Examining the descriptions of piezometric heads at two points in both the salt water and fresh water zones reveals that when the groundwater flow system is in steady state and satisfies the Dupuit assumption, the loca...Examining the descriptions of piezometric heads at two points in both the salt water and fresh water zones reveals that when the groundwater flow system is in steady state and satisfies the Dupuit assumption, the location of the fresh water-salt water interface in a homogeneous, isotropic, and unconfined coastal aquifer can be estimated based on a piezometric head of fresh water at a point in the fresh water zone （from the water table to the interface） vertically lined up with a piezometric head of salt water at a point in the salt water zone （from the interface down）. Research shows that the new method is a general relation and that both the Hubbert relation describing the location of the interface and the Ghy- ben--Herzberg relation are special cases of this method. The method requires two piezometric wells to be close to each other and each tapping into a different zone. Measurements of piezometric heads at a well cluster consisting of piezometric wells tapping separately into fresh water and salt water zones near Beihai, China at 5-day intervals for 15 months are used to illustrate the estimation of interface location. The depth of the interface for well H5 ranges from 32 to 72 m below the sea level.展开更多
Soil desertification and salinization are the main environmental disasters in arid and semi-arid areas.It is of great significance to study the water-salt migration law of saline soil and propose corresponding water-s...Soil desertification and salinization are the main environmental disasters in arid and semi-arid areas.It is of great significance to study the water-salt migration law of saline soil and propose corresponding water-salt regulation and control measures.Microbial-induced calcite precipitation(MICP)technology was proposed to improve saline soil based on salt inhibition,and the water–salt–heat coupling migration law and salt-frost heave deformation law of saline soil before and after improvement were studied using soil column model tests.XR1#,XR2#(Saline-alkali-tolerant mineralization bacteria isolated from saline soil)and Sporosarcina pasteurii were used in the MICP improvement and the effect of XR1#was the best.Under high-temperature evaporation,the water migration change rate,water loss rate,accumulated evaporation amount,and accumulated salt content of the improved soil columns within a depth range of 0–40 cm were reduced by an average of 53.6%,47.3%,69.5%,and 40%,respectively,compared with the untreated soil column.During low-temperature cooling,the characteristics of water-salt migration changed significantly,and the deformation of salt-frost heave decreased significantly.The water-salt content at the freezing point(−4.5°C)changed from a cliff-like steep drop(untreated saline soil)to a slow decrease at environmental temperature(MICP-treated saline soil),and the amount of water crystallization decreased from 81%to 56.7%at−5°C.At the end of the cooling process,the amount of salt-frost heaving on the surface of the soil columns decreased by an average of 62.7%.Based on the measured data,a numerical simulation was conducted using the HYDRUS-1D model,which had good reliability and accurately simulated and predicted the law of water-salt migration in saline soil under the conditions of microbial solidification and improvement.MICP technology significantly reduced the change rate of water-salt migration and water evaporation in saline soil,hindered salt accumulation,and reduced salt-frost heave deformation,which effectively improved saline soil.The research results provide an important innovation and theoretical basis for the improvement of saline soil.展开更多
To understand the water-salt transport process of saline soils in the Yellow River Delta region under traditional hydraulic remediation measures and to determine its engineering parameters, in this study, laboratory i...To understand the water-salt transport process of saline soils in the Yellow River Delta region under traditional hydraulic remediation measures and to determine its engineering parameters, in this study, laboratory investigations were made to measure the soil salt content using three remediation practices under simulated rainfall conditions. The results indicated that under the rainfall intensity of 100 mm/h, 6-8 h are needed when the soil salt content tends to be