Evaluation of CECOL, a model of winter rape (Brassica napus L.).

摘要

The CECOL model is a dynamic model that describes the growth and development of winter rape. The model is evaluated using sensitivity analysis, investigation of behaviour in extreme conditions, graphical analysis and estimation of the mean-squared error of prediction (MSEP) and its components. The MSEP value gives an overall value of model predictive accuracy. For CECOL, the value is 0.22 (t ha-1)2. This is somewhat smaller than the MSEP of the very simple model that uses the average of past yieldsto predict future yield. The other evaluation techniques are complementary to MSEP in that they help identify specific types of situation where the model is a poor predictor. The CECOL model predicts flowering dates that are too early for early sowing and too late for late sowing, does not correctly describe the differences between irrigated and non-irrigated treatments, and does not give reasonable values for very low plant densities. In practical terms, these last two errors are not very important.