Habilitación de un tepetate por efecto de mejoradores biológicos

En México uno de los principales problemas es la degradación del suelo debido al cambio de su uso como tierras de cultivo; este cambio ocasiona un deterioro que puede llegar a la pérdida total y el afloramiento del tepetate. Los tepetates son capas endurecidas de origen volcánico en zonas del Eje Neovolcánico Transmexicano, presentan bajos porcentajes de materia orgánica y nutrimentos, y una estructura masiva, lo que los hace impermeables y limita el crecimiento de las plantas. El objetivo de este estudio fue evaluar el efecto de tres enmiendas orgánicas, una especie vegetal (Ficus carica L.), micorriza (Glomus spp) y tiempo, en las características físicas y químicas de un tepetate fragmentado. El diseño experimental fue completamente al azar con un arreglo factorial de tratamientos (4×3×2) con los siguientes factores y nivieles: 1) la enmienda (sin enmienda, composta, vermicomposta y estiércol); 2) higuera (sin planta, con planta y planta más inóculo): 3) tiempo (6 y 12 meses). La aplicación de materia orgánica, la higuera y la micorriza favorecieron la formación de agregados a partir de tepetate y su estabilidad. El pH, la CIC, el contenido de materia orgánica y los cationes intercambiables del tepetate se modificaron favorablemente y permitieron el desarrollo de la higuera. Los cambios en las características físicas y químicas del tepetate por adición de enmiendas, el tiempo y la higuera favorecen su habilitación e incorporación a la productividad

Isolation and selection of rhizospheric bacteria with biofertilizing potential for corn cultivation

 Objective: isolate and determine at the greenhouse level the biofertilizing potential of rhizospheric bacteria associated with corn in the state of Campeche Design/methodology/approach: Rhizospheric soils were collected in zones with different management conditions. Bacterial strain were isolated from these samples and their biofertilizing potential was determined by in vitro and in vivo The data obtained in both tests were analyzed by analysis of variance (ANOVA) and a means comparison test (LSD, p? 0.01). Results: In total 16 rhizospheric bacteria were isolated, a greater number of strains in non-mechanized soils (n=10) compared to mechanized soils (n=6). In in vitro tests, the most representative activity corresponded to nitrogen fixation (81%) attributed to a higher percentage of bacteria, while the activity with a lower number of bacteria corresponded to the production IAA (25%). In in vivo tests in corn plants, theYM1 strain presented the highest fresh and dry root weight (20.00 and 2.00 g plant-1), the YM4 strain the highest height (63.33 cm), and YM5 the highest values in diameter stem (7.13 mm), root lenght (36.78 cm) and fresh weigh of the stem (12.03 g plant-1) Limitations on study/implications: Strain evaluation is limited to controlled greenhouse conditions. Findings/conclusions: The YM1, YM4 and YM5 strains show potential to be evaluated in the future as biofertilizers in the cultivation of corn in the fieldObjective: To isolate and determine in a greenhouse environment the biofertilizingpotential of rhizospheric bacteria associated to corn (Zea mays L.) at Campeche,Mexico.Design / methodology / approach: Rhizospheric soils were collected from twocorn production zones with different management conditions. Bacterial strains wereisolated from these samples and their biofertilizing potential determined by in vitro2 and in vivo tests. The obtained data from both tests were assessed using ananalysis of variance (ANOVA) and a means comparison test (LSD, p ? 0.01).Results: In total, 16 rhizospheric bacteria were isolated, a higher number in non-mechanized soils (n = 10) compared to mechanized ones (n = 6). In the in vitrotests, the most representative activity corresponds to nitrogen fixation (81%)attributed to a higher bacteria percentage, while the activity with lower bacterianumbers corresponds to IAA production (25%). At the in vivo tests in corn plants,the YM1 strain presented the highest fresh and dry root biomass (20 and 2 g plant -1 , respectively). The YM4 strain promoted greater plant height (63.33 cm), and YM5registered the highest values in stem diameter (7.13 mm), root length (36.78 cm)and fresh shoot weight (12.03 g plant -1 ).Limitations / Implications: Strain evaluations were limited to controlledgreenhouse conditions.Conclusion: The YM1, YM4 and YM5 strains show potential for further evaluationas biofertilizers for corn cultivation under field conditions

