Plant growth drives soil nitrogen cycling and N-related microbial activity through changing root traits

Relationships between plants and nitrogen-related microbes may vary with plant growth. We investigated these dynamic relationships over three months by analyzing plant functional traits (PFT), arbuscular mycorrhizal fungal (AMF) colonization, potential N mineralization (PNM), potential nitrification (PNA) and denitrification activities (PDA) in Dactylis glomerata cultures. D. glomerata recruited AMF during early growth, and thereafter maintained a constant root colonization intensity. This may have permitted high enough plant nutrient acquisition over the three months as to offset reduced soil inorganic N. PFT changed with plant age and declining soil fertility, resulting in higher allocation to root biomass and higher root C:N ratio. Additional to root AMF presence, PR' changes may have favored denitrification over mineralization through changes in soil properties, particularly increasing the quality of the labile carbon soil fraction. Other PFT changes, such as N uptake, modified the plants' ability to compete with bacterial groups involved in N cycling. (C) 2020 Elsevier Ltd and British Mycological Society. All rights reserved.Peer reviewe

Rôles,impacts et services issus des élevages en Europe. Synthèse du rapport d’expertise scientifique collective

L’élevage, secteur majeur pour l’économie de nombreux territoires et structurant beaucoup de paysages ruraux européens, fait l’objet de controverses, depuis au moins une décennie, notamment du fait des dommages environnementaux qu’il engendre. Dans un tel contexte, il est apparu nécessaire d’étayer les débats en faisant le point sur l’état des connaissances scientifiques relatives aux rôles, impacts et services environnementaux, économiques et sociaux issus des élevages européens et leurs produits. Pour ce faire, les ministères français en charge de l’Environnement et de l’Agriculture ainsi que l’Agence de l’environnement et de la maîtrise de l’énergie (Ademe) ont sollicité l’Inra pour réaliser une expertise scientifique collective (ESCo) abordant conjointement les multiples conséquences sur les milieux et le climat, l’emploi et le travail, les marchés et certains enjeux sociaux et culturels, de la production et de la consommation humaine de produits d’origine animale (bovins, ovins, caprins, porcins et avicoles). L’analyse de ces diverses dimensions s’appuie sur les démarches d’évaluation rapportées dans la littérature scientifique internationale. Abordées, dans un premier temps, de manière analytique et globale, les connaissances ont ensuite été mobilisées par « bouquet de services » au sein de territoires contrastés. Les relations entre les différents impacts ou services permettent d’identifier des compromis et des leviers d’action envisageables pour les systèmes d’élevage. Livestock production is a sector of major economic importance that defines many European rural areas. It has become the focus of controversy over the past decade or more, particularly with regard to the environmental impacts it causes. In this context, it seemed useful to support this debate with a critical review of the state of scientific knowledge on the role, impacts, and services – environmental, economic, and social – associated with European livestock production. Accordingly, the French ministries responsible for Agriculture and the Environment, in cooperation with the French Environment and Energy Management Agency (ADEME), requested INRA to undertake a collective scientific assessment addressing the many consequences – for the environment and the climate, for employment and labor, for markets, and for a variety of social and cultural issues – related to the production and human consumption of animal products (cattle, sheep, goats, pigs, and poultry). Analysis of these diverse dimensions was based on assessment methods utilized and described in the international scientific literature. Using a broad, analytical overview as a starting point, the review proceeded by identifying the "service bundles" associated with livestock production in contrasting areas

Quand l’élevage est garant de la conservation de milieux patrimoniaux

International audienc

Plant trait to fodder quality relationships at both species and community levels in wet grasslands

International audienceWet grasslands are now widely recognized as providing many ecosystem services. Wet grasslands are still endangered by both conversion to improved grasslands or crops, and abandonment due to the difficulties associated with exploiting such constrained lands. This paper focuses on forage quality, which is one of the most poorly studied provisioning services of wet grasslands. We tested if the relationship between functional traits (Specific Leaf Area (SLA), Leaf Dry Matter Content (LDMC) and Leaf Nitrogen Content (LNC)) and forage quality established for mesophilic grasslands are valid for wet grasslands. This study was conducted both at the species (44 grassland species) and the community scale. Besides evaluation of both the grassland species and the plant community fodder values for cattle feeding, our aim was to look for proxies of fodder quality through plant functional traits. Pepsin cellulase digestibility (dC) and crude protein content (CP), two uncorrelated indices, were chosen to estimate species fodder quality. At the species scale, SLA seems to be the best trait to estimate dC for forbs, sedges and rushes, while LDMC seems more pertinent for grasses. When considering communities, the weighted mean dC, estimated by these two leaf traits according to the species functional group, constitutes an interesting proxy. CP seemed more linked to LNC. This trait allows an estimation of CP at the species scale but is much less relevant at the community scale

The bouquets of ecosystem services rendered by permanent hay meadows

Permanent grasslands produce high-quality forage and host very diverse plant communities. They also play a key role in carbon storage. However, we still understand little about how pedoclimatic conditions and plant community management or functioning help generate ecosystem services. This study analysed 32 grasslands in Normandy, Lorraine, and Auvergne that offer different ecosystem services. Certain grasslands had high values for service indicators. However, no synergies among services were observed, which suggests that determinant factors were different. A functional traits approach showed that plant community functioning directly affected forage quality. Plant diversity was tied to agricultural management and is also likely related to grassland history and landscape structure. Carbon storage levels were related to the clay content of soils