Artículos y presentaciones en Congresos
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Examinando Artículos y presentaciones en Congresos por Autor "Ambrosino, Mariela Lis"
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Acceso Abierto Communities of arbuscular mycorrhizal fungi associated with perennial grasses of different forage quality exposed to defoliation(Elsevier, 2018) Ambrosino, Mariela Lis; Cabello, Marta Noemí; Busso, Carlos Alberto; Velázquez, María Silvana; Torres, Yanina Alejandra; Cardillo, Daniela Solange; Ithurrart, Leticia Soledad; Montenegro, Oscar Alberto; Giorgetti, Hugo; Rodriguez, GustavoVegetation management practices, such as defoliation may alter the composition of plant communities and/or the fungi-forming arbuscular mycorrhiza (AMF). We determined the species identity, density, frequency and diversity of AMF spores from soil under the canopies of three native perennial grass species in rangelands of Argentina: 1) Poa ligularis and Nassella tenuis (preferred by livestock) and 2) Amelichloa ambigua (not preferred). For each species, plants either remained undefoliated or were defoliated twice to a 5 cm stubble height during the growing season. Most active meristems remained on the plants after defoliations. AMF communities were sampled prior to (i.e., 48 soil samples) and following (i.e., 72 soil samples) each defoliation event. Spores were grouped in 15 morphospecies. Density, richness and diversity of AMF spores were not influenced by defoliation, and species richness and diversity of AMF were similar among species. Total spore density was greatest for P. ligularis at the sampling prior to defoliation, but this difference did not persist following the defoliation events. The most abundant AMF families were: Acaulosporaceae, Diversisporaceae and Glomeraceae. These results demonstrate that responses of the studied variables were insensitive to the defoliation treatments, and were largely unaffected by the studied grass species. - Artículo
Acceso Abierto Impacts of shrubs on soil quality in the native Monte rangelands of Southwestern Buenos Aires, Argentina(2023) Ambrosino, Mariela Lis; Torres, Yanina Alejandra; Lucero, Cinthia Tamara; Lorda, Graciela Susana; Ithurrart, Leticia Soledad; Martínez, Juan Manuel; Armando, Lorena Vanesa; Garayalde, Antonio; Busso, Carlos AlbertoShrub cover in semiarid rangelands may induce changes in soil resources and ecosystem functioning. However, it is unknown the real influence that shrub vegetation has on soil quality in rangelands used for livestock purposes. We evaluated the shrub cover effect on 12 chemical and biochemical parameters of soil quality. In a semiarid Monte rangeland of Argentina, 6 paddocks were selected and 10 m transects were placed in a patch with (Sh) and without shrubs (WSh). Then, sites with grasses (Sh-G and WSh-G), bare ground-litter (Sh-BL and WSh-BL), and under shrub cover (Sh-S) were selected. In spring 2017 and 2018, a composite soil sample (0–10 cm in depth) was taken at each site (n = 6). Sh-G and Sh-S sites presented high values of soil organic matter, soil organic nitrogen, particulate organic matter (POM), and cellulase activity (CA); WSh-BL and Sh-BL sites were associated with the lowest contents of these variables. For the rest of the soil quality parameters, the soil sampling sites showed similar values. These results show that woody presence should not be directly linked to soil quality loss. Although we did not detect a shrub effect in all parameters studied, in the context of appropriate grazing management, the presence of plant species of different functional groups has a positive effect on organic matter and N content of soil close to them. Moreover, in these sites, high POM values represent an important reservoir of potentially available nutrients, and promote CA necessary for fresh litter decomposition improving the soil quality of semiarid rangelands. - Comunicacion
Acceso Abierto Plant Species and Defoliation Efects on Soil Nitrogen Mineralization in a Semiarid Rangeland of Argentina(2021) Ambrosino, Mariela Lis; Martínez, Juan Manue; Busso, Carlos; Minoldo, Gabriela; Torres, Yanina Alejandra; Ithurrart, Leticia Soledad; Cardillo, Daniela SolangeThe objective of this study was to evaluate the efects of moderate defoliation and grass species on soil nitrogen (N) mineralization in a semiarid grassland of northeastern Patagonia, Argentina. Studied species were Poa ligularis and Nassella tenuis (desirable/preferred by cattle) and Amelichloa ambigua (undesirable/non preferred). Two defoliations were made to a 5 cm stubble height during the growing season. Hypotheses were that (1) net N mineralization and N availability in the soil are increased by a moderate defoliation and greater species forage quality, and (2) potential N mineralization is higher in the soil beneath the desirable than undesirable species. In 2013 and 2014, in situ net N mineralization was estimated using the tube incubation technique under feld conditions. Potential N mineralization was estimated by long-term laboratory incubations. Defoliation treatments did not afect the soil inorganic N dynamics. The soil under A. ambigua showed a greater in situ net N mineralization than other species, but only in 2013. Poa ligularis presented the highest initial inorganic N and potentially mineralizable N values. However, the opposite was recorded in this specie for the mineralization constant rate. These results demonstrated that moderate defoliations did not afect soil N availability, and presence of the desirable perennial grasses increased the potential N mineralization pool. Sustainable management practices that promote the persistence of these species in plant community are important to maintain soil fertility on semiarid grasslands. - Artículo
Acceso Abierto Soil microbial structure and activity in a semiarid rangeland of Patagonia, Argentina: Plant species and defoliation effects(2021) Ambrosino, Mariela Lis; Montecchia, Marcela Susana; Torres, Yanina Alejandra; Ithurrart, Leticia Soledad; Lucero, Cinthia Tamara; Busso, Carlos AlbertoNatural grasslands are an important renewable resource for livestock production. Grazing in these areas alters the plant community composition, litter quality, and soil microbial structure and activity. Three cool-season species were studied in a semiarid rangeland area of Argentina: Poa ligularis and Nassella tenuis (desirable/ preferred for livestock) and Amelichloa ambigua (undesirable/non preferred). The objective was to analyze the effect of moderate defoliation and plant species on the structure and activity of soil microbial communities associated with their roots. In winter 2012, soil samples (0–10 cm) were taken underneath marked plant canopies of the three species (n = 8). Immediately thereafter, half of the plants (n = 4) were defoliated (5 cm stubble height) and the other half remained undefoliated (controls). The defoliation treatment was conducted again in the spring. Soil samples were taken 30 days after each defoliation event. The study was repeated in 2013, using a different plant set. Bacterial community structure and soil microbial activity were analyzed using PCR-DGGE analysis and basal soil respiration, respectively. Moderate and early defoliations allowed compensatory growth in the defoliated plants. Variations in the soil genetic profiles of A. ambigua suggest a higher dependence on its rhizospheric bacterial communities. Defoliation treatments did not substantially affect basal soil respiration but showed strong links between desirable species and soil microbial activity. Sustainable management practices that promote the persistence of these species are important for the development of microbial communities that respond quickly to stress conditions, favoring decomposition processes that maintain soil fertility in semiarid grasslands.