Low-input soil management increases yield and decreases CO2-emissions but aggravates risk of nitrate leaching and diseases in winter wheat cropping systems under climate change

Understanding how climate change will affect crop performance is critical to ensure global food security and sustainability. Empirical data is key to anticipate the impact of climate change on cropping systems, but multifactorial climate change experiments remain scarce. In this study, the growth of winter wheat was examined in two agricultural soil management systems: one with long-term low organic inputs and the other one with high organic inputs. The wheat was grown in these differentially managed soils in an Ecotron, where the plant-soil mesocosms were subjected to three different climatic conditions. These conditions represent a gradient of ongoing climate change, simulating the weather patterns of the years 2013, 2068, and 2085 respectively. This approach allows to study the combined effects of projected increases in temperature, atmospheric CO2-concentrations, solar irradiation and altered precipitation patterns on the cropping system (wheat growth, grain yield, rhizosphere processes, greenhouse gases, disease dynamics). The low-input system outperformed the high-input system with higher yields and lower CO2-emissions in the future climates. On the other hand, the risk for plant diseases and nitrate leaching was also increased in the low-input system. To reduce the environmental impact of high-yielding cropping systems in the future it is therefore essential to identify management practices which allow fertiliser application and nutrient buffering without necessarily increasing organic inputs, like fertigation or biological nitrification inhibition. Under both here studied soil management systems the wheat plants developed natural coping mechanisms such as enhanced root growth and increased levels of proline and silicon to mitigate the adverse effects of environmental and biotic stresses. Unravelling the molecular mechanisms that trigger such inherent plant defences is a further interesting target for breeding future crops. Adapting crop rotations and cover crops to the shorter wheat cycle in the future is also an opportunity to break disease cycles