Tuesday, November 14, 2006 - 11:00 AM
205-6
Quantifying Plant N Uptake with 3D Root Architecture.
Lianhai Wu, John A. Baddeley, and Christine A. Watson. Scottish Agricultural College, Craibstone Estate, Aberdeen, AB21 9YA, United Kingdom
Root systems are not only central to the acquisition of water and nutrients by plants, but are also a major pathway for the inputs of carbon and nutrients to soil. The complexity of both biotic and abiotic interactions, combined with stochastic changes in root architecture, makes it difficult to understand below ground dynamics on the basis of experimentation alone. The integration of dynamic models of above ground growth, three-dimensional root system demography, and interactions between plants and the environment, into one single model is a major challenge because of the complexity of the systems. We have developed the SPACSYS model, a mechanistic and process-based model capable of simulating plant growth with a three-dimensional root system, interacting with environmental conditions around the plant including nitrogen and carbon cycling. An estimation of N uptake by individual roots is implemented in the root system. The model is a mixed dimensional, multi-layer, field scale, weather-driven and daily-time-step dynamic simulation model. The current version includes a plant growth and development component, a nitrogen cycling component, a carbon cycling component, plus a soil water component that includes representation of water flow to field drains as well as downwards through the soil layers, together with a heat transfer component. The components themselves and linkage among components are designed using Object-Oriented techniques, and inputs and outputs of all components are organised as a database in either Microsoft® SQL Server 2000, Access 2000 or MySQL. Root architecture is visualised by using the OpenGL graphics system. We will demonstrate that the model can improve the simulation accuracy in crop yield, nitrogen contents in grain and nitrate leaching compared with the model without detailed description of root system.