Search results for "nitrate"
showing 10 items of 580 documents
Differential Responses of Nitrate Reducer Community Size, Structure, and Activity to Tillage Systems
2009
ABSTRACT The main objective of this study was to determine how the size, structure, and activity of the nitrate reducer community were affected by adoption of a conservative tillage system as an alternative to conventional tillage. The experimental field, established in Madagascar in 1991, consists of plots subjected to conventional tillage or direct-seeding mulch-based cropping systems (DM), both amended with three different fertilization regimes. Comparisons of size, structure, and activity of the nitrate reducer community in samples collected from the top layer in 2005 and 2006 revealed that all characteristics of this functional community were affected by the tillage system, with increa…
Reduction of nitrate leaching: what is the contribution of the residual weed flora?
2018
International audience; Integrated crop protection tolerates residual weeds if they are not harmful for crop production. Weeds are often solely considered as a pest, causing crop yield loss, harvest pollution, diseases … However, they may also provide beneficial services for agroecosystems, promoting plant biodiversity and feeding other organisms potentially beneficial to crop production (pollinators, carabids…). The role of residual weed flora as nitrate catchers, during summer fallow, has however rarely been assessed. Yet, some weed species are known for their high potential to take up soil nitrogen. The present study aimed to (1) develop an indicator to account for the potential benefici…
Caractérisation de la dynamique de l'eau et des intrants à la parcelle: comparaison de dispositifs
2017
Notre système d’agriculture intensif cause une pollution accrue des eaux souterraines par lixiviationdes traitements appliqués sur les parcelles. Notamment l’utilisation des engrais azotés est, depuis 65 ans, enconstante augmentation. Cependant, cet azote rejoint les nappes phréatiques, rendant l’eau impropre à laconsommation. Le diagnostic de cette pollution azotée est donc un enjeu majeur de santé publique et est lié àdes conséquences économiques importantes car une nappe polluée devra être traitée et une autre nappeservira à la consommation, ce qui demande de nouvelles installations. Des instruments ont été créés pourprélever l’eau qui lixivie sous les parcelles agricoles afin d’analyser…
Characterization and role of nitric oxide production in Arabidopsis thaliana defense responses induced by oligogalacturonides
2011
Nitric oxide (NO) regulates a wide range of plant processes from development toenvironmental adaptation. In this study, NO production and its effects were investigated in aplant-pathogen context. The production of NO following Arabidopsis treatment witholigogalacturonides (OGs), an endogenous elicitor of plant defense, was assessed using the NOsensitive probe 4, 5-diamino fluorescein diacetate. Pharmacological and genetic approaches wereused to analyze NO enzymatic sources and its role in the Arabidopsis thaliana /Botrytis cinereainteraction. We showed that NO production involves both a L-arginine- and a nitrate reductase(NR)-pathways. OGs-induced NO production was Ca2+-dependent and modula…
Change in nitrate reducer community structure in wheat residue amended soil revealed by stable isotope probing
2007
Relative abundance of the membrane bound and periplasmic nitrate reductase in the environment
2007
Traking nitrate reducers and denitrifiers in the environment
2005
The ability to respire nitrate when oxygen is limited has been described in taxonomically diverse microorganisms including members of the alpha-, beta-, gamma- and epsilon-proteobacteria, high and low GC Gram-positive bacteria and even Archaea. Respiratory nitrate reduction is the first step of the denitrification pathway, which is important since it is the main biological process responsible for the return of fixed nitrogen to the atmosphere, thus completing the nitrogen cycle. During the last decade, considerable knowledge has been accumulated on the biochemistry and genetics of the nitrate reductases. In this paper, we summarize the recent progress in molecular approaches for studying th…
Impact of fertilization, tillage and direct seeding on nitrate reducers in Madagascar
2007
Dans quels systèmes de culture les adventices résiduelles peuvent-elles réduire la lixiviation du nitrate et l’érosion des sols ?
2019
National audience; Si les adventices sont un bioagresseur majeur des cultures, elles peuvent également fournir des services bénéfiques pour les agroécosystèmes. Cette étude, basée sur l’utilisation d’un modèle de simulation, vise à identifier les déterminants de deux bénéfices environnementaux dus aux adventives. Les résultats montrent que la contribution de la flore adventice résiduelle pour réduire la lixiviation du nitrate et l’érosion des sols sont davantage influencés par les techniques culturales, que par les caractéristiques biologiques des espèces adventices. Le travail du sol et la rotation des cultures sont les techniques culturales les plus influentes. Cette étude identifie quelq…
Signalisation moléculaire des réponses immunes chez la plante Medicago truncatula - Rôle de la nutrition
2014
Rapport de stage de Master II R SPE IPM CT1; Master