Wood Distillate Interactions with Urea in Soil: A First Step to Developing a Slow-Release Next-Generation Fertilizer

We tested the ability of wood distillate (WD) to interact with urea in agricultural soil. WD is a sustainable material that has been addressed as a promising alternative to synthetic soil corroborants. However, there is little information about the effect of WD on the nitrogen cycle. In this study, soils with different amounts of WD and with/without urea were tested for ammonium, urease, nitrate/nitrite, and potential nitrification activity at different points in a 30 day time frame. High concentrations of WD (1-2%) inhibited the hydrolysis of urea and the oxidation of ammonium to nitrate. Thermal desorption coupled to GC-MS and high-performance liquid chromatography-tandem mass spectrometry characterization allowed us to reveal that WD-urea interactions mainly involve lignin-derived compounds in the distillate, such as catechol, resorcinol, and syringol. This study provides the first evidence of a strong interaction between WD and urea in soil that could be used to develop slow-release fertilizers.