ISSN: 1659-2751



Elaboration of A controlled Release Fertilizer using a Biochar Matrix


The goal of this project was to create a slow release fertilizer using a biochar matrix and the study was divided into three phases: the production of biochar under controlled conditions; the creation of pellets using a combination of biochar and urea; and the identification and comparison of the nutrient release curves of the pellets and of conventional urea. More specifically, biochar was produced with woodchips at a pyrolysis temperature of 500 °C (±50 °C) for 45 minutes. Combining ground biochar (25 %) with urea (75 %) and heating the mixture at 150 °C for 15 minutes, firm homogenous pellets were formed. With leaching experiments, conducted with a daily application of 10.8 mm of H2O for a duration of six weeks in cylindrical columns of sand, it was determined that the pellets presented a more stable release of N, while the conventional urea presented an early peak in the second week (release 45.4 % higher than that of the pellets) followed by an immediate descent (85.7 % less N released in week 3), during its overall unstable release of N.

Key words: biochar, nutrient release curves, fertilizer efficiency, slow-release fertilizer pyrolysis.

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