干旱区研究 ›› 2025, Vol. 42 ›› Issue (6): 1138-1150.doi: 10.13866/j.azr.2025.06.16 cstr: 32277.14.AZR.20250616

• 农业生态 • 上一篇    下一篇

竖管地表滴灌土壤水热分布特征模拟及影响因素

范严伟1(), 吕自杰1(), 张尧1, 王磊1, 石雯2   

  1. 1.兰州理工大学能源与动力工程学院,甘肃 兰州 730050
    2.平凉市泾东水利水电勘测设计有限责任公司,甘肃 平凉 744000
  • 收稿日期:2024-12-06 修回日期:2025-03-15 出版日期:2025-06-15 发布日期:2025-06-11
  • 通讯作者: 吕自杰. E-mail: 1804344325@qq.com
  • 作者简介:范严伟(1982-),男,副教授,主要从事节水灌溉理论与新技术研究. E-mail: fanyanwei24@163.com
  • 基金资助:
    国家自然科学基金项目(52369007);国家自然科学基金项目(51969013)

Simulation of soil hydrothermal distribution characteristics and analysis of the influencing factors of vertical tube surface drip irrigation

FAN Yanwei1(), LYU Zijie1(), ZHANG Yao1, WANG Lei1, SHI Wen2   

  1. 1. School of Energy and Power Engineering, Lanzhou University of Science and Technology, Lanzhou 730050, Gansu, China
    2. Pingliang Jingdong Water Conservancy Hydropower Survey and Design, Co., Ltd.,Pingliang 744000, Gansu, China
  • Received:2024-12-06 Revised:2025-03-15 Published:2025-06-15 Online:2025-06-11

摘要:

在沙漠环境中实施植物固沙工程,土壤水热状况是影响固沙植物健康生长的关键因素。竖管地表滴灌是为缓解土壤干旱和地表高温对固沙植物幼苗的复合胁迫而提出的一种节水控温保育新技术,其土壤水热分布及迁移状况尚不清晰,推广应用到植物固沙区缺乏理论基础。为探明竖管地表滴灌模式下灌溉参数(滴头流量和灌溉水温)和竖管参数(竖管直径和竖管埋深)对土壤水热分布及迁移状况的影响,基于HYDRUS-2D软件,构建了竖管地表滴灌土壤水热迁移数学模型,通过室内试验,验证了所建模型及其求解方法的可靠性。在此基础上,采用单因素分析法,考虑滴头流量(1、2、3 L·h-1)、灌溉水温(10、20、30 ℃)、竖管直径(9.6、11.6、13.2 cm)及竖管埋深(15、20、25 cm)4个影响因素,设计9组模拟方案,获得竖管地表滴灌不同影响参数组合下的土壤水热分布特征及迁移规律。 结果表明:(1) 整个灌水过程湿润体内取9个有代表性的点位,其土壤水热变化均是通过以水调温实现的水热耦合,灌水初期竖管内土壤水热动态变化最为明显,尤其是管内地表层;随着灌水时间的延长,管内土壤水热状况逐渐稳定,水分通过管底孔向四周渗透,管外各点位土壤水分快速增加并趋于稳定,而温度则受灌溉水温的影响而略有增减。(2) 滴灌期间竖管直径对土壤水热状况的影响不显著,竖管埋深主要是影响土壤的水分状况,对土壤热环境的影响也不明显。不同竖管埋深情况下管外土壤湿润体水分分布以管底为分界线,其上部同一点位处的土壤含水率随埋深的增大而减小,其下部同一点位处的土壤含水率则随埋深的增大而增大。(3) 滴头流量对土壤温度分布的影响相对有限,但其是影响土壤水分状况的关键参数,滴头流量越大,管外同一点位处的土壤含水率越高。(4) 灌溉水温对土壤水分分布的影响相对微弱,但其是影响土壤温度状况的直接因素,灌溉水温越高,管内外同一点位处的土壤温度越高。(5) 在竖管直径和埋深固定难以调整的情况下,通过调整滴头流量和灌溉水温,可有效实现根区土壤水热调控。该研究可为固沙植物竖管地表滴灌工程设计、运行和管理提供科学依据。

关键词: 灌溉, 入渗, 水热迁移, 数值模拟, 竖管地表滴灌

Abstract:

The success of sand fixation projects in deserts is dependent on soil hydrothermal conditions, which are essential for the healthy growth of sand fixation plants. Vertical pipe surface drip irrigation is a new water-saving and temperature-control conservation technology focused on combating soil drought and surface heat stress on seedlings. However, the mechanisms regulating hydrothermal distribution and migration status remain unclear, and its widespread application in sand-fixing areas lacks a theoretical formulation. Thus, this study constructed a mathematical model of soil water-heat migration for vertical tube surface drip irrigation using HYDRUS-2D software. The study investigated the effects of key irrigation parameters (drip head flow rate and irrigation water temperature) and vertical tube parameters (tube diameter and burial depth) on soil water-heat distribution and migration. The accuracy of the constructed model was confirmed through indoor experiments. Consequently, a single-factor analysis was conducted involving nine simulation scenarios to study the impacts of four influencing factors—drip head flow rate (1, 2, and 3 L·h-1), irrigation water temperatures (10, 20, and 30 ℃), riser diameter (9.6, 11.6, and 13.2 cm), and riser depth (15, 20, and 25 cm) to obtain the distributions and migration patterns of the soil hydrothermal properties. The results showed the following. (1) Soil hydrothermal changes during irrigation occurred through water-heat coupling influenced by irrigation water temperature. Dynamic changes were most pronounced in the early stage of irrigation, particularly in the inner surface layer of the tube. Over time, these changes stabilized. Water infiltration from the bottom holes of the tube into the surrounding soil increased the soil moisture rapidly before stabilizing. Further, the soil temperature was affected by the irrigation water temperature, exhibiting slight increases or decreases. (2) The diameter of the vertical tube had a minimal effect on the soil hydrothermal changes during drip irrigation. However, the burial depth had a significant influence on the soil moisture but minimal impact on the thermal environment. Outside the tube, the soil moisture distribution around the tube formed a distinct pattern, with the bottom of the tube functioning as a dividing line. Above this line, the soil moisture content at the same point decreased as the burial depth increased, while below this line, the soil moisture content increased with greater burial depth. (3) The drip head flow was a critical factor in determining the soil moisture status although its impact on the soil temperature distribution was limited. The larger the drip head flow, the higher the soil moisture content at the same points outside the pipe. (4) The influence of the irrigation water temperature on the soil moisture distribution was relatively weak; however, it directly influenced the soil temperature. Higher irrigation water temperatures resulted in increased soil temperature at the same points inside and outside the pipe. (5) When adjustments to the vertical tube’s diameter and burial depth were not feasible, soil hydrothermal conditions in the root zone could be effectively regulated by adjusting the drip head flow rate and irrigation water temperature. Thus, this study offers a scientific basis for the design, operation, and management of a vertical pipe surface drip irrigation project for sand fixation plants.

Key words: irrigation, infiltration, hydrothermal transport, numerical simulation, vertical tube surface drip irrigation