Development and evaluation of HUME-OSR: A dynamic crop growth model for winter oilseed rape

Abstract

A new dynamic crop growth model based on empirically derived allometric partitioning rules was developed for winter oilseed rape. The model simulates dry matter production, nitrogen uptake and distribution, leaf, stem and pod area expansion and yield formation under optimal and water- and nitrogen-limited conditions.The model includes hibernation, senescence due to self-shading, freezing and aging, translocation of assimilates and nitrogen, light absorption and reflection by flower layer and oil synthesis. It was parameterized with two data sets from Hohenschulen, northern Germany, and validated with datasets from Germany, France, Great Britain, and the Czech Republic.Model performance in terms of prediction of total aboveground dry matter production gave an RMSE of 180 g m−2 and the linear regression between measured and simulated root/shoot ratios gave an r2 of 0.64. In addition, nitrogen uptake (RMSE 4.26 g m−2) and distribution (r2 simulated/measured leaf N/stem N = 0.44) are quite well represented. In contrast, year-to-year variability of final seed yield was less correctly estimated, probably due to variation in the harvest index, which is not included in the model prediction. Relative differences in seed yield due to sowing date and nitrogen application were well reproduced in most cases. Therefore the model has potential to be used for supporting optimization of management strategies, climate change scenario studies and future breeding progress.