-
土壤碳库作为陆地生态系统中最大的碳库,是陆地植物及土壤动物和微生物生存的养分库,而土壤对有机碳的矿物保护和团聚体保护,使得有机碳固存在土壤中,这对于减缓大气CO2浓度上升有重要意义[1]。而土壤有机碳的含量取决于其积累与分解的速率[2]。凋落物作为植物生长发育过程中的产物,其分解后残留在土壤中的有机碳是土壤碳库重要的来源之一[3]。研究者对凋落物分解做了很多研究,包括凋落物的分解及养分释放,主要有分解的过程、分解过程中状态的变化[4-8],还有不同类型、不同性状的凋落物或植物残体的分解[9-12],以及影响凋落物分解的因素研究[13-14]。影响凋落物分解的因素主要分为内在因素、气候因素、土壤因素等[15],而研究发现凋落物的分解还依赖于土壤动物[16]、土壤微生物多样性[17]等。蚯蚓作为典型的大型土壤动物,其生存所需来自土壤,但是又通过摄入土壤和凋落物或再分配等活动直接或间接影响土壤[18],对土壤的肥力和理化性质等的变化发挥不可小觑的作用。研究表明,蚯蚓对凋落物和有机质腐烂的影响强烈依赖于蚯蚓生态型和多样性,且蚯蚓生态型的高度多样性加速了凋落物的质量损失和有机质的腐烂[19]。
目前可以明确的信息是蚯蚓通过影响凋落物的分解为土壤碳库做出了巨大贡献,但是对于不同蚯蚓类群对土壤碳库的影响的研究过于单一,且研究大多集中于对土壤碳库总体的变化的阐明,缺少关于不同生态类型蚯蚓及其交互作用对凋落物源碳在土壤不同组分的分配规律的影响的研究。稳定碳同位素技术是研究土壤碳循环,探究土壤碳转化、分配的高效又科学的方法之一[20],用其标记植物后,可用来示踪植物残体有机碳在土壤中的转化与分配。因此,本研究采用稳定碳同位素技术,以不同生态类群蚯蚓和杨树叶凋落物为研究对象,结合室内培养实验,研究凋落物源碳在蚯蚓作用下在土壤中的转化与分配规律,揭示凋落物源碳在蚯蚓作用下在土壤中的去向,为深入研究不同生态型蚯蚓对杨树人工林土壤固碳增汇潜力的影响提供理论依据和数据支撑。
不同生态类群蚯蚓对凋落物源碳在土壤团聚体中的分配的影响
Effects of Different Ecological Groups of Earthworms on the Distribution of Litter into Aggregates
-
摘要:
目的 通过研究不同生态型蚯蚓作用下凋落物源碳在土壤中的转化与分配规律,揭示凋落物源碳在土壤中的去向,为深入探究蚯蚓对杨树人工林土壤固碳增汇潜力的影响提供理论依据和数据支撑。 方法 应用脉冲标记法标记富集13C的杨树幼苗叶片;接种3种不同生态型蚯蚓,通过室内短期培养试验(室温25℃,培养120 d),研究不同生态型蚯蚓作用下凋落物源碳在粗大团聚体(d>2 mm)、细大团聚体(2 mm≥d>0.25 mm)、微团聚体(0.25 mm≥d>0.053 mm)和粉-黏团聚体(d≤0.053 mm)4个粒径级别的水稳性团聚体中的分配。 结果 接种蚯蚓后,显著促进了凋落物源碳向土壤中的并入与分配,土壤δ13C值显著提高,单独接种表栖型蚯蚓提升的幅度最低,表栖型和表-内栖型共同作用提升的幅度最高;不同粒级土壤水稳性团聚体的δ13C值在蚯蚓的作用下均显著升高;4种土壤团聚体的δ13C值,都是粉-黏团聚体的最低,粗大团聚体和细大团聚体中最高,接种赤子爱胜蚓对凋落物向土壤团聚体中并入作用效果低于接种皮质远盲蚓和威廉环毛蚓。 结论 120 d的短期培养内,不同生态型蚯蚓作用显著促进凋落物源碳向土壤中的并入与分配,更是显著增加了凋落物源碳在粗大团聚体和细大团聚体中的积累,且在表-内栖型蚯蚓和深栖型参与作用下,更显著提高了凋落物源碳向团聚体中的分配。建议可以在林业生产经营过程中适当增加林木凋落物残体的施用,同时考虑不同生态型蚯蚓之间的协同和竞争作用,接种多种类型蚯蚓以改善或增强蚯蚓调节林业生态系统中土壤有机碳(SOC)动态的潜能,加速土壤中外源有机质向土壤中的并入与分配。 Abstract:Objective By studying the transformation and distribution patterns of litter-derived carbon in soil under the action of different ecotypes of earthworms, providing theoretical basis and data support for exploration of the impact of earthworms on the carbon sequestration and sink enhancement potential of soil in poplar plantations. Methods The leaves of poplar seedlings enriched with 13C were marked by pulse labeling method. Three different ecotypes of earthworms were inoculated to study the distribution of litter source carbon in water-stable aggregates of coarse aggregates (d>2 mm), fine aggregates (2≥d>0.25 mm), microaggregates (0.25≥d>0.053 mm) and silt-clay aggregates (d≤0.053 mm) under the action of different ecotypes of earthworms. Results After inoculation of earthworms, the incorporation and distribution of litter source carbon into the soil were significantly promoted, and the soil δ13C value was significantly