Crop growth; Diffuse radiation; Water use efficiency; Net ecosystem productivity
Revill Andrew, Emmel Carmen, D’Odorico Petra, Buchmann Nina, Hörtnagl Lukas, Eugster Werner (2019), Estimating cropland carbon fluxes: A process-based model evaluation at a Swiss crop-rotation site, in Field Crops Research
, 234, 95-106.
D'Odorico Petra, Emmel Carmen, Revill Andrew, Liebisch Frank, Eugster Werner, Buchmann Nina (2019), Vertical patterns of photosynthesis and related leaf traits in two contrasting agricultural crops, in Functional Plant Biology
, 46(3), 213-213.
Emmel Carmen, Winkler Annina, Hörtnagl Lukas, Revill Andrew, Ammann Christof, D&, apos, Odorico Petra, Buchmann Nina, Eugster Werner (2018), Integrated management of a Swiss cropland is not sufficient to preserve its soil carbon pool in the long term, in Biogeosciences
, 15(17), 5377-5393.
Emmel Carmen, Winkler Annina, Hörtnagl Lukas, Revill Andrew, Ammann Christof, D&, apos, Odorico Petra, Buchmann Nina, Eugster Werner (2018), Integrated management of a Swiss cropland is not sufficient to preserve its soil carbon pool in the long-term, in Biogeosciences Discussions
Vuichard Nicolas, Ciais Philippe, Viovy Nicolas, Li Longhui, Ceschia Eric, Wattenbach Martin, Bernhofer Christian, Emmel Carmen, Grünwald Thomas, Jans Wilma, Loubet Benjamin, Wu Xiuchen (2016), Simulating the net ecosystem CO2 exchange and its components over winter wheat cultivation sites across a large climate gradient in Europe using the ORCHIDEE-STICS generic model, in Agriculture, Ecosystems & Environment
, 226, 1-17.
van Dijk Albert I.J.M., Gash John H., van Gorsel Eva, Blanken Peter D., Cescatti Alessandro, Emmel Carmen, Gielen Bert, Harman Ian N., Kiely Gerard, Merbold Lutz, Montagnani Leonardo, Moors Eddy, Sottocornola Matteo, Varlagin Andrej, Williams Christopher A., Wohlfahrt Georg (2015), Rainfall interception and the coupled surface water and energy balance, in Agricultural and Forest Meteorology
, 214-215, 402-415.
Relevance - Diffuse radiation plays an important role for ecosystem productivity. However, its effect on the cropland C budget is largely unknown. Global crop yield modeled by Mercado et al. (2009) indicate a 25% increase in the net carbon sink due to increased diffuse radiation during the years 1960-1999. However, direct field measurements are scarce. Thus, these model results clearly stress the need for validation with in-depth experimental field measurements as proposed here.Overall Aim - The overall aim is to improve our understanding of how diffuse radiation affects the CO2 budget as well as the water use efficiency of crops. We will test and develop an integrated method with long-term as well as intensive field campaign measurements at one representative arable site in Switzerland (Oensingen CH-Oen2).Working Hypotheses - We aim at answering the two major questions: (1) How large are the differences in growth response to diffuse radiation among crop types?; and (2) Why is the observed response to diffuse radiation so variable between crop types? To answer these questions, we will test three working hypotheses:1.The effect of diffuse radiation on growth and thus net ecosystem productivity depends on crop type. This will be tested at the Oensingen flux site (arable site) using the typical crops in its crop rotation (winter wheat; winter barley; rapeseed; potatoes; peas/beans).2.On days with clear sky but high loads of aerosols, net ecosystem productivity shows the largest enhancement due to the increased fraction of diffuse radiation.3.On an ecosystem scale, the relevance of diffuse light conditions is most pronounced during peak growth when concurrent improvements of water use efficiency (WUE) are expected under diffuse light conditions.Methodical Approach - The proposed PostDoc candidate has developed a novel data mining approach to disentangle the climatic effect from the ecosystem properties and to understand the biophysical mechanisms that drive photosynthesis in relation to available diffuse and direct radiation. This approach uses an artificial neural network in combination with existing long-term data that are complemented with intensive field surveys during two cropping seasons a the Oensingen arable flux site, Switzerland.Expected Value of the Proposed Project - Improved functional understanding of crop responses to diffuse radiation that can be used by mechanistic simulation models to adequately represent the C cycle of European croplands; quantitative assessment of the effect of diffuse radiation on gross primary productivity, evapotranspiration, and their ratio WUE.