Comparison of theoretical and empirical approaches to the agroecosystem simulation on an example of photosynthesis description

Two alternative approaches for agroecosystem modelling on example of photosynthesis units have been analysed. The first one – an empirical (functional) approach is presented by the model AGROSIM-WW developed in Institute of Landscape Simulation (Muencheberg, Germany). The second – a theoretical (mechanistic) one – by the model AGROTOOL from Agrophysical Research Institute (Sanct-Petersburg, Russia). The description of mathematical algoritms and the comparison of model running results are enclosed. It permits to make the conclusions about the limits of model utility and their possible applications.