Adapting PILOTE model for water and yield management under direct seeding system: The case of corn and durum wheat in a Mediterranean context

Crop models are useful tools for integrating knowledge of biophysical processes governing the plant-soil-atmosphere system. But few of them are easily usable for water and yield management especially under specific cropping systems such as direct seeding. Direct seeding into mulch (DSM) is an alternative for conventional tillage (CT). DSM modifies soil properties and creates a different microclimate from CT. So that, we should consequently consider these new conditions to develop or to adapt models. The aim of this study was to calibrate and validate the PILOTE [Mailhol, J.C., Olufayo, A.A., Ruelle, P., 1997. Sorghum and sunflower evapotranspiration and yield from simulated leaf area index. Agric. Water Manag, 35, 167-182; Mailhol, J.C., Zairi A., Slatni A., Ben Nouma, B., El Amami, H., 2004. Analysis of irrigation systems and irrigation strategies for durum wheat in Tunisia. Agric. Water Manag, 70, 19-37], an operative crop model based on the leaf area index (LAI) simulation, for corn and durum wheat in both DSM and CT systems in Mediterranean climate. In DSM case, simple model modifications were proposed. This modified PILOTE version accounts for mulch and its impact on soil evaporation. In addition root progression was modified to account for lower soil temperatures in DSM for winter crops. PILOTE was calibrated and validated against field data collected from a 7-year trial at the experimental station of Lavalette (SE of France). Results indicated that PILOTE satisfactorily simulates LAI, soil water reserve (SWR), grain yield, and dry matter yield in both systems. The minimum coefficient of efficiency for SWR was 0.90. This new version of PILOTE can thus be used to manage water and yield under CT and DSM systems in Mediterranean climate. (C) 2008 Elsevier B.V. All rights reserved.