裴艳武, 黄来明, 邵明安, 李荣磊, 张应龙. 毛乌素沙地不同地下水位埋深下土壤水补给特征及影响因素[J]. 农业工程学报, 2021, 37(12): 108-116. DOI: 10.11975/j.issn.1002-6819.2021.12.013
    引用本文: 裴艳武, 黄来明, 邵明安, 李荣磊, 张应龙. 毛乌素沙地不同地下水位埋深下土壤水补给特征及影响因素[J]. 农业工程学报, 2021, 37(12): 108-116. DOI: 10.11975/j.issn.1002-6819.2021.12.013
    Pei Yanwu, Huang Laiming, Shao Ming'an, Li Ronglei, Zhang Yinglong. Characteristics and their influencing factors of water recharge under different groundwater levels in the Mu Us Sandy Land of China[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(12): 108-116. DOI: 10.11975/j.issn.1002-6819.2021.12.013
    Citation: Pei Yanwu, Huang Laiming, Shao Ming'an, Li Ronglei, Zhang Yinglong. Characteristics and their influencing factors of water recharge under different groundwater levels in the Mu Us Sandy Land of China[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(12): 108-116. DOI: 10.11975/j.issn.1002-6819.2021.12.013

    毛乌素沙地不同地下水位埋深下土壤水补给特征及影响因素

    Characteristics and their influencing factors of water recharge under different groundwater levels in the Mu Us Sandy Land of China

    • 摘要: 土壤水分是毛乌素沙地植被恢复与生态重建的关键因子,揭示不同地下水位(Groundwater Level,GWL)埋深下土壤水的补给与转化特征对于提高水资源利用效率和植被可持续建设具有重要意义。试验通过定期测定毛乌素沙地东南缘圪丑沟流域沙柳(GWL范围253~260 cm)、樟子松(GWL范围87~93 cm)和长柄扁桃林地(GWL范围172~176 cm)降水、土壤水及地下水δ2H和δ18O,分析了不同GWL埋深下3种林地土壤水补给特征及其影响因素。结果表明:沙柳、樟子松及长柄扁桃林地土壤水δ2H和δ18O均位于当地大气水线的下方,且3种林地土壤水线斜率(5.69~7.13)均小于当地大气水线斜率(7.79),表明各林地土壤水均在不同程度上受当地降水的补给。监测期间沙柳林地0~20 cm土壤水、樟子松和长柄扁桃林地0~40 cm土壤水均表现出重组分同位素贫化轻组分同位素富集的现象,且与降水同位素呈显著正相关关系(P < 0.05),表明不同林地浅层土壤水(< 40 cm)更易受降水补给的影响。不同林地深层土壤水(沙柳林地180 cm以下,樟子松林地60 cm以下,长柄扁桃林地120 cm以下)δ2H和δ18O的均值与地下水接近,且随深度增加土壤水重组分同位素逐渐贫化并趋于稳定(变异系数 < 10%)。根据不同深度土壤水δ18O和地下水δ18O之间的相关关系,得出监测期间3种林地(沙柳、樟子松和长柄扁桃林地)地下水向上补给土壤水的深度范围分别为73~80、27~33和52~56 cm。因此,毛乌素沙地浅层地下水对深层土壤水的补给可在一定程度上缓解旱季土壤水分亏缺,为保障该区人工固沙植被生长提供潜在的水分来源。

       

      Abstract: Abstract: Water and soil conservation have been highly critical to the vegetation restoration and ecological reconstruction in the arid and semi-arid regions, particularly in southeastern China. Thus, it is necessary to characterize the soil water recharge and movement under different Groundwater Levels (GWL) for water use efficiency and sustainable agriculture. In this study, the hydrogen and oxygen isotopic compositions (δ2H and δ18O) of rain water, soil water and groundwater were measured in three different woodlands (i.e., Salix psammophila woodland with GWL range of 253-260 cm, Pinus sylvestris L. var. mongholica Litv. woodland with GWL range of 87-93 cm and Amygdalus pedunculata Pall. woodland with GWL range of 172-176 cm) in the Gechougou watershed in the southeastern edge of Mu Us Sandy Land. The characteristics and influencing factors of soil water recharge were clarified in three types of woodland. Results showed that the δ2H and δ18O of soil water were plotted below the local meteoric water line, in Salix psammophila, Pinus sylvestris L. var. mongholica Litv., and Amygdalus pedunculata Pall. Woodland, where the slope of soil water line in the three types of woodlands (5.69-7.13) was less than that of the local meteoric water line (7.79), indicating that the soil water in each woodland was replenished by the local precipitation. The δ2H and δ18O of soil water in Salix psammophila (0-20 cm), Pinus sylvestris L. var. mongholica Litv. (0-40 cm), and Amygdalus pedunculata Pall. Woodland (0-40 cm) exhibited the depletion of heavy isotopes and enrichment of light isotopes in monitoring period, while significantly positive correlated (P < 0.05) with the hydrogen and oxygen isotopic compositions of precipitation, indicating that the shallow soil water (< 40 cm) under different woodlands was more easily replenished by the precipitation. The mean values of δ2H and δ18O of deep soil water in different types of woodlands (Salix psammophila (> 180 cm), Pinus sylvestris L. var. mongholica Litv. (> 60 cm), and Amygdalus pedunculata Pall. Woodland (> 120 cm)) were close to those of the groundwater, where the δ2H and δ18O of soil water tended to be more stable (CV < 10%) with the increase of depth. The depth ranges of soil water recharged by groundwater were about 73-80, 27-33, and 52-56 cm, respectively, during the monitored period in the three types of woodlands (Salix psammophila, Pinus sylvestris L. var., and Amygdalus pedunculata Pall. woodland), according to the correlations of δ18O between soil water and groundwater (i.e., in term of how easily the δ18O of soil water were mixed and displaced with the fluctuating groundwater). Consequently, the shallow soil water (<40 cm) in the three woodlands was mainly recharged by precipitation, especially in the rainy season, whereas, the deep soil water (27-80 cm above the GWL) was dominantly recharged by groundwater. Therefore, the deep soil water recharge by shallow groundwater can be expected to alleviate the deficit of soil water in the dry season, in turn providing potential water sources for vegetation growth in the study area. In any way, the shallow and deep sources of soil water were inevitable prerequisites for the construction of sand-fixing plants under the arid climate in the southeastern edge of Mu Us Sandy Land.

       

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