Search results for "soil"
showing 10 items of 3493 documents
Preliminary 1H NMR study on archaeological waterlogged wood.
2005
Magnetic Resonance Relaxation (MRR) and Magnetic Resonance Imaging (MRI) are powerful tools to obtain detailed information on the pore space structure that one is unlikely to obtain in other ways. These techniques are particularly suitable for Cultural Heritage materials, because they use water 1H nuclei as a probe. Interaction with water is one of the main causes of deterioration of materials. Porous structure in wood, for example, favours the penetration of water, which can carry polluting substances and promote mould growth. A particular case is waterlogged wood from underwater discoveries and moist sites; in fact, these finds are very fragile because of chemical, physical and biological…
Organic Fertilization in Traditional Mediterranean Grapevine Orchards Mediates Changes in Soil Microbial Community Structure and Enhances Soil Fertil…
2016
Soil microbial populations and their functions related to nutrient cycling contribute substantially to the regulation of soil fertility and the sustainability of agroecosystems. A field experiment was performed to assess the medium-term effect of a mineral fertilizer and two organic fertilization systems with different nitrogen sources on the soil microbial community biomass, structure, and composition (phospholipid fatty acids, pattern, and abundance), microbial activity (basal respiration, dehydrogenase, protease, urease, β-glucosidase, and total amount of phosphomonoesterase activities), and physical (aggregate stability) and chemical (total organic C, total N, available P and water-solu…
Decomposer communities in contaminated soil: Is altered community regulation a proper tool in ecological risk assessment of toxicants?
1997
Abstract Effects of patchy soil contamination on decomposer organisms, their community regulation and nutrient mineralization were studied in a microcosm experiment. Coniferous forest soil was patchily contaminated with three concentrations of sodiumpentachlorophenate PCP (0, 50 and 500 mg PCP kg−1 of dry soil). Abundance of microbes, enchytraeids, nematodes, small oribatids and predatory mites were reduced by the PCP. Direct toxicity of PCP and lowered microbial biomass seemed to affect animal community composition in the most contaminated patches. Some large oribatids which seemed to be tolerant to PCP increased their numbers in the most contaminated patches. Although predatory mites suff…
Soil animals and ecosystem processes: How much does nutrient cycling explain?
2008
Summary Trophic-dynamic hypotheses have been extensively tested by manipulating the presence of soil animals in experimental laboratory microcosms. Soil animals typically have pronounced effects on microbial populations, nutrient cycling and plant growth. However, because often only the total effect has been reported, the relative importance of feeding interactions versus non-trophic effects remains obscure. Using simple calculations based on mass conservation I argue that the observed faunal effect on microbes and system functioning is often larger than can be explained by trophic dynamics and nutrient cycling. Non-trophic effects may help to explain why microcosm experiments have failed t…
Soil-Water Interactions Unveiled by Fast Field Cycling NMR Relaxometry
2017
Early sowing can boost grain production by reducing weed infestation in organic no‐till wheat
2022
Conservative tillage techniques have several agro-ecological benefits for organic farming. The application of these techniques, however, can create quite a few challenges due to the increased weed competition. Here, we report the results of an organic field experiment in which the responses of wheat and weeds to no tillage (NT) were evaluated compared with conventional tillage (CT). We also tested the hypothesis that, under NT, moving up the sowing date, compared with using the ordinary sowing date for the study area, can result in increased competitiveness of the crop against weeds. Two wheat genotypes, a modern variety and an ancient landrace, were tested.Substantial reductions in grain y…
Re-Clustering tool using an Open-Reference method that improves OTU definition
2019
International audience; 1.Environmental microbial communities are now widely studied using metabarcoding approaches, thanks to the democratization of high‐throughput DNA sequencing technologies. The massive number of reads produced with these technologies requires bioinformatic solutions to be treated. A key step in the analysis is to cluster reads into Operational Taxonomic Units (or OTUs) and thus reduce the amount of data for downstream analyses. Due to the important impact of the clustering method on the quantity and quality of OTUs, finding an equilibrium between the reliability and time‐consuming nature of the chosen strategy is a real challenge. The present article proposes a new pos…
Phenotypic and genotypic characterization of root nodules rhizobia of Medicago littoralis Rhode and Melilotus indicus (L.) All. growing in the Oasis …
2015
Forty rhizobial strains were isolated from root nodules of Medicago littoralis Rhode and Melilotus indicus (L.) harvested from the sandy soils of Touggourt’s oases in the Oued Righ Valley, Algerian Sahara. The isolates were studied for their cultural, biochemical and symbiotic effectiveness. All of them were fast-growing bacteria; utilized a wide range of carbon sources, produced abundant extracellular polysaccharides, tolerated high concentrations of NaCl (up to 2.5 %), grew at temperatures between 28 and 45 °C and at pH values between 4.5 and 9. The isolates were sensitive to the antibiotics kanamycin, tetracycline and rifampicin but showed resistance to neomycin and erythromycin. All the…
The lithium and magnesium isotope signature of olivine dissolution in soil experiments
2021
Abstract This study presents lithium and magnesium isotope ratios of soils and their drainage waters from a well-characterised weathering experiment with two soil cores, one with olivine added to the surface layer, and the other a control core. The experimental design mimics olivine addition to soils for CO2 sequestration and/or crop fertilisation, as well as natural surface addition of reactive minerals such as during volcanic deposition. More generally, this study presents an opportunity to better understand how isotopic fractionation records weathering processes. At the start of the experiment, waters draining both cores have similar Mg isotope composition to the soil exchangeable pool. …