Do farmers in Germany exploit the potential yield and nitrogen benefits from preceding oilseed rape in winter wheat cultivation?

Field experiments show that wheat grown after oilseed rape (OSR) achieves higher yield levels, while the nitrogen (N) application is reduced. However, field experiment data are based on few locations with optimised management. We analysed a large dataset based on farm data to assess the true extent of break crop benefits (BCB) for yield and N fertilisation within German commercial farming.

Across all German states and years, average yield of wheat preceded by OSR was 0.56 Mg ha⁻¹ higher than yield of wheat preceded by cereals (7.09 Mg ha⁻¹), although considerable variation between regions was observed. Mean N application across all states to wheat after OSR was 5 kg ha⁻¹ lower than to wheat after cereals. Choice of wheat types for different end uses (bread flour or animal feed) showed higher (0.77 Mg ha⁻¹) or lower (0.44 Mg ha⁻¹) BCB for yield of wheat cultivated after OSR compared with after cereals. The calculated BCB for yield and N fertilisation were lower than expected from dedicated field experiments and fertiliser recommendations. Thus the advantages of OSR as a preceding crop are generally utilised by commercial farmers in Germany but there is room for improvement.