La microbiología del suelo en la agricultura sostenible

Physical, chemical and biological soil characteristics determine ecosystem and agroecosystem fertility. The role of microbial activity is very important in the kinetics of soil processes such as mineralization and immobilization, as well as other biogeochemical cycles of essential nutrients. The use of beneficial soil microorganisms in agriculture has been increasing, as these organisms directly influence development and plant growth on the agroecosystems. Microorganisms should be considered as basic agroecosystem components in order to reach sustainability, care of natural resources and environmental protection.El suelo, como ente vivo, posee características físicas, químicas y biológicas que definen el grado de fertilidad de ecosistemas y agroecosistemas. Los microorganismos benéficos influyen directamente en el crecimiento y desarrollo de las plantas de un determinado ecosistema o agroecosistema. El manejo de los sistemas agrícolas con un enfoque orgánico y sostenible permite que los microorganismos sean considerados como elementos básicos para lograr la sostenibilidad de los agroecosistemas en pro de las actividades agrícolas y conservación de los recursos naturales y del ambiente

La microbiología del suelo en la agricultura sostenible

Physical, chemical and biological soil characteristics determine ecosystem and agro ecosystem fertility. The role of microbial activity is very important in the kinetics of soil processes such as mineralization and immobilization, as well as other biogeochemical cycles of essential nutrients. The use of beneficial soil microorganisms in agriculture has been increasing, as these organisms directly influence development and plant growth on the agro ecosystems. Microorganisms should be considered as basic agro ecosystem components in order to reach sustainability, care of natural resources and environmental protection. El suelo, como ente vivo, posee características físicas, químicas y biológicas que definen el grado de fertilidad de ecosistemas y agro ecosistemas. Los microorganismos benéficos influyen directamente en el crecimiento y desarrollo de las plantas de un determinado ecosistema o agro ecosistema. El manejo de los sistemas agrícolas con un enfoque orgánico y sostenible permite que los microorganismos sean considerados como elementos básicos para lograr la sostenibilidad de los agros ecosistemas en pro de las actividades agrícolas y conservación de los recursos naturales y del ambiente.

La microbiología del suelo en la agricultura sostenible

El suelo, como ente vivo, posee características físicas, químicas y biológicas que definen el grado de fertilidad de ecosistemas y agroecosistemas. Los microorganismos benéficos influyen directamente en el crecimiento y desarrollo de las plantas de un determinado ecosistema o agroecosistema. El manejo de los sistemas agrícolas con un enfoque orgánico y sostenible permite que los microorganismos sean considerados como elementos básicos para lograr la sostenibilidad de los agroecosistemas en pro de las actividades agrícolas y conservación de los recursos naturales y del ambiente

Soil ecology in suistainable agricultural syatems

Indeks Bibliografi hlm. Setiap bab168 hlm. : il. ; 24 cm

Fitorremediación: Alternativa biotecnológica para recuperar suelos contaminados con DDT. Una revisión

