Etude de la régulation et du rôle du gène Lupme3 codant pour une pectine méthylestérase de lin (Linum usitatissimum) par transgenèse

AMIENS-BU Sciences (800212103) / SudocSudocFranceF

La Vie et les actions de la venerable mere Marie Alvequin de Jesus, religieuse de Monmartre, superieure & reformatrice des Dames augustines de S. Magloire dites Penitentes . Par M. Hierôme de Lacoux Sr de Marivaut, prêtre, licencié en theologie de la faculté de Paris.

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Investigating the combined effect of tillage, nitrogen fertilization and cover crops on nitrogen use efficiency in winter wheat

A field study was conducted in northern France over two consecutive years to evaluate the combined effect of conventional tillage (CT) vs no till (NT) with or without cover crops (cc) and nitrogen (N) fertilization on various agronomic traits related to N use efficiency in winter wheat. Five years after conversion of CT to NT, significant increases in N use efficiency, N utilization efficiency, N agronomic efficiency, N partial factor productivity, N apparent recovery fraction and N remobilization were observed under three N fertilization regimes (0, 161, 215 kg ha(-1)). It was also observed that grain yield and grain N content were similar under CT and NT. The N nutrition index was higher under NT at the three rates of N fertilization. Moreover, N use efficiency related traits were increased in the presence of cc both under NT and CT. Thus, agronomic practices based on continuous NT in the presence of cc, appear to be promising strategies to increase N use efficiency in wheat, while reducing both the use and the loss of N-based fertilizers

Conversion to no-till improves maize nitrogen use efficiency in a continuous cover cropping system

A two-year experiment was conducted in the field to measure the combined impact of tilling and N fertilization on various agronomic traits related to nitrogen (N) use efficiency and to grain yield in maize cultivated in the presence of a cover crop. Four years after conversion to no-till, a significant increase in N use efficiency N harvest index, N remobilization and N remobilization efficiency was observed both under no and high N fertilization conditions. Moreover, we observed that grain yield and grain N content were higher under no-till conditions only when N fertilizers were applied. Thus, agronomic practices based on continuous no-till appear to be a promising for increasing N use efficiency in maize

Estimating crop parameters using Sentinel-1 and 2 datasets and geospatial field data

International audienceCrop monitoring is essential for ensuring food security in a global context of population growth and climate change. Satellite images are commonly used to estimate crop parameters over large areas, and the freely available Synthetic Aperture Radar (SAR) Sentinel-1 (S-1) and optical Sentinel-2 (S-2) images are relevant for that purpose combining high temporal resolution and high spatial resolution. For this data article, field surveys were conducted from January to July 2017 in France to sample wheat and rapeseed crop parameters during the entire crops cycle. Phenological stages were identified in 83 wheat fields and 32 rapeseed fields in Brittany and Picardy regions. Moreover, Leaf Area Index (LAI), wet biomass, dry biomass and water content were sampled in three wheat fields and three rapeseed fields in Brittany. We assigned to each field sample 10 spectral bands and 12 vegetation indices from S-2 images and two backscattering coefficients, one backscattering ratio and four polarimetric indicators from S-1 images. This dataset can be used for crop monitoring in other regions, as well as for modelling development

In Winter Wheat, No-Till Increases Mycorrhizal Colonization thus Reducing the Need for Nitrogen Fertilization

Arbuscular mycorrhizal fungi (AMF) play a major role in the uptake of nutrients by agricultural plants. Nevertheless, some agricultural practices can interrupt fungal-plant signaling and thus impede the establishment of the mycorrhizal symbiosis. A field experiment performed over a 5-year period demonstrated that both the absence of tillage and of nitrogen (N) fertilization improved AMF colonization of wheat roots. Moreover, under no-till conditions, N uptake and aboveground biomass production did not vary significantly between N-fertilized and N-unfertilized plots. In contrast, both N uptake and above ground biomass were much lower when N fertilizer was not added during conventional tillage. This finding strongly suggests that for wheat, no-till farming is a sustainable agricultural system that allows a gradual reduction in N fertilizer use by promoting AMF functionality and at the same time increasing N uptake

Evaluation of Sentinel-1 & 2 time series for predicting wheat and rapeseed phenological stages

International audienc

Response of bacterial communities to Pb smelter pollution in contrasting soils

Anthropogenic inputs of trace elements (TE) into soils constitute a major public and environmental health problem. Bioavailability of TE is strongly related to the soil physicochemical parameters and thus to the ecosystem type. In order to test whether soil parameters influence the response of the bacterial community to TE pollution, we collected soil samples across contrasting ecosystems (hardwood, coniferous and hydromorphic soils), which have been contaminated in TE and especially lead (Pb) over several decades due to nearby industrial smelting activities. Bacterial community composition was analysed using high throughput amplicon sequencing and compared to the soil physicochemical parameters. Multivariate analyses of the pedological and biological data revealed that the bacterial community composition was affected by ecosystem type in the first place. An influence of the contamination level was also evidenced within each ecosystem. Despite the important variability in bacterial community structure, we found that specific bacterial groups such as γ-Proteobacteria, Verrucomicrobia and Chlamydiae showed a consistent response to Pb content across contrasting ecosystems. Verrucomicrobia were less abundant at high contamination level whereas Chlamydiae and γ-Proteobacteria were more abundant. We conclude that such groups and ratio's thereof can be considered as relevant bioindicators of Pb contamination

Relationships between plant community structure and forage quantity and nutritive quality in semi-natural grasslands

International audienc

Relationships between plant community structure and forage quantity and nutritive quality in semi-natural grasslands

International audienc