The CO₂ emission rates have been continuously incremented during the last decades. To mitigate it, a method to store carbon in terrestrial ecosystems is the addition of biochar to soil. After its application to soil, biochar suffers an ageing process, able to deteriorate its functional properties as soil improver. However, at present, it is not clear how to evaluate biochar ageing. The main aim of this study is to evaluate biochar ageing by determination of temporal changes on (a) soil respiration after biochar addition and (b) the relationship between CO₂ adsorption capacity and wettability of biochar as measurable parameters indicating biochar ageing. Results show that 1 month after biochar addition, soil respiration decreased when poplar and pine biochars were applied to bare soils, in the absence of vegetation. One year after biochar addition, this reduction on soil respiration disappeared, evidencing biochar ageing due to decrements on its CO₂ adsorption capacity. Compared with fresh biochar, decreased CO₂ adsorption capacity of biochar corresponded with enhanced biochar wettability for both biochar types. Its means that poplar and pine biochars, while initially hydrophobic, became hydrophilic after 1 year of its application to soil. It is concluded that changes of biochar CO₂ adsorption capacity in time go along with improved wettability as mutually opposed processes. Globally, pine biochar tends to adsorb a higher quantity of CO₂ than poplar biochar. The absence of CO₂ adsorption of soil without biochar demonstrates the remarkable capacity of both biochars to adsorb carbon dioxide and promote carbon storage in soils.

CO ₂排放率在过去几十年中不断增加。为了缓解这一问题，在陆地生态系统中储存碳的一种方法是在土壤中添加生物炭。在应用于土壤后，生物炭会经历老化过程，其作为土壤改良剂的功能特性会恶化。然而，目前尚不清楚如何评价生物炭的老化。本研究的主要目的是通过确定（a）添加生物炭后土壤呼吸的时间变化和（b）CO ₂吸附能力与生物炭润湿性之间的关系作为指示生物炭老化的可测量参数来评估生物炭老化。结果表明，添加生物炭1个月后，在没有植被的裸露土壤上施用杨树和松树生物炭时，土壤呼吸减少。添加生物炭一年后，土壤呼吸的这种减少消失，证明生物炭由于其CO ₂吸附能力下降而老化。与新鲜生物炭相比，两种生物炭类型的生物炭CO ₂吸附能力降低与生物炭润湿性增强相对应。这意味着杨树和松树生物炭虽然最初是疏水性的，但在施用于土壤一年后变得亲水性。结论是生物炭CO ₂吸附能力随时间的变化与润湿性的提高是相反的过程。在全球范围内，松树生物炭往往比杨树生物炭吸附更多的CO ₂量。没有生物炭的土壤不存在CO ₂吸附，这表明两种生物炭具有吸附二氧化碳和促进土壤碳储存的显着能力。