Soil and Water Research (Dec 2019)

Soil water response to rainfall in a dune-interdune landscape in Horqin Sand Land, northern China

  • Xueya Zhou,
  • Dexin Guan,
  • Jiabing Wu,
  • Fenghui Yuan,
  • Anzhi Wang,
  • Cangjie Jin,
  • Yushu Zhang

DOI
https://doi.org/10.17221/142/2018-SWR
Journal volume & issue
Vol. 14, no. 4
pp. 229 – 239

Abstract

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Soil water dynamic is considered an important process for water resource and plantation management in Horqin Sand Land, northern China. In this study, soil water content simulated by the SWMS-2D model was used to systematically analyse soil water dynamics and explore the relationship between soil water and rainfall among micro-landforms (i.e., top, upslope, midslope, toeslope, and bottomland) and 0-200 cm soil depths during the growing season of 2013 and 2015. The results showed that soil water dynamics in 0-20 cm depths were closely linked to rainfall patterns, whereas soil water content in 20-80 cm depths illustrated a slight decline in addition to fluctuations caused by rainfall. At the top position, the soil water content in different ranges of depths (20-40 and 80-200 cm) was near the wilting point, and hence some branches, and even entire plants exhibited diebacks. At the upslope or midslope positions, the soil water content in 20-80 or 80-200 cm depths was higher than at the top position. Soil water content was higher at the toeslope and bottomland positions than at other micro-landforms, and deep caliche layers had a positive feedback effect on shrub establishment. Soil water recharge by rainfall was closely related to rainfall intensity and micro-landforms. Only rainfalls > 20 mm significantly increased water content in > 40 cm soil depths, but deeper water recharge occurred at the toeslope position. A linear equation was fitted to the relationship between soil water and antecedent rainfall, and the slopes and R2 of the equations were different among micro-landforms and soil depths. The linear equations generally fitted well in 0-20 and 20-40 cm depths at the top, upslope, midslope, and toeslope positions (R2 value of about 0.60), with soil water in 0-20 cm depths showing greater responses to rainfall (average slope of 0.189). In 20-40 cm depths, the response was larger at the toeslope position, with a slope of 0.137. In 40-80 cm depths, a good linear fit with a slope of 0.041 was only recorded at the toeslope position. This study provides a soil water basis for ecological restoration in similar regions.

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