increased. The enhancement range of epigeic earthworms was the lowest, in contrast, that of epi-endogeic and anecic types was the highest. The δ13C values of soil water stable aggregates of different particle sizes increased significantly under the action of earthworms. The δ13C values of four kinds of soil aggregates were the lowest in silt-clay aggregates, and the highest in coarse aggregates and fine aggregates. The effect of Eisenia foetida on the incorporation of litter into soil aggregates was lower than that of Amynthas corticis and Pheretima guillelmi. Conclusion After 120 days of short-term culture, different ecotypes of earthworms significantly promotes the incorporation and distribution of litter-derived carbon into the soil, and significantly increases the accumulation of litter source carbon in coarse aggregates and fine aggregates. With the participation of epi-endogeic and anecic types, the distribution of carbon to aggregates from litter is significantly increased. We suggest that the application of forest litter residues should be appropriately increased in the process of forestry production and management, and the cooperation and competition among different ecotypes of earthworms should be taken into account. Multiple types of earthworms should be inoculated to improve or enhance the potential of earthworms to regulate soil organic carbon (SOC) dynamics in the forestry ecosystem, accelerating the incorporation and distribution of exogenous organic matter into the soil. -
Key words:
- earthworms
- / ecological groups
- / soil aggregates
- / litter-derived carbon
- / δ13C
-
[1] 汪业勖, 赵士洞, 牛 栋. 陆地土壤碳循环的研究动态[J]. 生态学杂志, 1999, 18(5):29-35. [2] 金 峰, 杨 浩, 赵其国. 土壤有机碳储量及影响因素研究进展[J]. 土壤, 2000(1):12-18. [3] 李常准, 陈立新, 段文标, 等. 凋落物处理对不同林型土壤有机碳全氮全磷的影响[J]. 中国水土保持科学, 2020, 18(1):100-109. [4] 胡肄慧, 陈灵芝, 陈清朗, 等. 几种树木枯叶分解速率的试验研究[J]. 植物生态学与地植物学学报, 1987, 11(2):124-132. [5] WANG B, BLONDEEL H, BAETEN L, et al. Direct and understorey-mediated indirect effects of human-induced environmental changes on litter decomposition in temperate forest[J]. Soil Biology and Biochemistry, 2019, 138: 107579. doi: 10.1016/j.soilbio.2019.107579 [6] 代松家, 周晨霓, 段 斐, 等. 组分和生境差异对藏东南原始冷杉林凋落物分解和养分释放特征的影响[J]. 中国水土保持科学(中英文), 2020, 18(6):72-80. [7] HEIM A, FREY B. Early stage litter decomposition rates for Swiss forests[J]. Biogeochemistry, 2004, 70(3): 299-313. doi: 10.1007/s10533-003-0844-5 [8] DJUKIC I, KEPFER-ROJAS S, SCHMIDT I K, et al. Early stage litter decomposition across biomes[J]. Science of the Total Environment, 2018, 628-629: 1369-1394. doi: 10.1016/j.scitotenv.2018.01.012 [9] 鲁 昱, 崔莎莎, 李文洋, 等. 