Recharge and discharge, such as rainfall infiltration and evapotranspiration in vertical direction, are major processes of water cycle in the shallow groundwater area of the North China Plain. During these processes, ...Recharge and discharge, such as rainfall infiltration and evapotranspiration in vertical direction, are major processes of water cycle in the shallow groundwater area of the North China Plain. During these processes, soil water movement in the unsaturated zone plays an important role in the transformation from rainfall infiltration to groundwater. The soil water movement models were developed by using HYDRUS-1D software at two typical experimental sites in Cangzhou(CZ) and Hengshui(HS) with different soil, vegetation and similar climate conditions. As shown in the results, the comparison in precipitation infiltration features between the two sites is distinct. The soil water experiences strong evaporation after precipitation infiltration, which accounts for 63% of the total infiltration at the HS site where the soil is homogenous. It is this strong evaporation effect that leads to slight increase of soil water storage. At the CZ site, where the soil is heterogeneous, the evaporation effect exists from July to October of the simulation period. The total evaporation accounts for 33% of the total infiltration, and the evaporation rate is slow. At the end of the simulation period, the soil water storage increases and the water table decreases, indicating a strong storage capacity at this site.展开更多
Biochar addition can improve the physical and hydraulic characteristics of sandy soil.This study investigated the effects of biochar on water holding capacity and water movement in sandy soil under drip irrigation.By ...Biochar addition can improve the physical and hydraulic characteristics of sandy soil.This study investigated the effects of biochar on water holding capacity and water movement in sandy soil under drip irrigation.By indoor simulation experiments,the effects of biochar application at five levels(0%,1%,2%,4%and 6%)on the soil water retention curve,infiltration characteristics of drip irrigation and water distribution were tested and analyzed.The results showed that biochar addition rate was positively correlated with water holding capacity of sandy soil and soil available water.Within the same infiltration time,with an increasing amount of added biochar,the diffusion distance of the horizontal wetting front(HWF)tended to decrease,while the infiltration distance of vertical wetting front(VWF)initially declined and then rose.The features of wetted bodies changed from"broad-shallow"to"narrow-deep"type.The relationship between the transport distances of HWF and VWF and the infiltration time was described by a power function.At the same distance from the point source,the larger the amount of added biochar,the higher the soil water content.Biochar had a great influence on the water content of the layer with biochar(0–200 mm)and had some effects at 200–250 mm without biochar;but it had less influence on the soil water content deeper than 250 mm.For the application rate of biochar of 4%,most water was retained within 0–250 mm soil layer.However,when biochar application amount was high(6%),it would be helpful for water infiltration.During the improvement of sandy soil,biochar application rate of 4%in the plow layer had the best effect.展开更多
An understanding of nutrient movement in soil is important for developing management strategies to minimize nutrient leaching and surface movement, thus improving nutrient uptake by plants, maintaining a sustainable s...An understanding of nutrient movement in soil is important for developing management strategies to minimize nutrient leaching and surface movement, thus improving nutrient uptake by plants, maintaining a sustainable soil system, and even protecting groundwater quality. Polyacrylamide (PAM) is known as one of soil conditioner that functions to stabilize soil structure, increase infiltration, and reduce surface runoff. This study assesses the effects of PAM on the vertical movement of soil-water and major/minor nutrients (NO3-N, NH3-N, T-N, PO4-P, T-P, K, Ca, Mg, and Fe) in soils. Saturated hydraulic conductivity (Ksat) increases with increasing PAM concen- trations up to 10 mg·L-1 for sand and 20 mg·L-1 for a mixture of sand and clay. Decreases in the loss of soluble nutrients, particularly NH3-N, PO4-P and T-P, are observed as PAM concentrations increase. In contrast, PAM concentration has no effect on nitrate and minor nutrient levels. These results indicate that the application of PAM may be a viable method for protecting water bodies from excessive nutrients and improving nutrient availability for plants.展开更多
This paper describes a new technology for solonchak soil reclamation in which surface flood irrigation of fresh water and pumped wells drainage of salty groundwater are combined. The comprehensive investigation of wat...This paper describes a new technology for solonchak soil reclamation in which surface flood irrigation of fresh water and pumped wells drainage of salty groundwater are combined. The comprehensive investigation of water and salt movement has been conducted through field test, laboratory simulation and numerical calculation. The dependence of desalination on irrigation water quantity, drainage quantity, leaching time and other parameters is obtained based on the field tests. The entire desalination process under the flood-irrigation and well-drainage operations was experimentally simulated in a vertical soil column. The water and salt movement has been numerically analysed for both the field and laboratory conditions. The present work indicates that this new technology can greatly improve the effects of desalination.展开更多
