CHRISTOF AMMANN results 17
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Coupling observational methods and the DayCent model to improve examinations of N2O production pathwaysNARA Subscribed
The traditional calibration approach for process-based models, such as DayCent, consists of the iterative adjustment of model parameters and comparison of the simulated total N 2 O flux to measured observations. However, the contributions of individual production pathways, namely nitrification and denitrification, are uncertain. Here, N 2 O emissions from the soil of sugar beet plots with control (Null) and mineral (NPK) ferti...
N2O emission factors for cattle urine: effect of patch characteristics and environmental driversNARA Subscribed
Urine patches from grazing cattle are hotspots of nitrous oxide (N 2 O) emissions. The default IPCC emission factor for urine patches (EF urine ) is 0.77% for wet climates and 0.32% for dry climates. However, literature reports a considerable range of cattle urine EF values and urine characteristics used in experimental studies, revealing contrary results on the effects of urine patch characteristics and seasonal pattern. Ther...
Global maps of soil temperatureNARA Subscribed
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1‐km 2 r...
Canopy photosynthesis of six major arable crops is enhanced under diffuse light due to canopy architectureNARA Subscribed
Diffuse radiation generally increases photosynthetic rates if total radiation is kept constant. Different hypotheses have been proposed to explain this enhancement of photosynthesis, but conclusive results over a wide range of diffuse conditions or about the effect of canopy architecture are lacking. Here, we show the response of canopy photosynthesis to different fractions of diffuse light conditions for five major arable cro...
This paper examines long‐term eddy covariance data from 18 European and 17 North American and Asian forest, wetland, tundra, grassland, and cropland sites under non‐water‐stressed conditions with an empirical rectangular hyperbolic light response model and a single layer two light‐class carboxylase‐based model. Relationships according to ecosystem functional type are demonstrated between empirical and physiological parameters,...
Bi‐directional soil/atmosphere N 2 O exchange over two mown grassland systems with contrasting management practicesNARA Subscribed
Nitrous oxide (N 2 O) fluxes from soil under mown grassland were monitored using static chambers over three growing seasons in intensively and extensively managed systems in Central Switzerland. Emissions were largest following the application of mineral (NH 4 NO 3 ) fertilizer, but there were also substantial emissions following cattle slurry application, after grass cuts and during the thawing of frozen soil. Continuous flux...
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