Gross Cole D, Bork Edward W, Carlyle Cameron N, Chang Scott X
Department of Renewable Resources, Faculty of Agricultural, Life and Environmental Sciences, University of Alberta, 442 Earth Sciences Building, Edmonton, AB T6G 2E3, Canada.
Department of Agricultural, Food and Nutritional Science, Faculty of Agricultural, Life and Environmental Sciences, University of Alberta, 410 Agriculture/Forestry Centre, Edmonton, AB T6G 2P5, Canada.
Sci Total Environ. 2022 Feb 1;806(Pt 3):151337. doi: 10.1016/j.scitotenv.2021.151337. Epub 2021 Oct 30.
Applying organic amendments to soil can increase soil organic carbon (SOC) storage and reduce greenhouse gas (GHG) emissions generated by agriculture, helping to mitigate climate change. However, it is necessary to determine which type of amendment produces the most desirable results. We conducted a 3-y field study comparing one-time addition of manure compost and its biochar derivative to a control to assess their effects on SOC and GHG emissions at ten annually cropped sites in central Alberta, Canada. Manure compost and biochar were applied at equivalent carbon rates (7 Mg ha) and tilled into the surface 10 cm of soil. Two years post-treatment, biochar addition increased surface (0-10 cm) SOC by 12 and 10 Mg ha relative to the control and manure addition, respectively. Therefore, biochar addition led to the sequestration of SOC at a rate of 2.5 Mg ha y relative to the control. No treatment effect on deeper (10-100 cm) or cumulative SOC was found. In 2018 and 2019, manure addition increased cumulative GHG (sum of CO, CH, and NO) emissions by 33%, on average, due to greater CO emissions relative to both the control and biochar addition. In contrast, in 2020, biochar addition reduced cumulative GHG emissions by an average of 21% due to lower CO emissions relative to both the control and manure addition. Our study shows that the application of biochar, rather than its manure compost feedstock, increased surface SOC sequestration and had either no effect on (first two years) or reduced GHG emissions (year three) relative to the control. We recommend that policy and carbon sequestration initiatives focus on optimizing biochar production-application systems to fully realize the potential of biochar application as a viable climate change mitigation practice in agriculture.
向土壤中添加有机改良剂可以增加土壤有机碳（SOC）储量，并减少农业产生的温室气体（GHG）排放，有助于缓解气候变化。然而，有必要确定哪种类型的改良剂能产生最理想的效果。我们进行了一项为期3年的田间研究，将一次性添加粪肥堆肥及其生物炭衍生物与对照进行比较，以评估它们对加拿大艾伯塔省中部10个常年种植地的土壤有机碳和温室气体排放的影响。粪肥堆肥和生物炭以等量碳率（7 Mg ha）施用，并翻耕到土壤表层10厘米。处理后两年，相对于对照和添加粪肥，添加生物炭分别使表层（0 - 10厘米）土壤有机碳增加了12 Mg ha和10 Mg ha。因此，相对于对照，添加生物炭导致土壤有机碳以每年2.5 Mg ha的速率固存。未发现对更深层（10 - 100厘米）或累积土壤有机碳有处理效果。在2018年和2019年，由于相对于对照和添加生物炭，二氧化碳排放量更高，添加粪肥平均使累积温室气体（二氧化碳、甲烷和一氧化二氮之和）排放量增加了33%。相比之下，在2020年，由于相对于对照和添加粪肥，二氧化碳排放量更低，添加生物炭平均使累积温室气体排放量减少了21%。我们的研究表明，与对照相比，应用生物炭而非其粪肥堆肥原料增加了表层土壤有机碳固存，并且在前两年对温室气体排放没有影响，在第三年减少了温室气体排放。我们建议政策和碳固存倡议应专注于优化生物炭生产 - 应用系统，以充分发挥生物炭应用作为农业中可行的气候变化缓解措施所具有的潜力。