constant. The distribution of the salt content presents a typically symmetrical shape regardless of the position of the saline soil relative to the concealed pipe, the open ditch, and the vertical shaft. The two-parameter exponential function indicates the relationship between the soil desalination rate and the horizontal distance from the pipe, the ditch or the shaft. The maximum spacing to build the salt drainage engineering of the concealed pipe, the open ditch or the vertical shaft in the laboratory is 4.79 m, 2.88 m, and 2.19 m, respectively. The effectiveness of salt drainage for coastal saline soils can be ranked from largest to smallest as the concealed pipe, the open ditch and the vertical shaft. The findings provide an experimental basis and reference for the application of hydraulic measures to remediate saline soils in this region.展开更多
An experiment was conducted in non-weighing lysimeters to study the effect of irrigation with saline water on water movement and salt accumulation and maize yield. The experiment was carried out in northwest China,bot...An experiment was conducted in non-weighing lysimeters to study the effect of irrigation with saline water on water movement and salt accumulation and maize yield. The experiment was carried out in northwest China,both sufficient and insufficient irrigation were applied in the first year,and only sufficient treatments in the second year. Irrigation with solute concentration of 9 g·L-1 and 6 g·L-1 led to salt accumulation about 6-8 dS·m-1 in certain depths,even downwards to 160 cm received about 4 dS·m-1 for 9 g·L-1 and 2 dS·m-1 for 6 g·L-1,which was two times more than initial. Salt-affected water extracted from soil behaved as low evapotranspiration under sufficient irrigation,and more water was left in the soil. Yield of spring maize was not affected when saturated soil paste electrical conductivity did not exceeded 1.2 dS·m-1.展开更多
[目的]探究不同灌溉方式和灌水量对土壤水盐变化规律及燕麦生长特征的影响,为提高盐碱地作物的生产效能和土壤水分管理提供科学参考。[方法]采用盆栽试验,设置3种灌溉方式:常规灌溉、固定单侧灌溉(fixed unilateral root zone irrigatio...[目的]探究不同灌溉方式和灌水量对土壤水盐变化规律及燕麦生长特征的影响,为提高盐碱地作物的生产效能和土壤水分管理提供科学参考。[方法]采用盆栽试验,设置3种灌溉方式:常规灌溉、固定单侧灌溉(fixed unilateral root zone irrigation,FURI)、交替灌溉(alternative partial root zone irrigation,APRI),3组灌水量:W_1(60%θ_f~70%θ_f,θ_f为田间持水率),W_2(70%θ_f~80%θ_f)和W_3(80%θ_f~90%θ_f),以常规灌溉作为对照,共9组交互处理。[结果](1)不同灌溉方式下,土壤各层含水率变化趋势基本一致,随灌水量增加洗盐效果越显著,常规灌溉的深层含水率总体高于其他两种灌溉方式。(2)燕麦株高、叶绿素相对含量(relative chlorophyll content of leaves,SPAD)、品质随灌水量的增加而上升,与常规灌溉相比,W_2灌溉水平下,分根交替灌溉处理的粗脂肪,粗蛋白,β-葡聚糖含量分别增加7.02%,3.76%,6.06%,但降低了燕麦叶片的SPAD值,影响其光合能力。(3)随着燕麦生育期的推进,土壤盐分均呈现不同程度的累积,分根交替灌溉的积盐率最低,同时对燕麦根系生长、水分利用效率及产量影响显著,其中根系总长、根系总表面积、根系总体积较相同灌水量(W_2)的常规灌溉分别增加6.75%,6.92%,12.5%,水分利用效率提高17.32%。[结论]采用分根交替灌溉方式下的中等灌水量(W_2)有利于提高燕麦的生产效能,对盐分累积的控制效果较好。展开更多
基金supported by the Fund for the Special Research of Doctorate Subjects of the Ministry of Education of China (No.20070491522)
文摘Examining the descriptions of piezometric heads at two points in both the salt water and fresh water zones reveals that when the groundwater flow system is in steady state and satisfies the Dupuit assumption, the location of the fresh water-salt water interface in a homogeneous, isotropic, and unconfined coastal aquifer can be estimated based on a piezometric head of fresh water at a point in the fresh water zone （from the water table to the interface） vertically lined up with a piezometric head of salt water at a point in the salt water zone （from the interface down）. Research shows that the new method is a general relation and that both the Hubbert relation describing the location of the interface and the Ghy- ben--Herzberg relation are special cases of this method. The method requires two piezometric wells to be close to each other and each tapping into a different zone. Measurements of piezometric heads at a well cluster consisting of piezometric wells tapping separately into fresh water and salt water zones near Beihai, China at 5-day intervals for 15 months are used to illustrate the estimation of interface location. The depth of the interface for well H5 ranges from 32 to 72 m below the sea level.
基金funded by grants from the National Natural Science Foundation of China(No.51968057),(No.52378348),(No.12262031)Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2023QN04016),(No.2019LH05028)+1 种基金Basic scientific research business fees for universities directly under the Inner Mongolia Autonomous Region of China(No.JY20220204)Doctoral Research Foundation of Inner Mongolia University of Technology of China(No.DC2300001265).
