植物生态学报 ›› 2017, Vol. 41 ›› Issue (2): 175-185.doi: 10.17521/cjpe.2016.0253

所属专题: 稳定同位素生态学

• 研究论文 • 上一篇    下一篇

黄土丘陵区典型天然灌丛和人工灌丛优势植物土壤水分利用策略

吕婷1, 赵西宁2,3,*(), 高晓东2,3, 潘燕辉4   

  1. 1西北农林科技大学水利与建筑工程学院, 陕西杨凌 712100
    2西北农林科技大学水土保持研究所, 陕西杨凌 712100
    3中国科学院水利部水土保持研究所, 陕西杨凌 712100
    4兰州大学西部环境教育部重点实验室, 兰州 730000
  • 收稿日期:2016-08-01 接受日期:2016-12-25 出版日期:2017-02-10 发布日期:2017-03-16
  • 通讯作者: 赵西宁 E-mail:zxnsbs@gmail.com;xiningz@aliyun.com
  • 作者简介:

    * 通信作者Author for correspondence (E-mail:sunzhiqiang1956@sina.com)

Soil water use strategy of dominant species in typical natural and planted shrubs in loess hilly region

Ting LÜ1, Xi-Ning ZHAO2,3,*(), Xiao-Dong GAO2,3, Yan-Hui PAN4   

  1. 1College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling, Shaanxi 712100, China

    2Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi 712100, China

    3Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China

    4Key Laboratory of Western China’s Environmental Systems of Ministry of Education, Lanzhou University, Lanzhou 730000, China
  • Received:2016-08-01 Accepted:2016-12-25 Online:2017-02-10 Published:2017-03-16
  • Contact: Xi-Ning ZHAO E-mail:zxnsbs@gmail.com;xiningz@aliyun.com
  • About author:

    KANG Jing-yao(1991-), E-mail: kangjingyao_nj@163.com

摘要:

细裂叶莲蒿(Artemisia gmelinii)是黄土高原农地退耕后长期存在的天然植物群落优势种。柠条锦鸡儿(Caragana korshinskii)灌丛是黄土高原防治水土流失的主要人工群落类型。研究它们的水分利用策略对评价气候暖干化趋势下黄土高原生态建设可持续性具有重要意义。该研究以退耕7年的天然草地细裂叶莲蒿群落、退耕30年的天然草地细裂叶莲蒿群落和退耕30年的人工灌木林柠条锦鸡儿群落为研究对象, 采用氧稳定同位素比率(δ18O)技术研究其对不同土层土壤水分利用的季节性变化, 通过MixSIR模型量化各土层土壤水分利用的贡献。结果表明: 在δD-δ18O分布图上, 对黄土丘陵区降水样的氢稳定同位素比率(δD)和δ18O回归分析得到当地的大气降水线, 土壤水和植物水中的氢氧稳定同位素组成在δD-δ18O分布图上都位于当地大气降水线的右下方, 表明研究区土壤水分中的同位素组成受强烈蒸发影响发生了富集作用。随着季节变化, 退耕7年的天然草地细裂叶莲蒿和退耕30年的人工灌木林柠条锦鸡儿植物水分来源可在不同土层之间较为灵活地转换, 当浅层(0-40 cm)土壤水可利用时, 植物主要利用40 cm以上的土壤水分; 当浅层土壤干燥时, 主要吸收40-80 cm土层土壤的水分。退耕30年天然草地中细裂叶莲蒿主要依赖于0-10 cm表层土壤的水分。这表明在未来极端干旱事件发生频率增大的情况下, 退耕7年的天然草地细裂叶莲蒿和退耕30年的人工灌木林柠条锦鸡儿具有更大的生存优势, 而退耕30年的天然草地细裂叶莲蒿受干旱等极端天气影响更为严重。

关键词: 氧稳定同位素, 水分来源, MixSIR模型, 细裂叶莲蒿, 柠条锦鸡儿

Abstract:
Aims Artemisia gmelinii is a dominant specie naturally established after abandonment of cultivated lands in the Loess Plateau, and Caragana korshinskii is one of the main planted shrub species to control soil erosion. Improved understanding of water use strategies of these two species is of great significance to evaluate the sustainable development of the Loess Plateau under the trend of climate warming and increasing drought events.
Methods Stable oxygen-18 isotope was used to determine seasonal variations in the water sources of native A. gmelinii communities established after abandonment of cultivated lands for 7 and 30 years and planted C. korshinskii after 30 years. The contributions of soil water from different depths to water uptake were estimated by the MixSIR Bayesian mixing model. The geometric mean regression method was used to fit the line of precipitation to get the local meteoric water line (LWML).
Important findings The stable hydrogen isotope rate (δD) and stable oxygen isotope rate (δ18O) of soil water and xylem water plotted to the right side of the LWML, indicating that the isotopic compositions of soil water were enriched due to evaporation. The native A. gmelinii communities established after abandonment of cultivated lands for 7 years and planted C. korshinskii after 30 years showed plasticity in switching water sources from different soil layers, extracting water from shallow soil (0-40 cm) when soil water was available, but deeper soil (40-80 cm) when shallow soil water was dry. In contrast, A. gmelinii growing in site after cultivation abandonment for 30 years mainly relied on water from the surface soil (0-10 cm) throughout the growing season. Our results suggest that the ability of A. gmelinii to compete for soil water reduces with aging of the community while the planted C. korshinskii will have competitive advantage under the condition of increasing frequency of drought events in the future.

Key words: oxygen stable isotopes, water-use source, MixSIR model, Artemisia gmelinii, Caragana korshinskii