三种常见挺水植物凋落物的分解动态及养分释放规律[J]. 植物科学学报, 2023, 41(1):17-25. [10] 梁嘉玲, 莫维维, 陆湘云, 等. 海岸带3种林分类型凋落物-土壤-酶活性动态变化[J]. 森林与环境学报, 2022, 42(5):521-528. [11] 牛喜妹, 李佳南, 王 平, 等. 羊草地上不同性状凋落物分解对土壤碳组分的影响[J]. 环境生态学, 2022, 4(9):54-60. [12] BA Z D, GEER T, DU H S, et al. Effects of different litter treatments on soil microbial biomass carbon and nitrogen in temperate grassland[J]. Journal of Biotech Research, 2022, 13: 260-268. [13] LUAN J W, LI S Y, DONG W, et al. Litter decomposition affected by bamboo expansion is modulated by litter-mixing and microbial composition[J]. Functional Ecology, 2021, 35(11): 2562-2574. doi: 10.1111/1365-2435.13911 [14] ANGST G, POKORNY J, MUELLER C W, et al. Soil texture affects the coupling of litter decomposition and soil organic matter formation[J]. Soil Biology and Biochemistry, 2021, 159(1): 108302. [15] 周庭宇, 肖 洋, 黄庆阳, 等. 森林凋落物分解的研究进展与展望[J]. 中国农学通报, 2022, 38(33):44-51. [16] 邓承佳, 袁 访, 卜通达, 等. 土壤动物对黔中地区喀斯特森林凋落物分解的影响[J]. 林业科学研究, 2022, 35(3):72-81. [17] 董学德, 高 鹏, 李 腾, 等. 土壤微生物群落对麻栎-刺槐混交林凋落物分解的影响[J]. 生态学报, 2021, 41(6):2315-2325. [18] 单 军, 季 荣. 土食性大型土壤动物转化土壤有机碳的14C示踪法应用研究进展[J]. 土壤, 2008, 40(6):863-871. [19] HUANG W, GONZÁLEZ G, ZOU X. Earthworm abundance and functional group diversity regulate plant litter decay and soil organic carbon level: A global meta-analysis[J]. Applied Soil Ecology, 2020, 150: 103473. doi: 10.1016/j.apsoil.2019.103473 [20] 李发东, 栗照鑫, 乔云峰, 等. 土壤有机碳同位素组成在农田生态系统碳循环中的应用进展[J]. 中国生态农业学报(中英文), 2023, 31(2):194-205. [21] BAHN M, LATTANZI F A, HASIBEDER R, et al. Responses of belowground carbon allocation dynamics to extended shading in mountain grassland[J]. New Phytologist, 2013, 198(1): 116-126. doi: 10.1111/nph.12138 [22] ZHANG W X, HENDRIX P F, DAME L E, et al. Earthworms facilitate carbon sequestration through unequal amplification of carbon stabilization compared with mineralization[J]. Nature Communications, 2013, 4(10): 2576. [23] SIX J, CALLEWAERT P, LENDERS S, et al. Measuring and understanding carbon storage in afforested soils by physical fractionation[J]. Soil Science Society of America Journal, 2002, 66(6): 1981-1987. doi: 10.2136/sssaj2002.1981 [24] 康玉娟, 武海涛. 蚯蚓对土壤碳氮循环关键过程的影响及其机制研究进展[J]. 土壤与作物, 2021, 10(2):150-162. [25] COQ S, BARTHES B G, OLIVER R, et al. Earthworm activity affects soil aggregation and organic matter dynamics according to the quality and localization of crop residues - An experimental study (Madagascar)[J]. Soil Biology and Biochemistry, 2007, 39(8): 2119-2128. doi: 10.1016/j.soilbio.2007.03.019 [26] ZHENG Y, WANG S, BONKOWSKI M, et al. Litter chemistry influences earthworm effects on soil carbon loss and microbial carbon acquisition[J]. Soil Biology and Biochemistry, 2018, 123: 105-114. doi: 10.1016/j.soilbio.2018.05.012 [27] 于建光, 胡 锋, 李辉信, 等. 