חיפוש מתקדם
Li, X., College of Water Resources and Civil Engineering, China Agricultural University, Beijing, China
Zuo, Q., College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
Shi, J., College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
Bengal, A., Agricultural Research Organization, Negev, Israel
Wang, S., College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
The technology of film mulched drip irrigation (FMDI) is applied widely for planting cotton in Xinjiang, China. Salts in the soils where FMDI is practiced tend to be leached downwards from the shallow root zone (0~40 cm) and to accumulate in the lower root zone (40~60 cm) where they become a secondary salinization hazard. Numerical simulation should be one of the most effective and rational methods to evaluate the effect of salt discharge by subsurface pipes in the cotton field with FMDI. In this study, a field experiment, in which the leaching water was supplied at the soil surface and the leachate was discharged using subsurface pipes (SSPs) located 60 cm below the soil surface in unsaturated soil with an interval of 500 cm, was conducted in Manas, Xinjiang, and numerical models were established to simulate soil water flow and salt transport under the drainage conditions of SSPs. Results from the field experiment were used to calibrate hydraulic parameters and verify the numerical models using the Hydrus-2D/3D software package. Simulated and observed soil water content distributions were in good agreement with the maximum root mean squared error (RMSE) and minimum coefficient of determination (R2) of 0.025 cm3/cm3 and 0.88, respectively. Correspondingly for soil salinity distributions, the values of maximum RMSE and minimum R2 were 2.74 g/kg and 0.93, respectively. Numerical simulations show that most (77.5%) of the salt in 0~60 cm soil layer was leached downwards,however,limited by the factors such as deep groundwater table and small surface area of the pipe for collecting flow from nearby domain, only about 11.7% of the salt in the 0~60 cm soil layer was discharged via the SSPs. The numerical models and the calibrated soil hydraulic parameters should be useful for further analyzing the dynamics of soil water and salt under the drainage condition of SSPs located in unsaturated soil,and for evaluation of alternative methods for salt leaching and discharge. © 2016, China Water Power Press. All right reserved.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Evaluation of salt discharge by subsurface pipes in the cotton field with film mulched drip irrigation in Xinjiang,China I. Calibration to models and parameters
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Li, X., College of Water Resources and Civil Engineering, China Agricultural University, Beijing, China
Zuo, Q., College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
Shi, J., College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
Bengal, A., Agricultural Research Organization, Negev, Israel
Wang, S., College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
Evaluation of salt discharge by subsurface pipes in the cotton field with film mulched drip irrigation in Xinjiang,China I. Calibration to models and parameters
The technology of film mulched drip irrigation (FMDI) is applied widely for planting cotton in Xinjiang, China. Salts in the soils where FMDI is practiced tend to be leached downwards from the shallow root zone (0~40 cm) and to accumulate in the lower root zone (40~60 cm) where they become a secondary salinization hazard. Numerical simulation should be one of the most effective and rational methods to evaluate the effect of salt discharge by subsurface pipes in the cotton field with FMDI. In this study, a field experiment, in which the leaching water was supplied at the soil surface and the leachate was discharged using subsurface pipes (SSPs) located 60 cm below the soil surface in unsaturated soil with an interval of 500 cm, was conducted in Manas, Xinjiang, and numerical models were established to simulate soil water flow and salt transport under the drainage conditions of SSPs. Results from the field experiment were used to calibrate hydraulic parameters and verify the numerical models using the Hydrus-2D/3D software package. Simulated and observed soil water content distributions were in good agreement with the maximum root mean squared error (RMSE) and minimum coefficient of determination (R2) of 0.025 cm3/cm3 and 0.88, respectively. Correspondingly for soil salinity distributions, the values of maximum RMSE and minimum R2 were 2.74 g/kg and 0.93, respectively. Numerical simulations show that most (77.5%) of the salt in 0~60 cm soil layer was leached downwards,however,limited by the factors such as deep groundwater table and small surface area of the pipe for collecting flow from nearby domain, only about 11.7% of the salt in the 0~60 cm soil layer was discharged via the SSPs. The numerical models and the calibrated soil hydraulic parameters should be useful for further analyzing the dynamics of soil water and salt under the drainage condition of SSPs located in unsaturated soil,and for evaluation of alternative methods for salt leaching and discharge. © 2016, China Water Power Press. All right reserved.
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