Through a simulation test carried out with soil columns (61.8 cm in diameter), the effect of precipitation on salt-water dynamics in soils was studied by in-situ monitoring of salt-water dynamics using soil salinity s...Through a simulation test carried out with soil columns (61.8 cm in diameter), the effect of precipitation on salt-water dynamics in soils was studied by in-situ monitoring of salt-water dynamics using soil salinity sensors and tensiometers. The results show that in the profile of whole silty loam soil, the surface runoff volume due to precipitation and the salt-leaching role of infiltrated precipitation increased with the depth of ground water; and in the profile with an intercalated bed of clay or with a thick upper layer of clay, the amount of surface runoff was greater but the salt-leaching role of precipitation was smaller than those in the profile of whole silty loam soil. In case of soil water being supplemented by precipitation, the evaporation of groundwater in the soil columns reduced, resulting in a great decline of salt accumulation from soil profile to surface soil. The effect of precipitation on the water regime of soil profile was performed via both water infiltration and water pressure transfer. The direct infiltration depth of precipitation was less than 1 m in general, but water pressure transfer could go up to groundwater surface directly.展开更多
Through a simulation test carried out with soil columns (61.8 cm in diameter), the changes of ioniccomposition in soil profile during the processes of water evaporation and infiltration were studied. Underevaporation ...Through a simulation test carried out with soil columns (61.8 cm in diameter), the changes of ioniccomposition in soil profile during the processes of water evaporation and infiltration were studied. Underevaporation conditions, ions moving upward with fresh groundwater were mainly Cl￣-, SO, Ca￣(2+), andNa￣+. When the mineralized groundwater took part in the salt accumulation, the ionic composition in soilswas close to that in ground water supplemented. Under rainfall infiltration conditions, the salt-leaching roleoccurred mainly in the top soil. With the decrease of total salt content, NO and Cl￣- reduced rapidly, SOdecreased slowly, but HCO had a little change only. Among cations, Na￣+ and Ca￣(2+) contents lowered atthe same speed, and Mg￣(2+) decreased slowly.展开更多
文摘Through a simulation test carried out with soil columns (61.8 cm in diameter), the effect of precipitation on salt-water dynamics in soils was studied by in-situ monitoring of salt-water dynamics using soil salinity sensors and tensiometers. The results show that in the profile of whole silty loam soil, the surface runoff volume due to precipitation and the salt-leaching role of infiltrated precipitation increased with the depth of ground water; and in the profile with an intercalated bed of clay or with a thick upper layer of clay, the amount of surface runoff was greater but the salt-leaching role of precipitation was smaller than those in the profile of whole silty loam soil. In case of soil water being supplemented by precipitation, the evaporation of groundwater in the soil columns reduced, resulting in a great decline of salt accumulation from soil profile to surface soil. The effect of precipitation on the water regime of soil profile was performed via both water infiltration and water pressure transfer. The direct infiltration depth of precipitation was less than 1 m in general, but water pressure transfer could go up to groundwater surface directly.
文摘Through a simulation test carried out with soil columns (61.8 cm in diameter), the changes of ioniccomposition in soil profile during the processes of water evaporation and infiltration were studied. Underevaporation conditions, ions moving upward with fresh groundwater were mainly Cl￣-, SO, Ca￣(2+), andNa￣+. When the mineralized groundwater took part in the salt accumulation, the ionic composition in soilswas close to that in ground water supplemented. Under rainfall infiltration conditions, the salt-leaching roleoccurred mainly in the top soil. With the decrease of total salt content, NO and Cl￣- reduced rapidly, SOdecreased slowly, but HCO had a little change only. Among cations, Na￣+ and Ca￣(2+) contents lowered atthe same speed, and Mg￣(2+) decreased slowly.
