中国农业气象 ›› 2019, Vol. 40 ›› Issue (04): 214-221.doi: 10.3969/j.issn.1000-6362.2019.04.002

• 论文 • 上一篇    下一篇

模拟降水氮沉降对藏北高寒草甸土壤呼吸的影响

葛怡情,闫玉龙,梁艳,干珠扎布,胡国铮,杨劼,高清竹,何世丞,旦久罗布   

  1. 1.内蒙古大学生态与环境学院,呼和浩特 010021;2.中国农业科学院农业环境与可持续发展研究所,北京 100081;3.西藏自治区那曲市草原站,那曲 852100
  • 出版日期:2019-04-20 发布日期:2019-04-17
  • 作者简介:葛怡情(1994-),女,硕士,主要从事草地生态学研究。E-mail:1757883815@qq.com
  • 基金资助:

    西藏自治区科技计划项目;国家自然科学基金项目(31170460);国家重点研发计划课题(2016YFC0502003)

The Effects of Nitrogen Deposition on Soil Respiration in an Alpine Meadow in Northern Tibet

GE Yi-qing, YAN Yu-long, LIANG Yan, HASBAGAN Ganjurjav, HU Guo-zheng,YANG Jie, GAO Qing-zhu, HE Shi-cheng, DANJIU Luobu   

  1. 1. School of Life Sciences, Inner Mongolia University, Hohhot 010021, China; 2. Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081; 3. Nagqu Grassland Station in Tibet Autonomous Region, Nagqu 852100
  • Online:2019-04-20 Published:2019-04-17

摘要:

全球范围内大气氮沉降量的升高,增加了陆地生态系统的氮输入,从而影响土壤CO2的排放。2014年采用生长季(6-8月)喷洒添加定量NH4NO3液体的方式模拟降水氮沉降,参照中国氮沉降分布格局决定氮素添加剂量为40kgN·hm-2·a-1(N40),以喷洒等量清水为对照(CK)。生长季内定期测定植物群落生物量,并利用LI-8100土壤碳通量测量系统,选两个典型晴天进行土壤呼吸速率日动态变化过程测定,同时在6月下旬-9月初定期测定土壤呼吸速率,以探究氮沉降增加对藏北高寒草甸土壤呼吸的影响。结果表明:(1)氮沉降使高寒草甸地上生物量显著增加(P<0.05)。(2)高寒草甸生长季土壤呼吸具有明显的典型日动态变化和生长季变化。典型日动态呈双峰曲线,土壤呼吸速率最大值出现在13:00-14:00和16:00;生长季变化呈单峰曲线,最大值出现在8月,生长季初期和末期土壤呼吸速率较低。(3)氮沉降极显著促进了高寒草甸的土壤呼吸,与对照相比,生长季平均土壤呼吸速率增加66.1%(P<0.001)。(4)土壤呼吸速率与土壤温度、土壤湿度和地上生物量呈极显著正相关关系(P<0.001)。(5)氮沉降对土壤呼吸的温度敏感性无显著影响。研究结果说明在高寒草甸,由于氮沉降导致地上地下生物量增加,从而导致土壤呼吸速率的增加。

关键词: 高寒草甸, 氮沉降, 土壤呼吸, 地上地下生物量, 土壤呼吸温度敏感性

Abstract:

The increase of nitrogen deposition in the world resulted increases of nitrogen input to terrestrial ecosystems and affects soil CO2 emissions. NH4NO3 was used to simulated nitrogen deposition to determine the effect of nitrogen deposition on soil respiration during the growing season (June-August) in 2014 in alpine meadow in northern Tibet. The nitrogen deposition rate is 40kgN·ha-1·y-1 (N40) according to the distribution pattern of nitrogen deposition in China, the added nitrogen was sprayed onto the N40 plots monthly, while CK plots received the same amount of water. Plant community biomass was measured regularly during the growing season. Meanwhile, the LI-8100 Automated Soil CO2 Flux System was used to measure soil respiration rates periodically from late June to early September, and measured in two Typical Clear Days as the diurnal dynamics of the soil respiration rate. The main results are showed as follow: (1) nitrogen deposition significantly increased the above-ground biomass in alpine meadow (P<0.05). (2) The soil respiration rate had obvious diurnal and monthly pattern in both treatments. And the diurnal dynamics of soil respiration showed a double peak curve and the peak values were assumed at about 13:00–14:00 and 16:00, respectively. The monthly dynamics of soil respiration showed a single-peak curve, and the maximum appeared in August and lower at early and end of growing season. (3) Nitrogen deposition significantly increased the average soil respiration by 66.1% (P<0.001) compared with control plots in growing season. (4) Soil respiration rates showed a significant positive correlation with soil temperature, soil moisture and above-ground biomass (P<0.001). (5) Nitrogen deposition had no significant effect on temperature sensitivity of soil respiration. The results showed that the increase of soil respiration due to the increase of above-ground and below-ground biomass caused by nitrogen deposition in the alpine meadow.

Key words: Alpine meadow, Nitrogen deposition, Soil respiration, Above-belowground biomass, Sensitivity of soil respiration