Abstract

Increasing fertilizer nitrogen use efficiency is one of the challenges agriculture faces nowadays. Agriculture is highly dependent on the use of fertilizers, which can produce high N losses, resulting in detrimental effects on the environment, also affecting the stability of agricultural ecosystems. A strategy to increase N fertilization efficiency is the use of natural nitrification inhibitors. In this study, we evaluated biochar as a matrix to adsorb plant extracts that act as natural inhibitors on nitrification. Biochar produced by pyrolysis of pine bark (Pinus radiata) and plant extracts from eucalyptus (Eucalyptus globulus), peumo (Cryptocarya alba), and pine bark were used. The biochar-plant extracts complexes were evaluated on soil biological processes related to N transformation. Most of the biochar-plant extracts complexes evaluated did not produce any detrimental effect on microbial biomass activity (soil respiration) and showed no effect on denitrification. Nevertheless, significant effects were observed on urease activity and N mineralization, with differences between treatments attributed to the different types and phenols content in the plant extracts.