文摘Soil desertification and salinization are the main environmental disasters in arid and semi-arid areas.It is of great significance to study the water-salt migration law of saline soil and propose corresponding water-salt regulation and control measures.Microbial-induced calcite precipitation(MICP)technology was proposed to improve saline soil based on salt inhibition,and the water–salt–heat coupling migration law and salt-frost heave deformation law of saline soil before and after improvement were studied using soil column model tests.XR1#,XR2#(Saline-alkali-tolerant mineralization bacteria isolated from saline soil)and Sporosarcina pasteurii were used in the MICP improvement and the effect of XR1#was the best.Under high-temperature evaporation,the water migration change rate,water loss rate,accumulated evaporation amount,and accumulated salt content of the improved soil columns within a depth range of 0–40 cm were reduced by an average of 53.6%,47.3%,69.5%,and 40%,respectively,compared with the untreated soil column.During low-temperature cooling,the characteristics of water-salt migration changed significantly,and the deformation of salt-frost heave decreased significantly.The water-salt content at the freezing point(−4.5°C)changed from a cliff-like steep drop(untreated saline soil)to a slow decrease at environmental temperature(MICP-treated saline soil),and the amount of water crystallization decreased from 81%to 56.7%at−5°C.At the end of the cooling process,the amount of salt-frost heaving on the surface of the soil columns decreased by an average of 62.7%.Based on the measured data,a numerical simulation was conducted using the HYDRUS-1D model,which had good reliability and accurately simulated and predicted the law of water-salt migration in saline soil under the conditions of microbial solidification and improvement.MICP technology significantly reduced the change rate of water-salt migration and water evaporation in saline soil,hindered salt accumulation,and reduced salt-frost heave deformation,which effectively improved saline soil.The research results provide an important innovation and theoretical basis for the improvement of saline soil.
基金supported by the National Natural Science Foundation of China(Grant No.51574156)the Key Development Program for Research of Shandong Province(Grant No.2018GNC110023).
文摘To understand the water-salt transport process of saline soils in the Yellow River Delta region under traditional hydraulic remediation measures and to determine its engineering parameters, in this study, laboratory investigations were made to measure the soil salt content using three remediation practices under simulated rainfall conditions. The results indicated that under the rainfall intensity of 100 mm/h, 6-8 h are needed when the soil salt content tends to be constant. The distribution of the salt content presents a typically symmetrical shape regardless of the position of the saline soil relative to the concealed pipe, the open ditch, and the vertical shaft. The two-parameter exponential function indicates the relationship between the soil desalination rate and the horizontal distance from the pipe, the ditch or the shaft. The maximum spacing to build the salt drainage engineering of the concealed pipe, the open ditch or the vertical shaft in the laboratory is 4.79 m, 2.88 m, and 2.19 m, respectively. The effectiveness of salt drainage for coastal saline soils can be ranked from largest to smallest as the concealed pipe, the open ditch and the vertical shaft. The findings provide an experimental basis and reference for the application of hydraulic measures to remediate saline soils in this region.
基金Supported by National Key Technology Research and Development Program of China (2006BAD11B08)the Program for Changjiang Scholars and Innovative Research Team in University (IRT0657)
文摘An experiment was conducted in non-weighing lysimeters to study the effect of irrigation with saline water on water movement and salt accumulation and maize yield. The experiment was carried out in northwest China,both sufficient and insufficient irrigation were applied in the first year,and only sufficient treatments in the second year. Irrigation with solute concentration of 9 g·L-1 and 6 g·L-1 led to salt accumulation about 6-8 dS·m-1 in certain depths,even downwards to 160 cm received about 4 dS·m-1 for 9 g·L-1 and 2 dS·m-1 for 6 g·L-1,which was two times more than initial. Salt-affected water extracted from soil behaved as low evapotranspiration under sufficient irrigation,and more water was left in the soil. Yield of spring maize was not affected when saturated soil paste electrical conductivity did not exceeded 1.2 dS·m-1.
文摘[目的]探究不同灌溉方式和灌水量对土壤水盐变化规律及燕麦生长特征的影响,为提高盐碱地作物的生产效能和土壤水分管理提供科学参考。[方法]采用盆栽试验,设置3种灌溉方式:常规灌溉、固定单侧灌溉(fixed unilateral root zone irrigation,FURI)、交替灌溉(alternative partial root zone irrigation,APRI),3组灌水量:W_1(60%θ_f~70%θ_f,θ_f为田间持水率),W_2(70%θ_f~80%θ_f)和W_3(80%θ_f~90%θ_f),以常规灌溉作为对照,共9组交互处理。[结果](1)不同灌溉方式下,土壤各层含水率变化趋势基本一致,随灌水量增加洗盐效果越显著,常规灌溉的深层含水率总体高于其他两种灌溉方式。(2)燕麦株高、叶绿素相对含量(relative chlorophyll content of leaves,SPAD)、品质随灌水量的增加而上升,与常规灌溉相比,W_2灌溉水平下,分根交替灌溉处理的粗脂肪,粗蛋白,β-葡聚糖含量分别增加7.02%,3.76%,6.06%,但降低了燕麦叶片的SPAD值,影响其光合能力。(3)随着燕麦生育期的推进,土壤盐分均呈现不同程度的累积,分根交替灌溉的积盐率最低,同时对燕麦根系生长、水分利用效率及产量影响显著,其中根系总长、根系总表面积、根系总体积较相同灌水量(W_2)的常规灌溉分别增加6.75%,6.92%,12.5%,水分利用效率提高17.32%。[结论]采用分根交替灌溉方式下的中等灌水量(W_2)有利于提高燕麦的生产效能,对盐分累积的控制效果较好。
