白晓, 贾小旭, 邵明安, 赵春雷. 黄土高原北部土地利用变化对长期土壤水分平衡影响模拟[J]. 水科学进展, 2021, 32(1): 109-119. DOI: 10.14042/j.cnki.32.1309.2021.01.011
引用本文: 白晓, 贾小旭, 邵明安, 赵春雷. 黄土高原北部土地利用变化对长期土壤水分平衡影响模拟[J]. 水科学进展, 2021, 32(1): 109-119. DOI: 10.14042/j.cnki.32.1309.2021.01.011
BAI Xiao, JIA Xiaoxu, SHAO Ming'an, ZHAO Chunlei. Simulating long-term soil water balance in response to land use change in the Northern China's Loess Plateau[J]. Advances in Water Science, 2021, 32(1): 109-119. DOI: 10.14042/j.cnki.32.1309.2021.01.011
Citation: BAI Xiao, JIA Xiaoxu, SHAO Ming'an, ZHAO Chunlei. Simulating long-term soil water balance in response to land use change in the Northern China's Loess Plateau[J]. Advances in Water Science, 2021, 32(1): 109-119. DOI: 10.14042/j.cnki.32.1309.2021.01.011

黄土高原北部土地利用变化对长期土壤水分平衡影响模拟

Simulating long-term soil water balance in response to land use change in the Northern China's Loess Plateau

  • 摘要: 为探明土地利用变化对黄土高原长期土壤水分平衡的影响,利用校验的Hydrus-1D模型模拟黄土高原北部神木六道沟小流域1981—2050年农耕地—苜蓿草地—天然草地情景下0~4 m土壤水分变化过程,量化土壤储水量、深层渗漏和蒸散发等水文变量的演变特征。结果显示:①农耕地期间年降水的88%为蒸散发消耗,11%为渗漏损失。②苜蓿草地种植后6 a内,蒸散发大幅增加至年降水的108%,土壤水分负平衡,0~4 m土壤储水量以52 mm/a的速率降低;至7~13 a,年降水几乎全部被蒸散发消耗。③苜蓿草地转变为天然草地后,蒸散发量下降31%,土壤水分以45 mm/a的速率逐渐补给,之后年降水量的92%用于蒸散发,8%为渗漏消耗,土壤水分处于相对稳定状态。研究表明不同土地利用方式下的土壤水分平衡模式具有显著差异,种植高耗水植被可造成土壤水分负平衡,导致土壤干燥化,进而对土壤水分补给产生负面效应,改变植被类型可使土壤干层得到有效改善。

     

    Abstract: To explore the impact of land-use change on the long-term soil water balance in Northern China's Loess Plateau, we used the Hydrus-1D model to simulate the soil water dynamics at depths of 0—4 m under the scenario of arable land-alfalfa land-natural grassland located in the Liudaogou watershed. The evolution characteristics of hydrological variables including soil water storage, deep seepage and evapotranspiration were quantified from 1981 to 2050. The results showed that soil water fluctuated with rainfall levels during arable land periods, with 88% of the annual precipitation consumed through evapotranspiration, and 11% was lost to deep seepage. The first stage of soil water change during the alfalfa land period was 1—6 years after plantation, during this period, evapotranspiration accounted for 108% of the annual rainfall, leaving the soil water in a negative balance. And the soil water storage of 0—4 m decreased at a rate of 52 mm/a. The second stage was 7—13 years after plantation, almost all rainfall was consumed by evapotranspiration. Eight years after alfalfa land transitioned into natural grassland, annual evapotranspiration decreased by 31%, and soil water storage gradually recharged at 45 mm/a. Subsequently, 92% of the annual rainfall was used for evapotranspiration, with the remaining 8% was lost to deep seepage. The soil water remained in a relatively stable state. These indicated that the soil water balance modes varied under different vegetation types. Planting vegetation with high-water-consumption could cause negative balance of soil water and led to serious soil desiccation, which then had a negative effect on soil water supply. However, the formed dry soil layer could be completely restored by changing the vegetation type.

     

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