Biochar application on a rainfed barley crop under a climate change scenario does not improve grain yield and quality

Climate change effects on agriculture is already a major threat for global crop production in terms of yields and quality of grains. In particular, sustainability of rainfed agriculture in semiarid regions is severely affected by warming and prolonged drought periods. Exploring new soil amendments such as biochar, which holds in countering climate change effects may be a sustainable method aimed at storing carbon, increasing soil quality and buffering the warming and drought stresses on soil and crops. However, we still need to better understand the effects of biochar application on crop yields, particularly under climate change conditions. To fill this knowledge gap, in a long-term field experiment, we investigated how cumulative biochar addition (20 t ha-1 year-1) under climate change conditions affected a barley crop. Rainout shelters and open-top chambers were set up to simulate a 30% rainfall reduction combined with an increase of 2°C in soil temperature. Unamended soils for both ambient conditions and climate change manipulation were used as a control. Our findings revealed that the barley yield was greatly impacted by climate manipulation reducing the grain yield by 74-81%. However, the application of biochar did not lead to improvements in crop yield under these altered conditions. Moreover, grain quality parameters (specific grain weight and weight of 1000 grains) were not enhanced by the application of biochar nor the simulated climate change conditions. Acknowledgments: this work was supported by the research projects TED2021-132342B-I00 (Spanish MICINN) and TUdi (Horizon 2020, GA 101000224).