摘要
树种是调控森林土壤有机碳(SOC)积累的重要因子。为明确树种变化对红壤侵蚀退化地表层SOC积累的影响,采用配对实验设计,选择不同恢复年限的马尾松纯林和马尾松+木荷混交林(19和39 a)为研究对象,对比分析表层(0~10 cm)SOC质量分数的差异,并利用相关性分析与结构方程模型探讨其与凋落物特征、土壤氮素水平和微生物群落组成的关系。结果表明:1)恢复19 a的纯林和混交林SOC质量分数无显著差异,而恢复39 a混交林SOC质量分数较恢复19 a纯林、恢复19 a混交林以及恢复39 a纯林分别高39.8%、48.0%和93.6%(P<0.05);2)SOC质量分数与土壤微生物生物量碳、土壤微生物生物量氮、磷脂脂肪酸总量、矿质氮和细菌呈显著或极显著正相关,与凋落物C/N和真菌细菌之比(F/B)呈显著或极显著负相关;3)结构方程模型分析表明,凋落物C/N是松阔混交后表层SOC质量分数变化的触发因子,矿质氮是微生物群落结构变化的关键因子。凋落物C/N可直接驱动SOC质量分数的变化(-0.35*),或通过矿质氮(-0.70***)诱导F/B、丛枝菌根真菌和细菌的变化起间接调控作用,以上因子共解释SOC质量分数变异的86.8%。综上,松阔混交促进侵蚀退化地SOC的积累,且其有效性随恢复年限增强。这个过程主要通过提升凋落物质量、增加微生物养分来源和土壤氮有效性、改变微生物群落结构完成。在我国实施“双碳”战略的背景下,多树种混交对红壤区退化马尾松林SOC提升具有重要意义。
[Background]Vegetation types play an important role in stimulating the carbon sequestration potential of eroded and degraded soil.However,how the changes of tree species in subtropical forest ecosystems affect the accumulation of soil organic carbon(SOC)in the surface soil of eroded and degraded red soil and its microbial mechanism are still unclear.Changting county of Fujian province is a typical eroded and degraded area of red soil in China and a key area of stand transformation.[Methods]Field investigation and sample collection were conducted in different age groups(19 and 39 years)Pinus massoniana pure plantation and P.massoniana and Schima superba mixed plantation.Soil samples were collected in top 0-10 cm layers to measure SOC content,microbial community and related environmental factors.Among them,the microbial community was measured by phospholipid fatty acid(PLFA)method.Correlation analysis and structural equation modeling were used to analyze the relationship between SOC and environmental factors and microbial community composition.[Results]1)There were no significant differences in SOC content between pure and mixed plantations after 19 years of restoration,while SOC content of the mixed plantation after 39 years of restoration were 39.8%,48.0%and 93.6%higher than that of the pure plantation after 19 years of restoration,the mixed plantation after 19 years of restoration,and the pure plantation after 39 years of restoration(P<0.05).2)SOC content was significantly and positively correlated with soil microbial biomass carbon,microbial biomass nitrogen,total phospholipid fatty acids,mineral nitrogen(N)and bacteria,and significantly negatively correlated with the ratio of litter C/N to fungal bacteria(F/B).3)Structural equation model analysis showed that litter C/N was the trigger factor for the change of SOC and mineral nitrogen was the key factor for the change of microbial community structure in the process of stand transformation.The litter C/N directly drove the change of SOC mass fraction(-0.35*),or indirectly regulated the changes of F/B,arbuscular mycorrhizal fungi and bacteria by mineral nitrogen(-0.70***).The above factors explained 86.8%of the variation of SOC mass fraction.[Conclusions]Mixed coniferous and broad leaf tree species promote SOC accumulation in eroded degraded land,and its effectiveness increases with the restoration years.The possible mechanism could be that the S.superba litter is continuously introduced,which significantly reduces C/N of litter,enhances the source of microbial nutrients and N availability and changes microbial community structure,ultimately increases SOC mass fraction.Under the background of“Double Carbon”in China,a multi-species mixture will become a key way to improve forest quality and SOC sequestration in eroded and degraded areas.
作者
王慧钦
吕茂奎
姜永孟
吴君梅
朱洪如
张世良
邓翠
谢锦升
WANG Huiqin;L Maokui;JIANG Yongmeng;WU Junmei;ZHU Hongru;ZHANG Shiliang;DENG Cui;XIE Jinsheng(College of Geographical Science,Key Laboratory of Humid Subtropical Eco-Geographical Processes of the Ministry of Education,Fujian Normal University,350007,Fuzhou,China;Fujian Sanming Forest Ecosystem National Observation and Research Station,350007,Fuzhou,China;Fujian Forestry Survey and Planning Institute,350003,Fuzhou,China)
出处
《中国水土保持科学》
CSCD
北大核心
2024年第1期12-20,共9页
Science of Soil and Water Conservation
基金
国家自然科学基金重点项目“亚热带森林恢复过程中植物来源的底物质量对稳定性土壤有机质的影响机制”(32030073)
福建省林业科技计划项目“长汀马尾松低效林森林质量精准提升抚育改造技术及模式优选”(2021FKJ16)。
关键词
土壤有机碳
针阔混交
林龄
微生物群落组成
凋落物质量
马尾松人工林
侵蚀退化地
soil organic carbon
coniferous and broadleaf tree mixture
stand age
microbial community composition
litter quality
Pinus massoniana plantation
eroded and degraded soil
