Fresh biochar application provokes a reduction of nitrate which is unexplained by conventional mechanisms

Soil-applied biochar has been reported to possess the potential mitigate nitrate leaching and thus, exert beneficial effects beyond carbon sequestration. The main objective of present study is confirm if a pine gasification that proven able decrease soil-soluble in previous research can indeed such an effect determine by which mechanism. For this purpose, lysimeters containing soil-biochar mixtures at 0, 12 50 t ha?1 were investigated two different scenarios: fresh scenario consisting fallow-managed soil, aged with 6-yr naturally crop-managed soil. Soil columns assessed under mimicked Mediterranean ambient within greenhouse setting during 8-mo period included barley crop cycle. A set parameters related nitrogen cycling, particularly mechanisms could directly or indirectly explain content reduction (i.e., sorption, leaching, microbially-mediated processes, volatilisation, plant uptake, ecotoxicological effects), assessed. Specific measurements soil solution leachate ionic composition, microbial biomass activity, gas (GHG) emissions, N O isotopic composition nitrate, yield quality, endpoints, among others. Nitrate was verified for both treatments coupled significant chloride, sodium, calcium magnesium. This noticed only after eight months application thus suggesting time-dependent process. All other tested being discarded, formation organo-mineral coating emerges as plausible explanation decrease.