Dynamics of Soil Water Content Across Different Landscapes in a Typical Desert-Oasis Ecotone
Dynamics of Soil Water Content Across Different Landscapes in a Typical Desert-Oasis Ecotone
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DOI：
10.3389/fenvs.2020.577406
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发表时间：
2020-11
期刊：
影响因子：
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通讯作者：
Guohua Wang;Q. Gou;Y. Hao;H. Zhao;Xiafang Zhang
中科院分区：
文献类型：
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作者：
Guohua Wang;Q. Gou;Y. Hao;H. Zhao;Xiafang Zhang
了解土壤水分动态对于不同景观下干旱荒漠-绿洲交错带的植被恢复具有重要意义。本研究对河西走廊2002—2013年生长季的荒漠、固沙灌丛和农田防护林3种典型景观下土壤含水量动态进行了调查。结果表明，荒漠和灌丛深层土壤含水量从20%~30%下降到3%~5%的稳定低水平。农田防护林地深层土壤含水量也有所下降，但下降幅度远小于荒漠和灌丛。荒漠-灌丛-林地深层土壤含水量的减少与地下水埋深的增加密切相关。地下水埋深增幅最大的时期主要出现在2008-2011年，而土壤含水量下降幅度最大的时期则出现在2009-2011年，对地下水埋深增加的响应存在时间滞后。这项研究为典型沙漠绿洲交错带在不同景观组成下受过度开采地下水影响的土壤含水量的长期动态提供了新的见解，而这是短期研究无法推断的。研究结果表明，地下水埋深急剧增加可能是粘土夹层土壤含水量减少的主要原因，地下水资源开发的可持续发展对于荒漠-绿洲交错带的长期管理具有重要意义。
An understanding of soil water content dynamics is important for vegetation restoration in an arid desert-oasis ecotone under different landscapes. In this study, the dynamics of soil water content under three typical landscapes (i.e., desert, sand-binding shrubland, and farmland shelter woodland) were investigated in the Hexi Corridor, northwest China, during the growing season from 2002 to 2013. The results showed that the soil water content in the deep layers decreased from 20–30% to a stable low level of 3–5% in the desert and shrubland. For the farmland shelter woodland, the soil water content at the deep layers also decreased, but the decrease rate was much smaller than the desert and shrubland. The decrease of soil water content in the deep soil layers among desert–shrubland–woodland was strongly associated with the increase of groundwater depths. The greatest increase of groundwater depths mainly occurred during 2008–2011, while the largest decrease of soil water content took place during the years 2009–2011, with a time-lag in response to increase in groundwater depths. This study provides new insight into the long-term dynamics of soil water content in a typical desert oasis ecotone under different landscape components from the influence of overexploiting groundwater that cannot be inferred from a short-term study. The findings demonstrate that the sharp increase of groundwater depths could be the main reason behind the reduction of soil water content in the clay interlayers, and sustainable development of groundwater resources exploitation is very important for the management of desert-oasis ecotone from a long-term perspective.