Stability analysis for grain yield of winter wheat in a long-term field experiment

The current study is based on a long-term field experiment that was conducted at the Rauischholzhausen field station of the University of Giessen (Germany). It includes six different crop rotation systems (CRSs), three mineral nitrogen (N) fertilization treatments and the varying annual weather conditions (AWCs) over 25 years (1993–2017). To ensure new insight into wheat cropping systems that have high yield stability, the dataset was assessed using different methods of stability analysis, including eco-valence, biplot and risk analysis. The results show that the factors which influence grain yield variation in winter wheat can be ranked in the following order: (1) N fertilization; (2) AWC; and (3) CRS. Compared to winter rye as the preceding cereal crop, field bean as the preceding legume crop had a clearly positive effect on the grain yield stability of winter wheat. Furthermore, the higher N fertilization level led to more stable grain yields of winter wheat for all investigated CRSs. Overall, in this study, crop rotation and N fertilization had a high impact on the yield stability of winter wheat. These are important factors to consider in agronomic management decisions under the increasingly difficult environmental conditions caused by climate change.