STICS - A GENERIC MODEL FOR THE SIMULATION OF CROPS AND THEIR WATER AND NITROGEN BALANCES - I - THEORY AND PARAMETERIZATION APPLIED TO WHEAT AND CORN

STICS (Simulateur mulTIdiscplinaire pour les Cultures Standard) is a c rop model constructed as a simulation tool capable of working under ag ricultural conditions. Outputs comprise the production (amount and qua lity) and the environment. Inputs take into account the climate, the s oil and the cropping system. STICS is presented as a model exhibiting the following qualities: robustness, an easy access to inputs and an u ncomplicated future evolution thanks to a modular (easy adaptation to various types of plant) nature and generic. However, STICS is not an e ntirely new model since most parts use classic formalisms or stem from existing models. The main simulated processes are the growth, the dev elopment of the crop and the water and nitrogenous balance of the soil -crop system. The seven modules of STICS development, shoot growth, yi eld components, root growth, water balance, thermal environment and ni trogen balance are presented in turn with a discussion about the theor etical choices in comparison to other models. These choices should ren der the model capable of exhibiting the announced qualities in classic environmental contexts. However, because some processes (e.g, ammonia c volatilization, drought resistance, etc.) are not taken into account , the use of STICS is presently limited to several cropping systems. ( (C) Inra/Elsevier, Paris.).