Efecto de las prácticas agrícolas sobre las poblaciones bacterianas del suelo en sistemas de cultivo en Chihuahua, México (original) (raw)

Seasonal Changes in a Maize-Based Polyculture of Central Mexico Reshape the Co-occurrence Networks of Soil Bacterial Communities

Frontiers in microbiology, 2017

The milpa is a traditional maize-based polyculture in Mexico that is typically practiced as rainfed agriculture. Because milpa cultivation has been practiced over a vast range of environmental and cultural conditions, this agroecosystem is recognized as an important repository of biological and cultural diversity. As for any agroecosystem, the relationship between plant development and the biogeochemical processes of the soil is critical. Although the milpa has been studied from different perspectives, the diversity and structure of microbial communities within milpa soils remain largely unexplored. In this study, we surveyed a milpa system in Central Mexico across cropping season: before planting (dry season; ), during the early growth of plants (onset of the rainy season; ), and before harvest (end of the rainy season; ). In order to examine changes in community structure through time, we characterized bacterial diversity through high-throughput sequencing of 16S rRNA gene amplico...

Effect of microbial consortia on maize yield in Chiapas, Mexico

Rev. Fac. Agron. (LUZ), 2023

The use of microbial consortia as biofertilizers allows improving crop productivity and the quality of agricultural soils, by incorporating microorganisms that facilitate the availability of nutrients for plants and change the soil physicochemical conditions. In order to evaluate the effect of microbial consortia on maize yield, inoculums from different environments were used in the maize crop of Villa Corzo and Villaflores municipalities, Chiapas. Six treatments with different consortia were defined: three from agricultural plots and three from mountains "La Frailescana", "Cerro Nambiyugua" and Biosphere Reserve "La Sepultura"-, and one control, under a randomized block experimental design with four replications. The application of the microbial consortia was made directly to the soil at 20, 40 and 60 days after sowing of the crop. The effect of the consortia on maize yield was determined using a design with nested effects in which the effects of the origin of the microbial consortia were controlled, and the nested treatments in the environments. The association between the physicochemical components of the consortia and the culture yield was evaluated using Pearson's correlation (p ≤ 0.05). Only the mountain consortiums from "La Sepultura" were the ones that showed maize yield increase. However, both the mountain and plot consortiums have the potential to be used as biofertilizers in maize cultivation, when combined with another source of organic fertilization, such as poultry manure. This scientific publication in digital format is a continuation of the Printed Review: Legal Deposit pp 196802ZU42,

Multivariate approach to characterizing soil microbial communities in pristine and agricultural sites in Northwest Argentina

Applied Soil Ecology, 2011

Land use effects on microbial communities may have profound impacts on agricultural productivity and ecosystem sustainability as they are critical in soil quality and health. The main aim of this study was to characterize the microbial communities of pristine and agricultural soils in the central Yungas region in Northwest Argentina. As a first step in the development of biological indicators of soil quality in this region, a comprehensive approach involving a structural and functional evaluation of microbial communities was used to detect changes in soil as consequence of land use. The sites selected included two pristine montane forest sites (MF1 and MF2), two plots under sugarcane monoculture for 40 and 100 years (SC40 and SC100), one plot under 20 years of soybean monoculture (SB20), a recently deforested and soybean cropped site (RC), and two reference sites of native forest adjacent to the sugarcane and soybean plots (PF1 and PF2). We used three microbial community profiling methods: denaturing gradient gel electrophoresis (DGGE) analysis of PCR amplified 16S rRNA genes, community-level physiological profiling (CLPP) using a BD oxygen biosensor system (BDOBS-CLPP) and phospholipid fatty acid (PLFA) analysis. Deforestation and agriculture caused expected increases in pH and decreases in organic carbon and microbial biomass. Additionally, shifts in the microbial community structure and physiology were detected with disturbance, including reduced diversity based on PLFA data. The higher respiratory response to several carbon substrates observed in agricultural soils suggested the presence of microbial communities with lower growth yield efficiency that could further reduce carbon storage in these soils.

