引用本文:卢晓蓉,尹 艳,冯竞仙,马红亮,高 人,尹云锋.杉木凋落物及其生物质炭对土壤原有有机碳矿化的影响[J].土壤学报,2020,57(4):943-953. DOI:10.11766/trxb201906040226
LU Xiaorong,YIN Yan,FENG Jingxian,MA Hongliang,GAO Ren,YIN Yunfeng.Effects of Chinese Fir Litter and its Biochar Addition on Mineralization of Native Soil Organic Carbon[J].Acta Pedologica Sinica,2020,57(4):943-953. DOI:10.11766/trxb201906040226
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杉木凋落物及其生物质炭对土壤原有有机碳矿化的影响
卢晓蓉, 尹 艳, 冯竞仙, 马红亮, 高 人, 尹云锋
湿润亚热带山地生态国家重点实验室培育基地,福建师范大学地理科学学院
摘要:
利用13C同位素技术和培养实验,研究不同添加量(0、10、20、30、40、50 g·kg-1)杉木凋落物和生物质炭(Biochar,BC,350℃热解)对土壤原有有机碳(原SOC)矿化及外源碳自身分解的影响。实验进行28 d,培养温度为25℃,水分保持为60%土壤持水量(Water holding capacity,WHC)。结果表明:凋落物及BC添加显著提高了土壤总CO2累积排放量(P<0.05),且凋落物的影响更为明显;来源于外源碳及原SOC的CO2累积排放量均随添加量的增加而增加。培养结束时,凋落物碳(LR-C)分解率为5.71%~13.68%,生物质炭碳(BC-C)分解率仅0.34%~0.50%,凋落物和BC处理下原SOC分解率分别为对照土壤的6.42倍~13.58倍与2.06倍~3.94倍。回归分析发现,2种外源碳处理下原SOC分解率与添加量均呈极显著的线性关系(P<0.01);LR-C分解率亦随添加量的增加而增加;但BC-C分解率则与添加量呈显著的开口向上的抛物线关系(P<0.05),并在10 g·kg-1添加量时达到最大。相关分析表明,短期内BC分解受微生物活动的影响较小,在土壤中更加稳定。因此,将凋落物制备为BC后施入更有利于杉木人工林土壤有机碳固存。
关键词:  凋落物  生物质炭  原有有机碳  分解率  人工林
基金项目:国家自然科学基金项目(31470628,31770659)和教育部科学技术研究项目(213019A)资助
Effects of Chinese Fir Litter and its Biochar Addition on Mineralization of Native Soil Organic Carbon
LU Xiaorong, YIN Yan, FENG Jingxian, MA Hongliang, GAO Ren, YIN Yunfeng
State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, School of Geographical Sciences, Fujian Normal University
Abstract:
【Objective】 Understanding of how soil organic carbon (SOC) mineralization in response to management practice and environment change is crucial for mitigating greenhouse gases emission and minimizing the impacts of forest ecosystems on climate. However, there is little information available about relationship of SOC mineralization with quantity of extraneous carbon. In this experiment, effects of addition of Chinese fir litter and its biochar (BC), on native SOC mineralization were investigated to provide certain scientific basis for building up soil fertility in Chinese fir plantations and utilizing biomass resources efficiently in subtropical China. 【Method】 In this study, soil samples (0-20 cm topsoil layer) were collected from the Cunninghamia lanceolata plantation at the Wanmulin Nature Reserve of Fujian Province. 13C-labeled litter (Chinese fir) and its biochar (pyrolysed at 350°C) were used as two different types of extraneous carbon (an easily decomposable carbon and a relatively stable carbon) in the indoor incubation experiment. The experiment consisted of 11 treatments, i.e. S (soil without any addition), SL1 (soil added with 10 g·kg-1 litter), SL2 (soil added with 20 g·kg-1 litter), SL3 (soil added with 30 g·kg-1 litter), SL4 (soil added with 40 g·kg-1 litter), SL5 (soil added with 50 g·kg-1 litter), SB1 (soil added with 10 g·kg-1 BC), SB2 (soil added with 20 g·kg-1 BC), SB3 (soil added with 30 g·kg-1 BC), SB4 (soil added with 40 g·kg-1 BC) and SB5 (soil added with 50 g·kg-1 BC). The carbon derived from different sources was distinguished with the 13C isotope technique. The soil samples were incubated at 25°C with water holding capacity kept at 60% for 28 days. 【Result】Results show that the addition of either litter or BC significantly increased the cumulative amount of CO2, and the effect of the litter treatments was more obvious than that of their corresponding BC treatments. Cumulative CO2 derived from added litter or BC and native SOC increased with increasing quantity of the extraneous carbon. After 28 days of incubation, 5.71%-13.68% of the litter carbon (LR-C) was decomposed, whereas only 0.34%-0.50% of the biochar carbon (BC-C) was, and 6.42-13.58 times and 2.06-3.94 times as much of the native SOC in the litter and BC treatments, respectively, as that in Treatment S was decomposed. Regression analysis shows that there was a significant linear relationship between native SOC decomposition rate and quantity of the extraneous carbon added (P<0.01). LR-C decomposition rate was positively related to addition rate of the extraneous carbon, while BC-C decomposition rate displayed a significant parabolic relationship (P<0.05) and peaked when the addition rate was 10 g·kg-1 (Treatment SB1). 【Conclusion】 Addition of litter and BC accelerated mineralization of native SOC and the effect increased with addition rates. Compared with decomposition of litter, that of BC was less affected by microbial activity due to its lower bioavailability and higher stability in the tested soil during the short incubation period. Therefore, it may be a management practice more conducive to enhancing soil carbon sequestration of the plantations in this region, to return biochar into the soil.
Key words:  Litter  Biochar  Native soil organic carbon  Decomposition rate  Plantation