| Nutrient migration and soil salinisation are the two major concerns in the research of soil solute transport. Such research should provide the theoretical backgrounds for the groundwater pollution control, such as NOs ~ ?N, improvement of nitrogen use efficiency and prevention of soil salinisation in the irrigated land. In this study, the soil water and solute movements in the air-dried soil columns were investigated under different irrigation frequencies, evaporation control and in the soil having groundwater table under different irrigation frequencies, quantities, and solute application. Dynamic models for solute transport at any given time have been presented in this study. The main results are:1. Evaporation influenced the soil water distribution mainly in the upper soil layer at the initial stages of irrigation. Less irrigation frequency would lead to greater uneven water distribution. The increasing total irrigation quantity reduced soil water deficit in the upper layer but enhanced such deficit in the lower layer. Higher the irrigation frequency, the decrease is faster. Irrigation frequency also changed the spatial distribution and storage of soil water. When irrigation frequency increased with the same irrigation quantity, the soil water content and storage in the upper layer would increase but the wet front in soil profile became shallow. Results suggest that a suitable irrigation frequency can increase the soil water storage.2. Evaporation and irrigation frequency influenced the solute transport. When irrigation frequency increased, NOs ~ concentration peak in soil with or without evaporation would become steeper and narrower with higher peak values and slower NC>3 downward movement. Under evaporation, NOs^concentration peak and front would also appeared in the shallower soil layer. The effective leaching water (or irrigation frequency) controlled the solute peak and front depth.3. Irrigation schedule and groundwater table had a great influence on the shallow ground-water evaporation. The evaporation of shallow groundwater increased at lowirrigation frequency when groundwater table was elevated, and decreased at low irrigation frequency under the same groundwater table when the quantity per irrigation increased. Deeper the groundwater table, the less evaporation. The evaporation of shallow groundwater would decrease substantially when irrigation frequency increased at the same groundwater table and same irrigation quantity.4. By analyzing the surface-applied solute transport in soil having different groundwater tables under three irrigation treatments, results showed that: 1) Groundwater table had a great influence on the BR- transport in soil regardless the irrigation treatment. BR-downward movement quickened when water table became shallower. BR- collection in soil surface increased when water table deepened. BR- content in the soil surface reduced gradually when total irrigation quantity increased, but the rate of the reduction slowed when water table deepened. 2) The reduction of Br" content in soil surface was faster in the soil with high irrigation frequency than low irrigation frequency at the same water table. The reduction of BR- content in soil surface quickened in the soil with higher or lower irrigation frequency when water table became shallower, but the reduction was faster in the soil with high irrigation frequency than with low irrigation frequency. The development of solute peak in the soil with high irrigation frequency was quickened when water table became shallower, leading to a more centralized BR-movement. The BR- distribution in the soil profile with low irrigation frequency was wider, and expect for the 5cm layer from the soil surface, and more uniform than with high irrigation frequency. The solute front movement also varied with the irrigation frequency and water table. In this experiment, 1.2m water table appeared as the turning point for quick or slow solute transport. When water table was deeper than 1.2m, solute transport in soil was fast...
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