A ¹⁵N tracing pot experiment was conducted using two types of wood-based biochars: a regular biochar and a Kon-Tiki-produced nutrient-enriched biochar, at two application rates (1% and 5% (w/w)), in addition to a fertilizer only and a control treatment. Ryegrass was sown in pots, all of which except controls received ¹⁵N-labelled fertilizer as either ¹⁵NH₄NO₃ or NH₄¹⁵NO₃. We quantified the effect of biochar application on soil N₂O emissions, as well as the fate of fertilizer-derived ammonium (NH₄⁺) and nitrate (NO₃⁻) in terms of their leaching from the soil, uptake into plant biomass, and recovery in the soil. We found that application of biochars reduced soil mineral N leaching and N₂O emissions. Similarly, the higher biochar application rate of 5% significantly increased aboveground ryegrass biomass yield. However, no differences in N₂O emissions and ryegrass biomass yields were observed between regular and nutrient-enriched biochar treatments, although mineral N leaching tended to be lower in the nutrient-enriched biochar treatment than in the regular biochar treatment. The ¹⁵N analysis revealed that biochar application increased the plant uptake of added nitrate, but reduced the plant uptake of added ammonium compared to the fertilizer only treatment. Thus, the uptake of total N derived from added NH₄NO₃ fertilizer was not affected by the biochar addition, and cannot explain the increase in plant biomass in biochar treatments. Instead, the increased plant biomass at the higher biochar application rate was attributed to the enhanced uptake of N derived from soil. This suggests that the interactions between biochar and native soil organic N may be important determinants of the availability of soil N to plant growth.

甲¹⁵ N种描绘盆栽试验使用两种类型的基于木材的生物炭的进行：定期生物炭和康奇基号产生的营养丰富的生物炭，在两个施用率（1％和5％（重量/重量）），在除仅施肥和对照处理外。黑麦草播种在盆中，除对照外，所有其他都接受了¹⁵ N标记的肥料，即¹⁵ NH ₄ NO ₃或NH ₄ ¹⁵ NO ₃。我们量化生物炭申请的效果对土壤氮素₂ O排放，以及肥料衍生铵的命运（NH ₄ ⁺）和硝酸盐（NO ₃ ^-）从土壤中浸出，吸收到植物生物质中以及土壤中的恢复方面。我们发现生物炭的应用减少了土壤矿物氮的淋失和N ₂ O的排放。同样，较高的生物炭施用率5％会显着增加地上黑麦草生物量的产量。但是，常规和富营养生物炭处理之间未观察到N ₂ O排放量和黑麦草生物量产量的差异，尽管在富营养生物炭处理中矿物氮的浸出趋向于低于常规生物炭处理。在¹⁵N分析表明，与仅施肥相比，生物炭的施用增加了植物吸收硝酸盐的吸收，但降低了植物吸收铵盐的吸收。因此，从添加的NH ₄ NO ₃肥料中吸收的总氮不受生物炭添加的影响，也不能解释生物炭处理中植物生物量的增加。取而代之的是，在较高的生物炭施用率下增加的植物生物量归因于来自土壤的氮的吸收增加。这表明生物炭和天然土壤有机氮之间的相互作用可能是土壤氮对植物生长可用性的重要决定因素。