Drylands soil bacterial community is affected by land use change and different irrigation practices in the Mezquital Valley, Mexico

Scientific reports, 2018

Dryland agriculture nourishes one third of global population, although crop irrigation is often mandatory. As freshwater sources are scarce, treated and untreated wastewater is increasingly used for irrigation. Here, we investigated how the transformation of semiarid shrubland into rainfed farming or irrigated agriculture with freshwater, dam-stored or untreated wastewater affects the total (DNA-based) and active (RNA-based) soil bacterial community composition, diversity, and functionality. To do this we collected soil samples during the dry and rainy seasons and isolated DNA and RNA. Soil moisture, sodium content and pH were the strongest drivers of the bacterial community composition. We found lineage-specific adaptations to drought and sodium content in specific land use systems. Predicted functionality profiles revealed gene abundances involved in nitrogen, carbon and phosphorous cycles differed among land use systems and season. Freshwater irrigated bacterial community is taxo...

Soil and Rhizosphere Bacterial Diversity in Maize Agro- Ecosystem

Sustainable Agriculture Research

Management practices used in maize production have an impact on soil agro- ecosystems where different microbial communities coexist. Soil inhabiting bacteria are numerous and diverse, but we know very little about their ecological distribution. Here we analyzed the bacterial community diversity in the rhizosphere of two transgenic maize cultivars, in agricultural soil before sowing and in non-cultivated soil in an experimental site in the south region of Uruguay. We followed two culture-independent methods: DGGE (denaturing gradient gel electrophoresis) and 454-pyrosequencing of 16S rRNA gene amplicon. Through pyrosequencing, the three environments analyzed presented differences in terms of bacterial composition. However, no differences were found in the relative abundance of the ten most represented phyla in the rhizosphere of the two cultivars at different phenological stages. We found significant differences of Bacteroidetes, Gemmatimonadetes, Planctomycetes, Proteobacteria and V...

Search of environmental descriptors to explain the variability of the bacterial diversity from maize rhizospheres across a regional scale

European Journal of Soil Biology, 2009

The regional scale variability of the bacterial community inhabiting the rhizosphere was studied with soil collected from maize fields located in the Santo Domingo Valley (SDV; Baja California Sur, Mexico), a semi-arid agricultural ecosystem of approximately 200 km 2 . The bacterial community structure was visualized by single-strand conformation polymorphism (SSCP) profiles of PCR-amplified partial 16S rRNA genes of directly extracted rhizosphere soil DNA. SSCP profiles of different SDV sites and an external field site in Germany were evaluated for their similarities and the contributing bacteria were characterized by DNA sequence analyses. SSCP profiles from each site were significantly different from the others, as revealed by permutation of pairwise similarities (P < 0.05). In comparison to the German site, SSCP profiles from SDV were more similar to each other despite contrasting soil salinity levels. Correspondence analysis revealed that among SDV sites, salinity levels, soil organic carbon and calcium (Ca 2þ ) were most influential on the bacterial community structure. Depending on the phylogenetic group analyzed (Bacteria, Alphaproteobacteria, Pseudomonas), the importance of these soil variables varied. Interestingly, the East-West direction also revealed an effect, suggesting that future explorations of bacterial diversity patterns should also consider landscape topography in search of explaining patterns of bacterial diversity in soils.

Bioinformatic study of the soil microbiome under different cropping systems

2022

The presentation of this doctoral thesis is made under "publication compendium mode", in accordance with Article 20 of the Regulation of Official Doctorates Studies of the Polytechnic University of Cartagena of March 24, 2022. The papers have been published in open access with the express authorization of director and co-directors of the present thesis. The papers were prepared and published after the beginning of the doctoral studies and its references are listed below:

Soil and plant effects on microbial community structure

Canadian Journal of Microbiology, 2002

We investigated the effects of two different plant species (corn and soybean) and three different soil types on microbial community structure in the rhizosphere. Our working hypothesis was that the rhizosphere effect would be strongest on fast-growing aerobic heterotrophs, while there would be little or no rhizosphere effect on oligotrophic and other slow-growing microorganisms. Culturable bacteria and fungi had larger population densities in the rhizosphere than in bulk soil. Communities were characterized by soil fatty acid analysis and by substrate utilization assays for bacteria and fungi. Fatty acid analysis revealed a very strong soil effect but little plant effect on the microbial community, indicating that the overall microbial community structure was not affected by the rhizosphere. There was a strong rhizosphere effect detected by the substrate utilization assay for fast-growing aerobic heterotrophic bacterial community structure, with soil controls and rhizosphere samples...