摘要
【目的】凋落物回归影响着杉木(Cunninghamia lanceolata)人工林土壤碳氮循环,是杉木人工林可持续经营和土壤地力维持的重要过程。通过分析添加杉木与木荷(Schima superba)凋落物处理下土壤碳氮含量和酶活性的变化特征,为杉木人工林近自然化改造及林分管理提供依据。【方法】以30年生杉木人工林土壤为研究对象,分别添加杉木凋落物(S)、木荷凋落物(M)以及杉木与木荷凋落物混合物(SM),混合质量比例设置为m(杉木)∶m(木荷)=5∶1。通过60 d室内培养,测定不同处理土壤中铵态氮(NH^(+)_(4)-N)、硝态氮(NO^(-)_(3)-N)、土壤有机碳(SOC)、水溶性有机碳(WSOC)、酸溶性有机碳(HHOC)、碱溶性有机碳(AHOC)、难溶性有机碳(ROC)含量及酶活性[β-葡萄糖苷酶(GC),β-N-乙酰氨基葡萄糖苷酶(NAG),多酚氧化酶(PPO),亮氨酸氨基肽酶(LAP)]。基于单因素方差分析和冗余分析方法,研究不同处理下土壤碳氮含量与土壤酶活性的关系,探讨添加不同凋落物对杉木人工林土壤碳氮含量及酶活性的影响。【结果】(1)SM处理的土壤腐殖化程度高于添加单一凋落物的;在添加单一凋落物的处理中,M处理的土壤腐殖化程度较低,土壤中ROC含量占比较高。(2)处理至15和30 d时,S处理土壤的GC、NAG、PPO酶活性显著高于M处理土壤的;SM处理的可显著提高土壤GC和NAG活性。(3)相关分析表明,土壤中AHOC含量与GC活性呈极显著正相关;NAG活性与WSOC含量呈极显著正相关,与NH~+_(4)-N含量呈极显著负相关;而PPO活性与NO~-_(3)-N含量呈极显著负相关,与ROC、HHOC含量呈极显著正相关(P<0.01)。【结论】添加不同凋落物对杉木人工林土壤碳氮含量及酶活性产生显著影响。与添加木荷凋落物相比,添加杉木凋落物的土壤腐殖化程度较高,与碳氮循环相关的酶活性较高;与添加单一凋落物相比,添加杉木木荷凋落物混合物更有利于土壤腐殖化程度的提升,提高土壤碳氮转化酶活性,进而有利于杉木人工林土壤碳氮循环。
【Objective】Litter regression can affect the soil carbon and nitrogen cycle,which is an important process of sustainable management and soil fertility maintenance in Chinese fir(Cunninghamia lanceolata)plantations.The changes in soil carbon content,nitrogen content,and enzyme activity under the treatment of adding C.lanceolata and Schima superba litter were analyzed to provide the basis for nature-approximating transformation and stand management of C.lanceolata plantations.【Method】In the present study,30-year-old C.lanceolata plantation soil was treated with C.lanceolata litter(S),S.superba litter(M),and a mixture of C.lanceolata and S.superba litter(mixed at a m(S):m(M)=5:1,SM).After 60 days of incubation,the content of ammonium nitrogen(NH_(4)^(+)-N),nitrate nitrogen(NO_(3)^(-)-N),soil organic carbon(SOC),water soluble organic carbon(WSOC),hydrochloric acid hydrolyzed organic carbon(HHOC),alkaline-hydrolyzable organic carbon(AHOC),recalcitrant organic carbon(ROC),and enzyme activities(β-glucosidase(GC);β-N-acetylglucosaminidase(NAG);polyphenol oxidase(PPO);and leucine aminopeptidase(LAP))in the soil were measured in the different treatments.The relationship among soil carbon content,nitrogen content,and enzyme activity in different treatments was analyzed,and the effects of different litter on soil carbon content,nitrogen content,and enzyme activity in C.lanceolata plantations were evaluated.【Result】The degree of humification in the soil treated with mixed litter was increased compared to the soils treated with either litter alone.In the single litter treatment,the degree of humification with S.superba treatment was low,and the proportion of soil recalcitrant organic carbon(ROC)was relatively higher.After 15 and 30 days of incubation,the soil GC,NAG and PPO enzyme activities with C.lanceolata litter were significantly higher than those with S.superba litter.The decomposition of mixed litter significantly improved soil GC and NAG enzyme activities.The results of redundancy analysis and correlation analysis showed that soil AHOC content was significantly positively correlated with soil GC enzyme activity.NAG enzyme activity was positively correlated with soil WSOC content and negatively correlated with NH_(4)^(+)-N content,while PPO enzyme activity was negatively correlated with NO_(3)^(−)-N content and positively correlated with ROC and HHOC contents(P<0.01).【Conclusion】The addition of different litters significantly affects the soil carbon content,nitrogen content,and enzyme activity in C.lanceolata plantations.Compared to the addition of S.superba litter,the addition of C.lanceolata litter results in a higher soil humification degree,as well as higher enzyme activities related to the carbon and nitrogen cycle.Further,the addition of both C.lanceolata and S.superba litter is more beneficial in improving the degree of soil humification,soil carbon invertase activity,and nitrogen invertase activity compared to the addition of either litter alone,thus ultimately benefitting the soil carbon and nitrogen cycle of C.lanceolata plantations.
作者
周梦田
刘莉
付若仙
李孝刚
ZHOU Mengtian;LIU Li;FU Ruoxian;LI Xiaogang(College of Ecology and Environment,Nanjing Forestry University,Nanjing 210037,China)
出处
《南京林业大学学报（自然科学版）》
CAS
CSCD
北大核心
2024年第5期131-138,共8页
Journal of Nanjing Forestry University：Natural Sciences Edition
基金
江苏省碳达峰碳中和科技创新专项资金项目(BE2022420)
国家自然科学基金项目(32122056)。
关键词
杉木人工林
凋落物分解
碳含量
氮含量
土壤酶
Cunninghamia lanceolate plantation
litter decomposition
carbon content
nitrogen content
soil enzyme
