Evaluation of the STICS crop model within the INTERCROP EU project to simulate pea-barley intercropping systems.

This work is devoted to the evaluation and utilization of the STICS intercrop/sole crop model taking into account the European environmental variability within an organic farming framework. The model ability to simulate intercropping systems was evaluated on the network of the INTERCROP EU project experiments. We first realized the difficulty to simulate relevant absolute production values in spite of a satisfactorily phase of parameterisation in conventional farming experiments. We attributed most of the discrepancies between simulations and measurements to the non accounting of biotic stresses. However, the relative values and in particular the Land Equivalent Ratios draw to the same results for simulation and observa-tion, i.e. the global advantage of intercropping compared to sole crops. Those conclusions caused us to think that the use of the model to test technical strategies was worthwhile. Among the different strategies we tested with the model, one showed that intercropping was very interesting in term of stability, and an other showed that the inter-row factor was a better driver factor for choosing density design than global density