Search results for "Soil"
showing 10 items of 3493 documents
Agricultural advances
2013
CT3 ; Département E.A. ; SOFIA; Agricultural advances
Carbon storage in soils by ancient and modern wheat varieties
2022
Les émissions anthropiques de gaz à effet de serre sont le principal moteur du changement climatique. Le plan Climat, issu de la COP 21 tenue à Paris en 2015, vise à atteindre la neutralité carbone à l'horizon 2050. Pour atteindre cette neutralité carbone, les gaz à effet de serre doivent d'abord être stabilisés, puis fortement réduits au cours du siècle prochain. Dans cette dynamique, l'initiative « 4 pour 1000 » fixe comme objectif d'atteindre un taux de croissance annuel du stock de carbone dans les sols de 0,4% par an. Ce stockage additionnel devrait compenser les émissions de CO2 dans l'atmosphère liée aux activités humaines. Les sols agricoles sont identifiés comme un compartiment de …
Study and modelling of the impacts of agricultural practices on the abundance of soil microbial communities: dynamics at the landscape scale
2022
Soil Microbial communities play a major role in soil fertility and are important as bioindicators to evaluate the impacts of agricultural practices on soils. The challenge is to promote their use in order to support / accelerate innovation in the agricultural sector. The goal of this thesis was to characterize spatial and temporal dynamics of soil microbialcommunities at the scale of an agricultural landscape in order to create models and propose a Decision Support Instrument (DSI) for stakeholders in the agricultural communities. For this, a multi-disciplinary approach was used combining microbial ecology, environment assessment, spatial computer modeling, associated to a participatory app…
Evidence of atrazine mineralization in a soil from the Nile Delta: Isolation of Arthrobacter sp. TES6, an atrazine-degrading strain
2011
International audience; The s-triazine herbicide atrazine was rapidly mineralized (i.e., about 60% of C-14-ring-labelled atrazine released as (CO2)-C-14 within 21 days) by an agricultural soil from the Nile Delta (Egypt) that had been cropped with corn and periodically treated with this herbicide. Seven strains able to degrade atrazine were isolated by enrichment cultures of this soil. DNA fingerprint and phylogenetic studies based on 165 rRNA analysis showed that the seven strains were identical and belonged to the phylogeny of the genus Arthrobacter (99% similarity with Arthrobacter sp. AD38, EU710554). One strain, designated Arthrobacter sp. strain TES6, degraded atrazine and mineralized…
Copper binding capacity of root exudates of cultivated plants and associated weeds
2001
International audience; Cu binding to root exudates of two cultivated plants, wheat (Triticum aestivum) and rape (Brassica napus), and two weeds associated with wheat, dog daisy (Matricaria inodora) and cornflower (Centaurea cyanus), was studied in vitro under hydroponic and sterile conditions. Nutrient solutions were prepared with or without P. A MetPLATE microbiological test was used to assess the metal complexing capacity of root exudates. In the P-deficient solutions, no exudation was observed for any of the four plants; consequently, no Cu binding occurred. When P was present in the nutrient solutions, the plant exudates displayed differing abilities to complex Cu. No difference was de…
Diversity and complexity of microbial communities from a chlor-alkali tailings dump
2015
Abstract Revegetation of the tailings dumps produced by various industrial activities is necessary to prevent dust storms and erosion and represents a great challenge for ecological restoration. Little is known about the microbial colonisation and community structure of revegetated tailings following site exploitation. Here, we report the sequencing of 16S rRNA and internal transcribed spacer (ITS) fungal RNA gene amplicons from chlor-alkali residue and from an adjacent undisturbed soil to define the composition and assembly of the rhizosphere microbial communities. After quality filtering, a total of 72,373 and 89,929 bacterial sequences and 122,618 and 111,209 fungal sequences remained fo…
Impact of a new bio-pesticide produced by Paenibacillus sp. strain B2 on the genetic structure and density of soil bacterial communities
2007
The effect of paenimyxin, a new biopesticide produced by Paenibacillus sp. strain B2, on the density of soil bacterial communities was assessed by colony counting and by 16S rDNA and nirK quantitative polymerase chain reaction (PCR). Paenimyxin had a negative effect on the bacterial colony-forming unit (CFU) number, which was significantly reduced 2 and 4 days after treatment. The effect of paenimyxin on cultivatable bacteria was negligible 7 days after treatment. Approximately 107 16S rDNA sequences per gram of soil (dry weight) were detected by quantitative PCR in all samples. Paenimyxin did not affect the quantification of 16S rDNA or of the denitrifying bacterial community. In addition,…
Spatial distribution of ammonia-oxidizing bacteria and archaea across a 44-hectare farm related to ecosystem functioning
2011
Characterization of spatial patterns of functional microbial communities could facilitate the understanding of the relationships between the ecology of microbial communities, the biogeochemical processes they perform and the corresponding ecosystem functions. Because of the important role the ammonia-oxidizing bacteria (AOB) and archaea (AOA) have in nitrogen cycling and nitrate leaching, we explored the spatial distribution of their activity, abundance and community composition across a 44-ha large farm divided into an organic and an integrated farming system. The spatial patterns were mapped by geostatistical modeling and correlations to soil properties and ecosystem functioning in terms …
The Largest Subunit of RNA Polymerase II as a New Marker Gene to Study Assemblages of Arbuscular Mycorrhizal Fungi in the Field
2014
Due to the potential of arbuscular mycorrhizal fungi (AMF, Glomeromycota) to improve plant growth and soil quality, the influence of agricultural practice on their diversity continues to be an important research question. Up to now studies of community diversity in AMF have exclusively been based on nuclear ribosomal gene regions, which in AMF show high intra-organism polymorphism, seriously complicating interpretation of these data. We designed specific PCR primers for 454 sequencing of a region of the largest subunit of RNA polymerase II gene, and established a new reference dataset comprising all major AMF lineages. This gene is known to be monomorphic within fungal isolates but shows an…
Protection de la ressource en eau du bassin de l’Auxerrois et transformation des pratiques agricoles
2022
Avec des taux de nitrates dépassant les seuils définis par la Directive européenne « nitrates », puis la présence de résidus de pesticides utilisés par les activités agricoles du secteur, l’eau des bassins d’alimentation de captages de l’Auxerrois fait l’objet de préoccupations depuis une trentaine d’année. C’est ainsi qu’à la fin des années 1990, les représentants des pouvoirs publics ont choisi de mettre en place une démarche préventive passant par un travail de transformation des pratiques agricoles. Notre article analyse comment la prise en charge collective de cette situation participe à la configuration des relations entre représentants des pouvoirs publics, agriculteurs et défenseurs…