The interspecific interactions in agroforestry systems enhance leaf water use efficiency and carbon storage in cocoa

Global climate changes include more intense and concentrated rainy seasons, al well as more severe and longer -lasting dry seasons. In this context, the benefits carried out within agroforestry systems (AFS) have played a significant role, especially for tropical crops such as cocoa. The present study evaluated the changes in photo-synthetic traits in cocoa and the physical, chemical, and microbiological soil properties in response to different shading tree species arrangements. Three cocoa genotypes (CCN51, TCS01, and TCS19) were cultivated under three AFS designs, differing in the accompanying shade tree species (Cariniana pyriformis, Tabebuia rosea, and Terminalia superba). No significant differences in CO2 assimilation rates among the different cocoa genotypes were observed. However, TCS01 exhibited a 20% higher leaf water use efficiency (WUEl) than the TCS19 ge-notype, associated with decreased stomatal conductance. The designs combining C. pyriformis with CCN51 and TCS01, as well as the design associating CCN51 with T. rosea, exhibited significantly higher WUEl for cocoa plants as compared to the systems involving T. superba combined with TCS19. In addition, the cocoa genotype TCS01 exhibited the highest potential for carbon storage when combined with C. pyriformis, whereas TCS19 exhibited the lowest potential for this feature under the T. superba association. Soil's chemical, physical and biological properties were evaluated, and an orthoPLS-DA multivariate analysis was performed to contrast the differences between TCS01 associated with C. pyriformis (higher WUEl and C sequestration) with the combina-tion of TCS19 with T. superba (lower WUEl and carbon sequestration). The results highlight the importance of soil acidity, and [Al], [Mn], and [Mg] concentrations for a better physiological performance exhibited by TCS01 under C. pyriformis AFS as compared to TCS19 under T. superba. Thus, the data obtained here suggest that species-genotype-dependent interactions in AFS-cocoa may determine soil characteristics, which may indirectly affect important physiological traits, such as leaf water use efficiency and long-term carbon storage of cocoa plants.