干旱区研究 ›› 2023, Vol. 40 ›› Issue (6): 916-925.doi: 10.13866/j.azr.2023.06.07

• 水土资源 • 上一篇    下一篇

降雨频率对甘南尕海湿草甸土壤碳氮磷化学计量特征的影响

关宇淇1(),李广1,潘雪2,徐国荣1,魏星星3,刘昊1,吴江琪1()   

  1. 1.甘肃农业大学林学院,甘肃 兰州 730070
    2.黑龙江省黑土保护利用研究院, 黑龙江 哈尔滨 150000
    3.中国气象局兰州干旱气象研究所,甘肃 兰州 730070
  • 收稿日期:2022-11-25 修回日期:2023-03-03 出版日期:2023-06-15 发布日期:2023-06-21
  • 通讯作者: 吴江琪. E-mail: 1462528657@qq.com
  • 作者简介:关宇淇(1999-),女,硕士研究生,主要从事水土保持与荒漠化防治研究. E-mail: 54747750@qq.com
  • 基金资助:
    甘肃省优秀研究生“创新之星”项目(2022CXZX-675);甘肃省高等教育创新基金项目(2022A-052);中国甘肃农业大学科研启动项目(GAU-KYQD-2021-15);甘肃省重点研发计划(22YF7FA116);甘肃省重点研发计划(20YF8NA135)

Effects of changing rainfall frequency on the soil carbon, nitrogen, and phosphorus ecostochimetrics in the Gahai wet meadow, Gannan

GUAN Yuqi1(),LI Guang1,PAN Xue2,XU Guorong1,WEI Xingxing3,LIU Hao1,WU Jiangqi1()   

  1. 1. College of Forestry, Gansu Agricultural University, Lanzhou 730070, Gansu, China
    2. Heilongjiang Research Institute of Black Soil Protection and Utilization, Harbin 150000, Heilongjiang, China
    3. Lanzhou Institute of Drought Meteorology, China Meteorological Administration, Lanzhou 730070, Gansu, China
  • Received:2022-11-25 Revised:2023-03-03 Online:2023-06-15 Published:2023-06-21

摘要:

降雨是湿地水资源补给量和土壤呼吸的重要扰动因子,全球气候变化导致的未来极端降雨变率增大对湿地生态系统有着重要影响。为探究极端降雨频率下青藏高原湿草甸土壤有机碳(SOC)、全氮(TN)、全磷(TP)含量及化学计量比的变化特征,本文以青藏高原东北边缘碌曲县尕海-则岔自然保护区境内的湿草甸土壤为研究对象,设置空白对照(CK:0 mm)、每周浇灌一次(DF1:25 mm×19次)、每两周浇灌一次(DF2:25 mm×9次)、每三周浇灌一次(DF3:25 mm×6次)和每四周浇灌一次(DF4:25 mm×4次)5种处理,分析极端降雨频率下0~40 cm土层土壤SOC、TN和TP化学计量特征的变化规律。结果表明:在不同降雨频率下,土壤SOC含量随降雨频率增加而增加,TN和TP含量则与之相反。在土壤垂直剖面上,SOC和TN含量均随土层深度增加而降低,TP含量随土层深度增加无显著变化;C:P和N:P均随土层加深有所降低,而C:N随土层加深无显著变化;C:N、C:P和N:P在不同降雨频率间差异不显著;此外,随着时间的推进,土壤SOC含量在生长季不同月份呈现先增后减的变化趋势,TN含量则呈现先减后增的变化趋势,而TP含量呈“M”型变化趋势。因此,随着全球降雨格局变化程度持续增加,较高的降雨频率会加剧高寒湿草甸浅层土壤氮磷含量的流失,造成高寒湿草甸水环境富营养化的危害加剧。

关键词: 青藏高原, 湿草甸, 土壤化学计量特征, 降雨频率

Abstract:

Rainfall is an important factor affecting water supply and soil respiration in wetland areas. Increases in extreme rainfall variability caused by global climate change are thus expected to impact wetland ecosystems. To investigate this, the changes in soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) in response to altered rainfall frequencies (weekly, fortnightly, three-weekly, four-weekly, and control irrigation treatments) were assessed in a wet meadow in the Gahai-Zecha Nature Reserve on the north-eastern edge of the Tibetan Plateau. The SOC was found to increase with increasing rainfall frequency, while TP and TN decreased. SOC and TN decreased with increasing soil depth and TP was inconsistent across the different soil layers. As a result, the ratios of C:P and N:P decreased with the soil layers, but the ratio of C:N did not show a significant change. The ratios of C:N, C:P, and N:P did not show significant responses to the rainfall treatments. The SOC, TN, and TP showed obvious seasonal variations, as the SOC showed an increasing and then decreasing trend, the TN showed a decreasing and then increasing trend, and the TP content showed an “M”-shaped decreasing trend. The results suggest that continuous changes in global rainfall, including an increased rainfall frequency, will aggravate the loss of nitrogen and phosphorus in the shallow soil of the alpine wet meadow, likely resulting in aggravated damage due to eutrophication in the water environment surrounding the alpine wet meadows.

Key words: Qinghai-Tibet Plateau, wet meadows, soil stoichiometric characteristics, rainfall frequency