Arid Zone Research ›› 2024, Vol. 41 ›› Issue (12): 2015-2026.doi: 10.13866/j.azr.2024.12.04

• Land and Water Resources • Previous Articles     Next Articles

Characteristics and influencing factors of soil macropores in the root zone of sand-fixing plants in the desert-oasis transition zone

LI Jianan1(), ZHOU Chengqian2, HU Guanglu2,3(), YANG Penghua2, LI Haochen2   

  1. 1. Gansu Provincial Institute of Soil and Water Conservation Science, Lanzhou 730020, Gansu, China
    2. School of Environment and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China
    3. Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou 730070, Gansu, China
  • Received:2024-04-02 Revised:2024-08-26 Online:2024-12-15 Published:2024-12-20
  • Contact: HU Guanglu E-mail:13919119754@163.com;hgl0814@163.com

Abstract:

Soil macropores are the main channels for soil moisture infiltration. Investigating their characteristics and influencing factors in the root zone of typical sand-fixing plants in the desert-oasis transition zone is crucial for regional ecological vegetation restoration and plant selection. In this study, we investigated the characteristics of soil macropores in the root zone of these plants in the middle reaches of the Heihe River desert-oasis transition zone through water penetration experiments. We analyzed the influencing factors of soil macropores and their impact on soil-saturated hydraulic conductivity. The results show the following: (1) The radius of soil macropores ranges from 0.5 to 1.6 mm, exceeding the minimum aeration pore radius of 0.3 mm. Soil moisture movement is mainly driven by gravitational water. The density of soil macropores in the root zone of sand-fixing plants in the transition zone decreases with increasing soil depth, characterized by a higher number of smaller pores and fewer larger pores. (2) Soil bulk density and other soil macropore indicators, except for the total number of macropores, showed a highly significant negative correlation. Conversely, saturated water content and other macroporosity indicators, except for the total number of macropores, exhibited a significant positive correlation. Additionally, organic matter content and various soil macropore indicators showed a highly significant positive correlation. (3) The saturated hydraulic conductivity of the soil ranged from 2.32 to 3.79 mm·min-1. The variation in saturated hydraulic conductivity was determined by the soil macroporous volume ratio (82%), macroporous area ratio (68%), the fourth power of the average radius of macroporous space (79%), and the total number of macropores (43%). (4) Under the same habitat conditions in the study area, planting sand-fixing plants significantly improved the water infiltration ability of the soil compared to bare land. Among the three sand-fixing plants studied, their water infiltration abilities ranked as follows, from strongest to weakest: Haloxylon ammodendron, Calligonum mongolicum, and Nitraria sphaerocarpa.

Key words: desert-oasis transition zone, sand fixing plants, water penetration curve, soil macropores