Search results for "use efficiency"
showing 4 items of 54 documents
Quantification of nitrogen fluxes and explanatory plant traits during a two year legume-cereal rotation
2018
National audience; A better understanding of how plant growth, N nutrition and symbiotic nitrogen fixation (SNF) are influenced by soil inorganic N availability, for a wide range of legume species, is crucial to optimise legume productivity, N2 fixation, while limiting environmental risks such as N leaching. A comparative analysis was performed for ten legume crops, grown in a field experiment and supplied with four levels of N fertiliser. Dry matter, N concentration and SNF were measured. Parallely, root traits were studied in a greenhouse experiment. For most species, inorganic N inputs had little effect on plant growth and N nutrition. SNF was negatively affected by soil inorganic N avai…
Water-use efficiency and transpiration across European forests during the Anthropocene
2015
Considering the combined effects of CO2 fertilization and climate change drivers on plant physiology leads to a modest increase in simulated European forest transpiration in spite of the effects of CO2-induced stomatal closure. The Earth’s carbon and hydrologic cycles are intimately coupled by gas exchange through plant stomata1,2,3. However, uncertainties in the magnitude4,5,6 and consequences7,8 of the physiological responses9,10 of plants to elevated CO2 in natural environments hinders modelling of terrestrial water cycling and carbon storage11. Here we use annually resolved long-term δ13C tree-ring measurements across a European forest network to reconstruct the physiologically driven r…
Prévenir et réduire les risques de sélection de résistances : de la théorie à la pratique, des pistes pour améliorer la durabilité des PPP
2015
SPEPôle GEAPSICT2communication orale invitée, résumé; La résistance est le résultat inéluctable de la sélection exercée par les PPP sur les populations de bio-agresseurs. On ne peut pas empêcher une résistance d’évoluer, mais on peut retarder substantiellement son évolution en mettant en place des stratégies appropriées avant (prévention) et après (gestion) la détection des premiers individus résistants. Le point-clef à retenir pour cela est que plus le contrôle d’un bio-agresseur est basé sur une chimie peu diversifiée, plus le risque de sélectionner rapidement une résistance est élevé. Un exemple type de ce qu’il ne faut pas faire est de contrôler un bio-agresseur présent sur de grandes s…
Determinants of the interannual relationships between remote sensed photosynthetic activity and rainfall in tropical Africa
2007
International audience; The response of photosynthetic activity to interannual rainfall variations in Africa South of the Sahara is examined using 20 years (1981-2000) of Normalised Difference Vegetation Index (NDVI) AVHRR data. Linear correlations and regressions were computed between annual NDVI and annual rainfall at a 0.5° latitude/longitude resolution, based on two gridded precipitation datasets (Climate Prediction Center Merged Analysis of Precipitation [CMAP] and Climatic Research Unit [CRU]). The spatial patterns were then examined to detect how they relate to the mean annual rainfall amounts, land-cover types as from the Global Land Cover 2000 data set, soil properties and soil typ…