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Modeling of Soil Water and Salt Dynamics and Its Effects on Root Water Uptake in Heihe Arid Wetland, Gansu, China

Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Northwest Agriculture and Forestry University, Yangling 712100, China
Department of Soil Science, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada
College of Water Resources and Architecture Engineering, Northwest Agriculture and Forestry University, Yangling 712100, China
Department of Environmental Science and Technology, University of Maryland, College Park, MD 20742, USA
Suide Test Station of Water and Soil Conservation, Yellow River Conservancy Committee of the Ministry of Water Resources, Yulin, Shanxi 719000, China
Authors to whom correspondence should be addressed.
These authors contributed equally to this work.
Academic Editor: Lutz Breuer
Water 2015, 7(5), 2382-2401;
Received: 2 February 2015 / Revised: 8 May 2015 / Accepted: 11 May 2015 / Published: 21 May 2015
(This article belongs to the Special Issue Hydro-Ecological Modeling)
PDF [761 KB, uploaded 9 June 2015]


In the Heihe River basin, China, increased salinity and water shortages present serious threats to the sustainability of arid wetlands. It is critical to understand the interactions between soil water and salts (from saline shallow groundwater and the river) and their effects on plant growth under the influence of shallow groundwater and irrigation. In this study, the Hydrus-1D model was used in an arid wetland of the Middle Heihe River to investigate the effects of the dynamics of soil water, soil salinization, and depth to water table (DWT) as well as groundwater salinity on Chinese tamarisk root water uptake. The modeled soil water and electrical conductivity of soil solution (ECsw) are in good agreement with the observations, as indicated by RMSE values (0.031 and 0.046 cm3·cm−3 for soil water content, 0.037 and 0.035 dS·m−1 for ECsw, during the model calibration and validation periods, respectively). The calibrated model was used in scenario analyses considering different DWTs, salinity levels and the introduction of preseason irrigation. The results showed that (I) Chinese tamarisk root distribution was greatly affected by soil water and salt distribution in the soil profile, with about 73.8% of the roots being distributed in the 20–60 cm layer; (II) root water uptake accounted for 91.0% of the potential maximal value when water stress was considered, and for 41.6% when both water and salt stress were considered; (III) root water uptake was very sensitive to fluctuations of the water table, and was greatly reduced when the DWT was either dropped or raised 60% of the 2012 reference depth; (IV) arid wetland vegetation exhibited a high level of groundwater dependence even though shallow groundwater resulted in increased soil salinization and (V) preseason irrigation could effectively increase root water uptake by leaching salts from the root zone. We concluded that a suitable water table and groundwater salinity coupled with proper irrigation are key factors to sustainable development of arid wetlands. View Full-Text
Keywords: arid wetland; water and salt dynamics; Hydrus-1D; root water uptake; Chinese tamarisk arid wetland; water and salt dynamics; Hydrus-1D; root water uptake; Chinese tamarisk

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Li, H.; Yi, J.; Zhang, J.; Zhao, Y.; Si, B.; Hill, R.L.; Cui, L.; Liu, X. Modeling of Soil Water and Salt Dynamics and Its Effects on Root Water Uptake in Heihe Arid Wetland, Gansu, China. Water 2015, 7, 2382-2401.

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