Biology subjects

Barbu, C. M.

Publications and source records attributed to Barbu, C. M..

3 recordsLinked to original sources

bioRxiv2019

Quantification of bioagressors induced yield gap for grain crops in France

Analyzing yield losses of crops is instrumental in sustaining high productivity. Here, we develop statistical modelling of yield losses by French department based on weather, soil and epidemiological data for 13 diseases and 12 insect pests of grain crops over 8 years. Those environmental factors explain up to 90% of yield variations (wheat). Weather and soil quality are first order determinants as manifested both by direct assessment and by strongly correlated yields of even taxonomically very different crops. Bioagressors are important second order determinants: losses of 5 qx/ha (~7%) on wheat and 2 qx/ha (~15%) on winter oilseed rape. Across models based on conceptually different achievable yields, only Septoria tritici and Sitobion avenae on wheat, and Ceutorhynchus picitarsis and Ceutorhynchus assimilis on winter oilseed rape are consistently and significantly detrimental to yield. Those bioagressors seem not fully controlled which is compatible with empirical observations in the non academical litterature.\n\nHighlightsO_LIGrain crop yields of similar growing seasons are highly correlated\nC_LIO_LIEnvironmental determinants explain up to 90% of yield variations\nC_LIO_LIBioagressors induced yield variations of 5 to 20%\nC_LIO_LISpecific pests and diseases with less than perfect control are identified\nC_LI

plant biology↗

bioRxiv2019

Spatiotemporal drivers of crop pests and pathogens abundance at the landscape scale

The agricultural landscape has been recognized as a relevant scale for the control of bioagressors (pest and pathogen) epidemics. In this study, we assess the consistency of the impacts of semi-natural areas and host crop fields in the landscape on bioagressor abundance in cultivated fields. Our approach relied on the analysis of systematic French epidemiosurveillance data spanning 9 years of observations over two third of the French territory. 30 majors bioagressors of arable crops (wheat, barley, maize, potato, oilseed rape and sugar beet) were jointly studied with landscape composition as described by official CAP data and woody vegetation maps. Beyond the simple correlation between landscape composition and bioagressors abundance, we controlled for the presence of the host crop the former years in the plot and for bioagressors former prevalence. Our findings highlighted that landscape simplification around a same crop does not in general favor epidemic outbreaks during the current growing season, but rather that its harmful effect lie in the season ahead. The effects of semi-natural areas were, however, very contrasted between organisms. This study used available tools and data to quantify automatically in an interpretable way the general impact of landscape components. Such findings have relevant implications for the design of bioagressor management strategies at the landscape scale. ResumeLe paysage agricole est reconnu comme une echelle pertinente pour la gestion des bioagresseurs, insectes arthropodes et maladies cryptogamiques. Dans cette etude, nous avons evalue la coherence et la regularite de limpact des espaces semi-naturels et cultures hotes dans le paysage sur labondance des bioagresseurs dans les parcelles cultivees. Cette approche a repose sur lanalyse de donnees nationales depidemiosurveillance regroupant 9 ans dobservations. 30 bioagresseurs du ble, du colza, de lorge, de la pomme de terre, du mais et de la betterave ont ete parallelement etudies a laide de cartes dassolement des cultures (RPG) et de la vegetation arboree (BD Topo (R)). Au-dela des simples correlations entre la composition du paysage et labondance de bioagresseurs, nous avons pris en compte leffet de la surface en culture hote et labondance des bioagresseurs de lannee precedant les observations. Les resultats ont mis en evidence quune importante surface dune meme culture hote dans le paysage ne favorisait pas systematiquement les epidemies de bioagresseurs durant la meme annee mais plutot durant la suivante. Les effets du paysage etaient quant a eux tres inconsistants. Cette etude controle des bioagresseurs a lechelle du paysage.

ecology↗

bioRxiv2019

Weed regulation by crop and grassland competition: critical biomass level and persistence rate

O_LIIt is widely agreed that competition regulates plant populations and shapes communities. Many studies have suggested that crop and grassland competition can be used for cost-effective sustainable weed control. However, effective weed management requires a precise knowledge of the effects of agronomic practices and there is a lack of quantitative indicators to compare and predict the success of weed biocontrol by competition.\nC_LIO_LIWe studied weed abundance dynamics over a 12-year period in crop-grassland rotations (rotation treatments consisted of maize, wheat and barley crops, alternating with temporary grassland maintained for three or six years in the rotation and fertilised with two different levels of nitrogen). In addition to classical statistical analysis of the different aforementioned rotation treatments, we also modelled weed abundance as a function of the crop and grassland competition, expressed here by biomasses harvested in the preceding years.\nC_LIO_LIWe show that weed abundance decreases over the years in grassland and subsequent crops only if the grassland receives sufficient nitrogen fertiliser. Our model had a much greater explanatory power than the rotation treatments. This model estimates a critical biomass level above which weeds are suppressed in subsequent years, and below which they tend to thrive. This critical biomass level was 24.3 and 4.7 tonnes ha-1 of dry matter for crops and grassland, respectively, highlighting the greater competitiveness of grasslands than of crops. Several clear differences between weed functional groups emerged.\nC_LIO_LISynthesis and applications - This new modelling approach directly links the interannual dynamics of weed populations to current and previous biomass production levels. This approach facilitates the development of environment-friendly weed management strategies and paves the way for comparisons of the competitiveness against weeds of crops and grassland under various pedoclimatic conditions and agronomic practices.\nC_LI

plant biology↗