The study combines experiments and farm-level data from the Netherlands with crop modelling to better understand why yield growth has levelled off since the 1990s. The analysis examines the respective contributions of genetic progress, historical climate change and on-farm management practices.
A region with stable yields
North-west Europe is a major wheat-growing region, with more than 10 million hectares of wheat cultivated each year. Until the mid-1990s, yields increased steadily, by an average of around 120 kilograms per hectare per year. After that, growth slowed and yields in many countries stabilised at roughly 7 to 9 tonnes per hectare. For a long time, the causes of this trend were unclear.
Genetic progress continues
Official variety trials show that plant breeding has continued to deliver yield gains even after the mid-1990s. Between 1994 and 2016, genetic progress averaged 74 to 84 kilograms per hectare per year. Modern wheat varieties have a longer grain-filling period and use light slightly more efficiently. This indicates that, in north-west Europe, a genetic yield ceiling had not yet been reached during this period.
Historical climate supports yields
Historical climate change also appears not to have constrained yields over the period studied. Using a crop model, researchers simulated the effects of climate change while keeping genetics and management constant. The results show that climate change has so far contributed positively to yield growth, adding between 26 and 60 kilograms per hectare per year. This benefit is mainly linked to higher CO₂ concentrations and more light during grain filling, due to earlier flowering. The study does not draw conclusions about the impact of future climate extremes.
Management plays a key role
Because both genetics and climate still offer scope for yield growth, the analysis points to agronomic management at farm level as a major factor behind the lack of further yield increases. This refers to operational and tactical decisions on crop rotation, cultivation practices and soil management. The contribution of management was derived indirectly, as the gap between actual farm yields and the yield gains that can be attributed to genetics and climate change. On this basis, an estimated 67 to 114 kilograms per hectare of potential yield increase remains unused each year.
In this region, water and nitrogen management do not appear to be strongly limiting factors. Instead, the results point to intensive crop rotations with a high share of economically attractive root and tuber crops, and the associated risks of disease pressure and soil compaction, as factors that can slow yield growth in practice. Such rotations increase pressure on soils and crop health, and make it more difficult to manage wheat in a timely and optimal way.
Other management choices under the spotlight
The findings suggest that further yield improvements should not primarily be sought in water or nutrient supply, but in other aspects of management, such as the design of crop rotations, soil management and related cultivation choices. At the same time, the researchers stress that higher yields must always be weighed against economic feasibility and production within environmental limits.
Overall, the study makes clear that under the conditions examined, the potential for wheat production in north-west Europe continues to grow, but that further progress is strongly linked to management choices on farms.