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
Efficiency of salt removal using subsurface pipes (SSPs) located in the unsaturated zone of agricultural soils is very low due to a limited effective flow collecting area (Scf). In this study, the dynamics of soil water movement and salt transport were simulated using the calibrated models and parameters for HYDRUS-2D/3D in order to investigate two possible methods for improvement of ameliorating saline soils in cases where drainage pipes are located well above the groundwater table. The first improvement method attempted to enlarge Scf by laying seepage-proof material (SPM) underneath the SSPs. The effect of SPM width (Lf) and distance between SSPs was evaluated. Simulations continued until the salinity of the 0~40 and 40~60 cm soil layers was less than 3.0 and 6.0 g/kg, respectively, levels believed to allow successful cotton cultivation. Compared to the treatment without SPM, the salt discharge ratio (SDR) and the water use efficiency for salt discharge (WUESD) were enhanced from 11.9% and 1.86 kg/m3 to a maximum of 32.1% and 3.15 kg/m3, respectively, when a SPM was present. While, in general, increasing Lf enhanced WUESD, considerations of installation costs suggest an optimal practical Lf of between 20 and 100 cm. The SDR and WUESD were further enhanced by decreasing the space interval between pipes from 500 cm, typically found in commercial fields, to 200 cm. In additional simulations, the SSP was used to both supply water and discharge leachate, eliminating the need for wetting of the entire profile and potentially enhancing salt discharge efficiency. Results showed that the approach had limited practical value as very little salt could be discharged through the SSP, and the maximum WUESD was not more than 0.6 kg/m3 even when a SPM was laid beneath SSP and the space interval between pipes was narrowed to 200 cm. The modeling approach presented should be useful in evaluation of further approaches using SSP to improve reclamation of saline agricultural soils where drainage of saturated zones is unpractical. © 2016, China Water Power Press. All right reserved.
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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 II: Application of the calibrated 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 II: Application of the calibrated models and parameters
Efficiency of salt removal using subsurface pipes (SSPs) located in the unsaturated zone of agricultural soils is very low due to a limited effective flow collecting area (Scf). In this study, the dynamics of soil water movement and salt transport were simulated using the calibrated models and parameters for HYDRUS-2D/3D in order to investigate two possible methods for improvement of ameliorating saline soils in cases where drainage pipes are located well above the groundwater table. The first improvement method attempted to enlarge Scf by laying seepage-proof material (SPM) underneath the SSPs. The effect of SPM width (Lf) and distance between SSPs was evaluated. Simulations continued until the salinity of the 0~40 and 40~60 cm soil layers was less than 3.0 and 6.0 g/kg, respectively, levels believed to allow successful cotton cultivation. Compared to the treatment without SPM, the salt discharge ratio (SDR) and the water use efficiency for salt discharge (WUESD) were enhanced from 11.9% and 1.86 kg/m3 to a maximum of 32.1% and 3.15 kg/m3, respectively, when a SPM was present. While, in general, increasing Lf enhanced WUESD, considerations of installation costs suggest an optimal practical Lf of between 20 and 100 cm. The SDR and WUESD were further enhanced by decreasing the space interval between pipes from 500 cm, typically found in commercial fields, to 200 cm. In additional simulations, the SSP was used to both supply water and discharge leachate, eliminating the need for wetting of the entire profile and potentially enhancing salt discharge efficiency. Results showed that the approach had limited practical value as very little salt could be discharged through the SSP, and the maximum WUESD was not more than 0.6 kg/m3 even when a SPM was laid beneath SSP and the space interval between pipes was narrowed to 200 cm. The modeling approach presented should be useful in evaluation of further approaches using SSP to improve reclamation of saline agricultural soils where drainage of saturated zones is unpractical. © 2016, China Water Power Press. All right reserved.
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