Résumé
Aims Increasing the leaf silicification of cereal crops to ameliorate defenses against stresses and improve yields constitutes a major challenge in (sub-)tropical regions with highly desilicated soils. We tested the efficacy of different biochars - as readily available alternatives to commercial fertilizers - to increase leaf silicification and understand subsequent impacts of leaf traits that might benefit crops. Methods We compared the application of two biochars (rice-derived biochar with 198 g kg(- 1) of Si and cotton-derived biochar with 4 g kg(- 1) of Si) and wollastonite (240 g kg(- 1) of Si) at two application rates on the leaf silicification patterns and leaf traits of rice growing in pots containing highly desilicated soil (Ferric Lixisol) from Burkina Faso. Results Leaf Si increased from 19.0 to 70.4 g kg(- 1) with Si addition (control < cotton biochar < wollastonite < rice biochar), resulting in larger epidermal silica deposits. Leaf carbon (C), leaf mass per area (LMA) and leaf arc decreased and were negatively correlated with leaf Si, however, surprisingly, the leaf force to punch and the plant biomass decreased. Conclusions We demonstrate the effective use of rice biochar in desilicated environments to improve the Si status of cereal crops and their associated leaf traits. In particular, the decrease in LMA with rice biochar application shows a promising capacity of rice biochar to reduce rice leaf C costs. In situ trials are now needed to investigate whether or not these beneficial effects may result in increased crop yields through resilience against environmental stresses.