PH) from central Mexico by contrasting two equations based on the USLE. Samples were randomly obtained at three sites (P1, P2, P3) of a four-hectare area. The percentage of organic matter, textural class, soil structure, and profile permeability were determined. The results reveal differences between the estimated FK (FKe) and reference FK (FKr), whose values were +0.015, +0.028, and +0.029 for P1, P2, and P3, respectively. The differences represent underestimations that are up to 1.7 times greater in magnitude for FKr with respect to FKe. The statistical analysis rejects the null hypothesis (H0) that the means of each site evaluated are the same (P1 = P2 = P3). Although the variances between the factors of erodibility obtained using the equation specific to the Mollisols in Yunnan Province, China, and the reference nomography developed primarily in United States are significantly different (α ≥ 0.01), a combination of both could provide a range of maximums and minimums in the FK estimates and would yield better results than with the use of default values that tend to underestimate erosion rates.

This work was conducted with the objective to evaluate the effect of vermicompost application on chemical characteristics, energetic parameters and amino acids prof ile of hybrid race corn grain cultivated under open-f ield and rained conditions. The experiment was accomplished under a randomized complete design with three repetitions. Three treatments were evaluated: 1) Maize after inoculation with a commercial mycorrhizal arbuscular fungi mixture (Tec Myc 60®) plus vermicompost (V+M); vermicompost (V) and chemical fertilization (CF). Starch content in grain was 1.9% higher in V+M treatment in comparison with chemical, whereas crude protein, ether extract, crude f iber, acid detergent f iber, neutral detergent f iber, total phosphorous and phytic phosphorous were not different between treatments. Energetic parameters were not different between three treatments. 17 amino acids were evaluated of wich only tryptophan, leucine, valine, histidine and aspartic acid were higher in CF and V treatments in comparison with V+M treatment. In conclusion, it is possible to cultivate maize using vermicompost as fertilizer because chemical characteristics, energetic parameters and amino acids prof ile in maize grain were not affected compared with the maize cultivated with vermicompost added with biofertilizers (V+M) or with corn cultivated with chemical fertilizers (CF).

In this work, we present the results of a soil study in the Teuhtli volcano, located to the south of the Basin of Mexico with the aim to understand the pedogenetic pathways and the evolution of the landscape dynamics. Two different types of soil prof iles were sampled: in “conserved” areas, with less anthropogenic influence and in sites with intense agriculture activities since pre-Hispanic times. The three conserved prof iles are located in different landscape positions: the Cima prof ile in the summit, the Ladera prof ile in the high slope, and the Yotecón in a lower position of the piedemont. The agriculture prof iles are La Cruz, La Era and El Llano, situated in the foothill. Properties in both kind of soils are similar, however, in agriculture sites, structure (evaluated in macro and microscale) is weaker, total organic carbon content is smaller and bulk density is higher. Both soils show two main pedogenetic processes: andosolization and carbonate formation. Despite the age of the parent material (36 000 years), the Andosol phase has not been lost. This is because of the geomorphological dynamics of the zone, in which the processes of erosion and colluviation promote soil loss, restarting the pedogenetic clock. The detection of lithological discontinuities (by the Ti/Zr ratio) documents these processes. By the other hand, the formation of pedogenic carbonates is governed by the seasonal conditions of drought. The age of these carbonates places their formation in the mid-Holocene, an epoch for which drier conditions are detected in other sites of the Basin of Mexico. The agricultural land use has also promoted morphological, chemical and physical changes in the soils. The continuous tillage of the sites has prevented the soils from developing. This could have a negative effect on the fertility of those soils currently used to sustain the peri-urban agroecosystems of Mexico City.