Daisy: Modelling the plant-soil-atmosphere system

Figure 3: Illustration of the over-all principle in the Daisy model

The purpose of the original Daisy model was to simulate water and nitrogen dynamics in agricultural fields as influenced by agricultural practices. That Daisy is a well-functioning model has been confirmed in a number of successful comparative tests.
In later years, Daisy has been transferred into a new code which has several advantage to the original one: It allows for in-built alternative process descriptions so that, for example, plant competition can be taken into regard; it gives room for new water flow models which makes it easy to add new processes to the model, notably to simulate the fate of pesticides and other agro-chemicals in the soil-plant-atmosphere system; and it provides an interface to other model systems, in particular the hydrological catchment model MIKE/SHE, a most interesting feature since MIKE/SHE forms the basis of the "DK Model" developed by GEUS to estimate Danish water resources better. In addition, the new code supports distributed use of the Daisy model.
The new features have proven valuable in ongoing research, e.g. the projects "Pesticides and Groundwater" under The Danish Environmental Research Programme, and "Remote Sensing based Crop Simulation and Soil-Vegetation-Atmosphere-Transport Modelling" under The Earth Observation Programme. The code architecture efficiently supports the development of new process descriptions and adds new functionality to the model.
The project has shown the value of using new and sound computer science principles. The implementation of the generic framework for adding alternate process descriptions has only been possible thanks to the financial support from Dina. The framework is an early adoption of software engineering research and is as such risky and inappropriate for funding through the more application-oriented projects. However such funding was provided for the actual implementation of alternate process descriptions, and this helped in testing the Dina-financed framework.