DDT (dichloride diphenyl trichloroethane or 1,1,1-trichloro-2,2-bis-ethane) represent a significant risk for human health. This is since it is associated with diseases such as breast cancer, Alzheimer’s, Parkinson’s, and its accumulation in the blood. The recent findings of the clandestine use of DDT agrochemical make it necessary to implement technologies for the recovery of agricultural soils contaminated with this compound. Phytoremediation is a sustainable technology that uses the potential of plants to remove organic and inorganic contaminants. This technology is improved with the inoculation of rhizospheric microorganisms that mediate the transport of nutrients and even degrade organic compounds such as DDT. This review compiles scientific information related to the study of phytoremediation and microorganism-assisted phytoremediation of sites contaminated by DDT and its metabolites, dichlorodiphenyldichlorethylene (DDE) and dichlorodiphenyldichloroethane (DDD), in the last 10 years. In addition, the most important points that make phytoremediation a strategy for the recovery of soils contaminated with DDT, DDE and DDD are highlighted.El DDT (Dicloro Difenil Tricloroetano o 1,1,1-tricloro-2,2-bis-etano) representa un riesgo importante para la salud humana, debido a que se asocia con enfermedades como cáncer de mama, Alzheimer, Parkinson y su acumulación en sangre. Los recientes hallazgos del uso clandestino del DDT como agroquímico hacen necesaria la implementación de tecnologías de recuperación de suelos agrícolas contaminados con este compuesto. La fitorremediación es una tecnología sustentable, que utiliza el potencial de las plantas para remover contaminantes orgánicos e inorgánicos. Esta tecnología es mejorada con la inoculación de microorganismos rizosféricos que median el transporte de nutrientes y degradan compuestos orgánicos como el DDT. Esta revisión recopila información científica de los últimos diez años sobre: fitorremediación y fitorremediación asistida por microorganismos en sitios contaminados por DDT, y sus metabolitos diclorodifenildicloroetileno (DDE) y diclorodifenildicloroetano (DDD. Además, se resaltan los puntos más importantes que hacen de la fitorremediación una estrategia para la recuperación de suelos contaminados con DDT, DDE y DDD

Influencia de la degradación de los suelos volcánicos mejicanos en la población microbiana

9 páginasTotal and specific micro-organisms were determinated through the serial dilution technique in a topo-sequence of volcanica soils located in the Mexican Neo-volcanic Ridge in order to study the existing relationship between microbial abundance, classified by groups, and the level of degradation of these soils. Microbial population was limited in the most eroded soil, while the better-conserved soils had a high microbial abundance. The month of sampling also influenced on the soil microbiology, appearing the higher values in the month with the highest rainfall (August).Investigación financiada por la Unión Europea a través del Proyecto REVOLSO (Programa INCO, Ref. ICA4-ct-2001-10052).Peer reviewe

Isolation and evaluation of endophytic bacteria from root nodules of Glycine max L. (Merr.) and their potential use as biofertilizers

Aim of study: To isolate and characterize endophytic bacteria inhabiting soybean root nodules collected from two tropical cropping systems in Mexico, and to evaluate the bacterial effects in soybean plants under controlled conditions.Area of study: The study was carried out at two locations (San Antonio Cayal and Nuevo Progreso municipalities) of Campeche State, Mexico.Material and methods: Two experimental stages were performed: 1) isolation, morphological and biochemical characterization, and molecular identification of endophytic bacteria from root-nodules of four soybean varieties grown at field conditions; and 2) evaluation of the effects of endophytic isolates on soybean growth and nodule development, and the effects of bacterial co-inoculation on soybean plants, under controlled conditions.Main results: Twenty-three endophytic bacteria were isolated from root nodules, and identified as Agrobacterium, Bradyrhizobium, Rhizobium, Ensifer, Massilia, Chryseobacterium, Enterobacter, Microbacterium, Serratia, and Xanthomonas. Under controlled conditions, Rhizobium sp. CPO4.13C or Agrobacterium tumefaciens CPO4.15C significantly increased the plant height (46% and 41%, respectively), whereas Bradyrhizobium sp. CPO4.24C promoted the nodule formation (36 nodules/plant). The co-inoculation of B. japonicum USDA110 and Bradyrhizobium sp. CPO4.24C enhanced plant growth, height (33.87 cm), root nodulation (69 nodules/plant) and N-fixation (3.10 µmol C2H4 h-1 plant-1) in comparison to the negative control.Research highlights:  Results suggest that the native Bradyrhizobium sp. CPO4.24C may be used as a biofertilizer directed to developing sustainable soybean cropping at tropical regions