Effects of biochar on the chemical properties of soils and the volume of wood in a plantation of Acacia mangium Willd in the Colombian Orinoquía (highlands)

Purpose: Exploring alternatives to mitigate soil degradation has been gaining importance in recent years. Biochar promises to improve properties such as soil fertility and soil conditioning. This research involved an experiment with different levels of biochar in associating it with some chemical properties and the wood yield of A. mangium. Method: We used a design including nine treatments and three repetitions of each treatment, employing two materials: biochar from Acacia mangium W. (BAM) and synthetic fertilizer (SF). We used a Bayesian principal component analysis to reduce dimensionality, and the two extracted dimensions were labeled by treatment to visualize their grouping. We validated the grouping using cluster analysis algorithms. Volume in wood was used as the response, and the same soil variables were used to run a regression by partial least squares where the explanatory variables were characterized by relative importance. Result: We found an increase in the different chemical variables of the soil analyzed in treatments with BAM and BAM + SF and an increase in the volume of the stem of the trees in treatments with BAM + SF. The analysis by partial least squares showed how the EC and SOC variables were the most important in explaining the volume of wood. Conclusion: Responses of the different variables analyzed increased with the addition of biochar, either alone or mixed with synthetic fertilizer. It was also possible to determine that the volume of A. mangium wood was influenced by soil chemical variables. Highlights Biochar applications can reduce synthetic fertilizer applications to the soil. Applications of synthetic fertilizer and biochar mixtures can be functional in terms of wood volume increase in A. mangium. When biocarbon is added in a mixture with synthetic fertilizers, the chemical properties of soils are increased. When biocarbon is added in a mixture with synthetic fertilizers, fundamental soil nutrients are increased in the growth of A. mangium. The application of Bayesian principal components not only allowed us to reduce dimensionality but also to generate a visual way of classifying the treatments.