Evidence of the role of earthworms in the regeneration of compacted soils under field conditions

At the INRA Estrées-Mons experimental site, the possible role of earthworm in the regeneration of compacted soils was studied in a reduced tillage plot where a compaction event was done using a 8-tons tractor on a wet soil. Earthworm communities and earthworm burrow systems were then studied either 2 weeks after or 8 or 24 months after the compaction in the control or compacted zone. Earthworms were observed to recolonise the compacted zone in less than 8 months whereas the regeneration of earthworm burrows was a slower process under field conditions

Performance of innovative cropping systems diversified with oilseeds and protein crops: identification and resolution of methodological issues, using the Syppre experimental network as a case study☆

Agroecological transition requires that innovative and diversified cropping systems be developed. Conducting system experiments is an approach well-suited to the analysis of performance of cropping systems when subjected to soil, weather and biotic stresses. Conducting system experiments nevertheless gives rise to methodological challenges. Using the Syppre network of experiments, consisting of five sites in France, we present an original case study that provides valuable methodological and agronomic lessons on system experiments. The innovative cropping systems tested there are based on crop diversification (including oilseeds and protein crops), as well as flexible tillage, technical innovations and optimized crop management. From a methodological standpoint, we show that (i) mixed models are adapted to a range of experimental questions and constraints; (ii) multifactorial analysis enables the characterization of relationships between performance indicators; (iii) a multisite experimental network is an efficient approach not only for answering agronomic questions, but also for addressing methodological issues. From an agronomic standpoint, we showed that reconciling multiple indicators of performance is still challenging. Overall, innovative and diversified systems improved the performance of input utilization and environmental impacts, but with lower productivity and profitability. Introducing legume crops is a promising strategy because this contributes significantly to reductions in mineral N fertilizer use, energy consumption and greenhouse gas emissions, without major trade-offs against other performance indicators. Finally, we showed that the nature of the production situation had a major influence on the performance profile. This led us to be cautious in making overall analyses especially with regard to general conclusions

The large area detector onboard the eXTP mission

The Large Area Detector (LAD) is the high-throughput, spectral-timing instrument onboard the eXTP mission, a flagship mission of the Chinese Academy of Sciences and the China National Space Administration, with a large European participation coordinated by Italy and Spain. The eXTP mission is currently performing its phase B study, with a target launch at the end-2027. The eXTP scientific payload includes four instruments (SFA, PFA, LAD and WFM) offering unprecedented simultaneous wide-band X-ray timing and polarimetry sensitivity. The LAD instrument is based on the design originally proposed for the LOFT mission. It envisages a deployed 3.2 m2 effective area in the 2-30 keV energy range, achieved through the technology of the large-area Silicon Drift Detectors - offering a spectral resolution of up to 200 eV FWHM at 6 keV - and of capillary plate collimators - limiting the field of view to about 1 degree. In this paper we will provide an overview of the LAD instrument design, its current status of development and anticipated performance

The Large Observatory For X-ray Timing: LOFT

LOFT, the Large Observatory for X-ray Timing, is a new space mission concept devoted to observations of Galactic and extra-Galactic sources in the X-ray domain with the main goals of probing gravity theory in the very strong field environment of black holes and other compact objects, and investigating the state of matter at supra-nuclear densities in neutron stars. The instruments on-board LOFT, the Large area detector and the Wide Field Monitor combine for the first time an unprecedented large effective area (~10 m2 at 8 keV) sensitive to X-ray photons mainly in the 2-30 keV energy range and a spectral resolution approaching that of CCD-based telescopes (down to 200 eV at 6 keV). LOFT is currently competing for a launch of opportunity in 2022 together with the other M3 mission candidates of the ESA Cosmic Vision Progra

Système d'Information Agrosyst

Agrosyst est un système d'information développé par l'Inra pour les besoins du réseau DEPHY dans le cadre du plan gouvernemental Ecophyto. Son objectif est de capitaliser et de permettre la valorisation des données sur les systèmes de culture économes en pesticides issues du réseau national DEPHY, composé de 2000 fermes et de 180 sites expérimentaux

Polymorphic microsatellites in Simulium damnosum s.l. and their use for differentiating two savannah populations : implications for epidemiological studies

En Afrique de l'Ouest, #Onchocerca volvulus, l'agent responsable de l'onchocercose chez l'homme, est transmis par des espèces du complexe #Simulium damnosum. La variabilité intra-spécifique et ses conséquences sur la capacité vectorielle ont été peu étudiées. Cette étude décrit l'utilisation des marqueurs microsatellites pour différencier des populations de #S. damnosum$ s.l. Cinq loci microsatellites ont été caractérisés et utilisés pour caractériser des individus de deux populations savanicoles du Mali, distantes de 120 km. Quatre loci se sont révélés très polymorphes avec 8-12 allèles par locus et des diversités géniques variant de 77,9 à 88,2%. Un déficit en hétérozygotes significatif a été observé dans les deux populations. Ce déficit peut être expliqué par la consanguinité, la structuration des populations (l'effet Walhund) ou par la présence d'allèles nuls. Pour tester cette dernière hypothèse, de nouvelles amorces ont été désignées pour deux loci et utilisées pour analyser les individus homozygotes. Malgré cette correction des allèles nuls, le déficit en hétérozygotes persiste. La subdivision des populations dans les deux foyers reste l'explication la plus probable. Nos résultats montrent que les marqueurs microsatellites peuvent différencier des populations de simulies, ce qui en fait des outils de choix pour l'étude de la structure génétique des populations. (Résumé d'auteur

