模拟干旱和磷添加对热带低地雨林氮矿化过程的影响  

Effects of simulated drought and phosphorus addition on nitrogen mineralization in tropical lowland rain forests

作　　者：赵阳 栾军伟 王一 杨怀 刘世荣[2] ZHAO Yang;LUAN Jun-Wei;WANG Yi;YANG Huai;LIU Shi-Rong(Institute of Resources and Environment,International Center for Bamboo and Rattan,Key Laboratory of National Forestry and Grassland Administra-tion/Beijing for Bamboo and Rattan Science and Technology,Beijing 100102,China;and 2Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration,Ecology and Nature Conservation Institute,Chinese Academy of Forestry,Beijing 100091,China)

机构地区：[1]国际竹藤中心竹藤资源与环境研究所,国家林业和草原局/北京市共建竹藤科学与技术重点实验室,北京100102 [2]中国林业科学研究院森林生态环境与自然保护研究所,国家林业和草原局森林生态环境重点实验室,北京100091

出　　处：《植物生态学报》2022年第1期102-113,共12页Chinese Journal of Plant Ecology

基　　金：国际竹藤中心基本科研业务费学科发展项目(1632019006和1632021023);国家自然科学基金(31930078和31971461)。

摘　　要：土壤氮矿化作为氮转化的主要过程决定土壤供氮能力。热带森林生态系统往往受磷限制,氮矿化过程对干旱的响应是否受磷限制的调控值得探讨。该研究以海南三亚甘什岭自然保护区热带低地雨林为研究对象,利用2019年建立的林内穿透雨减少(50%)及磷添加双因素交互实验平台,通过野外树脂芯原位培养法研究模拟干旱及磷添加对土壤无机氮(包括铵态氮和硝态氮)含量和氮矿化过程的影响。结果表明:1)减雨处理显著降低了5和15 cm深度土壤的水分含量,而对土壤温度没有显著影响。2)减雨处理和减雨与磷添加共同处理无论在旱季还是湿季对0–10cm土壤无机氮含量均没有产生显著影响,但磷添加处理在旱季显著降低了土壤硝态氮含量,表明磷添加处理对氮有效性的影响主要体现在旱季,而非湿季。3)干旱处理在旱季和湿季均显著降低了土壤净氨化速率和净氮矿化速率,而磷添加处理和减雨与磷添加共同处理无论在旱季还是湿季对净氨化速率、净硝化速率和净氮矿化速率均没有产生显著影响,结果表明了干旱能够显著降低土壤净氮矿化速率。4)土壤水分含量与土壤净氨化速率和净氮矿化速率呈显著正相关关系,同时减雨处理显著影响了土壤净氨化速率与铵态氮含量的关系,并且在铵态氮含量相等的情况,随着干旱的影响净氨化速率下降得更快。这表明土壤水分含量变化是影响该研究样地土壤氮矿化的主要因素。上述研究结果说明,降水变化对热带低地雨林中土壤氮矿化有重要影响,短期磷添加没有显著影响,减雨与磷添加对土壤氮矿化过程并没有交互效应。Aims Soil nitrogen(N) mineralization is the main process of N transformation, which determines soil N supply capacity. According to the report that the intensity and frequency of extreme hydrological events such as drought would continue to increase in the future. However, how drought impact on soil N mineralization in tropical lowland rain forests, and if this process is regulated by phosphorus(P) are less understood, given that tropical ecosystem is normally considered as P-limited.Methods Here, we employed a two-factor climate change manipulative experiment(50% throughfall reduction and P addition), which was established in 2019 in a tropical lowland rain forest in the Ganza Ridge Nature Reserve in Sanya, Hainan. The in-situ resin core method was used to study the effects of drought and P addition on soil inorganic N and N mineralization process.Important findings Our results show that: 1) Rainfall reduction significantly reduced the soil moisture at depths of 5 cm and 15 cm, but had no significant effect on soil temperature. 2) Rainfall reduction and the interactive treatment of rainfall reduction and P addition did not impact on soil inorganic N(including ammonium N and nitrate N) content in the dry season or wet season, but P addition significantly reduced soil nitrate N in the dry season, indicated that the effect of P addition on N availability was mainly reflected in the dry season rather than wet season. 3) Rainfall reduction significantly reduced the net ammonification rate and net N mineralization rate in both dry and wet seasons, however, these processes did not respond to P addition or their interaction. 4) Soil moisture positively correlated with the soil net ammonification rate and the net N mineralization rate. Meanwhile, rainfall reduction significantly affected the relationship between the soil net ammonification rate and the ammonium N content, where when the ammonium N was comparable, the net ammonification rate dropped faster under the impact of drought. This indicated that the change of soi

关 键 词：热带低地雨林 干旱 磷添加 氮循环 无机氮 土壤氮矿化 

分 类 号：Q948[生物学—植物学]