Film hole irrigation has been widely adopted as an effective water-saving irrigation technology in the arid and semiarid areas of China.To investigate the effects of initial soil moisture content(θ0)on soil water and...Film hole irrigation has been widely adopted as an effective water-saving irrigation technology in the arid and semiarid areas of China.To investigate the effects of initial soil moisture content(θ0)on soil water and nitrogen transport characteristics under muddy water film hole infiltration,the laboratory experiments were conducted with muddy water film hole infiltration,using five initial soil moisture content treatments.The models for describing the relationships between the cumulative infiltration(I(t))and infiltration duration(t);the relationship among the horizontal and vertical migration distances of the wetting front(Fx,Fz),θ0 and t,were established.The results showed that the initial soil moisture content had a significant effect on I(t),Fx,Fz and moisture content distribution in the wetted body.The change of I(t)over t conformed to Kostiakov model.With the increase ofθ0,the infiltration coefficient(K)gradually decreased.NO-3-N was mainly distributed in the range of the wetting radius of 15 cm,while NH+4-N was mainly distributed in the range of the wetting radius of 8 cm.This study can provide a theoretical basis and technical support for film hole irrigation.展开更多
Intense rainfall infiltration is one of the primary triggers for landslides.Developing a robust model for rainfall infiltration analysis is crucial for mitigating landslide disasters.Although the numerical solution of...Intense rainfall infiltration is one of the primary triggers for landslides.Developing a robust model for rainfall infiltration analysis is crucial for mitigating landslide disasters.Although the numerical solution of Richard's equation provides high computational accuracy,it often encounters convergence issues.In contrast,the Green-Ampt(GA)model,which is more computationally efficient,lacks accuracy in dealing with the non-uniform distribution of the initial volumetric water content(VWC)and the pore-water redistribution process.Therefore,this study proposes a novel model for analyzing the slope rainfall infiltration process based on the GA model.The proposed model discretizes both the geological layers of the slope and the rainfall event in spatial and temporal scales,respectively,improving accuracy by adjusting step sizes of discretization adaptively.The proposed model is applied to analyze the permeability,stability and reliability of heterogeneous infinite slopes considering uncertainties in multiple parameters.Comparative studies with the numerical solution of Richard's equation and other models demonstrate that the proposed model can provide high computational accuracy and superior analysis convergence in rainfall infiltration modeling.It also indicates that neglecting the pore-water redistribution underestimates the probability of slope failure,overestimates the factor of safety(FOS)of the slope,and inaccurately estimates the depth of the critical slip surface.Moreover,the uncertainties in shear strength parameters may overshadow the influence of initial VWC uncertainties on the slope reliability.This study provides a theoretical basis for the analysis of rainfall infiltration on heterogeneous slopes and the formulation of strategies for landslide disaster prevention.展开更多
To examine the working principle of vertical tube irrigation, variations in vertical tube emitter discharge and their causes were analyzed in the laboratory experiment. The effects of the pressure head, initial soil w...To examine the working principle of vertical tube irrigation, variations in vertical tube emitter discharge and their causes were analyzed in the laboratory experiment. The effects of the pressure head, initial soil water content, and tube diameter on the emitter discharge of the vertical tube were studied. The results show that quantitative relationship between the time and cumulative infiltration and emitter discharge of the vertical tube is obtained, and R 2 is more than 0.98. Emitter discharge exhibits a positive and negative correlation with the pressure head and soil water content, respectively. Tube dia- meter has a nonsignificant effect on the emitter discharge. Changes of the soil water content around the emitter water outlet are the main causes of emitter discharge variations. In the experiments, the range of vertical tube emitter discharge is 0.056-1.102 L/h. The emitter of vertical tube irrigation automatically adjusts the soil water content and maintains the root zone soil water content within an appropriate range, which achieves continuous irrigation, and further achieves the effect of water-saving.展开更多
Mulching and soil water content(SWC) have a significant impact on soil erosion,and this study investigated the effect of straw mulching on water infiltration and soil loss under different initial SWC treatments in a r...Mulching and soil water content(SWC) have a significant impact on soil erosion,and this study investigated the effect of straw mulching on water infiltration and soil loss under different initial SWC treatments in a rainfall simulation experiment conducted in northern China.Increasing initial SWC can decrease soil infiltration and increase soil loss.During an 80 mm rainfall event(80 mm·h–1for 60 min),8%,12% and 16% initial SWC treatments decreased cumulative infiltration by8.7%,42.5% and 58.1%,and increased total sediment yield by 44,146 and 315 g,respectively,compared to 4%initial SWC.However,in all the straw mulching treatments,there was no significant difference in stable infiltration rate between the different initial SWC treatments.For all initial SWC treatments,straw mulching of30% or more significantly enhanced water infiltration by over 31% and reduced soil loss by over 49%,compared to the unmulched treatment.Taking into consideration the performance of no-till planters,a maize straw mulching rate of 30% to 60%(1400–3100 kg·hm–2) is recommended for the conservation of water and soil in northern China.展开更多
基金This study was financially supported by the National Key Research and Development Program of China(Grant No.2016YFC0400204)the National Natural Science Foundation of China(Grant No.52079105,51779205 and 51479161)+1 种基金and the Public welfare industry research special project(Grant No.201203003)The authors acknowledge the anonymous reviewers and the editor for their valuable comments and suggestions.
