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

据报道，在土壤中施用生物炭具有减轻硝酸盐浸出的潜力，因此，除了固碳以外，还可以发挥有益的作用。本研究的主要目的是确认在先前的研究中已证明能够减少土壤可溶性硝酸盐的松树气化生物炭是否确实可以发挥这种作用，并确定其机理。为此，溶氧计含有0、12和50 t生物炭ha ^-1的土壤-生物炭混合物我们在两种不同的情况下进行了调查：由新鲜生物炭和休耕土壤组成的新鲜生物炭情景，以及在作物管理土壤中具有6年自然老化生物炭的老化生物炭情景。在模拟的地中海环境下，在温室环境中，在8个月内（包括大麦种植周期），对土壤柱进行了评估。评估了一组与氮循环有关的参数，特别是与可以直接或间接解释硝酸盐含量降低的机制有关的参数（即吸附，浸出，微生物介导的过程，挥发，植物吸收和生态毒理效应）。具体测量包括土壤溶液和渗滤液离子组成，微生物生物量和活性，温室气体（GHG）排放，硝酸盐的氮和氧同位素组成，作物产量和质量，以及生态毒理学终点。在12 t和50 t ha的新鲜生物炭情景下，已验证了土壤溶液中硝酸盐含量的减少^-1处理，并显着减少了氯化物，钠，钙和镁。仅在施用生物炭八个月后才注意到这种效果，因此表明了时间依赖性过程。丢弃所有其他测试机制，出现了有机矿物涂层的形成，可以作为离子含量降低的合理解释。