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Scientia Silvae Sinicae ›› 2022, Vol. 58 ›› Issue (6): 1-12.doi: 10.11707/j.1001-7488.20220601

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Soil Water Use and Niche Characteristics of Dominant Tree Species in Arbor Layer and Shrub Layer in Two Plantations of Pinus tabulaeformis and Robinia pseudoacacia in Loess Region of Western Shanxi Province

Fei Yang1,Yiyan Lin2,Lixin Chen1,*,Lu Han1,Yingming Wu1,Yajie Yu1   

  1. 1. Key Laboratory of Soil and Water Conservation & Desertification Combating, National Forestry and Grassland Administration College of Soil and Water Conservation, Beijing Forestry University Beijing 100083
    2. Gardening and Landscape Department, Fujian Vocational College of Agriculture Fuzhou 350303
  • Received:2020-02-22 Online:2022-06-25 Published:2022-09-24
  • Contact: Lixin Chen

Abstract:

Objective: In order to explore water use strategies and competition/complementarity relationships of arbors and shrubs under different magnitudes of rainfall in the same stand, we analysed the soil water use resource and water niche characteristics of dominant species in arbor layer and shrub layer in the Robinia pseudoacacia and Pinus tabulaeformis plantations in the Loess region of Western Shanxi Province, it is expected to provide a theoretical basis for vegetation restoration and management in the Loess region. Method: We collected the xylem of upper story arbors (R. pseudoacacia and P. tabulaeformis) and lower story shrubs (Rosa xanthina and Abelia biflora), the soil of 0-10, 10-20, 20-30, 30-40, 40-60, 60-80, and 80-120 cm layers and rainfall samples to study18O characteristics and dynamic changes before and after rainfall events. The MixSIAR model was adopted to calculate the contribution rate of soil water at different soil layers to different plant species, and the niche width and niche overlap were calculated using the Levins index and Levins overlap formula. Result: The results showed that the soil water content, 18O of soil water, water absorption depth of trees and shrubs, and niche characteristics of water were affected by rainfall, but the impact and duration of different rainfalls were different. Before and after 12.7 and 33.4 mm precipitation, P. tabulaeformis and the understory shrubs R. xanthina mainly took water from 0-80 cm soil layers, but the utilization ratio of 0-40 cm soil water after rainfall was significantly higher than that before rainfall. The rainfall of 3.1 mm had no significant effect on the water use of R. pseudoacacia and A. biflora. After 106.6 mm precipitation, R. pseudoacacia increased the absorption proportion of 0-40 cm soil water, but it had a time lag. A. biflora responded quickly to rainfall, it increased the absorption proportion of 0-40 cm soil water to 49.3%-62.5% after rainfall. We also found that the water niche breadth of upper story trees kept stable during the study period, but that of lower story shrubs changed with rainfall and soil water content; different magnitudes of rainfall were able to change the niche overlap degrees. Conclusion: Except for rainfall of 3.1 mm, the water use strategies and water niche characteristics of the upper story trees (P. tabulaeformis and R. pseudoacacia) and the lower story shrubs (R. xanthina and A. biflora) in the same community were different at different rainfall levels. Our research suggested that the influence of rainfall on the niche width of the lower story shrubs was greater than that of the upper story trees. The water use strategies of P. tabulaeformis was similar to the lower story shrub R. xanthina; R. pseudoacacia and its lower story shrubs A. biflora had different water use strategies. For vegetation restoration, deep-rooted plants can be planted in combination with shallow-rooted plants to reduce water competition.

Key words: water use strategy, water niche characteristics, Pinus tabulaeformis, Robinia pseudoacacia, Loess Plateau, MixSIAR

CLC Number: