Differences in biomass yield development of early, medium, and late maize varieties during the 21st century in Northern Germany

Abstract

Background: Though there exists a general notion on how maize yields might develop throughout Europe during the current century, modeling approaches on a regional level that account for small-scale variations are not yet universally available. Furthermore, many studies only refer to one variety of maize. However, the few studies that include at least two varieties indicate that the respective choice will play a major role in how the yields will develop under a changing climate throughout the 21st century. This study will evaluate how far this choice of variety will affect future yields, identify the main factors to explain potential differences, and determine the magnitude of spatial variability. Results: The results suggest clearly differentiated development paths of all varieties. All varieties show a significant positive trend until the end of the century, though the medium variety also shows a significant decline of 5% during the first 30 years and only a slight recovery towards +5% around the century’s end. The late variety has the clearest and strongest positive trend, with peaks of more than +30% increase of biomass yields and around 25% average increase in the last three decades. The early variety can be seen as in-between, with no negative but also not an as-strong positive development path. All varieties have their strongest increase after the mid of the 21st century. Statistical evaluation of these results suggests that the shift from a summer rain to a winter rain climate in Germany will be the main limiting factor for all varieties. In addition, summer temperatures will become less optimal for all maize crops. As the data suggests, the increasing atmospheric CO2 concentrations will play a critical role in reducing the crops water uptake, thus enabling yield increases in the first place. Conclusions: This study clearly shows that maize yields will develop quite differently under the assumed climatic changes of the 21st century when different varieties are regarded. However, the predominant effect is positive for all discussed varieties and expected to be considerably stronger in the second half of the century.