文摘Film hole irrigation has been widely adopted as an effective water-saving irrigation technology in the arid and semiarid areas of China.To investigate the effects of initial soil moisture content(θ0)on soil water and nitrogen transport characteristics under muddy water film hole infiltration,the laboratory experiments were conducted with muddy water film hole infiltration,using five initial soil moisture content treatments.The models for describing the relationships between the cumulative infiltration(I(t))and infiltration duration(t);the relationship among the horizontal and vertical migration distances of the wetting front(Fx,Fz),θ0 and t,were established.The results showed that the initial soil moisture content had a significant effect on I(t),Fx,Fz and moisture content distribution in the wetted body.The change of I(t)over t conformed to Kostiakov model.With the increase ofθ0,the infiltration coefficient(K)gradually decreased.NO-3-N was mainly distributed in the range of the wetting radius of 15 cm,while NH+4-N was mainly distributed in the range of the wetting radius of 8 cm.This study can provide a theoretical basis and technical support for film hole irrigation.
基金supported by the National Natural Science Foundation of China(Grant Nos.52179103 and 52222905)Jiangxi Provincial Natural Science Foundation(Grant No.20242BAB24001).
文摘Intense rainfall infiltration is one of the primary triggers for landslides.Developing a robust model for rainfall infiltration analysis is crucial for mitigating landslide disasters.Although the numerical solution of Richard's equation provides high computational accuracy,it often encounters convergence issues.In contrast,the Green-Ampt(GA)model,which is more computationally efficient,lacks accuracy in dealing with the non-uniform distribution of the initial volumetric water content(VWC)and the pore-water redistribution process.Therefore,this study proposes a novel model for analyzing the slope rainfall infiltration process based on the GA model.The proposed model discretizes both the geological layers of the slope and the rainfall event in spatial and temporal scales,respectively,improving accuracy by adjusting step sizes of discretization adaptively.The proposed model is applied to analyze the permeability,stability and reliability of heterogeneous infinite slopes considering uncertainties in multiple parameters.Comparative studies with the numerical solution of Richard's equation and other models demonstrate that the proposed model can provide high computational accuracy and superior analysis convergence in rainfall infiltration modeling.It also indicates that neglecting the pore-water redistribution underestimates the probability of slope failure,overestimates the factor of safety(FOS)of the slope,and inaccurately estimates the depth of the critical slip surface.Moreover,the uncertainties in shear strength parameters may overshadow the influence of initial VWC uncertainties on the slope reliability.This study provides a theoretical basis for the analysis of rainfall infiltration on heterogeneous slopes and the formulation of strategies for landslide disaster prevention.
基金National Natural Science Foundation of China (41571222)。
文摘To examine the working principle of vertical tube irrigation, variations in vertical tube emitter discharge and their causes were analyzed in the laboratory experiment. The effects of the pressure head, initial soil water content, and tube diameter on the emitter discharge of the vertical tube were studied. The results show that quantitative relationship between the time and cumulative infiltration and emitter discharge of the vertical tube is obtained, and R 2 is more than 0.98. Emitter discharge exhibits a positive and negative correlation with the pressure head and soil water content, respectively. Tube dia- meter has a nonsignificant effect on the emitter discharge. Changes of the soil water content around the emitter water outlet are the main causes of emitter discharge variations. In the experiments, the range of vertical tube emitter discharge is 0.056-1.102 L/h. The emitter of vertical tube irrigation automatically adjusts the soil water content and maintains the root zone soil water content within an appropriate range, which achieves continuous irrigation, and further achieves the effect of water-saving.
基金supported by Changjiang Scholars and Innovative Research Team in University of China(IRT13039)Special Fund for Agro-scientific Research in the Public Interest(201503136)
文摘Mulching and soil water content(SWC) have a significant impact on soil erosion,and this study investigated the effect of straw mulching on water infiltration and soil loss under different initial SWC treatments in a rainfall simulation experiment conducted in northern China.Increasing initial SWC can decrease soil infiltration and increase soil loss.During an 80 mm rainfall event(80 mm·h–1for 60 min),8%,12% and 16% initial SWC treatments decreased cumulative infiltration by8.7%,42.5% and 58.1%,and increased total sediment yield by 44,146 and 315 g,respectively,compared to 4%initial SWC.However,in all the straw mulching treatments,there was no significant difference in stable infiltration rate between the different initial SWC treatments.For all initial SWC treatments,straw mulching of30% or more significantly enhanced water infiltration by over 31% and reduced soil loss by over 49%,compared to the unmulched treatment.Taking into consideration the performance of no-till planters,a maize straw mulching rate of 30% to 60%(1400–3100 kg·hm–2) is recommended for the conservation of water and soil in northern China.