Assessment of the benefits of frost-sensitive companion plants in winter rapeseed

International audienceThe intercropping of rapeseed with frost-sensitive companion plants (CP) has recently been proposed as a way to mitigate the negative environmental impact of rapeseed crops. Using mixed-effect linear models, we compared the yield and weed amounts of rapeseed intercropped with different CP species with that of rapeseed as a sole crop in an unique dataset of 79 field experiments covering a wide range of climate, soil and practices conditions in the northwestern part of France, from 2009 to 2015. Bayesian model averaging procedure was used to determine the relative contributions of sites characteristics to the effects of intercropping.& para;& para;Before winter, field pea and faba bean had accumulated the largest amounts of dry mass, with more than 100 g m(-2). Rapeseed biomass was reduced by 56% by non-legume CPs and by only 18% by legume CPs, the largest decrease being caused by pea. Non-legumes decreased the nitrogen nutrition index of rapeseed by 7%, whereas pea and faba bean increased this index by 6% and 3%, respectively. Intercropping with non-legume and legume CPs reduced weed amounts by 52% and 38% respectively, with no difference between CP species. Non legume CPs decreased rapeseed yield at harvest by 0.581 ha(-1), whereas faba bean and faba bean + lentil in creased yield by 0.16 and 0.12 t ha(-1) respectively, when fertilized at the recommended rate. Intercropping with faba bean, lentil or a mixture of both made it possible to reduce nitrogen applications by 30-40 kg ha(-1) with no significant decrease in rapeseed yield. Faba bean and faba bean + lentil mixtures had the best overall performance. This work suggests that intercropping rapeseed is promising, particularly in soils with low nitrogen content with an early sowing date in the late summer

Les systèmes d'information en appui à la connaissance et la diffusion des systèmes de culture économes en pesticides : l'exemple du système d'information Agrosyst du réseau de fermes et d'expérimentations du plan Ecophyto

National audienc

Demonstration of the role of earthworms on the removal of highly compacted zones in field conditions

National audienceBy their excavation activities, earthworms are thought to contribute to the removal of highly compacted zones (“delta” zones) but the quantitative measurements of their impact is lacking. A first experiment was carried out in semi-field conditions (caging experiment). Adult earthworm from the most common species (Lumbricus terrestris, Aporrectodea giardi, A. caliginosa and A. rosea) were in presence of different compacted zones: (i) horizontal, (ii) vertical layer and (iii) isolated zone representing different natural situations (under wheel or timmage compaction). Depending on the species (and their behaviour) we observed different impacts on compacted zones (L. terrestris is more prone to cross horizontal layer whereas A. caliginosa is more prone to colonize vertical ones). A second experiment was carried out in field conditions to characterise the dynamics of the recolonisation by earthworms after a compaction (through a 8t vehicle). Under and between wheels zones were followed during 2 years. We studied earthworm bulk density, earthworm community, 2D vertical macroporosity and water infiltration measurements were done. We observed that earthworm recolonisation is a rapid process (less than 6 months to recover similar abundances) whereas macroporosity and water infiltration are much slower processes. This illustrates the difficulty of using earthworm abundance as way to estimate the physical consequences of earthworm activity. Moreover, 3D soil cores were collected at different dates under and between wheels and analysed through Xray tomography. This enables us to visualize the (slow) recolonisation of the soil with earthworm macropores and to discuss the effect of the different species present in the field

Polymorphic microsatellites in Simulium damnosum s.l. and their use for differentiating two savannah populations : implications for epidemiological studies

En Afrique de l'Ouest, #Onchocerca volvulus, l'agent responsable de l'onchocercose chez l'homme, est transmis par des espèces du complexe #Simulium damnosum. La variabilité intra-spécifique et ses conséquences sur la capacité vectorielle ont été peu étudiées. Cette étude décrit l'utilisation des marqueurs microsatellites pour différencier des populations de #S. damnosum$ s.l. Cinq loci microsatellites ont été caractérisés et utilisés pour caractériser des individus de deux populations savanicoles du Mali, distantes de 120 km. Quatre loci se sont révélés très polymorphes avec 8-12 allèles par locus et des diversités géniques variant de 77,9 à 88,2%. Un déficit en hétérozygotes significatif a été observé dans les deux populations. Ce déficit peut être expliqué par la consanguinité, la structuration des populations (l'effet Walhund) ou par la présence d'allèles nuls. Pour tester cette dernière hypothèse, de nouvelles amorces ont été désignées pour deux loci et utilisées pour analyser les individus homozygotes. Malgré cette correction des allèles nuls, le déficit en hétérozygotes persiste. La subdivision des populations dans les deux foyers reste l'explication la plus probable. Nos résultats montrent que les marqueurs microsatellites peuvent différencier des populations de simulies, ce qui en fait des outils de choix pour l'étude de la structure génétique des populations. (Résumé d'auteur