中文关键词青藏高原矿化作用硝化作用无机氮氮损失 英文关键词Qinghai-Tibet Plateaumineralizationnitrificationinorganic nitrogennitrogen loss

作者	单位	E-mail
何芳	云南大学国际河流与生态安全研究院, 昆明 650000 中国科学院生态环境研究中心, 北京 100085	hf2456404030@163.com
张丽梅	中国科学院生态环境研究中心, 北京 100085
申聪聪	中国科学院生态环境研究中心, 北京 100085
陈金全	云南大学生态与环境学院, 昆明 650000
刘四义	中国科学院生态环境研究中心, 北京 100085	syliu@rcees.ac.cn

中文摘要 矿化和硝化过程是森林生态系统氮素循环的重要组成部分，对生态系统功能的维持与土壤环境质量有着重要影响.净矿化和净硝化速率是评价土壤氮素供应能力和氮损失风险的常用指标.为探究青藏高原林地土壤氮转化特征及其影响因素，以气候差异较大的祁连山和藏东南地区作为研究对象，采集了327个林地土壤样本，通过样本处理及室内培养试验，分析了土壤中无机氮含量、净矿化速率、净硝化速率及其与环境因子之间的相关关系.结果表明，藏东南地区林地土壤的无机氮含量、净矿化速率和净硝化速率［109.70 mg·kg^-1、3.08 mg·（kg·d）^-1和2.19 mg·（kg·d）^-1］均显著高于祁连山地区［49.47 mg·kg^-1、0.70 mg·（kg·d）^-1和0.69 mg·（kg·d）^-1］；土壤的净矿化速率与年平均温度、年平均降水量、湿润指数及土壤有机质含量之间具有极显著的正相关关系（P<0.001）.净硝化速率与年平均温度、年平均降水量之间无显著正相关关系，但与土壤净矿化速率呈极显著的正相关关系（P<0.001）.这表明藏东南地区林地土壤具有比祁连山林地土壤更高的氮素供应水平，而水热条件可能是造成两地土壤净矿化速率差异的主要原因，净矿化速率是净硝化速率的限制因子，对青藏高原林地土壤的氮素损失有着重要影响.这些结果强调了水热条件等气候环境因子对青藏高原林地土壤净矿化和净硝化速率的重要影响，进一步加深了人们对青藏高原林地土壤氮素转化规律的认识. 英文摘要 Mineralization and nitrification, two important processes of the N cycle in forest ecosystems, play an important role in the maintenance of ecosystem function and soil environmental quality. The net mineralization rate and net nitrification rate are two common indexes for evaluation of the N supply and N loss risk in soil. In order to study the soil N transformation characteristics and their influencing factors in woodlands of the Qinghai-Tibet Plateau, the inorganic N concentrations, net N mineralization rates, and net nitrification rates of 327 soils sampled from the Qilian Mountains and Southeast Tibet were analyzed using indoor incubation experiments. The results showed that the inorganic N concentration, net N mineralization rate, and net nitrification rate of the woodland soil in Southeast Tibet ［109.70 mg·kg^-1, 3.08 mg·(kg·d)^-1, and 2.19 mg·(kg·d)^-1］ were significantly higher than those in the Qilian Mountains ［49.47 mg·kg^-1, 0.70 mg·(kg·d)^-1, and 0.69 mg·(kg·d)^-1］. The net mineralization rate of soil was positively correlated with the mean annual temperature (MAT), mean annual precipitation (MAP), moisture index, and soil organic matter concentrations (P<0.001). There were no significant positive relationships between the net nitrification rate and the MAT and MAP, but the net nitrification rate was positively correlated with the net N mineralization rate (P<0.001). These results indicated that the N supply ability of woodland soil in Southeast Tibet is significantly higher than that in the Qilian Mountains, and the hydrothermal conditions (MAT and MAP) are likely responsible for the difference in the net mineralization rate between the two studied regions. The net mineralization rate is the limiting factor for the net nitrification rate, which has an important influence on the spatial distribution of the forest soil nitrification process in the Qinghai-Tibet Plateau. These results emphasize the important roles of climatic and environmental factors, such as hydrothermal conditions, on the net N mineralization and nitrification rates of woodland soil in the Qinghai-Tibet Plateau, and will further deepen the understanding of the law of soil N transformation in woodlands in the Qinghai-Tibet Plateau.

PDF全文下载地址:

https://www.hjkx.ac.cn/hjkx/ch/reader/create_pdf.aspx?file_no=20210538&flag=1&journal_id=hjkx&year_id=2021