• Adapt a simulation model to pea-barley intercropping with a special emphasis on nitrogen uptake by the crops.

• Test intercropping potentialities in Europe and identify optimization strategies.

·         Workpackage 6.1 (Partner 4): During year 1 and 2 using the basic pea-barley design (WP2) the state variables involved in the simulation model will be recorded. It includes weekly measurements of crop phenology, leaf area and light transmission into the dominant and understorey canopy, dry matter accumulation and partitioning, rooting pattern and detph (with the herbicide injection technique), N₂ fixation, shoot N concentration, yield components including grain N content, soil N and water content. ¹⁵N enrichment method will be used in order to record both N₂ fixation and soil N use. Experimental data will be split into two sets : a “parameterisation” data set collected by partner 4 and devoted to the identification of the model parameters and a “validation” data set collected by the other partners devoted to the model evaluation and confidence.

·         Workpackage 6.2 (Partners 6, 4): Development of the model structure relying on i) the existent pure crop model and ii) a first version of the intercrop model driven by the partitioning of radiation resource and iii) the development of the specificity of legume/cereal intercrops with a special focus on N nutrition sub-model by incorporating N₂ fixation-soil N interaction in relation to root competition.

·         Workpackage 6.3 (Partners 6, 4): Parameter identification relying on i) a sensitivity analysis allowing the appropriate choice of the parameters to be fitted, ii) the use of mathematical least square minimisation procedure to fit parameters on the state variables of the pure crop experiments and iii) checking whether the intercrop model requires specific intercrop parameters on the state variables of the intercrop experiment.

·         Workpackage 6.4 (Partners 6, 4, 1, 3, 5, 7): Evaluation of the model (starting month 12) using the “validation” data set and partners’ expert knowledge.

·         Workpackage 6.5 (Partners 6, 4): Simulation study of intercropping strategies (sowing dates, plant density, earliness) for each component of the intercrop for various soil x climate environments, using available data from other partners (starting month 18).

    Professor Yves Crozat (y.crozat@esa-angers.educagri.fr) from Ecole Supérieure d'Agriculture (Angers) is the partner responsible for this Workpackage.