基金financially supported by the 100-Talent Project of Chinese Academy of Sciencesthe Key Program of the National Natural Science Foundation of China (No.41471028)
文摘Recharge and discharge, such as rainfall infiltration and evapotranspiration in vertical direction, are major processes of water cycle in the shallow groundwater area of the North China Plain. During these processes, soil water movement in the unsaturated zone plays an important role in the transformation from rainfall infiltration to groundwater. The soil water movement models were developed by using HYDRUS-1D software at two typical experimental sites in Cangzhou(CZ) and Hengshui(HS) with different soil, vegetation and similar climate conditions. As shown in the results, the comparison in precipitation infiltration features between the two sites is distinct. The soil water experiences strong evaporation after precipitation infiltration, which accounts for 63% of the total infiltration at the HS site where the soil is homogenous. It is this strong evaporation effect that leads to slight increase of soil water storage. At the CZ site, where the soil is heterogeneous, the evaporation effect exists from July to October of the simulation period. The total evaporation accounts for 33% of the total infiltration, and the evaporation rate is slow. At the end of the simulation period, the soil water storage increases and the water table decreases, indicating a strong storage capacity at this site.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest(20130313006,201503136)the National Natural Science Foundation of China(31660073)+1 种基金the National Key Research and Development Program of China(2017YFD0200803-04,2018YFD0800804,2017YFD0201900)the Youth Foundation of Xinjiang Academy of Agricultural Sciences(xjnkq-2015002)
文摘Biochar addition can improve the physical and hydraulic characteristics of sandy soil.This study investigated the effects of biochar on water holding capacity and water movement in sandy soil under drip irrigation.By indoor simulation experiments,the effects of biochar application at five levels(0%,1%,2%,4%and 6%)on the soil water retention curve,infiltration characteristics of drip irrigation and water distribution were tested and analyzed.The results showed that biochar addition rate was positively correlated with water holding capacity of sandy soil and soil available water.Within the same infiltration time,with an increasing amount of added biochar,the diffusion distance of the horizontal wetting front(HWF)tended to decrease,while the infiltration distance of vertical wetting front(VWF)initially declined and then rose.The features of wetted bodies changed from"broad-shallow"to"narrow-deep"type.The relationship between the transport distances of HWF and VWF and the infiltration time was described by a power function.At the same distance from the point source,the larger the amount of added biochar,the higher the soil water content.Biochar had a great influence on the water content of the layer with biochar(0–200 mm)and had some effects at 200–250 mm without biochar;but it had less influence on the soil water content deeper than 250 mm.For the application rate of biochar of 4%,most water was retained within 0–250 mm soil layer.However,when biochar application amount was high(6%),it would be helpful for water infiltration.During the improvement of sandy soil,biochar application rate of 4%in the plow layer had the best effect.
文摘An understanding of nutrient movement in soil is important for developing management strategies to minimize nutrient leaching and surface movement, thus improving nutrient uptake by plants, maintaining a sustainable soil system, and even protecting groundwater quality. Polyacrylamide (PAM) is known as one of soil conditioner that functions to stabilize soil structure, increase infiltration, and reduce surface runoff. This study assesses the effects of PAM on the vertical movement of soil-water and major/minor nutrients (NO3-N, NH3-N, T-N, PO4-P, T-P, K, Ca, Mg, and Fe) in soils. Saturated hydraulic conductivity (Ksat) increases with increasing PAM concen- trations up to 10 mg·L-1 for sand and 20 mg·L-1 for a mixture of sand and clay. Decreases in the loss of soluble nutrients, particularly NH3-N, PO4-P and T-P, are observed as PAM concentrations increase. In contrast, PAM concentration has no effect on nitrate and minor nutrient levels. These results indicate that the application of PAM may be a viable method for protecting water bodies from excessive nutrients and improving nutrient availability for plants.
基金The project supported by the National Natural Science Foundation of China
文摘This paper describes a new technology for solonchak soil reclamation in which surface flood irrigation of fresh water and pumped wells drainage of salty groundwater are combined. The comprehensive investigation of water and salt movement has been conducted through field test, laboratory simulation and numerical calculation. The dependence of desalination on irrigation water quantity, drainage quantity, leaching time and other parameters is obtained based on the field tests. The entire desalination process under the flood-irrigation and well-drainage operations was experimentally simulated in a vertical soil column. The water and salt movement has been numerically analysed for both the field and laboratory conditions. The present work indicates that this new technology can greatly improve the effects of desalination.