接种蚯蚓对土壤团聚体分布、稳定性及有机碳赋存的影响[J]. 水土保持学报, 2010, 24(3):175-179 + 184. [28] ZHU X Y, HU Y C, WANG W, et al. Earthworms promote the accumulation of maize root-derived carbon in a black soil of Northeast China, especially in soil from long-term no-till[J]. Geoderma, 2019, 340: 124-132. doi: 10.1016/j.geoderma.2019.01.003 [29] HOANG D T T, BAUKE S L, KUZYAKOV Y, et al. Rolling in the deep: Priming effects in earthworm biopores in topsoil and subsoil[J]. Soil Biology and Biochemistry, 2017, 114: 59-71. doi: 10.1016/j.soilbio.2017.06.021 [30] FERLIAN O, EISENHAUER N, AGUIRREBENGOA M, et al. Invasive earthworms erode soil biodiversity: A meta-analysis[J]. Journal of Animal Ecology, 2018, 87(1): 162-172. doi: 10.1111/1365-2656.12746 [31] LUBBERS I M, VAN GROENIGEN K J, FONTE S J, et al. Greenhouse-gas emissions from soils increased by earthworms[J]. Nature Climate Change, 2013, 3(3): 187-194. doi: 10.1038/nclimate1692 [32] 徐 璇, 王维枫, 阮宏华. 土壤动物对森林凋落物分解的影响: 机制和模拟[J]. 生态学杂志, 2019, 38(9):2858-2865. [33] SIX J, PAUSTAIN K, ELLIOT E T, et al. Soil structure and organic matter: I. Distribution of aggregate-size classes and aggregate-associated carbon[J]. Soil Science Society of America Journal, 2000, 64(2): 681-689. doi: 10.2136/sssaj2000.642681x [34] 慈 恩, 杨林章, 马 力, 等. 长期耕作水稻土的有机碳分布和稳定碳同位素特征[J]. 水土保持学报, 2007, 21(5):72-75 + 179. [35] 李涵诗, 毛艳玲, 邹双全. δ13C标记林木残体碳在土壤团聚体中的分布[J]. 土壤学报, 2017, 54(4):1038-1046. [36] 吕元春, 薛丽佳, 尹云锋, 等. 外源新碳在不同类型土壤团聚体中的分配规律[J]. 土壤学报, 2013, 50(3):534-539. [37] BOSSUYT H, SIX J, HENDRIX P F. Interactive effects of functionally different earthworm species on aggregation and incorporation and decomposition of newly added residue carbon[J]. Geoderma, 2006, 130(1-2): 14-25. doi: 10.1016/j.geoderma.2005.01.005 [38] WU J T, LI H Q, ZHANG W X, et al. Contrasting impacts of two subtropical earthworm species on leaf litter carbon sequestration into soil aggregates[J]. Journal of Soils and Sediments, 2017, 17(6): 1672-1681. doi: 10.1007/s11368-017-1657-9 [39] BOSSUYT H, SIX J, HENDRIX P F. Protection of soil carbon by microaggregates within earthworm casts[J]. Soil Biology and Biochemistry, 2005, 37(2): 251-258. doi: 10.1016/j.soilbio.2004.07.035 [40] YAVITT J B, FAHEY T J, SHERMAN R E, et al. Lumbricid earthworm effects on incorporation of root and leaf litter into aggregates in a forest soil, New York state[J]. Biogeochemistry, 2015, 125(2): 261-273. doi: 10.1007/s10533-015-0126-z