Expert-N

Expert-N is a development system for nitrogen turnover models to simulate the N cycle in arable agriculture. The system consists of modular model components for soil water flow, for soil heat and N transport and for crop growth. These components are built up of different standardized model units representing each a single process for the component as N mineralization for N transport or root water uptake for crop growth.

The modular structure allows an easy exchange of model units to compare different submodels or model algorithms describing the same process. For each model component and model unit several distinct interchangeable submodels are available and additional user defined submodels can be included easily by the supported use of dynamic link libraries. This enables the user to analyse the impact of different or new modelling approaches on the simulation results component by component.

By the modular structure Expert-N is also an extremely flexible simulation model for N dynamics in soil-plant systems, which can be easily adapted to the actual simulation purpose including management or research, to the specific site conditions involving crop, soil and agricultural practice and to the quality and availability of data.

Based on a user friendly graphical interface, a windows system for personal computers, Expert-N comprises a menu driven interactive input system to enter all necessary soil, weather, fertilizer and crop data for a particulary field and growing season. This and an online help function offering detailed documentations for every model unit allows even users with minimal computing experience to apply Expert-N and to calculate the mass balance and turnover of N in soils. Simulations are further supported by the possibility to display online the development of important state variables such as soil water content, soil temperature, amount of soil nitrate and plant or root biomass.