Numerical simulation of soil water transport under film-hole irrigation based on FlexPDE
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DOI:10.7606/j.issn.1000-7601.2019.04.05
Key Words: FlexPDE  film-hole irrigation  water storage  water distribution  numerical simulation
Author NameAffiliation
ZHAO Wen-gang Hunan Water Resources and Hydropower Research Institute, Changsha, Hunan 410007, China 
FAN Yan-wei College of Energy &Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 720050, China 
LIU Xiao-qun .Hunan Water Resources and Hydropower Research Institute, Changsha, Hunan 410007, China 
SHI Lin .Hunan Water Resources and Hydropower Research Institute, Changsha, Hunan 410007, China 
XING Xu-guang Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China 
MA Xiao-yi Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China 
SONG Wen Hunan Water Resources and Hydropower Research Institute, Changsha, Hunan 410007, China 
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Abstract:
      To explore the applicability of FLexPDE, characteristics of infiltration, and water distribution in soil profile under film-hole irrigation with a constant pressure head, the soil water transport was simulated by FlexPDE with the measured soil diffusivity and soil water characteristic curve. The results showed that: The mean relative errors between the measured moisture content and the FlexPDE simulated of silty clay loam (treatments 2 and 3) and sandy loam (treatments 1 and 4) were 5.930%, 8.340%, 9.600%, and 14.040%, respectively. In terms of the relative error between simulation and the measured soil moisture content of silty clay loam, less than 5%, 10% and 20% were 40%, 68%, and 84%, respectively. For the sandy loam, less than 5%, 10%, and 20% were 12%, 40%, and 72%, respectively. Therefore, the simulated effect of silty clay loam is better than sandy loam. Accumulated infiltration had a good linear correlation with simulated water storage, and the correlation coefficients were all greater than 0.9. Meanwhile, the accumulated infiltration and water storage grew in function of power along with increasing time, but the increase rate slowed. Using FlexPDE to predict and analyze the impact of hole spacing, hole diameter, and infiltration depth on the unidirectional intersection moment, water distribution, and water storage of mulching hole irrigation in silty clay loam, it was found that the hole spacing had a great impact on the soil water distribution at the initial intersection stage, and the diameter of film hole had a significant impact on the soil intersection time and water storage.